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Question 1
Correct
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A young patient presents with the features of an easily recognisable infectious disease.Which of the following infectious diseases typically has an incubation period of less than 1 week? Select ONE answer only.
Your Answer: Cholera
Explanation:Cholera has an incubation period of 12 hours to 6 days.Other infectious disease that have an incubation period of less than 1 week include:Staphylococcal enteritis (1-6 hours)Salmonella enteritis (12-24 hours)Botulism (18-36 hours)Gas gangrene (6 hours to 4 days)Scarlet fever (1-4 days)Diphtheria (2-5 days)Gonorrhoea (3-5 days)Yellow fever (3-6 days)Meningococcaemia (1-7 days)Brucellosis has an incubation period of 7-21 days.Measles has an incubation period of 14-18 days.Falciparum malaria usually has an incubation period of 7-14 days. The other forms of malaria have a longer incubation period of 12-40 days.Rubella has an incubation period of 14-21 days.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 2
Correct
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A 36-year-old woman is 22-weeks pregnant and is investigated for a possible thyroid disorder. When her total thyroid hormone levels does not correlate with her thyrometabolic status, her thyroid-binding globulin levels are checked.What percentage of circulating thyroid hormones is bound to thyroid-binding globulin?
Your Answer: 70%
Explanation:Only a very small fraction of the thyroid hormones circulating in the blood are free. The majority is bound to transport proteins. Only the free thyroid hormones are biologically active, and measurement of total thyroid hormone levels can be misleading. The relative percentages of bound and unbound thyroid hormones are:Bound to thyroid-binding globulin -70%Bound to albumin -15-20%Bound to transthyretin -10-15%Free T3 -0.3%Free T4 -0.03%
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 3
Incorrect
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Which of the following is the most abundant peripheral blood leucocyte:
Your Answer: Macrophages
Correct Answer: Neutrophils
Explanation:Neutrophils are the most abundant peripheral blood leucocyte, comprising about 50 – 70% of circulating white cells. Neutrophils have a characteristic dense nucleus consisting of between two and five lobes, and a pale cytoplasm with an irregular outline containing many fine pink-blue or grey-blue granules. The granules are divided into primary, which appear at the promyelocyte stage, and secondary, which appear at the myelocyte stage and predominate in the mature nucleus. Both types of granule are lysosomal in origin; the primary contains myeloperoxidase and other acid hydrolases; the secondary contains lactoferrin, lysozyme and other enzymes. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 4
Correct
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A 53 year old women presents to the emergency room with a chronic cough. The pulmonary receptors likely to be involved in causing her cough are:
Your Answer: Irritant receptors
Explanation:Throughout the airways, there are irritant receptors which are located between epithelial cells which are made of rapidly adapting afferent myelinated fibres in the vagus nerve. A cough is as a result of receptor stimulation located in the trachea, hyperpnoea is as a result of receptor stimulation in the lower airway. Stimulation may also result in reflex bronchial and laryngeal constriction. Many factors can stimulate irritant receptors. These include irritant gases, smoke and dust, airway deformation, pulmonary congestion, rapid inflation/deflation and inflammation. Deep augmented breaths or sighs seen every 5 – 20 minutes at rest are due to stimulation of these irritant receptors. This reverses the slow lung collapse that occurs in quiet breathing.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 5
Incorrect
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Which one of the listed cells are typically found in a granuloma?
Your Answer: B lymphocytes
Correct Answer: Epithelioid cells
Explanation:Typically, granuloma has Langhan’s cells (large multinucleated cells ) surrounded by epithelioid cell aggregates, T lymphocytes and fibroblasts.Antigen presenting monocytic cells found in the skin are known as Langerhan’s cells.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 6
Correct
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A 50-year-old man, known hypertensive on amlodipine has been visiting his GP with symptoms of headache, tiredness, and muscle weakness. His blood test today shows a low potassium level of 2.8 mmol/L, and a slightly raised sodium level at 147 mmol/L.What is the MOST LIKELY diagnosis?
Your Answer: Conn’s syndrome
Explanation:When there are excessive levels of aldosterone independent of the renin-angiotensin aldosterone axis, primary hyperaldosteronism occurs. Secondary hyperaldosteronism occurs due to high renin levels.Causes of primary hyperaldosteronism include:Conn’s syndromeAdrenal hyperplasiaAdrenal cancerFamilial aldosteronismCauses of secondary hyperaldosteronism include:Renal vasoconstrictionOedematous disordersDrugs – diureticsObstructive renal artery diseaseAlthough patients are usually asymptomatic, when clinical features are present, classically hyperaldosteronism presents with:HypokalaemiaSodium levels can be normal or slightly raisedHypertensionMetabolic alkalosisLess common, clinical features are:LethargyHeadachesIntermittent paraesthesiaPolyuria and polydipsiaMuscle weakness (from persistent hypokalaemia)Tetany and paralysis (rare)
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 7
Correct
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Regarding airway resistance, which of the following statements is INCORRECT:
Your Answer: In the lower respiratory tract, airway resistance is mostly determined by the smallest bronchioles.
Explanation:Airway resistance is primarily determined by the airway radius according to Poiseuille’s law, and whether the flow is laminar or turbulent. The major site of airway resistance is the medium-sized bronchi. The smallest airways would seem to offer the highest resistance, but they do not because of their branching parallel arrangement.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 8
Correct
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Following a road traffic collision, a patient sustains damage to the long thoracic nerve. Which of the following clinical findings would you most expect to see on examination:
Your Answer: Winged scapula deformity
Explanation:Damage to the long thoracic nerve results in weakness/paralysis of the serratus anterior muscle. Loss of function of this muscle causes the medial border, and particularly the inferior angle, of the scapula to elevate away from the thoracic wall, resulting in the characteristic ‘winging’ of the scapula. This deformity becomes more pronounced if the patient presses the upper limb against a wall. Furthermore, normal elevation of the arm is no longer possible.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 9
Correct
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On which of the following types of receptors does loperamide act?
Your Answer: Opioid receptors
Explanation:Loperamide inhibits acetylcholine release from the myenteric plexus acts by action on opioid mu-receptors, and this then reduces bowel motility. The intestinal transit time is increased, thereby facilitating water reabsorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 10
Incorrect
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An injury to the brachial plexus can cause Erb's palsy. The following is expected to happen to a patient suffering from this condition, except for which one:
Your Answer: Loss of sensation over the lateral arm
Correct Answer: Weakness of medial rotation of the arm
Explanation:Erb’s palsy can be caused by a traumatic force downward on the upper arm and shoulder that damages the upper root of the brachial plexus. The patient will lose shoulder abduction (deltoid, supraspinatus), shoulder external rotation (infraspinatus), and elbow flexion as a result of this condition (biceps, brachialis).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 11
Correct
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Which of the following statements is correct with regards to heparin-induced thrombocytopaenia (HIT)?
Your Answer: HIT typically develops 5-10 days after starting heparin.
Explanation:Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder caused by antibodies that recognize complexes of platelet factor 4 (PF4) and heparin. HIT is frequently considered in the differential diagnosis of thrombocytopenia occurring in patients on heparin therapy. HIT is a challenging diagnosis because of routine heparin use in hospitalized patients, the common occurrence of thrombocytopenia. The process of heparin dependent IgG antibodies binding to heparin/platelet factor 4 complexes activates platelets and produces a hypercoagulable state. This syndrome typically develops 5-10 days (range 4-15 days) after heparin is commenced. It can occur with unfractionated heparin, low molecular weight heparin, or, rarely, fondaparinux. The diagnosis of HIT requires the combination of a compatible clinical picture and laboratory confirmation of the presence of heparin dependent platelet activating HIT antibodies. Discontinuation of heparin alone or initiation of a vitamin K antagonist alone like warfarin, is not sufficient to stop the development of thrombosis in patients with acute HIT. If there is moderate clinical suspicion for HIT, all sources of heparin must be discontinued and there must be consideration of anticoagulant treatment with a non-heparin drug.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 12
Incorrect
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A patient with a diagnosis of HIV presents with a fever, sore throat, and general malaise and you are concerned the patient may have an AIDS defining illness.Which one of these, according to the CDC definition, would mean a patient infected with HIV has AIDS?
Your Answer: CD8 T-cell count of less than 200 cells/mm 3
Correct Answer: CD4 T-cell percentage of total lymphocytes of less than 15%
Explanation:According to the CDC definition, a patient co-infected with HIV can be diagnosed with AIDS if he or she has:A CD4 T-cell count of less than 200 cells/mm3 or;A CD4 T-cell percentage of total lymphocytes of less than 15% or;An AIDS defining infectionA Streptococcal throat infection is not an AIDS defining infection.A normal CD4 count ranges from 500-1000 cells/mm3. A CD4 (not CD8) count of less than 200 cells/mm3 is AIDS defining.The CD4 count can vary from day to day and depending upon the time that the blood test is taken. It can also be affected by the presence of other infections or illnesses. Treatment with anti-retroviral therapy should be considered at CD4 count of less than 350 cells/mm3.Serum concentrations of the p24 antigen (the viral protein that makes up most of the core of the HIV) are usually high in the first few weeks after human immunodeficiency virus (HIV) infection and testing for p24 antigen is therefore a useful way of diagnosing very early infection.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 13
Incorrect
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Regarding renal clearance, which of the following statements is CORRECT:
Your Answer: Creatinine clearance is the gold standard for measurement of GFR.
Correct Answer: The MDRD equation uses plasma creatinine to estimate the GFR making an adjustment for age, sex and race.
Explanation:Clearance is defined as the volume of plasma that is cleared of a substance per unit time. Inulin clearance is the gold standard for measurement of GFR but creatinine clearance is typically used instead. Creatinine is freely filtered and not reabsorbed, but there is a little creatinine tubular secretion. In practice, GFR is usually estimated from the plasma creatinine using a formula e.g. the MDRD equation making an adjustment for age, sex and race.
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This question is part of the following fields:
- Physiology
- Renal
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Question 14
Correct
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Which of the following side effects would you least associated with ciprofloxacin:
Your Answer: Folate deficiency
Explanation:Common side effects include diarrhoea, dizziness, headache, nausea and vomiting.Other adverse effects include: Tendon damage (including rupture), Seizures (in patients with and without epilepsy), QT-interval prolongation, Photosensitivity and Antibiotic-associated colitis
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 15
Correct
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A 36 year old man who is overweight with a history of gout, presents to emergency room with an acutely painful big toe which is red, hot and swollen. However, he is apyrexic and otherwise systemically well. He has been diagnosed with acute gout. The most appropriate first line treatment for him is which of the following?
Your Answer: NSAIDs
Explanation:The first line treatment for acute gout includes NSAIDs like diclofenac, indomethacin or naproxen. In patients in whom NSAIDs are contraindicated, not tolerated or ineffective, colchicine is an alternative. In those who cannot tolerate or who are resistant to NSAIDs and colchicine, oral or parenteral corticosteroids are an effective alternative. In acute monoarticular gout, intra-articular injection of a corticosteroid can be used occasionally. In acute gout. allopurinol is not used in the actual treatment, but its use should be continued during an acute attack if the patient is already established on long term therapy.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 16
Incorrect
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An analytical cohort study is done to compare the relationship between omega 3 intake and occurrence of myocardial infarction (MI) among males aged over 65 years. The following are the data from the study:No. of subjects taking placebo: 100 menNo. of subjects taking placebo who suffered an MI: 15 menNo. of subjects taking omega 3: 100 menNo. of subjects taking omega 3 who suffered an MI: 5 menCompute for the absolute risk in the treatment (omega 3) group.
Your Answer:
Correct Answer: 0.05
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.AR = 5/100 = 0.05
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This question is part of the following fields:
- Evidence Based Medicine
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Question 17
Incorrect
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A 23 year old woman has noticed her skin seems to have a yellow tinge and presents to the emergency room. On examination she is found to have jaundice and mild splenomegaly, and blood tests show that her Hb is 79 g/L. She only takes one regular medication. The medication that is most likely to cause haemolytic anaemia is:
Your Answer:
Correct Answer: Mefenamic acid
Explanation:Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that is used short-term (7 days or less) to treat mild to moderate pain in adults and children who are at least 14 years old. Mefenamic acid is also used to treat menstrual pain. It has only minor anti-inflammatory properties and has occasionally been associated with diarrhoea and haemolytic anaemia. If these occur, treatment should be discontinued.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 18
Incorrect
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Regarding T helper cells, which of the following statements is CORRECT:
Your Answer:
Correct Answer: They form the vast majority (about 75%) of the total circulating T-cell population.
Explanation:CD4+ T-cells (Helper T cells)Recognise antigen only in association with HLA class II molecules (found on antigen presenting cells (APCs) e.g. dendritic cells, B-cells; present exogenous antigens that have been phagocytosed/endocytosed into intracellular vesicles)Form most of the circulating T-cell population (about 75%)Secrete cytokines (e.g. IFN-gamma) which are required for recruitment and activation of other immune cells such as macrophages, T cytotoxic cells and NK cells and for the activation of and production of immunoglobulin from B-cells
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 19
Incorrect
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A 42-year-old woman presents with face swelling prominently affecting her upper lip and hands. She has previously been diagnosed with hereditary angioedema.Which of these is the most appropriate management option for this acute attack?
Your Answer:
Correct Answer: Fresh frozen plasma
Explanation:Hereditary angioedema is inherited as an autosomal dominant disorder and is caused by deficiency of C1 esterase inhibitor, a protein that forms part of the complement system.Attacks can be precipitated by stress and minor surgical procedures. Clinical features of hereditary angioedema include oedema of the skin and mucous membranes commonly affecting the face, tongue and extremities.Angioedema and anaphylaxis due to a deficiency of C1 esterase inhibitor are resistant to adrenaline, steroids and antihistamines. Treatment is with fresh frozen plasma or C1 esterase inhibitor concentrate, which contains C1 esterase inhibitor.Short-term prophylaxis for events that may precipitate angioedema attack is achieved with C1 esterase inhibitor or fresh frozen plasma infusions before the event while long-term prophylaxis can be achieved with antifibrinolytic drugs (tranexamic acid) or androgenic steroids.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 20
Incorrect
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Which of the following neurotransmitter and receptor combinations is present at the neuromuscular junction:
Your Answer:
Correct Answer: Acetylcholine acting at nicotinic receptors
Explanation:At the neuromuscular junction, acetylcholine is released from the prejunctional membrane which acts on cholinergic nicotinic receptors on the postjunctional membrane.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 21
Incorrect
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A patient presents with a laceration on his hand and wrist that has cut the nerve that innervates opponens pollicis.The opponens pollicis muscle is innervated by which of the following nerves? Select ONE answer only.
Your Answer:
Correct Answer: The recurrent branch of the median nerve
Explanation:Opponens pollicis is a small, triangular muscle that forms part of the thenar eminence. It originates from the flexor retinaculum and the tubercle of trapezium bone and inserts into the whole length of the first metacarpal bone on its radial side.Opponens pollicis is innervated by the recurrent branch of the median nerve and receives its blood supply from the superficial palmar arch.The main action of opponens pollicis is to flex the first metacarpal bone at the carpometacarpal joint, which opposes the thumb towards the centre of the palm. It also medially rotates the first metacarpal bone at the carpometacarpal joint.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 22
Incorrect
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You examine a 48-year-old patient who has had proximal weakness, hypertension, and easy bruising in the past. She exhibits considerable face fullness and truncal obesity on examination. You diagnose her with Cushing's syndrome.When would her random cortisol level likely be abnormal?
Your Answer:
Correct Answer: 2400 hrs
Explanation:Cortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep.The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater throughout the 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 23
Incorrect
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Regarding propofol, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: A lower induction dose of propofol is required in children.
Explanation:Elderly patients have a reduced volume of distribution and slower clearance of the drug. They are therefore more sensitive to the effects of propofol and the drug wears off more slowly. They need less of the drug, which should be injected slowly, monitoring its effect on the patient. The opposite is true in children, who need larger doses of propofol. This is particularly so in children under three years of age. Propofol is not recommended for induction of anaesthesia in children under one month of age or for maintenance of anaesthesia in children under three years old.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 24
Incorrect
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Which of the following side effects is most likely caused by erythromycin:
Your Answer:
Correct Answer: QT - prolongation
Explanation:The side effects of erythromycin include abdominal pain, anaphylaxis, cholestatic hepatitis, confusion, diarrhoea, dyspepsia, fever, flatulence, hallucinations, hearing loss, headache, hypertrophic pyloric stenosis, hypotension, Interstitialnephritis, mild allergic reactions, nausea, nervous system effects,including seizures, pain, pruritus, pseudomembranous colitis, QT prolongation, rash, skin eruptions, tinnitus, urticaria, ventricular arrhythmias, ventricular tachycardia, vertigo, vomiting
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 25
Incorrect
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Compliance is greater in all but which one of the following:
Your Answer:
Correct Answer: Pulmonary oedema
Explanation:Compliance changes at different lung volumes. Initially at lower lung volumes the compliance of the lung is poor and greater pressure change is required to cause a change in volume. This occurs if the lungs become collapsed for a period of time. At functional residual capacity (FRC) compliance is optimal since the elastic recoil of the lung tending towards collapse is balanced by the tendency of the chest wall to spring outwards. At higher lung volumes the compliance of the lung again becomes less as the lung becomes stiffer. At all volumes, the base of the lung has a greater compliance than the apex. Patients with emphysema have increased compliance. Compliance is affected by a person’s age, sex and height.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 26
Incorrect
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Calcium-channel blockers can be divided into two categories: dihydropyridines and non-dihydropyridines. The basic chemical structure of these two classes differs, as does their relative selectivity for cardiac versus vascular L-type calcium channels. The phenylalkylamine class and the benzothiazepine class are two subgroups of non-dihydropyridines.A phenylalkylamine calcium-channel blocker is, for example, which of the following?
Your Answer:
Correct Answer: Verapamil
Explanation:Calcium-channel blockers, also known as calcium antagonists, stop calcium from entering cells through the L-type calcium channel. This causes vascular smooth muscle in vessel walls to relax, resulting in a decrease in peripheral vascular resistance. They can be used for a variety of things, including:HypertensionAnginaAtrial fibrillationMigraineCalcium-channel blockers can be divided into two categories: dihydropyridines and non-dihydropyridines. The basic chemical structure of these two classes differs, as does their relative selectivity for cardiac versus vascular L-type calcium channels.Dihydropyridines have a high vascular selectivity and lower systemic vascular resistance and blood pressure. As a result, they’re frequently used to treat hypertension. Modified release formulations are also used to treat angina, but their powerful systemic vasodilator and pressure-lowering effects can cause reflex cardiac stimulation, resulting in increased inotropy and tachycardia, which can counteract the beneficial effects of reduced afterload on myocardial oxygen demand.The suffix -dpine distinguishes dihydropyridines from other pyridines. Examples of dihydropyridines that are commonly prescribed include:AmlodipineFelodipineNifedipineNimodipineThe phenylalkylamine class and the benzothiazepine class are two subgroups of non-dihydropyridines.Phenylalkylamines are less effective as systemic vasodilators because they are relatively selective for the myocardium. This group of drugs lowers myocardial oxygen demand and reverses coronary vasospasm, making them useful in the treatment of angina. They are also occasionally used to treat arrhythmias. A phenylalkylamine calcium-channel blocker like verapamil is an example.In terms of selectivity for vascular calcium channels, benzothiazepines fall somewhere between dihydropyridines and phenylalkylamines. They can lower arterial pressure without producing the same level of reflex cardiac stimulation as dihydropyridines because they have both cardiac depressant and vasodilator effects. Diltiazem is the only benzothiazepine currently in clinical use.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 27
Incorrect
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A 1-year-old male is brought to the paediatrician by his mother due to swelling of the right knee after a minor fall. On examination, the right knee is swollen, fluctuant and tender. Ultrasound-guided aspiration reveals a massive hemarthrosis. Family history shows that his older brother also has a bleeding disorder. Which one of the following conditions does the patient most likely have?
Your Answer:
Correct Answer: Haemophilia A
Explanation:A diagnosis of Haemophilia is supported in this patient by the family history and the presence of hemarthrosis-both characteristics of Haemophilia. Haemophilia A is caused by Factor VIII deficiency, leading to impaired coagulation. This disease typically presents after six months when the child starts crawling. Von Willebrand disease presents with nosebleeds and hematomas. Idiopathic thrombocytopenic purpura presents with bruises that resemble a rash. Glucose-6-phosphate dehydrogenase (G6PD) deficiency presents with haemolytic anaemia induced by specific drugs or foods. Factor V Leiden mutation causes blood clotting rather than bleeding.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 28
Incorrect
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Fibrinoid necrosis is typically seen in which of the following:
Your Answer:
Correct Answer: Malignant hypertension
Explanation:Fibrinoid necrosis occurs in malignant hypertension where increased arterial pressure results in necrosis of smooth muscle wall. Eosinophilic and fibrinous deposits are seen.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 29
Incorrect
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A 17-year-old patient with a headache, fever, and a non-blanching rash is brought to the emergency room. Meningococcal infection is confirmed by a lumbar puncture. Neisseria meningitidis uses one of the following immune evasion mechanisms:
Your Answer:
Correct Answer: Secretes IgA protease
Explanation:Meningococci have 3 important virulence factors, as follows:Polysaccharide capsule – Individuals with immunity against meningococcal infections have bactericidal antibodies against cell wall antigens and capsular polysaccharides; a deficiency of circulating anti meningococcal antibodies is associated with the disease.Lipo-oligosaccharide endotoxin (LOS)Immunoglobulin A1 (IgA1)
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This question is part of the following fields:
- Microbiology
- Principles
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Question 30
Incorrect
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You intend to suture a hand wound with plain 1 percent lidocaine.In 1 mL of plain 1 percent lidocaine solution, how much lidocaine hydrochloride is there?
Your Answer:
Correct Answer: 10 mg lidocaine hydrochloride
Explanation:10 mg of lidocaine hydrochloride is contained in each 1 mL of plain 1 percent lidocaine solution.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 31
Incorrect
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Which of these is NOT a lithium side effect:
Your Answer:
Correct Answer: Peptic ulcer disease
Explanation:Adverse Effects of lithium IncludeLeucocytosis (most patients)Polyuria/polydipsia (30-50%)Dry mouth (20-50%)Hand tremor (45% initially, 10% after 1 year of treatment)Confusion (40%)Decreased memory (40%)Headache (40%)Muscle weakness (30% initially, 1% after 1 year of treatment)Electrocardiographic (ECG) changes (20-30%)Nausea, vomiting, diarrhoea (10-30% initially, 1-10% after 1-2 years of treatment)Hyperreflexia (15%)Muscle twitch (15%)Vertigo (15%)Extrapyramidal symptoms, goitre (5%)Hypothyroidism (1-4%)Acne (1%)Hair thinning (1%)
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 32
Incorrect
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An elderly female with a diagnosed psychiatric illness was prescribed prochlorperazine for her complaints of dizziness and nausea. Two days later, she returned to the clinic with no improvement in the symptoms. Which one of the following is the mechanism of action of prochlorperazine?
Your Answer:
Correct Answer: Dopamine receptor antagonism
Explanation:Prochlorperazine is a phenothiazine drug as it is categorized as a first-generation antipsychotic. It mainly blocks the D2 (dopamine 2) receptors in the brain. Along with dopamine, it also blocks histaminergic, cholinergic, and noradrenergic receptors.It exerts its antiemetic effect via dopamine (D2) receptor antagonist. It is used to treat nausea and vomiting of various causes, including labyrinthine disorders.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 33
Incorrect
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A 32-year-old woman with a history of bipolar disorder exhibits lithium toxicity symptoms.Which of the following is the MOST LIKELY feature to be present?
Your Answer:
Correct Answer: Clonus
Explanation:Lithium toxicity manifests itself in the following ways:AtaxiaClonusComaConfusionConvulsionsDiarrhoeaIncreased muscle toneNausea and vomitingNephrogenic diabetes insipidusRenal failureTremor
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 34
Incorrect
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Glomerular filtration rate can be calculated using any substance that:
Your Answer:
Correct Answer: is freely filtered and neither reabsorbed nor secreted by the nephron
Explanation:Clearance of a substance can provide an accurate estimate of the glomerular filtration rate (GFR) provided that the substance is:freely filterednot reabsorbed in the nephronnot secreted in the nephronnot synthesised or metabolised by the kidney
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This question is part of the following fields:
- Physiology
- Renal
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Question 35
Incorrect
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Cryptococcus neoformans is primarily implicated in which of the following conditions:
Your Answer:
Correct Answer: Chronic lymphocytic meningitis
Explanation:Cryptococcus neoformans typically causes a chronic lymphocytic meningitis in immunosuppressed patients or those with intense exposure e.g. pigeon fanciers.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 36
Incorrect
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Which of the following is NOT a common side effect of diazepam:
Your Answer:
Correct Answer: Bradycardia
Explanation:Adverse effects include:Drowsiness and lightheadednessConfusion and ataxia (especially in the elderly), amnesia, muscle weaknessHeadache, vertigo, tremor, dysarthria, hypotension, decreased libido, erectile dysfunction, gynaecomastia, urinary retentionParadoxical effects such as talkativeness, excitement, irritability, aggression, anti-social behaviour, and suicidal ideationWithdrawal symptoms, for example anxiety, depression, anorexia, impaired concentration, insomnia, abdominal cramps, palpitations, tremor, tinnitus and perceptual disturbancesTolerance and dependence (people who use benzodiazepines longer term can develop tolerance and eventual dependence)
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 37
Incorrect
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A newborn baby is rushed to the neonatal ICU 4 hours after birth due to sudden onset severe jaundice and generalised oedema. Family history reveals that this is the second baby, while blood testing shows that the mother has an Rh-negative blood group while the baby is Rh-positive. A diagnosis of haemolytic disease of the newborn is established. Which one of the following hypersensitivity reactions have occurred in this case?
Your Answer:
Correct Answer: Type II hypersensitivity reaction
Explanation:Hepatitis A usually doesn’t pose a special risk to a pregnant woman or her baby. Maternal infection doesn’t result in birth defects, and a mother typically doesn’t transmit the infection to her baby. HAV is almost always transmitted by the faecal-oral route and is usually acquired through close personal contact or via contaminated food.When a woman has chickenpox in the first 20 weeks of pregnancy, there is a 1 in 50 chance for the baby to develop a set of birth defects. This is called the congenital varicella syndrome. It includes scars, defects of muscle and bone, malformed and paralyzed limbs, small head size, blindness, seizures, and intellectual disability.TORCH Syndrome refers to infection of a developing foetus or newborn by any of a group of infectious agents. “TORCH” is an acronym meaning (T)oxoplasmosis, (O)ther Agents, (R)ubella (also known as German Measles), (C)ytomegalovirus, and (H)erpes Simplex.Infection with any of these agents may cause a constellation of similar symptoms in affected newborns. These may include fever; difficulties feeding; small areas of bleeding under the skin, causing the appearance of small reddish or purplish spots; enlargement of the liver and spleen (hepatosplenomegaly); yellowish discoloration of the skin, whites of the eyes, and mucous membranes (jaundice); hearing impairment; abnormalities of the eyes; and other symptoms and findings.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 38
Incorrect
-
C3 deficiency leads to particular susceptibility of infection with which of the following:
Your Answer:
Correct Answer: Encapsulated bacteria
Explanation:Macrophages and neutrophils have C3b receptors and they phagocytose C3b-coated cells. C3 deficiency thus leads to increased susceptibility of infection with encapsulated organisms (e.g. S. pneumoniae, H. influenzae).The early stages of the complement cascade leading to coating of the cells with C3b can occur by two different pathways:The classical pathway usually activated by IgG or IgM coating of cellsThe alternative pathway which is more rapid and activated by IgA, endotoxin and other factors
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 39
Incorrect
-
Antispasmodic drugs are primarily indicated in which of the following conditions:
Your Answer:
Correct Answer: Irritable bowel syndrome
Explanation:Antispasmodics, such as antimuscarinics, may be used in the management of irritable bowel syndrome. Other antispasmodics used include direct-acting smooth muscle relaxants such as mebeverine, alverine, and peppermint oil. Antispasmodics are contraindicated in bowel obstruction and severe inflammatory bowel disease. Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects. Antimuscarinics are contraindicated in urinary retention.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 40
Incorrect
-
At which vertebral level does the spinal cord normally end in adults?
Your Answer:
Correct Answer: L1/L2
Explanation:The spinal cord starts at the foramen magnum, where it is continuous with the medulla oblongata, which is the most caudal portion of the brainstem.It then extends inferiorly through the vertebral canal. In adults, it usually ends at the level of the first or second lumbar vertebra.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 41
Incorrect
-
What is the primary route of transmission of Neisseria Gonorrhoeae?
Your Answer:
Correct Answer: Sexually transmitted
Explanation:Neisseria gonorrhoeae is primarily spread by sexual contact or through transmission during childbirth. It causes gonorrhoea which is a purulent infection of the mucous membrane surfaces.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 42
Incorrect
-
Arterial baroreceptors are located primarily in which of the following:
Your Answer:
Correct Answer: Carotid sinus and aortic arch
Explanation:Arterial baroreceptors are located in the carotid sinus and aortic arch, and detect the mean arterial pressure (MAP). A decrease in MAP (such as in postural hypotension, or haemorrhage) reduces arterial stretch and decreases baroreceptor activity, resulting in decreased firing in afferent nerves travelling via the glossopharyngeal nerve (carotid sinus) and vagus nerve (aortic arch) to the medulla where the activity of the autonomic nervous system is coordinated. Sympathetic nerve activity consequently increases, causing an increase in heart rate and cardiac contractility, peripheral vasoconstriction with an increase in TPR, and venoconstriction with an increase in CVP and thus an increase in cardiac output and blood pressure. Parasympathetic activity (vagal tone) decreases, contributing to the rise in heart rate.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 43
Incorrect
-
An ambulance transports a 37-year-old woman who is having a seizure. She is moved to resuscitation and given a benzodiazepine dose, which quickly ends the seizure. You later learn that she has epilepsy and is usually treated with carbamazepine to control her seizures.What is carbamazepine's main mechanism of action?
Your Answer:
Correct Answer: Sodium channel blocker
Explanation:Carbamazepine is primarily used to treat epilepsy, and it is effective for both focal and generalised seizures. It is not, however, effective in the treatment of absence or myoclonic seizures. It’s also commonly used to treat neuropathic pain, as well as a second-line treatment for bipolar disorder and as a supplement for acute alcohol withdrawal.Carbamazepine works as a sodium channel blocker that preferentially binds to voltage-gated sodium channels in their inactive state. This prevents an action potential from firing repeatedly and continuously.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 44
Incorrect
-
A 29-year-old woman presents with night sweats, fever, and haemoptysis. A diagnosis of tuberculosis was suspected.Which of the following statements regarding the diagnosis of tuberculosis is considered correct?
Your Answer:
Correct Answer: Mycobacteria tuberculosis can be typed using a RFLP method
Explanation:Although a variety of clinical specimens may be submitted to thelaboratory to recover MTB and NTM, respiratory secretions suchas sputum and bronchial aspirates are the most common. Anearly-morning specimen should be collected on three consecutivedays, although recent studies have suggested that the addition ofa third specimen does not significantly increase the sensitivityof detecting Mycobacteria.Mycobacterium tuberculosis appear red on acid-fast staining because they take up the primary stain, which is carbolfuchsin, and is not decolorized by the acid alcohol anymore.Culture on Lowenstein-Jensen medium should be read within 5 to 7 days after inoculation and once a week thereafter for up to 8 weeks.Nucleic acid amplification assays designed to detect M. tuberculosis complexbacilli directly from patient specimens can be performed in as little as 6 to 8 hours on processed specimens.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 45
Incorrect
-
A 17-year-old student presents with a headache and petechial rash. A diagnosis of meningitis was suspected, with a causative agent of Neisseria meningitidis. Which of the following statements is considered correct regarding Neisseria meningitidis?
Your Answer:
Correct Answer: The antiphagocytic polysaccharide capsule is the main determinant of its pathogenicity
Explanation:N. meningitidis is a Gram-negative cocci and can be found as a commensal as well as an invasive pathogen. It is an important etiologic agent of endemic and epidemic meningitis and meningococcaemia and rarely pneumonia, purulent arthritis, or endophthalmitis. N. meningitidis has also been recovered from urogenital and rectal sites as a result of oral-genital contact. Meningococcal carriage, usually involving nonencapsulated strains, may cause an increase in protective antibody against the pathogenic strains. Of the 12 meningococcal encapsulated serogroups, A, B, C, Y, and W-135 account for most cases of disease in the world. N. meningitidis possesses a polysaccharide capsule that is antiphagocytic and serves as an important virulence factor.It can be found on the mucosal surfaces of the nasopharynx and oropharynx in 30% of the human population. The organism is transmitted by close contact with respiratory droplet secretions from a carrier to a new host. Only a few newly colonized hosts develop meningococcal disease, with the highest incidence being found in infants and adolescents.The quadrivalent vaccine Menactra is a polysaccharide-protein conjugated vaccine with antigens to serogroups A, C, Y, and W-135. This conjugate vaccine is licensed for people 2 to 55 years old. This vaccine does not protect against meningitis caused by serogroup B because group B polysaccharide is a very poor immunogen in humans.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 46
Incorrect
-
A patent has weakness of humeral flexion and extension. A CT scan reveals that he has suffered damage to the nerve that innervates pectoralis major.Pectoralis major receives its innervation from which of the following nerves? Select ONE answer only.
Your Answer:
Correct Answer: Lateral and medial pectoral nerves
Explanation:Pectoralis major is a thick, fan-shaped muscle situated in the chest. It makes up the bulk of the chest musculature in the male and lies underneath the breast in the female. It overlies the thinner pectoralis minor muscle.Superficial muscles of the chest and arm showing pectoralis major (from Gray’s Anatomy)Pectoralis major has two heads; the clavicular head and the sternocostal head. The clavicular head originates from the anterior border and medial half of the clavicle. The sternocostal head originates from the anterior surface of the sternum, the superior six costal cartilages and the aponeurosis of the external oblique muscle. It inserts into the lateral lip of the bicipital groove of the humerus.Pectoralis major receives dual innervation from the medial pectoral nerve and the lateral pectoral nerve.Its main actions are as follows:Flexes humerus (clavicular head)Extends humerus (sternocostal head)Adducts and medially rotates the humerusDraws scapula anteriorly and inferiorly
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 47
Incorrect
-
Loop diuretics primarily act on which Na+ transporter?
Your Answer:
Correct Answer: Na + /K + /2Cl - symporter
Explanation:The most potent diuretics are loop diuretics e.g. furosemide. They work by inhibiting the Na+/K+/2Cl-symporter in the thick ascending limb of the loop of Henle, which inhibits sodium, potassium, and chloride reabsorption. As a result, there is diuresis with loss of these electrolytes. There is a reduction in transcellular voltage difference, paracellular calcium and magnesium reabsorption.The medullary interstitium becomes more concentrated by salt reabsorption in the ascending limb. Loop diuretics block this process and reduce the ability of the kidney to concentrate urine. In the collecting duct, there is increased sodium delivery to the principal cells, which increases potassium secretion in return for sodium reabsorption.
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This question is part of the following fields:
- Physiology
- Renal
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Question 48
Incorrect
-
Lidocaine's antiarrhythmic mode of action is as follows:
Your Answer:
Correct Answer: Blocks inactivated Na+ channels
Explanation:Lidocaine is a class 1B antidysrhythmic; combines with fast Na channels and thereby inhibits recovery after repolarization, resulting in decreasing myocardial excitability and conduction velocity. However, in ischaemic areas, where anoxia causes depolarisation and arrhythmogenic activity, many Na+ channels are inactivated and therefore susceptible to lidocaine.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 49
Incorrect
-
Atracurium is used as a muscle relaxant during endotracheal intubation. This drug’s mechanism of action is best described by which of the following?
Your Answer:
Correct Answer: Nicotinic acetylcholine receptor antagonist
Explanation:Atracurium is a non-depolarizing neuromuscular blocker that is used to help with intubation and controlled ventilation by causing muscle relaxation and paralysis. At the neuromuscular junction’s post-synaptic membrane, atracurium competes with acetylcholine for nicotinic (N2) receptor binding sites. This prevents the receptors from being stimulated by acetylcholine. Muscle paralysis occurs gradually due to the competitive blockade.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 50
Incorrect
-
A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle weakness and headaches. She is known to be hypertensive and takes amlodipine to control this. Her blood results today show that her potassium level is low at 3.0 mmol/L, and her sodium level is slightly elevated at 146 mmol/L.Which of the following is the SINGLE most appropriate INITIAL investigation?
Your Answer:
Correct Answer: Plasma renin and aldosterone levels
Explanation:Primary hyperaldosteronism occurs when there are excessive levels of aldosterone independent of the renin-angiotensin axis. Secondary hyperaldosteronism occurs due to high renin levels.The causes of primary hyperaldosteronism include:Adrenal adenoma (Conn’s syndrome) – the most common cause of hyperaldosteronism (,80% of all cases). These are usually unilateral and solitary and are more common in women.Adrenal hyperplasia – this accounts for ,15% of all cases. Usually, bilateral adrenal hyperplasia (BAH) but can be unilateral rarely. More common in men than women.Adrenal cancer – a rare diagnosis but essential not to missFamilial aldosteronism – a rare group of inherited conditions affecting the adrenal glandsThe causes of secondary hyperaldosteronism include:Drugs – diureticsObstructive renal artery disease – renal artery stenosis and atheromaRenal vasoconstriction – occurs in accelerated hypertensionOedematous disorders – heart failure, cirrhosis and nephrotic syndromePatients are often asymptomatic. When clinical features are present, the classically described presentation of hyperaldosteronism is with:HypertensionHypokalaemiaMetabolic alkalosisSodium levels can be normal or slightly raisedOther, less common, clinical features include:LethargyHeadachesMuscle weakness (from persistent hypokalaemia)Polyuria and polydipsiaIntermittent paraesthesiaTetany and paralysis (rare)Often the earliest sign of hyperaldosteronism is from aberrant urea and electrolytes showing hypokalaemia and mild hypernatraemia. If the patient is taking diuretics, and the diagnosis is suspected, these should be repeated after the patient has taken off diuretics.If the diagnosis is suspected, plasma renin and aldosterone levels should be checked. Low renin and high aldosterone levels (with a raised aldosterone: renin ratio) is suggestive of primary aldosteronism.If the renin: aldosterone ratio is high, then the effect of posture on renin, aldosterone and cortisol can be investigated to provide further information about the underlying cause of primary hyperaldosteronism. Levels should be measured lying at 9 am and standing at noon:If aldosterone and cortisol levels fall on standing, this is suggestive of an ACTH dependent cause, e.g. adrenal adenoma (Conn’s syndrome)If aldosterone levels rise and cortisol levels fall on standing, this is suggestive of an angiotensin-II dependent cause, e.g. BAHOther investigations that can help to distinguish between an adrenal adenoma and adrenal hyperplasia include:CT scanMRI scanSelective adrenal venous sampling
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 51
Incorrect
-
By what mechanism does Vibrio cholerae causes diarrhoea?
Your Answer:
Correct Answer: Increases Cl- secretory channels in crypt cells
Explanation:Cholera is a severe diarrheal illness caused by the Vibrio cholerae bacteria infecting the bowel. Ingesting cholera-infected food or drink is the a way to contract the disease. In the intestinal crypt cells, the toxigenic bacterium Vibrio cholera activates adenylate cyclase and raises cyclic adenosine monophosphate (cAMP). cAMP stimulates the Cl-secretory channels in crypt cells, resulting in the secretion of chloride with sodium ions and water. The toxin it produces causes the body to secrete massive amounts of water, resulting in diarrhoea and significant fluid and electrolyte loss.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 52
Incorrect
-
Your consultant requests that you do a lumbar puncture on a patient who is suspected of having meningitis. This patient, a 15-year-old female, presented to the emergency department with a fever, headache, and neck stiffness. Where should you aspirate a sample of CSF?
Your Answer:
Correct Answer: Subarachnoid space
Explanation:A lumbar puncture, also known as a spinal tap, is a procedure that involves inserting a needle into the lower back’s lumbar region. A needle is inserted into the space between the arachnoid mater and the pia mater, also known as the subarachnoid space, to remove a sample of cerebrospinal fluid.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 53
Incorrect
-
A 35 year old man presents with a deep laceration to the proximal part of the forearm. On further assessment, the patient is unable to flex the metacarpophalangeal joints and interphalangeal joints of the index, middle finger and the thumb. The ring and little fingers are intact but there is weakness at the proximal interphalangeal joint.There is also loss of sensation over the lateral palm and the palmar surface of the lateral three and a half fingers. Which of these nerve(s) has most likely been affected?
Your Answer:
Correct Answer: Median nerve
Explanation:A median nerve injury affecting the extrinsic and intrinsic muscles of the hand will present with:Loss of sensation to the lateral palm and the lateral three and a half fingers.Weakness of flexion at the metacarpophalangeal joints of the index and middle finger. This is because of paralysis of the lateral two lumbricals. Weakness of flexion of the proximal interphalangeal joints of all four fingers due to paralysis of the flexor digitorum superficialisWeakness of flexion at the distal interphalangeal joints of the index and middle finger following paralysis of the lateral half of the flexor digitorum profundus.Weakness of thumb flexion, abduction and opposition due to paralysis of the flexor pollicis longus and thenar muscles
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 54
Incorrect
-
Discontinuous capillaries are typically found where in the body:
Your Answer:
Correct Answer: Reticuloendothelial system
Explanation:Discontinuous capillaries, found in the reticuloendothelial system (bone marrow, liver and spleen), have large gaps between endothelial cells and are permeable to red blood cells.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 55
Incorrect
-
Approximately what percentage of filtered bicarbonate is reabsorbed in the proximal tubule:
Your Answer:
Correct Answer: 0.8
Explanation:Bicarbonate is freely filtered at the glomerulus. Less than 0.1% of filtered bicarbonate is normally excreted in the urine (if plasma [HCO3-] increases, maximum tubular transport is exceeded and some HCO3-is excreted in urine). About 80% of bicarbonate is reabsorbed in the proximal tubule. For each H+secreted into the lumen, one Na+and one HCO3-are reabsorbed into the plasma. H+is recycled so there is little net secretion of H+at this stage. A further 10 – 15% of HCO3-is similarly reabsorbed in the thick ascending limb of the loop of Henle. In the early distal tubule, H+secretion is predominantly by Na+/H+exchange but more distally, the Na+gradient is insufficient so secretion is via H+ATPase and H+/K+ATPase in intercalated cells, which contain plentiful carbonic acid. As secreted H+is derived from CO2, new HCO3-is formed and returns to the blood.H+secretion is proportional to intracellular [H+] which itself is related to extracellular pH. A fall in blood pH will therefore stimulate renal H+secretion. In the proximal tubule secretion of H+serves to reclaim bicarbonate from glomerular filtrate so it is not lost, but in the distal nephron, secretion leads to net acid excretion and generation of new bicarbonate.
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This question is part of the following fields:
- Physiology
- Renal
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Question 56
Incorrect
-
Regarding inflammatory bowel disease, acute mild to moderate disease of the rectum or rectosigmoid should be treated initially with:
Your Answer:
Correct Answer: Local aminosalicylate
Explanation:Acute mild to moderate disease affecting the rectum (proctitis) or the rectosigmoid is treated initially with local application of an aminosalicylate; alternatively, a local corticosteroid can be used but it is less effective. A combination of a local aminosalicylate and a local corticosteroid can be used for proctitis that does not respond to a local aminosalicylate alone.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 57
Incorrect
-
Regarding the intervertebral disc, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In L4 - L5 disc herniation, the L5 spinal nerve root is the most commonly affected.
Explanation:A posterolateral herniation of the disc at the L4 – L5 level would be most likely to damage the fifth lumbar nerve root, not the fourth lumbar nerve root, due to more oblique descending of the fifth lumbar nerve root within the subarachnoid space.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 58
Incorrect
-
A 65-year-old man presents with cough and shortness of breath. His sputum is rusty in colour and is suffering from a fever. Upon examination, it was noted that he has crackles in the right upper lobe. A chest X-ray showed the presence of a right upper lobe cavitation.Among the following microorganisms, which is considered to be mostly associated with a cavitating upper lobe pneumonia?
Your Answer:
Correct Answer: Klebsiella pneumoniae
Explanation:Klebsiella pneumoniae is among the most common Gram-negative bacteria encountered by physicians worldwide and accounts for 0.5-5.0% of all cases of pneumonia. This organism can cause extensive pulmonary necrosis and frequent cavitation.It is one of the causes that could be suspected when there is cavitatory pneumonia with or without a bulging fissure sign. Often, there can be extensive lobar opacification with air bronchograms.A helpful feature which may help to distinguish from pneumococcal pneumonia is that Klebsiella pneumoniae develops cavitation in 30-50% of cases (in comparison, cavitation is rare in pneumococcal pneumonia). This occurs early and progresses quickly.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 59
Incorrect
-
All of the following statements is considered true regarding Streptococcus pneumoniae, except:
Your Answer:
Correct Answer: It is the commonest cause of erysipelas
Explanation:Erysipelas is a rare infection of the skin and subcutaneous tissues observed frequently in elderly patients. It is characterized by an acute spreading skin lesion that is intensely erythematous with a plainly demarcated but irregular edge. It is most commonly caused by Streptococcus pyogenes or Group A Streptococcus (GAS).GAS are susceptible to penicillin, which remains the drug of choice for treatment. For patients allergic to penicillin, erythromycin can be used.S. pyogenes colonizes the throat and skin on humans, making these sites the primary sources of transmission. Infections resulting from S. pyogenes include pharyngitis, scarlet fever, skin or pyodermal infections, and other septic infections. In addition, the sequelae rheumatic fever and acute glomerulonephritis can occur as a result of infection with S. pyogenes.Agammaglobulinemia is mostly associated with S. pneumoniae.The M protein is attached to the peptidoglycan of the cell wall and extends tothe cell surface. The M protein is essential for virulence. The polysaccharide capsule is characteristic of S. pneumoniae.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 60
Incorrect
-
Which of the following statements is correct with regards to immunoglobulin?
Your Answer:
Correct Answer: The isotype of immunoglobulin is determined by the heavy chain.
Explanation:The composition of immunoglobulin molecules is two identical heavy and two identical light chains. These chains are linked by disulphide bridges and are each have highly variable regions which give the immunoglobulin its specificity. In addition, they have constant regions and there is virtual complete correspondence in amino acid sequence in all antibodies of a given isotype. Five isotypes of immunoglobulin exist – these are IgG, IgA, IgM, IgE and IgD. They are determined by the heavy chain (gamma, alpha, mu, epsilon or delta respectively). The light chains are either kappa or lambda.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 61
Incorrect
-
Regarding acute lymphoblastic leukaemia (ALL), which of the following statements is CORRECT:
Your Answer:
Correct Answer: 75% of cases occur before the age of 6 years.
Explanation:Acute lymphoblastic leukaemia (ALL) is caused by an accumulation of lymphoblasts in the bone marrow and is the most common malignancy of childhood. The incidence of ALL is highest at 3 – 7 years, with 75% of cases occurring before the age of 6. 85% of cases are of B-cell lineage. Haematological investigations reveal a normochromic normocytic anaemia with thrombocytopenia in most cases. There is great variation in the chance of individual patients achieving a long-term cure based on a number of biological variables. Approximately 25% of children relapse after first-line therapy and need further treatment but overall 90% of children can expect to be cured. The cure rate in adults drops significantly to less than 5% over the age of 70 years.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 62
Incorrect
-
Regarding penicillin antibiotics, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Patients with a history of atopy are at higher risk of hypersensitivity reactions.
Explanation:Allergic reactions to penicillins occur in 1 – 10% of exposed individuals; anaphylactic reactions occur in fewer than 0.05% of treated patients. Patients with a history of atopic allergy are at higher risk of anaphylactic reactions to penicillins. Patients with a history of anaphylaxis, urticaria, or rash immediately after penicillin use should not receive a penicillin or other beta-lactam antibiotics; about 0.5 – 6.5 % of penicillin-sensitive patients will also be allergic to the cephalosporins. Patients with a history of a more minor rash (i.e. non-confluent, non-pruritic rash restricted to a small area of the body) or delayed reaction (rash occurring more than 72 hours after penicillin administration), may not be truly allergic and may be considered for penicillin or beta-lactam treatment in severe infection (although possibility of allergy should be borne in mind). Other beta-lactam antibiotics (including cephalosporins) can be used in these patients.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 63
Incorrect
-
The fracture of the medial epicondyle will cause damage to the ulnar nerve. Which of the following motions would be impaired by this type of injury?
Your Answer:
Correct Answer: Adduction of the thumb
Explanation:Fracture of the medial epicondyle is most likely to result in damage to the ulnar nerve. The three hypothenar muscles, two medial lumbricals, seven interossei, the adductor pollicis, and the deep head of the flexor pollicis brevis are all innervated by the deep branch of the ulnar nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 64
Incorrect
-
The functional residual capacity (FRC) will be increased in which of the following:
Your Answer:
Correct Answer: Emphysema
Explanation:Factors increasing FRC:EmphysemaAir trapping in asthmaAgeing (due to loss of elastic properties)Increasing height of patient
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 65
Incorrect
-
A 22-year-old student presents with a painful, red and itchy right eye. On examination, there is mild erythema of palpebral conjunctiva, and follicles are visible on eversion of the eyelid. Lid oedema is evident, and you can also see a few petechial subconjunctival haemorrhages. The eye appears watery, and there is no purulent discharge. He has recently recovered from a mild upper respiratory tract infection.Which of these is the most likely causative organism?
Your Answer:
Correct Answer: Adenovirus
Explanation:The most frequent cause of red eye is conjunctivitis. It is caused by inflammation of the conjunctiva which can be infective or allergic and accounts for about 35% of all eye problems presenting to general practice.Viral conjunctivitis is commonly caused by adenoviruses and it is the most common infectious conjunctivitis.The common bacterial causes of conjunctivitis are Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus.The clinical features of infective conjunctivitis include:Acute onset of conjunctival erythemaFeeling ‘grittiness’, ‘foreign body’ or ‘burning’ sensation in the eye.Watering and discharge which may cause transient blurring of visionFeatures of viral conjunctivitis include: watery and non-purulent eye discharge, lid oedema, follicles present on eyelid eversion, petechial subconjunctival haemorrhages and pseudomembranes may be seen on the tarsal conjunctival surfaces.This patients features are consistent with a viral aetiology, and the most likely causative organism is adenovirus,
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 66
Incorrect
-
A patient who was put on low molecular weight heparin for suspected DVT and was scheduled for an ultrasound after the weekend, arrives at the emergency department with significant hematemesis. Which of the following medications can be used as a heparin reversal agent:
Your Answer:
Correct Answer: Protamine sulfate
Explanation:The management of bleeding in a patient receiving heparin depends upon the location and severity of bleeding, the underlying thromboembolic risk, and the current aPTT (for heparin) or anti-factor Xa activity (for LMW heparin). As an example, a patient with minor skin bleeding in the setting of a mechanical heart valve (high thromboembolic risk) and a therapeutic aPTT may continue heparin therapy, whereas a patient with major intracerebral bleeding in the setting of venous thromboembolism several months prior who is receiving heparin bridging perioperatively may require immediate heparin discontinuation and reversal with protamine sulphate. If haemorrhage occurs it is usually sufficient to withdraw unfractionated or low molecular weight heparin, but if rapid reversal of the effects of the heparin is required, protamine sulphate is a specific antidote (but only partially reverses the effects of low molecular weight heparins). Clinician judgment and early involvement of the appropriate consulting specialists is advised.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 67
Incorrect
-
A 15-year-old boy was brought to the emergency room with complaints of a headache, stiffness of the neck, and photophobia. Upon observation, the following were noted: HR 124, BP 86/43, RR 30, SaO 95%, temperature 39.5 deg C. A recently developed non-blanching rash on his legs was also observed.What is most likely the causative agent of the case presented above?
Your Answer:
Correct Answer: Neisseria meningitidis group B
Explanation:The meningococcus is solely a human pathogen, and up to 50% of the population may carry meningococci in the nasopharynx. Factors that lead to invasion and production of disease include complex inter-relationships of genetic predisposition, host status, environmental conditions, and virulence of the organism.Meningococcal disease is the most common infectious cause of death in childhood in developed countries. It presents as septicaemia, meningitis, or a combination. Septicaemia is the more dangerous presentation, especially with septic shock; meningitis is more likely to lead to neurodevelopmental sequelae. Classic features of septicaemia are a non-blanching rash in a feverish, ill child.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 68
Incorrect
-
Regarding Hodgkin lymphoma, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Some patients may complain alcohol-induced nodal pain and pruritus
Explanation:Lymphomas are a group of diseases caused by malignant lymphocytes that accumulate in lymph nodes and other lymphoid tissue and cause the characteristic clinical feature of lymphadenopathy. The major subdivision of lymphomas is into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) and this is based on the histological presence of Reed-Sternberg cells present in HL. Hodgkin lymphoma can present at any age but is rare in children and has a peak incidence in young adults. There is an almost 2 : 1 male predominance. Most patients present with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes. Cervical nodes are involved in 60-70% of cases, axillary nodes in 10-15% and inguinal nodes in 6-12%. Modest splenomegaly occurs during the course of the disease in 50% of patients; the liver may also be enlarged. Bone marrow failure involvement is unusual in early disease. The prognosis depends on age, stage and histology, but overall approximately 85% of patients are cured. Alcohol‐induced pain and pruritus are two well‐known but rare symptoms in HL.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 69
Incorrect
-
Which of the following is most true of the sinoatrial node:
Your Answer:
Correct Answer: Frequency of depolarisation is increased by sympathetic stimulation.
Explanation:Cardiac myocyte contraction is not dependent on an external nerve supply but instead the heart generates its own rhythm, demonstrating inherent rhythmicity. The heartbeat is initiated by spontaneous depolarisation of the sinoatrial node (SAN), a region of specialised myocytes in the right atrium close to the coronary sinus, at a rate of 100-110 beats/min. This intrinsic rhythm is primarily influenced by autonomic nerves, with vagal influences being dominant over sympathetic influences at rest. This vagal tone reduces the resting heart rate down to 60-80 beats/min. To increase heart rate, the autonomic nervous system increases sympathetic outflow to the SAN, with concurrent inhibition of vagal tone. These changes mean the pacemaker potential more rapidly reaches the threshold for action potential generation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 70
Incorrect
-
Regarding apoptosis, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Apoptosis leads to cell swelling and eventual cell lysis.
Explanation:Apoptosis is a controlled form of cell death in which no cellular contents are released from the dying cell, and thus no inflammatory reaction is seen. Apoptosis may occur physiologically or pathologically. Apoptosis may be induced in two main ways: by the engagement of surface death receptors e.g. TNF-alpha (extrinsic pathway) or through cellular injury (intrinsic pathway). The end result is the activation of proteases enzymes called caspases which dismantle the cell cytoplasm and nucleus. Apoptotic cells shrink down and fragment into apoptotic bodies, each of which retains an intact cell membrane; apoptotic bodies are then targeted or rapid removal by adjacent cells. Disordered apoptosis is thought to be central to a number of important disease processes, particularly carcinogenesis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 71
Incorrect
-
Monoamine oxidase is primarily involved in the degradation of which of the following:
Your Answer:
Correct Answer: Noradrenaline
Explanation:Catecholamines are broken down extracellularly and in the liver by catechol-O-methyltransferase (COMT) and intracellularly by monoamine oxidase (MAO).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 72
Incorrect
-
When an elderly dehydrated patient is moved from a supine to a standing position, her heart rate increases. Which of the following accounts for the increase in heart rate upon standing:
Your Answer:
Correct Answer: Decreased venous return
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 73
Incorrect
-
A 23-year-old man is discovered to have an infection from Helicobacter pylori. Which of the following types of cancer is mostly associated with Helicobacter pylori infection?
Your Answer:
Correct Answer: Gastric cancer
Explanation:H. pylori is recognized as a major cause of type B gastritis, a chronic condition formerly associated primarily with stress and chemical irritants. In addition, the strong association between long-term H. pylori infection and gastric cancer has raised more questions regarding the clinical significance of this organism. There is speculation that long-term H. pylori infection resulting in chronic gastritis is an important risk factor for gastric carcinoma resulting in H. pylori being classified as a carcinogen.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 74
Incorrect
-
When a child has mumps, how long should he or she be off from school?
Your Answer:
Correct Answer: 5 days from onset of swelling
Explanation:To avoid the spread of infection, infected patients should be isolated. Patients should avoid going to school, childcare, or job for five days after the swelling has occurred.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 75
Incorrect
-
In the emergency room, a patient was diagnosed with acute bacterial tonsillitis. Which of the following postinfectious complications is most commonly linked to Streptococcus pyogenes:
Your Answer:
Correct Answer: Glomerulonephritis
Explanation:Poststreptococcal glomerulonephritis (PSGN) is caused by prior infection with specific nephritogenic strains of group A beta-haemolytic streptococcus. The clinical presentation of PSGN varies from asymptomatic, microscopic haematuria to the full-blown acute nephritic syndrome, characterized by red to brown urine, proteinuria (which can reach the nephrotic range), oedema, hypertension, and acute kidney injury.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 76
Incorrect
-
The most important nerve for plantar flexion of the foot at the ankle joint is:
Your Answer:
Correct Answer: Tibial nerve
Explanation:Muscles of the posterior compartment of the leg, innervated by the tibial nerve, perform plantar flexion of the foot at the ankle joint. The fibularis longus (innervated by the superficial fibular nerve) assists in plantar flexion but is not the most important.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 77
Incorrect
-
Regarding hepatitis B, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months.
Explanation:Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months. Hepatitis B has a long incubation period of about 2 – 6 months. Hepatitis B vaccine has recently been introduced to the routine childhood immunisation schedule – given at 2, 3 and 4 months. It is also given to babies born to hepatitis B infected mothers at birth, four weeks and 12 months old. Treatment of acute hepatitis is supportive. Treatment with antivirals should be considered in chronic infection as responders have a reduced risk of liver damage and liver cancer in the long term.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 78
Incorrect
-
You are prescribing ipratropium bromide for a patient who has presented with an exacerbation of her COPD. What is the mechanism of action of ipratropium bromide:
Your Answer:
Correct Answer: Muscarinic antagonist
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma)
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 79
Incorrect
-
Regarding the power of a study, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The power of a study is not affected by data variability.
Explanation:A study should only be undertaken if the power is at least 80%; a study power set at 80% accepts a likelihood of 1 in 5 (20%) of missing a statistically significant difference where one exists.The determinants of power are:the sample size (the power increases with sample size)the variability of the observations (the power increases as the variability decreases)the effect size of interest (the power is greater for a larger expected effect size)and the significance level, α (the power is greater if the significance level is larger); therefore the probability of a type I error increases as the probability of a type II error decreases.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 80
Incorrect
-
A 33-year-old heavily muscled man presents with left-sided chest pain. After taking part in a powerlifting competition, he felt a painful snap at the front of his shoulder and chest. There is also the presence of bruising and swelling over the left side of his chest. A ruptured pectoralis major muscle was suspected upon examining the injured area. Which of the following statements regarding the surface markings of the pectoralis major muscle is considered correct?
Your Answer:
Correct Answer: It inserts into the lateral lip of the bicipital groove of the humerus
Explanation:The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla.Its origin lies anterior surface of the medial half of the clavicle, the anterior surface of the sternum, the first 7 costal cartilages, the sternal end of the sixth rib, and the aponeurosis of the external oblique of the anterior abdominal wall.The insertion of the pectoralis major is at the lateral lip of the intertubercular sulcus of the humerus. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin. The function of the pectoralis major is 3-fold and dependent on which heads of muscles are involved:- Flexion, adduction and medial rotation of the arm at the glenohumeral joint- Clavicular head causes flexion of the extended arm- Sternoclavicular head causes extension of the flexed armArterial supply of the pectoralis major, the pectoral artery, arises from the second branch of the axillary artery, the thoracoacromial trunk.The 2 heads of the pectoralis major have different nervous supplies. The clavicular head derives its nerve supply from the lateral pectoral nerve. The medial pectoral nerve innervates the sternocostal head. The lateral pectoral nerve arises directly from the lateral cord of the brachial plexus, and the medial pectoral nerve arises from the medial cord.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 81
Incorrect
-
Excessive gastric acid output is detected in a patient with a history of recurrent stomach ulcers. It's possible that the patient has Zollinger-Ellison syndrome.Which of the following statements about stomach acid is correct?
Your Answer:
Correct Answer: The proton pump located in the canalicular membrane is vital to its secretion
Explanation:The stomach produces gastric acid, which is a digesting fluid. The stomach secretes about 2-3 litres every day. It is involved in tissue breakdown, the conversion of pepsinogen to active pepsin, and the creation of soluble salts with calcium and iron, and has a pH range of 1.5-3.5. It also serves as an immune system by destroying microbes.The following substances are found in gastric acid:WaterAcid hydrochloridePepsinogenmucous Intrinsic factorThe parietal cells in the proximal 2/3 (body) of the stomach release gastric acid. The concentration of hydrogen ions in parietal cell secretions is 1-2 million times that of blood. Chloride is released against both a concentration and an electric gradient, and active transport is required for the parietal cell to produce acid.The following is how stomach acid is secreted:1. Gastric acid secretion is dependent on the H+/K+ ATPase (proton pump) situated in the canalicular membrane. The breakdown of water produces hydrogen ions within the parietal cell. The hydroxyl ions produced in this reaction mix quickly with carbon dioxide to generate bicarbonate ions. Carbonic anhydrase is the enzyme that catalyses this process.2. In return for chloride, bicarbonate is carried out of the basolateral membrane. The ‘alkaline tide’ occurs when bicarbonate is released into the bloodstream, resulting in a modest rise in blood pH. The parietal cell’s intracellular pH is maintained by this procedure. Conductance channels carry chloride and potassium ions into the lumen of canaliculi.3. Through the action of the proton pump, hydrogen ions are pushed out of the cell and into the lumen in exchange for potassium; potassium is thus efficiently recycled.4. The canaliculi accumulate osmotically active hydrogen ions, which creates an osmotic gradient across the membrane, allowing water to diffuse outward.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 82
Incorrect
-
Which of the following microbes is spread by a vector:
Your Answer:
Correct Answer: Plasmodium falciparum
Explanation:The female Anopheles mosquito is the vector for Plasmodium falciparum transmission. Treponema pallidum is transmitted through sexual transmission or direct skin contact. Clostridium perfringens is spread by direct skin contact or through oral-faecal route. The oral-faecal pathway is how Vibrio cholerae spreads. Mycoplasma tuberculosis is spread via the airborne route.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 83
Incorrect
-
A 29-year-old female with chronic anaemia secondary to sickle cell disease is being transfused. A few minutes after starting the blood transfusion, she develops widespread itching with urticarial rash, wheezing, nausea and chest pain. Her BP reduces to 60/40 mmHg.What is the most appropriate treatment?
Your Answer:
Correct Answer: Stop the transfusion and administer adrenaline
Explanation:Anaphylaxis transfusion reaction occurs when an individual has previously been sensitized to an allergen present in the blood and, on re-exposure, releases IgE or IgG antibodies. Patients with anaphylaxis usually develop laryngospasm, bronchospasm, abdominal pain, nausea, vomiting, hypotension, shock, and loss of consciousness. The transfusion should be stopped immediately and the patient should be treated with adrenaline, oxygen, corticosteroids, and antihistamines.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 84
Incorrect
-
After what time period should intravenous phenytoin be used as second-line treatment of status epilepticus?
Your Answer:
Correct Answer: 25 minutes
Explanation:If seizures recur or fail to respond after initial treatment with benzodiazepines within 25 minutes of onset, phenytoin sodium, fosphenytoin sodium, or phenobarbital sodium should be used.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 85
Incorrect
-
EMLA cream is a topical local anaesthetic containing which of the following:
Your Answer:
Correct Answer: 50/50 mixture 2.5% lidocaine and 2.5% prilocaine
Explanation:EMLA cream, an effective topical local anaesthetic, is a 50/50 mixture of 2.5% prilocaine and 2.5% lidocaine.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 86
Incorrect
-
What does the correlation coefficient r = 0 indicate with regards to linear relationships between two variables?
Your Answer:
Correct Answer: There is no correlation between two variables
Explanation:r = 0 if there is no correlation between two variables. The closer that r is to 0, the weaker the correlation.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 87
Incorrect
-
The common bile duct drains into the duodenum in which of the following regions:
Your Answer:
Correct Answer: Second part of the duodenum
Explanation:As the common bile duct descends, it passes posterior to the first part of the duodenum before joining with the pancreatic duct from the pancreas, forming the hepatopancreatic ampulla (ampulla of Vater) at the major duodenal papilla, located in the second part of the duodenum. Surrounding the ampulla is the sphincter of Oddi, a collection of smooth muscle which can open to allow bile and pancreatic fluid to empty into the duodenum.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 88
Incorrect
-
Which of the following laboratory findings is NOT typical of von Willebrand disease (VWD):
Your Answer:
Correct Answer: Thrombocytopaenia
Explanation:Laboratory findings typically show (although this varies depending on VWD type):Abnormal PFA-100 testLow factor VIII levels (if low a factor VIII/VWF binding assay is performed)Prolonged APTT (or normal)Normal PTLow VWF levelsDefective platelet aggregationNormal platelet count
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This question is part of the following fields:
- Haematology
- Pathology
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Question 89
Incorrect
-
Regarding CSF (cerebrospinal fluid) production, approximately how much is produced per day?
Your Answer:
Correct Answer: 500 ml
Explanation:CSF fills the ventricular system, a series of interconnected spaces within the brain, and the subarachnoid space directly surrounding the brain. The intraventricular CSF reflects the composition of the brain’s extracellular space via free exchange across the ependyma, and the brain “floats” in the subarachnoid CSF to minimize the effect of external mechanical forces. The volume of CSF within the cerebral ventricles is approximately 30 mL, and that in the subarachnoid space is about 125 mL. Because about 0.35 mL of CSF is produced each minute, CSF is turned over more than three times daily. Approximately 500 mL of CSF is produced per day, at a rate of about 25 mL per hour.CSF is a filtrate of capillary blood formed largely by the choroid plexuses, which comprise pia mater, invaginating capillaries, and ependymal cells specialized for transport. The choroid plexuses are located in the lateral, third, and fourth ventricles. The lateral ventricles are situated within the two cerebral hemispheres. They each connect with the third ventricle through one of the interventricular foramina (of Monro). The third ventricle lies in the midline between the diencephalon on the two sides. The cerebral aqueduct (of Sylvius) traverses the midbrain and connects the third ventricle with the fourth ventricle. The fourth ventricle is a space defined by the pons and medulla below and the cerebellum above. The central canal of the spinal cord continues caudally from the fourth ventricle, although in adult humans the canal is not fully patent and continues to close with age.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 90
Incorrect
-
Which of the following is NOT an effect of cytokine activity:
Your Answer:
Correct Answer: Opsonisation of bacteria for phagocytosis
Explanation:Cytokines are a family of chemical messengers, secreted by leucocytes, that act over short distances by binding specific receptors on target cell surfaces. They include: interleukins (act between leucocytes), interferons (inhibit replication of viruses within cells and activate macrophages and natural killer cells), growth factors, and tumour necrosis factors (kill tumour cells). Effects include: induction of fever and acute phase response, stimulation of leucocyte differentiation and maturation, leucocyte recruitment and activation and increased antibody production.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 91
Incorrect
-
A patient presents with acute severe asthma. Her initial salbutamol nebulization produced a poor response and you administer another nebuliser with ipratropium bromide added on.Which statement about ipratropium bromide is true?
Your Answer:
Correct Answer: It can trigger acute closed-angle glaucoma
Explanation:Ipratropium bromide is an antimuscarinic drug. It is used in the management of acute asthma and COPD. It provides short-term relief in chronic asthma. Short-acting β2agonists are preferred and act more quickly.The commonest side effect of ipratropium bromide is dry mouth. Tremor is commonly seen with β2agonists. It can trigger acute closed-angle glaucoma in patients that are susceptible. First-line treatment for moderate asthma attacks is short-acting β2agonists.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) be added to β2agonist treatment in patients with a poor initial response to β2agonist therapy or with acute severe or life-threatening asthma.Its duration of action is 3-6 hours, maximum effect occurs 30-60 minutes after use, and bronchodilation can be maintained with three times per day dosing.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 92
Incorrect
-
Pressure across the wall of a flexible tube (the transmural pressure) increases wall tension and extends it.Which law best describes transmural pressure?
Your Answer:
Correct Answer: Laplace’s law
Explanation:The transmural pressure (pressure across the wall of a flexible tube) can be described by Laplace’s law which states that:Transmural pressure = (Tw) / rWhere:T = Wall tensionw = Wall thicknessr = The radiusA small bubble with the same wall tension as a larger bubble will contain higher pressure and will collapse into the larger bubble if the two meet and join.Fick’s law describes the rate of diffusion in a solutionPoiseuille’s law is used to calculate volume of flow rate in laminar flowDarcy’s law describes the flow of a fluid through a porous medium.Starling’s law describes cardiac haemodynamics as it relates to myocyte contractility and stretch.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 93
Incorrect
-
Which of the following is NOT a common side effect of amiodarone:
Your Answer:
Correct Answer: Blue/green teeth discolouration
Explanation:Common side effects of amiodarone include: Bradycardia, Nausea and vomiting, Thyroid disorders – hypothyroidism and hyperthyroidism, Persistent slate grey skin discoloration, Photosensitivity, Pulmonary toxicity (including pneumonitis and fibrosis), Hepatotoxicity, Corneal microdeposits (sometimes with night glare), Peripheral neuropathy and Sleep disorders.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 94
Incorrect
-
The following are all examples of type IV hypersensitivity EXCEPT for:
Your Answer:
Correct Answer: Extrinsic allergic alveolitis
Explanation:Examples of type IV reactions includes:Contact dermatitisHashimoto’s thyroiditisPrimary biliary cholangitisTuberculin skin test (Mantoux test)Chronic transplant rejectionGranulomatous inflammation (e.g. sarcoidosis, Crohn’s disease)
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 95
Incorrect
-
In adults, the conus medullaris of the spinal cord lies at which of the following vertebral levels:
Your Answer:
Correct Answer: L1/L2
Explanation:At birth, the conus medullaris lies at L3. By the age of 21, it sits at L1/L2.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 96
Incorrect
-
A 31-year-old man with sickle-cell disease receives a blood transfusion for symptomatic anaemia. He presents to the Emergency Department three weeks later with a rash, fever, and diarrhoea. He has pancytopenia and abnormal liver function results on blood tests.Which of the transfusion reactions is most likely to have happened?
Your Answer:
Correct Answer: Graft-vs-host disease
Explanation:Blood transfusion can be a life-saving treatment with significant clinical benefits, but it also comes with a number of risks and potential complications, including:Immunological side effectsErrors in administration (episodes of ‘wrong blood’)Viruses and Infections (bacterial, viral, possibly prion)ImmunodilutionA culture of better safety procedures as well as steps to reduce the use of transfusion has emerged as a result of growing awareness of avoidable risk and improved reporting systems. Transfusion errors, on the other hand, continue to occur, and some serious adverse reactions go unreported.Transfusion-associated graft-vs-host disease (TA-GVHD) is a rare blood transfusion complication that causes fever, rash, and diarrhoea 1-4 weeks after the transfusion. Pancytopenia and liver function abnormalities are common laboratory findings.TA-GVHD, unlike GVHD following allogeneic marrow transplantation, causes profound marrow aplasia with a mortality rate of >90%. Survival is uncommon, with death occurring within 1-3 weeks of the onset of symptoms.Because of immunodeficiency, severe immunosuppression, or shared HLA antigens, viable T lymphocytes in blood components are transfused, engraft, and react against the recipient’s tissues, and the recipient is unable to reject the donor lymphocytes.The following is a list of the most common transfusion reactions and complications:1) Reaction to a febrile transfusionThe temperature rises by one degree from the baseline. Chills and malaise are also possible symptoms.The most common response (1 in 8 transfusions).Cytokines from leukocytes in transfused red cell or platelet components are usually to blame.Only supportive. The use of paracetamol is beneficial.2) Acute haemolytic reaction is a type of haemolytic reaction that occurs when theFever, chills, pain at the transfusion site, nausea, vomiting, and dark urine are all symptoms of a transfusion reaction.Early on, many people report a sense of ‘impending doom.’The most serious reaction. ABO incompatibility is frequently caused by a clerical error.STOP THE TRANSFUSION OF INFORMATION. IV fluids should be given. It’s possible that diuretics will be required.3) Haemolytic reaction that is delayedIt usually happens 4 to 8 days after a blood transfusion.Fever, anaemia, jaundice, and haemoglobinuria are all symptoms that the patient has.Positive Coombs test for direct antiglobulin.Because of the low titre antibody, it is difficult to detect in a cross-match, and it is unable to cause lysis at the time of transfusion.The majority of delayed haemolytic reactions are harmless and do not require treatment.Anaemia and renal function should be monitored and treated as needed.4) Reaction to allergensForeign plasma proteins are usually to blame, but anti-IgA could also be to blame.Urticaria, pruritus, and hives are typical allergic reactions. It’s possible that it’s linked to laryngeal oedema or bronchospasm.Anaphylaxis is a rare occurrence.Antihistamines can be used to treat allergic reactions symptomatically. It is not necessary to stop transfusions.If the patient develops anaphylaxis, the transfusion should be stopped and the patient should be given adrenaline and treated according to the ALS protocol.5) TRALI (Transfusion Related Acute Lung Injury)Within 6 hours of transfusion, there was a sudden onset of non-cardiogenic pulmonary oedema.It’s linked to the presence of antibodies to recipient leukocyte antigens in the donor blood.The most common cause of death from transfusion reactions is this.STOP THE TRANSFUSION OF INFORMATION. Oxygen should be given to the patient. Around 75% of patients will require aggressive respiratory support.The use of diuretics should be avoided.6) TACO (Transfusion Associated Circulatory Overload)Acute or worsening respiratory distress within 6 hours of a large blood transfusion. Fluid overload and pulmonary and peripheral oedema can be seen. Rapid blood pressure rises are common. BNP is usually 1.5 times higher than it was before the transfusion. It is most common in the elderly and those who have chronic anaemia.Blood transfusions should be given slowly, over the course of 3-4 hours.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 97
Incorrect
-
Which of the following antibiotics may be used for malaria prophylaxis:
Your Answer:
Correct Answer: Doxycycline
Explanation:Doxycycline may be used for malaria prophylaxis and as an adjunct to quinine in the treatment of Plasmodium falciparum malaria.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 98
Incorrect
-
A patient who is a known case of rheumatoid arthritis presents to the clinic as his grandson was recently diagnosed with chickenpox. His grandson spent the weekend with her, and he was in close contact with him. He takes 50 mg of prednisolone once daily and has been for the past six months. There is no history of chickenpox.Out of the following, which is TRUE regarding the next plan of action for her care?
Your Answer:
Correct Answer: She should receive prophylactic varicella-zoster Immunoglobulin (VZIG)
Explanation:Varicella-zoster immunoglobulin (VZIG) is indicated for post exposure prevention and treatment of varicella. It is recommended as prophylaxis for high-risk patients with no known immunity (i.e. no known previous chickenpox) who have had a significant exposure to varicella-zoster (considered >4 hours close contact).The high-risk groups are:1. Neonates2. Pregnant women3. The immunocompromised (e.g. cancer, immunosuppressive therapies)4. Those on high dose steroids (children on more than 2 mg/kg/day for more than 14 days, or adults on 40 mg/day for more than a week)This patient is at high risk of developing adrenal insufficiency and may need a temporary increase in her steroid dose during infection or stress. It would be inappropriate to stop or wean down her dose of prednisolone and can cause side effects.Since he is on steroids without immunity for chickenpox, he is at risk of developing severe varicella infection, with possible complications including pneumonia, hepatitis and DIC. If he develops a varicella infection, he will need to be admitted and require a specialist review and intravenous Acyclovir.
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This question is part of the following fields:
- Immunological Products & Vaccines
- Pharmacology
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Question 99
Incorrect
-
A 28-year-old woman in her second trimester is diagnosed with a psychiatric illness. She is started on treatment with a drug. The treatment results in her baby being born with poor tone, feeding problems, hypothyroidism, and a goitreOut of the following, which drug is most likely responsible for the baby's condition?
Your Answer:
Correct Answer: Lithium
Explanation:In pregnancy and postpartum, lithium is an effective treatment for relapse prevention in bipolar disorder. However, lithium has also been associated with risks during pregnancy for both the mother and the unborn child. Recent large studies have confirmed the association between first-trimester lithium exposure and an increased risk of congenital malformations.Lithium levels need to be monitored more frequently throughout pregnancy and the postnatal period. If given in the 1st-trimester, lithium is associated with a risk of fetal cardiac malformations, such as Ebstein’s anomaly. If given in the 2nd and 3rd-trimesters, there is a risk of the following:1. hypotonia2. lethargy3. feeding problems4. hypothyroidism5. goitre6. nephrogenic diabetes insipidus in the neonate
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 100
Incorrect
-
You suspect an anaphylactic reaction in a patient who is hypotensive, with trouble breathing after eating peanuts. Which of the following diagnostic tests will confirm this?
Your Answer:
Correct Answer: Mast cell tryptase
Explanation:The concentration of serum tryptase rises in anaphylaxis and anaphylactoid responses. Because tryptase is a significant component of mast cell granules, mast cell degranulation causes elevated tryptase levels in the blood. Although tryptase levels are not always high during anaphylaxis, it is considered a particular marker.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 101
Incorrect
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What is the most common application of Nitrates?
Your Answer:
Correct Answer: Angina
Explanation:In patients with exertional stable angina, nitrates improve exercise tolerance, time to onset of angina, and ST-segment depression during exercise testing. In combination with beta-blockers or calcium channel blockers, nitrates produce greater anti-anginal and anti-ischemic effects.While they act as vasodilators, coronary vasodilators, and modest arteriolar dilators, the primary anti ischemic effect of nitrates is to decrease myocardial oxygen demand by producing systemic vasodilation more than coronary vasodilation. This systemic vasodilation reduces left ventricular systolic wall stress.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 102
Incorrect
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Following an injury sustained during a rugby match, a 16-year-old boy is brought to the Emergency Department by his mother. His forearm appears to be deformed, and you believe he has a distal radius fracture. A numerical rating scale is used to assess his pain, and the triage nurse informs you that he is in moderate pain.'The RCEM guidance recommends which of the following analgesics for the treatment of moderate pain in a child of this age?
Your Answer:
Correct Answer: Oral codeine phosphate 1 mg/kg
Explanation:According to a 2018 audit conducted by the Royal College of Emergency Medicine (RCEM), the standard of care for children presenting to EDs with fractured limbs has deteriorated, with most patients waiting longer than ever before for pain relief. More than one-tenth of the children who came in with significant pain from a limb fracture received no pain relief at all.For all patients, including children, the Agency for Health Care Policy and Research (AHCPR) in the United States recommends using the ABCs of pain management:A – Ask about pain regularly. Assess pain systematically.B – Believe the patient and family in their reports of pain and what relieves it.C – Choose pain control options appropriate for the patient, family, and setting.D – Deliver interventions in a timely, logical, coordinated fashion.E – Empower patients and their families. Enable patients to control their course to the greatest extent possible.The RCEM guidelines recommend assessing a child’s pain within 15 minutes of arrival. This is a fundamental requirement. For the assessment of pain in children, a variety of rating scales are available; which one is used depends on the child’s age and ability to use the scale. These are some of them:Faces of Wong-Baker Scale for assessing painScale of numerical evaluationThe behavioural scale is a scale that measures how people behave.The RCEM has provided the following visual guide:The RCEM has established the following guidelines for when patients in severe pain should receive appropriate analgesia:100% within 60 minutes of arrival or triage, whichever is earliest75% within 30 minutes of arrival or triage, whichever is earliest50% within 20 minutes of arrival or triage, whichever is earliest
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 103
Incorrect
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Regarding the accessory nerve, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Accessory nerve palsy results in the inability to nod the head.
Explanation:Accessory nerve palsy results in inability to shrug the shoulders and to rotate the head to look at the opposite side to the lesion.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 104
Incorrect
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A 25-year old male is brought to the emergency room after a traffic accident. Upon examination, there was tenderness and erythema on the right acromioclavicular joint, with notable step deformity. On radiographic imaging, there is a superior elevation of the clavicle, a twice than normal coracoclavicular distance, and absence of fracture.Which of the following structure/s is/are likely to have ruptured?
Your Answer:
Correct Answer: Acromioclavicular ligament, coracoclavicular ligament and joint capsule
Explanation:Acromioclavicular joint injuries account for more than forty percent of all shoulder injuries. Mild injuries are not associated with any significant morbidity, but severe injuries can lead to significant loss of strength and function of the shoulder. Acromioclavicular injuries may be associated with a fractured clavicle, impingement syndromes, and more rarely neurovascular insults.The AC joint is a diarthrodial joint defined by the lateral process of the clavicle articulating with the acromion process as it projects anteriorly off the scapula. The joint is primarily stabilized by the acromioclavicular ligament, which is composed of an anterior, posterior, inferior, and superior component. Of note, the superior portion of the AC ligament is the most important component for the stability of the AC joint. Supporting structures include two coracoclavicular ligaments (trapezoid and conoid ligaments), which provide vertical stability, as well as the coracoacromial ligament.Patients with an AC joint injury typically present with anterosuperior shoulder pain and will describe a mechanism of injury of blunt trauma to the abducted shoulder or landing on an outstretched arm, suggestive of this type of injury. They may describe pain radiating to the neck or shoulder, which is often worse with movement or when they try to sleep on the affected shoulder. On examination, the clinician may observe swelling, bruising, or a deformity of the AC joint, depending on the degree of injury. The patient will be tender at that location. They may have a restriction in the active and passive range of motion secondary to pain. Piano key sign may be seen, with an elevation of the clavicle that rebounds after inferior compression.Standard X-rays are adequate to make a diagnosis of acromioclavicular joint injury and should be used to evaluate for other causes of traumatic shoulder pain.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 105
Incorrect
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Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 106
Incorrect
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What is the partial pressure of oxygen if it makes up 20.9 percent of the ambient air composition and the atmospheric pressure of ambient air is 760 mmHg?
Your Answer:
Correct Answer: 159 mmHg
Explanation:Ambient air is atmospheric air in its natural state. Ambient air is typically 78.6% nitrogen and 20.9% oxygen. The extra 1% is made up of carbon, helium, methane, argon and hydrogen. The partial pressure of any gas can be calculated using this formula: P = atmospheric pressure (760 mmHg) x percent content in the mixture. Atmospheric pressure is the sum of all of the partial pressures of the atmospheric gases added together: The formula for atmospheric pressure is: Patm = PN2 + PO2 + PH2O + PCO2. The atmospheric pressure is known to be 760 mmHg. The partial pressures of the various gases can be estimated to have partial pressures of approximately 597.4 mmHg for nitrogen, 158.8 mm Hg for oxygen, and 7.6 mmHg for argon.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 107
Incorrect
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Leukaemia has been diagnosed in a 6-year-old child on your list. He comes to the ER with a complication related to this diagnosis.Which type of leukaemia do you think this is?
Your Answer:
Correct Answer: Acute lymphoblastic leukaemia
Explanation:Acute lymphoblastic leukaemia (ALL) is the most common childhood cancer that primarily affects children. ALL is most common between the ages of 2 and 4, and it is uncommon in adults.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 108
Incorrect
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A 54-year-old man who is acutely unwell has his blood sent for test and the results come back with a CRP of 115.Which of these statements about C-reactive protein is FALSE?
Your Answer:
Correct Answer: It is produced in the bone marrow
Explanation:C-reactive protein(CRP) is synthesized in the liver in response to increased interleukin-6 (IL-6) secretion by macrophages and T-cells. Some conditions that cause CRP levels to a rise include: bacterial infection, fungal infection, severe trauma, autoimmune disease, Organ tissue necrosis, malignancy and surgery.It is useful in the clinical setting as a marker of inflammatory activity and can be used to monitor infections. CRP levels start to rise 4-6 hours after an inflammatory trigger and reaches peak levels at 36-50 hours.In the absence of a disease process, the normal plasma concentration is less than 5 mg/l.CRP is useful for monitoring inflammatory conditions (e.g. rheumatoid arthritis and malignancy), can be used as a prognostic marker in acute pancreatitis, and serial measurement can be used to recognize the onset of nosocomial infections in the intensive care settling.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 109
Incorrect
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One of your patients is in resuscitation and is suffering from kidney failure. The intensive care outreach team arrives to assess them and determines that a dopamine infusion is necessary.Dopamine primarily acts on which of the following receptors at low doses?
Your Answer:
Correct Answer: Dopamine receptors
Explanation:Dopamine is a catecholamine that occurs naturally and is used to treat low cardiac output, septic shock, and renal failure. It is both adrenaline and noradrenaline’s immediate precursor.Dopamine acts on D1 and D2 dopamine receptors in the renal, mesenteric, and coronary beds at low doses (1-5 g/kg/min). Dopamine causes a significant decrease in renal vascular resistance and an increase in renal blood flow at these doses. Within this dose range, it is also involved in central modulation of behaviour and movement.Dopamine stimulates beta- and alpha-adrenergic receptors directly and indirectly at higher doses. Beta-stimulation predominates at a rate of 5-10 g/kg/min, resulting in a positive inotropic effect that increases cardiac output and coronary blood flow. Alpha-stimulation predominates at infusion rates greater than 15 g/kg/min, resulting in peripheral vasoconstriction and an increase in venous return and systolic blood pressure.Below is a summary of the mechanisms and effects of various inotropic agents:InotropeMechanismEffectsAdrenaline (epinephrine)Beta-1 and -2 agonist at increasing doses;Alpha-agonist at high dosesIncreased cardiac output;Vasoconstriction at higher dosesNoradrenaline (norepinephrine)Mainly alpha-agonist;Beta-1 and -2 agonist at increasing dosesVasoconstriction;Some increased cardiac outputDopamineDopamine agonist at low doses;Beta-1 and -2 agonist at increasing doses;Alpha-agonist at high dosesIncreased cardiac output;Vasoconstriction at higher dosesDobutamineMainly beta-1 agonistIncreased cardiac output
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 110
Incorrect
-
Which of these statements about experimental studies is true?
Your Answer:
Correct Answer: Randomisation serves to remove potential bias
Explanation:In experimental studies, the researcher introduces an intervention and studies the effect. The study subjects are allocated into different groups by the investigator through the use of randomisation. Randomisation serves to remove any potential bias.A cohort study is a form of longitudinal, observational study that follows a group of patients (the cohort) over a period of time to monitor the effects of exposure to a proposed aetiological factor upon them.A case-control study is a type observational study. Here, patients who have developed a disease are identified and compared on the basis of proposed causative factors that occurred in the past, to a control group.Clinical trials are experimental studies. Examples include: double blind, single blind, and unblinded studies(both patient and researcher are aware of the treatment they receive)
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This question is part of the following fields:
- Evidence Based Medicine
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Question 111
Incorrect
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Regarding the UK routine childhood immunisation schedule which of the following vaccines is given at 3 months:
Your Answer:
Correct Answer: Rotavirus
Explanation:At 3 months the following vaccines are given:Diphtheria, tetanus, pertussis, polio, Hib and hepatitis B (2nd dose)Pneumococcal (13 serotypes)Rotavirus (2nd dose)
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This question is part of the following fields:
- Immunoglobulins And Vaccines
- Pharmacology
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Question 112
Incorrect
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Vitamin D is a group of secosteroids that play a role in calcium and phosphate control. Vitamin D's hormonally active metabolite is 1,25-dihydroxycholecalciferol.Which enzyme hydroxylates 25-hydroxycholecalciferol to form 1,25-dihydroxycholecalciferol?
Your Answer:
Correct Answer: 1-alpha-hydroxylase
Explanation:The hormone-active metabolite of vitamin D is 1,25-dihydroxycholecalciferol (commonly known as calcitriol). Its activities raise calcium and phosphate levels in the bloodstream.In the presence of UVB light, 7-dehydrocholesterol is converted to cholecalciferol in the epidermal layer of the skin, resulting in 1,25-dihydroxycholecalciferol.Cholecalciferol is then converted to 25-hydroxycholecalciferol in the endoplasmic reticulum of liver hepatocytes by 25-hydroxylase (calcifediol).Finally, 1-alpha-hydroxylase converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol in the kidney. The key regulatory point in the formation of 1,25-dihydroxycholecalciferol is 1-alpha-hydroxylase, which is induced by parathyroid hormone or hypophosphatemia.The following are the primary effects of 1,25-dihydroxycholecalciferol:Calcium and phosphate absorption in the small intestine is increased.Calcium reabsorption in the kidneys is increased.Increases phosphate reabsorption in the kidneys.Increases the action of osteoclastic bacteria (increasing calcium and phosphate resorption from bone)Inhibits the action of 1-alpha-hydroxylase in the kidneys (negative feedback)
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 113
Incorrect
-
Which of the following statements accurately describes the number needed to harm?
Your Answer:
Correct Answer: The NNH is the number of patients that need to be treated for one to experience the side effect
Explanation:Number needed to harm (NNH) corresponds to the number of individuals that must be treated, so that one of them presents an adverse reaction accountable to the treatment.Hence, a NNH of 100 means that 100 individuals need to be treated in order to produce an adverse effect of the treatment in one individual.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 114
Incorrect
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Metabolic hyperaemia harmonizes local blood flow with local O2 demand. If there is an increase in metabolic rate, the production of vasoactive metabolites increases. These metabolites act locally on the surrounding arterioles, causes vasodilation and an increase blood supply.Which of these metabolites is the most potent vasodilator in skeletal muscle?
Your Answer:
Correct Answer: K +
Explanation:Hyperaemia is the process where the body adjusts blood flow to meet the metabolic needs of different tissues in health and disease. Vasoactive mediators that take part in this process include K+, adenosine, CO2, H+, phosphates and H2O2. Although the mechanism is not clear, all these mediators likely contribute to some extent at different points.Specific organs are more sensitive to specific metabolites:K+ and adenosine are the most potent vasodilators in skeletal musclesCO2 and K+ are the most potent vasodilators in cerebral circulation.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 115
Incorrect
-
What is the main mechanism of action of dobutamine as an inotropic sympathomimetic:
Your Answer:
Correct Answer: Beta1-receptor agonist
Explanation:Dobutamine directly stimulates the beta1-adrenergic receptors in the heart and increases contractility and cardiac output with little effect on the rate. In addition action on beta2-receptors causes vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 116
Incorrect
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Which of the following does not increase renal phosphate excretion?
Your Answer:
Correct Answer: Vitamin D
Explanation:PO43-renal excretion is regulated several mechanisms. These include:-parathyroid hormone – increases excretion by inhibiting reabsorption in the proximal tubule-acidosis – increases excretion-glucocorticoids – increases excretion-calcitonin – increases excretion-activated vitamin D – decreases excretion by increasing reabsorption in the distal tubule
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This question is part of the following fields:
- Physiology
- Renal
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Question 117
Incorrect
-
A 54-year-old woman presents with polyuria and polydipsia. She is known to suffer from bipolar disorder, which has been well controlled by the use of lithium for many years.What is the SINGLE most likely diagnosis?
Your Answer:
Correct Answer: Nephrogenic diabetes insipidus
Explanation:Diabetes insipidus is the inability to produce concentrated urine. It is characterised by the presence of excessive thirst, polyuria and polydipsia. There are two distinct types of diabetes insipidus:Cranial (central) diabetes insipidus and;Nephrogenic diabetes insipidusCranial diabetes insipidus is caused by a deficiency of vasopressin (anti-diuretic hormone). Patients with cranial diabetes insipidus can have a urine output as high as 10-15 litres per 24 hours, but adequate fluid intake allows most patients to maintain normonatraemia. 30% of cases are idiopathic, and a further 30% are secondary to head injuries. Other causes include neurosurgery, brain tumours, meningitis, granulomatous disease (e.g. sarcoidosis) and drugs, such as naloxone and phenytoin. A very rare inherited form also exists that is associated with diabetes mellitus, optic atrophy, nerve deafness and bladder atonia.Nephrogenic diabetes insipidus is caused by renal resistance to the action of vasopressin. As with cranial diabetes insipidus, urine output is markedly elevated. Serum sodium levels can be maintained by secondary polydipsia or can be elevated. Causes of nephrogenic diabetes insipidus include chronic renal disease, metabolic disorders (e.g. hypercalcaemia and hypokalaemia) and drugs, including long-term lithium usage and demeclocycline.In view of the history of long-term lithium use, in this case, nephrogenic diabetes insipidus is the most likely diagnosis.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 118
Incorrect
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Adenosine has a half-life of approximately:
Your Answer:
Correct Answer: 8 - 10 seconds
Explanation:Adenosine stimulates A1-adenosine receptors and opens acetylcholine sensitive K+ channels, increasing K+ efflux. This hyperpolarises the cell membrane in the atrioventricular node and, by inhibiting the calcium channels, slows conduction in the AVN. As it has a very short duration of action (half-life only about 8 – 10 seconds), most side effects are short lived.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 119
Incorrect
-
For which of the following infections is phenoxymethylpenicillin (penicillin V) primarily used?
Your Answer:
Correct Answer: Streptococcal tonsillitis
Explanation:Phenoxymethylpenicillin (penicillin V) is less active than benzylpenicillin but both have similar antibacterial spectrum. Because penicillin V is gastric-acid stable, it is suitable for oral administration, but should not be used for serious infections as absorption can be unpredictable and plasma concentrations can be variable. Its uses are:1. mainly for respiratory tract infections in children2. for streptococcal tonsillitis 3. for continuing treatment after one or more injections of benzylpenicillin when clinical response has begun. 4. for prophylaxis against streptococcal infections following rheumatic fever and against pneumococcal infections following splenectomy or in sickle-cell disease. It should not be used for meningococcal or gonococcal infections.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 120
Incorrect
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Which of the following is a clinical effect of hyperkalaemia:
Your Answer:
Correct Answer: Muscle weakness
Explanation:Clinical features of hyperkalaemia may include: paraesthesia, muscle weakness or paralysis, cardiac conduction abnormalities and dysrhythmias. Clinical features of hypokalaemia may include: muscle weakness, muscle cramps, rhabdomyolysis and myoglobinuria, ascending paralysis resulting in respiratory failure, constipation, gut ileus with distension, anorexia, nausea and vomiting, impaired ADH action with polyuria and polydipsia, ECG changes and cardiac arrhythmias.
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This question is part of the following fields:
- Physiology
- Renal
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Question 121
Incorrect
-
Identify the type of graph described below:This graph has been used to create visual representations to communicate the risks and benefits of treatments using 4 face categories.
Your Answer:
Correct Answer: Cates plot
Explanation:Cates Plot, since 1999, has been used to create visual representations to communicate the risks and benefits of treatments. The essence of Cates Plot is the use of 4 face categories to visually indicate the following:People not affected by a treatment (green faces for those with a good outcome and red for those with a bad outcome)People for which treatment changes their category from a bad outcome to a good outcome (yellow faces)People for which treatment causes an adverse event and changes their category from a good outcome to a bad outcome (crossed out green faces)
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This question is part of the following fields:
- Evidence Based Medicine
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Question 122
Incorrect
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A 18 year old university student develops facial swelling and dark frothy urine. Urine dipstick demonstrates haematuria and proteinuria. Approximately 3 weeks ago, he was treated with oral antibiotics for a sore throat. His condition is most likely to be secondary to infection with:
Your Answer:
Correct Answer: Streptococcus pyogenes
Explanation:Post-streptococcal glomerulonephritis is a postinfectious immune-mediated reaction secondary to infection with Streptococcus pyogenes. It typically occurs 2 weeks or more after acute/initial infection, and presents with haematuria, reduced urine output, peripheral oedema, proteinuria, and hypertension. Permanent kidney damage is rare.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 123
Incorrect
-
Which of the following is not true regarding the structure and function of glomerular filtration membrane?
Your Answer:
Correct Answer: The absence of a basement membrane reduces impedance to filtration
Explanation:The glomerular filtration membrane is composed of fenestrated capillary endothelium, basement membrane, and filtration slits. It is an organized, semipermeable membrane preventing the passage of most of the proteins into the urine. The anatomical arrangement of the glomerular filtration membrane maximizes the surface area available for filtration. The arrangement of its arterioles results in high hydrostatic pressures and facilitates filtration. Fenestrated capillary endothelium of the glomerular filtration membrane is with relatively large pores. It allows the free movement of plasma proteins and solutes but still restricts the movement of blood cells. Filtration slits are the smallest filters and restrict the movement of plasma proteins but still allow free movement of ions and nutrients. The glomerular basement membrane (GBM) is a critical component of the glomerular filtration membrane. Thus, it is not true that its absence will reduce the resistance of flow. The basement membrane is true to be more selective and contains negatively charged glycoproteins. However, it still allows free passage of water, nutrients, and ions. Severe structural abnormalities of the GBM can result in protein (albumin) leakage.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 124
Incorrect
-
A patient is complaining of painless jaundice. His bilirubin levels are abnormally high.Which of the following statements about bile is correct?
Your Answer:
Correct Answer: Bile acids are amphipathic
Explanation:The liver produces bile on a constant basis, which is then stored and concentrated in the gallbladder. In a 24-hour period, around 400 to 800 mL of bile is generated.Bile is involved in the following processes:Fats are broken down into fatty acids.Waste products are eliminated.Cholesterol homeostasis is the balance of cholesterol in the body.The enteric hormones cholecystokinin and secretin are primarily responsible for bile secretion. When chyme from an unprocessed meal enters the small intestine, they are released, and they play the following function in bile secretion and flow:Cholecystokinin promotes gallbladder and common bile duct contractions, allowing bile to reach the intestine.Secretin enhances the secretion of bicarbonate and water by biliary duct cells, increasing the amount of bile and its flow into the gut.Bile acids have a hydrophobic and hydrophilic area, making them amphipathic. Bile acids’ amphipathic nature allows them to perform the following crucial functions:Emulsification of lipid aggregates increases the surface area of fat and makes it easier for lipases to digest it.Lipid solubilization and transport: solubilizes lipids by creating micelles, which are lipid clumps that float in water.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 125
Incorrect
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A 56-year-old man presents with pneumonia 8 days after being admitted for an open fracture of his tibia and fibula. Upon history taking and observation, it was established that he has no known drug allergies, has coarse left basal crackles and evidence of consolidation in the left lower lobe based on his chest X-ray.Which of the following antibacterial agents would be the most appropriate to prescribe according to the latest NICE guidelines?
Your Answer:
Correct Answer: Ciprofloxacin
Explanation:The current NICE guidelines for hospital-acquired pneumonia are as follow:- First-choice oral antibiotic if non‑severe symptoms or signs, and not at higher risk of resistance (guided by microbiological results when available): co-amoxiclav- Alternative oral antibiotics if non‑severe symptoms or signs, and not at higher risk of resistance, for penicillin allergy or if co‑amoxiclav unsuitable (based on specialist microbiological advice and local resistance data): doxycycline, cefalexin, co-trimoxazole, levofloxacin- First-choice intravenous antibiotics if severe symptoms or signs (for example, symptoms or signs of sepsis) or at higher risk of resistance (based on specialist microbiological advice and local resistance data): piperacillin with tazobactam, ceftazidime, ceftriaxone, cefuroxime, meropenem, ceftazidime with avibactam, levofloxacin- Antibiotics to be added if suspected or confirmed methicillin-resistant Staphylococcus aureus infection (dual therapy with a first-choice intravenous antibiotic): vancomycin, teicoplanin, linezolid
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 126
Incorrect
-
Which of the following body location is the appropriate site to apply pressure when performing a carotid sinus massage?
Your Answer:
Correct Answer: Thyroid cartilage
Explanation:The common carotid artery runs through the neck and divides into internal and external carotid arteries on both sides near the upper thyroid cartilage. In emergency situations, carotid sinus massage is also used to diagnose or treat paroxysmal supraventricular tachycardia. During the procedure, to maximize access to the carotid artery, the patient is put in a supine position with the neck extended (i.e. elevating the chin away from the chest). The carotid sinus is normally positioned inferior to the angle of the jaw, near the arterial impulse, at the level of the thyroid cartilage. For 5 to 10 seconds, pressure is administered to one carotid sinus. Although pulsatile pressure applied in a vigorous circular motion may be more effective, continuous pressure is preferred since it is more reproducible. If the predicted reaction is not obtained, the operation is repeated on the opposite side after a one- to two-minute wait.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 127
Incorrect
-
A young farmer who is caught under farm machinery and suffering from a major crush injury is taken to the emergency department and requires a quick induction sequence. In this type of injury, which of the following anaesthetic medicines should be avoided?
Your Answer:
Correct Answer: Suxamethonium
Explanation:Suxamethonium is a neuromuscular blocker. It is contraindicated in patients who have experienced massive trauma, hyperkalemic, or burn injuries.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 128
Incorrect
-
A 37-year-old man presents with breathlessness on exertion and dry cough, fever for the past 2 days and bilateral pleuritic chest pain. He had been diagnosed with HIV and commenced on HAART but due to side effects, his compliance has been poor over the last few months.On examination you note scattered crackles and wheeze bilaterally, cervical and inguinal lymphadenopathy, and oral thrush. At rest his oxygen saturation is 97% but this drops to 87% on walking. There is perihilar fluffy shadowing seen on his chest X-ray.Which of these organisms is the most likely causative organism?
Your Answer:
Correct Answer: Pneumocystis jirovecii
Explanation:All of the organisms listed above can cause pneumonia in immunocompromised individuals but the most likely cause in this patient is Pneumocystis jirovecii.It is a leading AIDS-defining infection in HIV-infected individuals and causes opportunistic infection in immunocompromised individuals. HIV patients with a CD4 count less than 200 cells/mm3 are more prone.The clinical features of pneumonia caused by Pneumocystis jirovecii are:Fever, chest pain, cough (usually non-productive), exertional dyspnoea, tachypnoea, crackles and wheeze.Desaturation on exertion is a very sensitive sign of Pneumocystis jirovecii pneumonia.Chest X-ray can show perihilar fluffy shadowing (as is seen in this case) but can also be normal.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 129
Incorrect
-
What type of visual field defect are you likely to see in a lesion of the visual cortex:
Your Answer:
Correct Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:A lesion of the visual cortex will result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 130
Incorrect
-
An elderly patient presents to ED following a fall after feeling light headed when standing up. You are reviewing his medication and note that he is taking a high dose of furosemide. Loop diuretics act primarily at which of the following sites in the nephron:
Your Answer:
Correct Answer: Thick ascending limb
Explanation:Loop diuretics inhibit the Na+/K+/2Cl- symporter on the luminal membrane in the thick ascending limb of the loop of Henle, thus preventing reabsorption of NaCl and water. These agents reduce reabsorption of Cl- and Na+ and increase Ca2+ excretion and loss of K+ and Mg2+.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 131
Incorrect
-
A blood culture was performed from a sample taken from a patient. It was noted that a Gram-negative coccus organism was grown.Among the following microorganisms, which is considered an example of a Gram-negative coccus?
Your Answer:
Correct Answer: Neisseria menigitidis
Explanation:Staphylococcus aureus = Gram-positive coccusBacillus cereus = Gram-positive bacillusCampylobacter jejuni = Gram-negative bacillusEscherichia coli = Gram-negative bacillusIn Gram staining, crystal violet is a purple stain that is used to stain the bacteria first. The stained bacteria are decolorized and then stained with a red stain, which is safranin. Bacteria with thick cell walls keep the purple stain and are called Gram-positive. Thin-walled bacteria are easily decolorized so when safranin, the red stain, is placed on the organisms, they become red or Gram-negative. Neisseria species appear as Gram-negative diplococci because they form pairs and their adjacent ends are flattened that is why they are also described to have a coffee-bean or kidney-bean shape.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 132
Incorrect
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An elderly man with chronic heart and lung disease develops Legionnaires' disease. Which of the following clinical features is NOT typical of Legionnaires' disease:
Your Answer:
Correct Answer: Haemoptysis
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 133
Incorrect
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During bedside rounds, an 82-year old female in the Medicine Ward complains of pain and tingling of all fingers of the right hand. The attending physician is considering carpal tunnel syndrome.Which of the following is expected to undergo atrophy in carpal tunnel syndrome?
Your Answer:
Correct Answer: The thenar eminence
Explanation:Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression of the median nerve as it travels through the wrist’s carpal tunnel. It is the most common nerve entrapment neuropathy, accounting for 90% of all neuropathies. Early symptoms of carpal tunnel syndrome include pain, numbness, and paraesthesia’s. These symptoms typically present, with some variability, in the thumb, index finger, middle finger, and the radial half (thumb side) of the ring finger. Pain also can radiate up the affected arm. With further progression, hand weakness, decreased fine motor coordination, clumsiness, and thenar atrophy can occur.The muscles innervated by the median nerve can be remembered using the mnemonic ‘LOAF’:L– lateral two lumbricalsO– Opponens pollicisA– Abductor pollicisF– Flexor pollicis brevisIn the early presentation of the disease, symptoms most often present at night when lying down and are relieved during the day. With further progression of the disease, symptoms will also be present during the day, especially with certain repetitive activities, such as when drawing, typing, or playing video games. In more advanced disease, symptoms can be constant.Typical occupations of patients with carpal tunnel syndrome include those who use computers for extended periods of time, those who use equipment that has vibration such as construction workers, and any other occupation requiring frequent, repetitive movement.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 134
Incorrect
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The 'pump handle' movement of the thoracic wall describes which of the following movements:
Your Answer:
Correct Answer: The anterior ends of the ribs moving upwards and forwards
Explanation:Because the anterior ends of the ribs are inferior to the posterior ends, when the ribs are elevated, the anterior end moves upwards and forwards, moving the sternum upwards and forwards in turn. This ‘pump handle’ upwards and forwards movement changes the anteroposterior (AP) dimension of the thorax.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 135
Incorrect
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A 49-year-old woman with haemoglobin of 6 g/dL following persistent vaginal bleeding receives blood transfusion. She developed pain and burning at her cannula site and complains of a feeling of “impending doom”, nausea, and severe back pain shortly after transfusion was started. Her temperature is 38.9ºC.What is the most appropriate treatment?
Your Answer:
Correct Answer: Stop the transfusion and administer IV fluids
Explanation:Acute haemolytic transfusion reactions present with: Feeling of ‘impending doom’ as the earliest symptom, fever and chills, pain and warmth at transfusion site, nausea and vomiting, back, joint, and chest pain. Transfusion should be stopped immediately and IV fluid (usually normal saline) administered.Supportive measures and paracetamol can be given since patient has fever but it is not the immediate first step.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 136
Incorrect
-
A 50-year-old man has recently been on antibiotics for a chest infection. He suffers from COPD and is currently on Seretide inhalers, salbutamol, and Phyllocontin continus. Since commencing the antibiotics, he has developed nausea, vomiting and abdominal pain.Which of the following antibiotics has he MOST LIKELY been on for his chest infection?
Your Answer:
Correct Answer: Erythromycin
Explanation:Phyllocontin continues contains aminophylline, a bronchodilator used in the management of asthma and COPD.The index patient is exhibiting symptoms of theophylline toxicity. This may have been triggered by the antibiotic he took. Macrolide antibiotics, like erythromycin and quinolone antibiotics, like ciprofloxacin and levofloxacin, increases the plasma concentration of theophyllines and can lead to toxicity.Factors that enhance theophylline clearance include cigarette smoking, carbamazepine, phenobarbital, phenytoin, primidone, and rifampin. Medications that inhibit clearance include ethanol, ciprofloxacin, erythromycin, verapamil, propranolol, ticlopidine, tacrine, allopurinol, and cimetidine.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 137
Incorrect
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Question 138
Incorrect
-
One of the following pathogens is a conditional pathogen:
Your Answer:
Correct Answer: Neisseria meningitidis
Explanation:Obligate pathogens include Mycobacterium TB, HIV, Treponema pallidum, and Neisseria gonorrhoeae. Neisseria meningitidis, on the other hand, is a conditional pathogen.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 139
Incorrect
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A 58-year-old man showing symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that he has a full, plethoric aspect to his face, as well as significant supraclavicular fat pads, when you examine him. His blood pressure is 158/942 mmHg, and his glucose tolerance has lately been impaired. His potassium level is 3.2 mmol/L.What is the MOST LIKELY diagnosis?
Your Answer:
Correct Answer: Cushing’s syndrome
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.Cushing’s syndrome has a wide range of clinical manifestations that are dependent on the degree of cortisol overproduction. The appearance might be vague and the diagnosis difficult to detect when cortisol levels are just somewhat elevated. On the other hand, in long-term cases of severely increased cortisol levels, the presentation might be colourful and the diagnosis simple.Cushing’s syndrome has the following clinical features:Obesity and weight growth in the true senseSupraclavicular fat pads are fat pads that are located above the clavicle.Buffalo humpFullness and plethora of the face (‘moon facies’)Muscle atrophy and weakening at the proximal levelDiabetes mellitus, also known as impaired glucose toleranceHypertensionSkin thinning and bruisingDepressionHirsutismAcneOsteoporosisAmenorrhoea or oligomenorrhoeaCortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater during the whole 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed. As a result, random cortisol testing is not an effective screening technique and is not advised.The following are the two most common first-line screening tests:Cortisol levels in the urine are measured every 24 hours.A diagnosis of Cushing’s syndrome can be made if more than two collections measure cortisol excretion more than three times the upper limit of normal.Physical stress (e.g., excessive exercise, trauma), mental stress (e.g., sadness), alcohol or drug misuse, complex diabetes, and pregnancy can all cause false positives.Renal dysfunction, inadequate collection, and cyclical Cushing’s disease can all cause false negatives.The overnight low-dose dexamethasone suppression test (LDDST) involves giving 1 mg of dexamethasone at 11 p.m. and measuring blood cortisol levels at 8 a.m. the next day.Cushing’s syndrome is diagnosed when cortisol is not suppressed to less than 50 nmol/L.It might be difficult to tell the difference between mild Cushing’s disease and normal cortisol production.False positives can occur as a result of depression, severe systemic sickness, renal failure, prolonged alcohol misuse, old age, and the use of hepatic enzyme-inducing medicines, among other things.False negatives are extremely uncommon in Cushing’s disease patients.A characteristic biochemical picture might also be helpful in confirming the diagnosis of Cushing’s syndrome. The following are the primary characteristics:HypokalaemiaAlkalosis metabolique
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 140
Incorrect
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A 63-year-old man presents with severe abdominal pain and vomiting of blood. An endoscopy was performed and a peptic ulcer was found to have eroded into an artery nearby.Which of the following most likely describes the location of the ulcer?
Your Answer:
Correct Answer: The posterior duodenum
Explanation:The most common cause of upper gastrointestinal bleeding is peptic ulcer disease, particularly gastric and duodenal ulcers. Duodenal ulcers are most commonly associated with bleeding compared with gastric ulcers. Posterior duodenal ulcers are considered to be the most likely to cause severe bleeding because of its proximity to the branches of the gastroduodenal artery (GDA).
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 141
Incorrect
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Regarding relationships between two variables, what does a negative correlation coefficient indicate:
Your Answer:
Correct Answer: The two variables are inversely related
Explanation:A negative correlation coefficient means that the two variables are inversely related e.g. socio-economic class and mortality.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 142
Incorrect
-
The primary mechanism of action of ketamine is:
Your Answer:
Correct Answer: N-methyl-D-aspartate (NMDA)-receptor antagonist
Explanation:Ketamine is a non-competitive antagonist of the calcium-ion channel in the NMDA (N-methyl-D-aspartate) receptor. It further inhibits the NMDA-receptor by binding to its phencyclidine binding site. Ketamine also acts at other receptors as an opioid receptor agonist (analgesic effects), as an muscarinic anticholinergic receptor antagonist (antimuscarinic effects) and by blocking fast sodium channels (local anaesthetic effect).Overdose may lead to panic attacks and aggressive behaviour; rarely seizures, increased ICP, and cardiac arrestVery similar in chemical makeup to PCP (phencyclidine), but it is shorter acting and less toxic
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 143
Incorrect
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A 58-year-old man with a traumatic brain injury is brought into the ER. A medical student asks you about the processes that occur in the brain following a traumatic injury.One of these best describes the central nervous systems response to injury.
Your Answer:
Correct Answer: Degeneration of the axon occurs proximally before it occurs distally
Explanation:Following neuronal injury, as seen in traumatic brain injury, the axon undergoes anterograde degeneration. Degradation starts from the cell body (proximally) and progresses distally. The axon becomes fragmented and degenerates. The brain shows no reactive changes to injury is incorrect. Following major injury such as stroke, the brain undergoes a process of liquefactive degeneration, which leaves cystic spaces within the brain.Axonal regeneration does not occur to any significant extent within the central nervous system unlike what is seen in the peripheral nervous system. Astrocytes undergo reactive gliosis, leaving behind a firm translucent tissue around sites of damage.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 144
Incorrect
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Which of the following is the correct sequential order of the phases of healing:
Your Answer:
Correct Answer: Haemostasis, inflammation, proliferation, remodelling
Explanation:Acute wound healing has four main stages: haemostasis, inflammation, proliferation and remodelling.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 145
Incorrect
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The renin-angiotensin-aldosterone system (RAAS) controls blood pressure and fluid balance.Which of the following sites produces the most angiotensinogen?
Your Answer:
Correct Answer: The liver
Explanation:Angiotensinogen is an alpha-2-globulin generated predominantly by the liver and released into the blood. Renin, which cleaves the peptide link between the leucine and valine residues on angiotensinogen, converts it to angiotensin I.Angiotensinogen levels in the blood are raised by:Corticosteroid levels have risen.Thyroid hormone levels have risen.Oestrogen levels have risen.Angiotensin II levels have risen.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 146
Incorrect
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Which of the following is NOT a typical clinical feature of diabetic ketoacidosis:
Your Answer:
Correct Answer: Cheyne–Stokes respiration
Explanation:Clinical features of DKA: Symptoms: Polyuria, polydipsia, thirst, lethargy, weight loss, nausea, vomiting, anorexia, abdominal pain, dehydration, headache, altered mental stateSigns: Dry mucous membranes, ketotic breath, tachycardia, hypotension, Kussmaul breathing, focal signs of precipitant e.g. infection
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 147
Incorrect
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Which of the following increases the tendency for oedema to occur?
Your Answer:
Correct Answer: Increased venous pressure
Explanation:When more fluid is filtered out of the capillaries than can be returned to the circulation by the lymphatics, oedema occurs. Changes that increase capillary hydrostatic pressure or decrease plasma oncotic pressure will increase filtration. Arteriolar constriction reduces hydrostatic capillary pressure and transiently increase absorption of fluid. Dehydration increases plasma protein concentration and therefore increases plasma oncotic pressure and absorption. Capillary hydrostatic pressure and filtration are increased when there is increased venous pressure.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 148
Incorrect
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A 20-year-old with type I diabetes mellitus has an episode of hypoglycaemia following inadvertent administration of too much insulin.The mechanism by which insulin causes glucose to be transported into cells is?
Your Answer:
Correct Answer: Facilitated diffusion
Explanation:The only mechanism by which insulin facilitates uptake of glucose into cells is by facilitated diffusion through a family of hexose transporters.The major transporter used for glucose uptake is GLUT4. GLUT4 is made available in the plasma membrane by the action of insulin.When insulin concentrations are low, GLUT4 transporters are present in cytoplasmic vesicles, where they are cannot be used for transporting glucose.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 149
Incorrect
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For which of the following is micelle formation necessary to facilitate intestinal absorption?
Your Answer:
Correct Answer: Vitamin D
Explanation:The arrangement of micelles is such that hydrophobic lipid molecules lie in the centre, surrounded by hydrophilic bile acids that are arranged in the outer region. This arrangement allows the entry of micelles into the aqueous layers surrounding the microvilli. As a result, the products of fat digestion (fatty acids and monoglycerides), cholesterol and fat-soluble vitamins (such as vitamin D) can then diffuse passively into the enterocytes. The bile salts are left within the lumen of the gut where they are reabsorbed from the ileum or excreted in faeces.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 150
Incorrect
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Which of the following virulence factors of E. coli is important for attachment to host epithelial cells in the pathogenesis of urinary tract infections:
Your Answer:
Correct Answer: Pili
Explanation:Escherichia coli is the most common cause of urinary tract infection. Uropathic strains are characterised by pili with adhesion proteins that bind to specific receptors on the urinary tract epithelium. The motility of E. coli aids its ability to ascend the urethra into the bladder or ascend the ureter into the kidney.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 151
Incorrect
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You review an 83-year-old woman who has stage 5 chronic kidney disease. She has a number of electrolyte problems.Which ONE of the following decreases the renal reabsorption of phosphate?
Your Answer:
Correct Answer: Parathyroid hormone
Explanation:Parathyroid hormone (PTH) is a polypeptide containing 84 amino acids. It is the principal controller of free calcium in the body.The main actions of parathyroid hormone are:Increases plasma calcium concentrationDecreases plasma phosphate concentrationIncreases osteoclastic activity (increasing calcium and phosphate resorption from bone)Increases renal tubular reabsorption of calciumDecreases renal phosphate reabsorptionIncreases renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol (via stimulation of 1-alpha hydroxylase)Increases calcium and phosphate absorption in the small intestine (indirectly via increased 1,25-dihydroxycholecalciferol)
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 152
Incorrect
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The Treppe effect refers to an increase in contractility secondary to an increase in heart rate.
Explanation:Although Ca2+entry during the action potential (AP) is essential for contraction, it only accounts for about 25% of the rise in intracellular Ca2+. The rest is released from Ca2+stores in the sarcoplasmic reticulum (SR). In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane. When more action potentials occur per unit time, more Ca2+enters the cell during the AP plateau, more Ca2+is stored in the SR, more Ca2+is released from the SR and thus more Ca2+is left inside the cell and greater tension is produced during contraction. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Cardiac glycosides such as digoxin have a positive inotropic effect.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 153
Incorrect
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At rest, skeletal muscle accounts for between 15-20% of cardiac output and accounts for around 50% of body weight. This can increase to nearly 80% of cardiac output during exercise. Skeletal muscle circulation is highly controlled and has a number of specialized adaptations as a result of this high degree of disparity during exercise, in combination with the diversity in the size of skeletal muscle around the body.What is the primary mechanism for boosting skeletal muscle blood flow during exercise?
Your Answer:
Correct Answer: Metabolic hyperaemia
Explanation:In skeletal muscle, blood flow is closely related to metabolic rate. Due to the contraction of precapillary sphincters, most capillaries are blocked off from the rest of the circulation at rest and are not perfused. This causes an increase in vascular tone and vessel constriction. As metabolic activity rises, this develops redundancy in the system, allowing it to cope with greater demand. During exercise, metabolic hyperaemia, which is induced by the release of K+, CO2, and adenosine, recruits capillaries. Sympathetic vasoconstriction in the active muscles is overridden by this. Simultaneously, blood flow in non-working muscles is restricted, preserving cardiac output. During exercise, muscle contractions pump blood through the venous system, raising the pressure differential between arterioles and venules and boosting blood flow via capillaries.Capillary angiogenesis is evident when muscles are used repeatedly (e.g. endurance training). It is a long-term effect, not a quick fix for increased blood flow.The local partial pressure of alveolar oxygen is the primary intrinsic control of pulmonary blood flow (pAO2). Low pAO2 promotes arteriole vasoconstriction and vice versa. The hypoxic pulmonary vasoconstriction (HPV) reflex allows blood flow to be diverted away from poorly ventilated alveoli and towards well-ventilated alveoli in order to maximize gaseous exchange.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 154
Incorrect
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A 22-year-old woman comes in with an asthmatic flare. Salbutamol is her only regular medication.What is the dosage per inhalation of a standard metered dose salbutamol inhaler?
Your Answer:
Correct Answer: 100 micrograms
Explanation:The dose of a conventional metered dose inhaler is 100 micrograms per metered inhalation.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 155
Incorrect
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A newborn baby girl is delivered vaginally to a 19-year old female, however with complications due to cephalopelvic disproportion. Upon examination by the attending paediatrician, there is a notable 'claw hand' deformity of the left, and sensory loss of the ulnar aspect of the left distal upper extremity.What is the most probable diagnosis of the case above?
Your Answer:
Correct Answer: Klumpke’s palsy
Explanation:Klumpke palsy, named after Augusta Dejerine-Klumpke, is a neuropathy involving the lower brachial plexus. In contrast, the more common Erb–Duchenne palsy involves the more cephalic portion of the brachial plexus C5 to C6. The brachial plexus is a bundle of individual nerves that exit between the anterior and middle scalene muscles in the anterior lateral and basal portion of the neck. Although the most common anatomical presentation of the brachial plexus is between the anterior and middle scalene, there are variations, with the most common being penetration of the anterior scalene. The main mechanism of injury to the lower brachial plexus is hyper-abduction traction, and depending on the intensity, it will lead to signs and symptoms consistent with a neurological insult.The most common aetiology resulting in Klumpke palsy is a hyper-abduction trauma to the arm that has enough intensity to traction the lower brachial plexus. Trauma during birth can cause brachial plexus injuries, but again hyper-abduction and traction forces to the upper extremity are usually present.The history presented by the patient usually depicts a long axis hyper-abduction traction injury with high amplitude and velocity. The typical patient presentation is a decrease of sensation along the medial aspect of the distal upper extremity along the C8 and T1 dermatome. The patient might also present myotome findings that can range from decreasing muscular strength to muscular atrophy and positional deformity. For example, if the neurological damage has led to muscular atrophy and tightening, the patient may present with a claw hand. This deformity presents a finger and wrist flexion. The patient may also describe the severe pain that starts at the neck and travels down the medial portion of the arm. One other sign of a lower brachial plexus injury is Horner syndrome; because of its approximation to the T1 nerve root, it may damage the cephalic sympathetic chain. If this happens, the patient will develop ipsilateral ptosis, anhidrosis, and miosis.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 156
Incorrect
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A 34-year-old man presents with loss of vision in his left eye due to an episode of optic neuritis. Upon history taking, it was noted that he has a history of multiple sclerosis. Which of the following anatomical points in the visual pathway has the lesion occurred?
Your Answer:
Correct Answer: Optic nerve
Explanation:A lesion in the optic nerve causes ipsilateral monocular visual loss.Optic neuritis is an inflammatory demyelination of the optic nerve that is highly associated with multiple sclerosis. The two most common symptoms of optic neuritis are vision loss and eye pain.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 157
Incorrect
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Regarding loop diuretics, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The risk of hypokalaemia is greater with loop diuretics than with an equipotent dose of a thiazide diuretic.
Explanation:Hypokalaemia can occur with both thiazide and loop diuretics. The risk of hypokalaemia depends on the duration of action as well as the potency and is thus greater with thiazides than with an equipotent dose of a loop diuretic. Hypokalaemia is dangerous in severe cardiovascular disease and in patients also being treated with cardiac glycosides. Often the use of potassium-sparing diuretics avoids the need to take potassium supplements. In hepatic failure, hypokalaemia caused by diuretics can precipitate encephalopathy, particularly in alcoholic cirrhosis.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 158
Incorrect
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Which of the following features of cell damage tends to be reversible:
Your Answer:
Correct Answer: Swelling of endoplasmic reticulum and some mitochondria
Explanation:Features of cell damage that tend to be reversible include: swelling of endoplasmic reticulum and some mitochondrialoss of ribosomescell stress responseFeatures of cell damage that tend to be irreversible include: loss of nucleolus, no ribosomes, swelling of all mitochondria, nuclear condensation, membrane blebs and holes, lysosome rupture, fragmentation of all inner membranes, nuclear breakup
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 159
Incorrect
-
Which of the following best describes a natural killer cell:
Your Answer:
Correct Answer: A large granular lymphocyte that kills by inducing target cell apoptosis.
Explanation:Natural killer (NK) cells are cytotoxic CD8 positive cells that lack the T-cell receptor. They are large cells with cytoplasmic granules. NK cells are designed to kill target cells that have a low level of expression of HLA class I molecules, such as may occur during viral infection or on a malignant cell. NK cells do this by displaying several receptors for HLA molecules on their surface. When HLA is expressed on the target cell these deliver an inhibitory signal into the NK cell. When HLA molecules are absent on the target cell this inhibitory signal is lost and the NK cell can then kill its target. In addition, NK cells display antibody-dependent cell-mediated cytotoxicity. In this, antibody binds to antigen on the surface of the target cell and then NK cells bind to the Fc portion of the bound antibody and kill the target cell.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 160
Incorrect
-
Gentamicin is contraindicated in which of the following:
Your Answer:
Correct Answer: Myasthenia gravis
Explanation:Gentamicin is the aminoglycoside of choice in the UK and is used widely for the treatment of serious infections. It has a broad spectrum but is inactive against anaerobes and has poor activity against haemolytic streptococci and pneumococci. When used for the blind therapy of undiagnosed serious infections it is usually given in conjunction with a penicillin or metronidazole (or both). The main toxic effects are nephrotoxicity and ototoxicity due to damage to the vestibulocochlear nerve (CN VIII).Gentamicin is contraindicated in myasthenia gravis and should be used with caution in renal disease which may result in accumulation and a greater risk of toxic side effects.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 161
Incorrect
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A patient has an elevated potassium level of 6.7 mmol/L. All of the following conditions may cause elevated potassium levels, except for which one?
Your Answer:
Correct Answer: Bartter’s syndrome
Explanation:Bartter’s syndrome is an autosomal recessive renal tubular disorder characterized by hypokalaemia, hypochloraemia, metabolic alkalosis, and hyperreninemia with normal blood pressure. The underlying kidney abnormality results in excessive urinary losses of sodium, chloride, and potassium. Bartter’s syndrome does not cause an elevated potassium level, but instead causes a decrease in its concentration (hypokalaemia). The other choices are causes of hyperkalaemia or elevated potassium levels. Renal failure, Addison’s disease (adrenal insufficiency), congenital adrenal hyperplasia, renal tubular acidosis (type 4), rhabdomyolysis, burns and trauma, tumour syndrome, and acidosis are non-drug causes of hyperkalaemia. On the other hand, drugs that can cause hyperkalaemia include ACE inhibitors, angiotensin receptor blockers, NSAIDs, beta-blockers, digoxin, and suxamethonium.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 162
Incorrect
-
A 78-year-old male presents to the Orthopaedic clinic with lower back pain for the past month. His past medical history reveals a history of cancer. After examination, you diagnose Metastatic Spinal Cord Compression (MSCC). Which one of the following cancers is this patient most likely to have had?
Your Answer:
Correct Answer: Prostate cancer
Explanation:Compression of the thecal sac causes metastatic Spinal Cord Compression (MSCC) due to a Metastatic tumour and its components. It can cause symptoms of limb weakness, sensory disturbances and back pain depending on the extent and level of Compression. The most common source of a tumour causing MSCC is a prostate carcinoma that metastasized to the spinal cord via the vertebral venous plexus.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 163
Incorrect
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Which of the following statements is correct regarding the lymphatic system?
Your Answer:
Correct Answer: Lymphatic vessels contain both smooth muscle and unidirectional valves.
Explanation:Fluid filtration out of the capillaries is usually slightly greater than fluid absorption into the capillaries. About 8 L of fluid per day is filtered by the microcirculation and returns to the circulation by the lymphatic system. Lymphatic capillaries drain into collecting lymphatics, then into larger lymphatic vessels. Both of these containing smooth muscle and unidirectional valves. From this point, lymph is propelled by smooth muscle constriction and vessel compression by body movements into afferent lymphatics. It then goes to the lymph nodes where phagocytes remove bacteria and foreign materials. It is here that most fluid is reabsorbed by capillaries, and the remainder returns to the subclavian veins via efferent lymphatics and the thoracic duct. The lymphatic system has a major role to play in the body’s immune defence and also has a very important role in the absorption and transportation of fats.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 164
Incorrect
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You are reviewing a patient following a fall from a horse. You suspect they may have an Erb's palsy as a result of a brachial plexus injury. Regarding Erb's palsy, which one of the following statements is CORRECT:
Your Answer:
Correct Answer: Erb's palsy may result in loss of sensation of the regimental badge area.
Explanation:Erb’s palsy is caused by damage to the C5 and C6 nerve roots and thus primarily involves the musculocutaneous, suprascapular and axillary nerves. It commonly result from an excessive increase in the angle between the neck and the shoulder e.g. a person thrown from a motorbike or horseback or during a difficult birth. There is loss or weakness of abduction, lateral rotation and flexion of the arm and flexion and supination of the forearm and loss of sensation on the lateral arm. A characteristic ‘Waiter’s tip’ deformity may be present where the limb hangs limply by the side, medially rotated by the unopposed action of pectoralis major with the forearm pronated due to paralysis of the biceps brachii.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 165
Incorrect
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A 60-year-old man presents with marked breathlessness. He has with a history of ischaemic heart disease. On examination, there is coarse bibasal crackles, marked peripheral oedema and chest X-ray taken is consistent with severe pulmonary oedema. RR is 28 per minute. Which receptor is responsible for detecting pulmonary oedema and the subsequent increase in respiratory rate?
Your Answer:
Correct Answer: Juxtacapillary receptors
Explanation:Pulmonary oedema causes stimulation of the Juxtacapillary receptors (J receptors) leading to a reflex increase in breathing rate. These receptors are also thought to be involved in the sensation of dyspnoea. The J receptors are sensory cells and are located within the alveolar walls in juxtaposition to the pulmonary capillaries.Aortic baroreceptor are involved in detecting blood pressureCentral chemoreceptors detect changes in CO2 and hydrogen ion within the brainAtrial volume receptors regulate plasma volume
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 166
Incorrect
-
A 58-year-old man with a long history of depression presents with a deliberate overdose of verapamil tablets, which he is prescribed for a heart condition.What is verapamil's mechanism of action?
Your Answer:
Correct Answer: L-type calcium channel blockade
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.The standard ABC approach should be used to resuscitate all patients as needed. If life-threatening toxicity is expected, intubation and ventilation should be considered early on. If hypotension and shock are developing, early invasive blood pressure monitoring is recommended.The primary goal of specific treatments is to support the cardiovascular system. These are some of them:1. Fluid resuscitation: Give up to 20 mL of crystalloid per kilogramme of body weight.2. Calcium supplementationThis can be a good way to raise blood pressure and heart rate temporarily.via central venous access: 10% calcium gluconate 60 mL IV (0.6-1.0 mL/kg in children) or 10% calcium chloride 20 mL IV (0.2 mL/kg in children)Boluses can be given up to three times in a row.To keep serum calcium >2.0 mEq/L, consider a calcium infusion.3. Atropine: 0.6 mg every 2 minutes up to 1.8 mg is an option, but it is often ineffective.4. HIET (high-dose insulin-euglycemic therapy):The role of HIET in the step-by-step management of cardiovascular toxicity has changed.5. Vasoactive infusions:This was once thought to be a last-ditch measure, but it is now widely recommended that it be used sooner rather than later.Insulin with a short half-life 50 mL of 50 percent glucose IV bolus plus 1 U/kg bolus (unless marked hyperglycaemia present)Short-acting insulin/dextrose infusions should be continued.Glucose should be checked every 20 minutes for the first hour, then hourly after that.Regularly check potassium levels and replace if they fall below 2.5 mmol/L.Titrate catecholamines to effect (inotropy and chronotropy); options include dopamine, adrenaline, and/or noradrenaline infusions.6. Sodium bicarbonate: Use 50-100 mEq sodium bicarbonate (0.5-1.0 mEq/kg in children) in cases where a severe metabolic acidosis develops.7. Cardiac pacing: It can be difficult to achieve electrical capture, and it may not improve overall perfusion.Bypass AV blockade with ventricular pacing, which is usually done at a rate of less than 60 beats per minute.8. Intralipid transportCalcium channel blockers are lipid-soluble agents, so they should be used in refractory cases.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 167
Incorrect
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Which of the following could denote a diagnosis of acquired immunodeficiency syndrome (AIDS) in a patient infected with HIV:
Your Answer:
Correct Answer: CD4 count < 200 cells/uL
Explanation:A diagnosis of AIDS can be made in a patient infected with HIV if the patient has a CD4 count < 200 cells/uL, or an AIDS-defining illness. Antiretroviral treatment should be considered in patients with CD4 counts < 350 cells/uL. Oral candidiasis is not an AIDS defining illness – candidiasis of the bronchi, trachea or lungs or of the oesophagus is an AIDS defining illness. A positive p24 antigen test seen in early HIV infection and does not indicate the development of AIDS.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 168
Incorrect
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Which of the following movements is controlled by the pectoralis major muscle?
Your Answer:
Correct Answer: Flexion, adduction and medial rotation of the humerus
Explanation:The pectoralis major is a muscle that runs across the top of the chest and connects to a ridge on the back of the humerus (the bone of the upper arm). Adduction, or lowering, of the arm (opposed to the deltoideus muscle) and rotation of the arm forward around the axis of the body are two of its main functions.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 169
Incorrect
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A 69-year-old man with a history of chronic anaemia is transfused. He takes bisoprolol and furosemide for his cardiac failure, and his most recent BNP was 123 pmol/l. He developed shortness of breath and his pre-existing peripheral oedema became worse 5 hours after transfusion was commenced. His BP rises to 170/105 mmHg and a repeat measurement of his BNP is 192 pmol/l.What is the most likely transfusion reaction to have occurred?
Your Answer:
Correct Answer: TACO
Explanation:Transfusion-associated circulatory overload (TACO) presents as acute or worsening respiratory distress within 6 hours of transfusion of a large volume of blood. It is common in patients with diminished cardiac reserve or chronic anaemia. Elderly patients, infants and severely anaemic patients are particularly susceptible. Typical clinical features of TACO include: Acute respiratory distress, Tachycardia, Hypertension, Acute/worsening pulmonary oedema on chest X-ray. The BNP is usually raised to at least 1.5 times the pre-transfusion baseline.Febrile transfusion reaction presents with a 1 degree rise in temperature from baseline during transfusion. Patient may have chills and malaise. It is the most common transfusion reaction (1 in 8 transfusions) and is usually caused by cytokines released from leukocytes in transfused red cell or platelet components. TRALI (Transfusion Related Acute Lung Injury) is a clinical syndrome with abrupt onset of non-cardiogenic pulmonary oedema within 6 hours of transfusion not explained by another risk factor. Associated with the presence of antibodies in the donor blood to recipient leukocyte antigens. patients present with dyspnoea, hypertension, hypotension, acute leukopenia. Graft versus host disease(GVHD) is an immune mediated condition that arises from a complex interaction between donor and recipients adaptive immunity. It presents as dermatitis, hepatitis and enteritis developing within 100 days after stem cell or bone marrow transplant.Acute haemolytic reaction aka immediate haemolytic transfusion reaction presents with fever, chills, pain at transfusion site, nausea, vomiting, dark urine and feeling of ‘impending doom’. Often, it occurs due to ABO incompatibility.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 170
Incorrect
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A 14-year-old female is brought to the Emergency Room by her mother after a fall from a tree in which she injured her elbow. An elbow fracture is suspected based on the examination findings, and she is given Entonox for analgesia as her elbow is set in a cast. Which one of the following statements regarding this drug is true?
Your Answer:
Correct Answer: It can cause inhibition of vitamin B12 synthesis
Explanation:Entonox is a mixture of 50% Oxygen and 50% nitrous oxide and is given in an inhaled form as a quick form of analgesia. Entonox causes non-competitive inhibition of NMDA (N-methyl-D-aspartate) receptors, which are a subtype of the glutamate receptor. It is stored in blue and white cylinders and administered via a pressure regulator and demand valve. The administration of this medicine reduces pain and anxiety in paediatric and dental procedures ands during labour. Effects are apparent after 20 seconds, and peak action occurs after 3 to 5 minutes as it is a drug with a rapid onset and the patient will also recover rapidly from its effects. Entonox is widely used as it does not accumulate in the body and does not cause many side effects. However, a notable side effect is the inhibition of Vitamin B12 synthesis.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 171
Incorrect
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The extensor digitorum longus is supplied by which nerve?
Your Answer:
Correct Answer: Deep peroneal nerve
Explanation:The extensor digitorum longus is innervated by the deep fibular nerve (L5, S1), a branch of the common fibular nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 172
Incorrect
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A 24 year old male sustained an insect bite and presents with a red hot arm and acute cellulitis has been diagnosed. The predominant white cells in this type of acute inflammation are:
Your Answer:
Correct Answer: Neutrophils
Explanation:Neutrophil polymorphs are the predominant type of white cells in an acute reaction. They pass between endothelial cell junctions to invade damaged tissue so that the effects of injury can be combated. Extravasation occurs with the movement of leukocytes out of the vessel lumen, and is achieved in five phases which are margination, ‘rolling’, adhesion, transmigration and chemotaxis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 173
Incorrect
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What is the effect of a positive inotrope on the Starling curve:
Your Answer:
Correct Answer: Shifts the curve upwards
Explanation:Contractility (inotropy) is the intrinsic ability of cardiac muscle to develop force at a given muscle length. It is determined by the intracellular [Ca2+] and can be estimated by the ejection fraction. Increases in contractility cause an increase in stroke volume/cardiac output for any level of right atrial pressure or end-diastolic volume, and hence shift the Starling curve upwards. Decreases in contractility cause a decrease in stroke volume/cardiac output for any level of right atrial pressure or end-diastolic volume and hence shift the Starling curve downwards.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 174
Incorrect
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You are reviewing a patient in the Emergency Department brought in by the ambulance team from a burning building. After examination, you decide to intubate the patient due to laryngeal oedema. The induction agent you are planning to use is propofol. Which one of the following statements about this medicine is TRUE?
Your Answer:
Correct Answer: It decreases cardiac output by approximately 20%
Explanation:Propofol is a short-acting anaesthetic that is thought to work by potentiating GABA and glycine. It induces anterograde amnesia and anaesthetic effects and is used to induce anaesthesia, outpatient surgeries and preoperative sedation. The dose for induction of anaesthesia is 1.5-2.5mg/kg. The dose for maintenance of anaesthesia is 4-12 mg/kg/hour. Following intravenous injection, propofol acts within 30 seconds and its duration of action is 5-10 minutes.Propofol produces a 15-25% decrease in blood pressure and systemic vascular resistance without a compensatory increase in heart rate. It is negatively inotropic and decreases cardiac output by approximately 20%.The main side effects of propofol are:Pain on injection (in up to 30%)HypotensionTransient apnoeaHyperventilationCoughing and hiccoughHeadacheThrombosis and phlebitis
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 175
Incorrect
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A patient presents with an acute severe asthma attack. Following a poor response to his initial salbutamol nebuliser, you administer a further nebuliser that this time also contains ipratropium bromide.After what time period would you expect the maximum effect of the ipratropium bromide to occur? Select ONE answer only.
Your Answer:
Correct Answer: 30 -60 minutes
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma)
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 176
Incorrect
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A 45-old woman is on several medications and being treated for epilepsy and bipolar disorder. In the ward rounds, you are asked to examine her in detail and discover she has a noticeable tremor. You believe that one of her medications may be responsible for this new onset tremor. Which of the following medications is least likely to be responsible for this tremor?
Your Answer:
Correct Answer: Carbamazepine
Explanation:The only medication that does not commonly cause tremors is carbamazepine.The other drugs present with the following types of tremors as a side effect to their usage:1. Sodium valproate – Postural tremor is most common, but a resting tremor can also occur. Approximately 25% of patients taking sodium valproate are found to develop a tremor within 12 months of starting therapy.2. Lithium – fine hand tremor is very commonly seen and reported in as many as 50% of patients during the first week of therapy. The tremor tends to reduce with time and is only present in around 5% of patients taking the medication two years or longer.3. Atypical antipsychotics, such as olanzapine and quetiapine – tremor and limb shakiness.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 177
Incorrect
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A 30-year-old man suffers from an open fracture of his forearm. As a consequence of his injury, the nerve that innervates the pronator quadratus muscle was severed. Which of the following statements regarding the pronator quadratus muscle is considered correct?
Your Answer:
Correct Answer: Its deep fibres bind the radius and ulna together
Explanation:Pronator quadratus is a deep-seated, short, flat, and quadrilateral muscle with fibres running in a parallel direction. It arises from the oblique ridge on the anterior surface of the distal fourth of the Ulna. It is inserted in lateral border and anterior surface of the distal fourth of the radius. It is innervated by the anterior interosseous nerve, a branch of the median nerve (C8-T1). It is vascularized by the anterior interosseous artery.The action of the pronator quadratus muscle along with the pronator teres result in the pronation of the radioulnar joint. Contraction of this muscle pulls the distal end of the radius over the ulna, resulting in the pronation of the radioulnar joint
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 178
Incorrect
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Which of the following statements accurately describes the flexor digitorum superficialis muscle?
Your Answer:
Correct Answer: It flexes the middle phalanges of the medial four fingers at the proximal interphalangeal joints
Explanation:Flexor digitorum superficialis is the largest muscle of the anterior compartment of the forearm. It belongs to the superficial flexors of the forearm, together with pronator teres, flexor carpi radialis, flexor carpi ulnaris and palmaris longus. Some sources alternatively classify this muscle as an independent middle/intermediate layer of the anterior forearm, found between the superficial and deep groups.Flexor digitorum superficialis is innervated by muscular branches of the median nerve, derived from roots C8 and T1 that arises from the medial and lateral cords of the brachial plexus. The skin that overlies the muscle is supplied by roots C6-8 and T1.The primary arterial blood supply to the flexor digitorum superficialis is derived from the ulnar artery and its anterior recurrent branch. In addition to branches of the ulnar artery, the anterior and lateral surfaces of the muscle are supplied by branches of the radial artery; and its posterior surface also receives branches from the median artery.The main function of flexor digitorum superficialis is flexion of the digits 2-5 at the proximal interphalangeal and metacarpophalangeal joints. Unlike the flexor digitorum profundus, flexor digitorum superficialis has independent muscle slips for all four digits. This allows it to flex the digits individually at their proximal interphalangeal joints. In addition, flexor digitorum superficialis aids the aids flexion of the wrist.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 179
Incorrect
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Which of the following study designs is considered the most appropriate to safely determine whether an association exists between a well-established, commonly used, anti-hypertensive medication and causing type II diabetes mellitus?
Your Answer:
Correct Answer: A meta-analysis
Explanation:Evidence-based medicine may be defined as the systematic, quantitative, preferentially experimental approach to obtaining and using medical information. Therefore, meta-analysis, a statistical procedure that integrates the results of several independent studies, plays a central role in evidence-based medicine.Meta-analysis is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 180
Incorrect
-
A young 20-year-old boy is a known case of type I diabetes mellitus. Today, he presents with polyuria, polydipsia, and abdominal pain in the emergency department. His blood sugar is drawn, which is markedly elevated to 7 mmol/L. Quick ABGs are drawn, which show metabolic acidosis. You diagnose the patient to be suffering from diabetic ketoacidosis (DKA) and immediately commence its treatment protocol in which insulin is also administered. Out of the following, which parameter is MOST likely to change due to initiating insulin?
Your Answer:
Correct Answer: Potassium
Explanation:Diabetes ketoacidosis is an acute complication of diabetes mellitus. Insulin is administered to achieve euglycemia, and crystalloids or colloidal solution is administered to achieve euvolemia and euelectrolytaemia. Potassium levels severely fluctuate during the treatment of DKA, hypokalaemia being more common. Insulin promotes the cell to take up potassium from the extracellular space via increased sodium-potassium pump activity. It is important to monitor potassium levels during the treatment of DKA regularly. It is widely suggested that the normal saline shall be used for initial resuscitation, and once the potassium level is retrieved, the patient can be started on potassium replacement should the serum potassium level be between 3.3 and 4.5 mmol/L If potassium levels fall below 3.3 mmol/l, insulin administration may need to be interrupted to correct the hypokalaemia.
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This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 181
Incorrect
-
A patient with a wound infection on his right leg has reddening and oedema of the surrounding muscles. His condition has worsened considerably over the past few hours with the area now appearing blackened. There is also palpable crepitus under the skin. You suspect gas gangrene.Which statement about Clostridium perfringens is true?
Your Answer:
Correct Answer: Gas gangrene is caused by the release of an alpha-toxin
Explanation:Clostridium perfringens, a Gram-positive, anaerobic, spore forming rod-shaped, pathogenic bacterium is the most commonly associated with gas gangrene (85-90% of cases), although other species can also be implicated. Clostridium perfringens is capsulate and produces a range of toxins. Alpha-toxin is the most important and is the cause of gas gangrene.Gas gangrene develops when a devitalized wound becomes infected with Clostridium perfringens spores from the environment. The spores germinate and multiplies in the ischaemic conditions, releasing toxins, which further damage tissues.Usually, the clinical features of gas gangrene appear within 24 hours of injury.Clostridium perfringens spores are not destroyed by cooking. During slow cooling and unrefrigerated storage, they germinate to form vegetative cells.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 182
Incorrect
-
A newborn baby is born by vaginal delivery to a mother who has a Chlamydia infection and who is started on treatment after the delivery. The neonate subsequently develops an infection also.Which one of these is the most common neonatal manifestation of Chlamydia trachomatis infection?
Your Answer:
Correct Answer: Conjunctivitis
Explanation:Conjunctivitis is the most common neonatal manifestation of Chlamydia trachomatis infection. The second commonest neonatal manifestation is pneumoniaOphthalmia neonatorum refers to any conjunctivitis in the newborn period, irrespective of causative organism. Presently, chlamydia is the single most common cause, accounting for up to 40% of cases. Ophthalmia neonatorum caused by chlamydia typically presents 5 to 14 days after birth with unilateral or bilateral watery discharge that progressively becomes more copious and purulent. There is no associated risk of ulceration and perforation, and the eyes are less inflamed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 183
Incorrect
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A blood test of a 7-year-old child with a 6-day history of bloody diarrhoea reveals a low platelet count, anaemia, and impaired kidney function. What bacteria is suspected of causing such a condition?
Your Answer:
Correct Answer: Escherichia coli
Explanation:Escherichia coli produces shiga toxin that causes diarrhoea, hemorrhagic colitis, and haemolytic uremic syndrome. Haemolytic uremic syndrome is characterized by anaemia, thrombocytopenia, and acute renal failure. Transmission of E. coli is possible after consuming contaminated, undercooked drinks and foods. E. coli enters the body via the faecal-oral pathway.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 184
Incorrect
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A type II error occurs when:
Your Answer:
Correct Answer: The null hypothesis is accepted when it is false.
Explanation:A type II error occurs when the null hypothesis is wrongly accepted when it is actually false and we conclude that there is no evidence of a difference in effect when one really exists (a false negative result).
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 185
Incorrect
-
Cefotaxime (or ceftriaxone) is used first line for which of the following infections:
Your Answer:
Correct Answer: Blind treatment of suspected bacterial meningitis
Explanation:Cefotaxime (or ceftriaxone) are indicated first line in:- Blind treatment of meningitis in patients > 3 months (with amoxicillin if patient > 50 years)- Meningitis caused by meningococci- Meningitis caused by pneumococci- Meningitis caused by H. influenzae- Severe or invasive salmonellosis- Typhoid fever- Gonorrhoea- Gonococcal arthritis- Haemophilus influenzae epiglottitis
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 186
Incorrect
-
In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic is a protein synthesis inhibitor.Which of the following antimicrobial drugs is prescribed to this patient?
Your Answer:
Correct Answer: Gentamicin
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA and thus preventing initiation of protein synthesis.Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors. Penicillins and cephalosporins are the major antibiotics that inhibit bacterial cell wall synthesis. They inactivate transpeptidases that help cross-link peptidoglycans in cell walls. Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA. Ciprofloxacin inhibits prokaryotic enzymes topoisomerase II (DNA gyrase) and topoisomerase IV.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 187
Incorrect
-
A 62-year-old woman presents with cold sensitivity, tiredness, and weight gain. A series of blood tests done shows a grossly elevated TSH level and a diagnosis of hypothyroidism is made.What is the commonest cause of hypothyroidism worldwide?
Your Answer:
Correct Answer: Iodine deficiency
Explanation:Hypothyroidism occurs when there is a deficiency of circulating thyroid hormones. It is commoner in women and is most frequently seen in the age over 60.Iodine deficiency is the commonest cause of hypothyroidism worldwide.In the UK and other developed countries, iodine deficiency is not a problem and autoimmune thyroiditis is the commonest cause.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 188
Incorrect
-
All of the following are indications for beta-blockers EXCEPT for:
Your Answer:
Correct Answer: Prinzmetal's angina
Explanation:Beta-blockers are contraindicated in Prinzmetal’s angina.Beta-blockers may be indicated in:HypertensionPheochromocytoma (only with an alpha-blocker)AnginaSecondary prevention after ACSArrhythmias including atrial fibrillationHeart failureThyrotoxicosisAnxietyProphylaxis of migraineEssential tremorGlaucoma
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 189
Incorrect
-
A migrant from Eastern Europe needs to have screening performed for tuberculosis (TB) because he is a high-risk patient.Which statement concerning TB screening in the UK is true?
Your Answer:
Correct Answer: Vaccination with the BCG can result in a false positive test
Explanation:Vaccination with the BCG can result in a false positive test.The Mantoux test replaced the Heaf test as the TB screening test in the UK in 2005.The ‘Sterneedle’ gun is used to inject 100,000 units/ml of tuberculin purified protein derivative into the skin for the Heaf testThe Mantoux test involves the injection of 5 Tuberculin units (0.1mL) intradermally and the result read 2-3 days later. The interferon gamma release assay (IGRA) should NOT be used for neonates
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 190
Incorrect
-
What is the approximate lifespan of the mature erythrocyte:
Your Answer:
Correct Answer: 120 days
Explanation:Erythrocytes have a normal lifespan of about 120 days. Mature erythrocytes are biconcave discs with no nucleus, ribosomes or mitochondria but with the ability to generate energy as ATP by the anaerobic glycolytic pathway. The red cell membrane consists of a bipolar lipid layer with a membrane skeleton of penetrating and integral proteins anchoring carbohydrate surface antigens. The shape and flexibility of red cells allows them to deform easily and pass through capillaries.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 191
Incorrect
-
Which of the following antibiotics is the first line of treatment for a patient who has been diagnosed with chlamydia infection?
Your Answer:
Correct Answer: Azithromycin
Explanation:The Centres for Disease Control and Prevention (CDC) recommends azithromycin, a single 1 g dose, and doxycycline, 100 mg bd for 7 days, as first-line medications for chlamydial infection treatment. Second-line medications (such as erythromycin, penicillins, and sulfamethoxazole) are less effective and have more side effects
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 192
Incorrect
-
A 77 year old lady presents to ED with her left leg shortened and externally rotated following slipping and falling on a wet bathroom floor. There is an intracapsular fracture of the neck of femur seen on imaging studies. She is at risk of avascular necrosis of the head of femur. This is caused by lack of blood supply from which of these arteries?
Your Answer:
Correct Answer: Medial circumflex artery
Explanation:The primary blood supply to the head of the femur is from branches of the medial femoral circumflex artery. The superior and inferior gluteal arteries supply the hip joint but not the head of femur.The lateral circumflex artery anastomoses with the medial femoral circumflex artery and assists in supplying the head of femur. The obturator artery is an important source of blood supply in children up to about 8 years. It gives rise to the artery of the head of femur which runs in the ligamentum teres and is insufficient to supply the head of femur in adults.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 193
Incorrect
-
Which of the following statements is correct regarding gentamicin?
Your Answer:
Correct Answer: Gentamicin is ineffective against anaerobic bacteria.
Explanation:Gentamicin is the aminoglycoside of choice in the UK and is a parenterally administered, broad spectrum antibiotic typically used for moderate to severe gram negative infections. However, it is inactive against anaerobes. There is poor activity against haemolytic streptococci and pneumococci. It is usually given in conjunction with a penicillin or metronidazole (or both) when used for the blind treatment of undiagnosed serious infections. Nephrotoxicity and ototoxicity are the main toxic effects due to damage to the vestibulocochlear nerve (CN VIII).It is contraindicated in myasthenia gravis and should be used with great care in renal disease as it may result in accumulation and a higher risk of toxic side effects.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 194
Incorrect
-
A 2-day-old male is referred to a tertiary care hospital by the community midwife after a home visit due to jaundice and dyspnoea. After history and examination, the relevant blood work is performed, and the baby is found to have conjugated hyperbilirubinemia. The paediatric team suspects a hepatic origin for jaundice based on the findings. Which one of the following aetiologies is the most likely cause of jaundice in this case?
Your Answer:
Correct Answer: Alpha 1-antitrypsin deficiency
Explanation:The presence of dyspnoea makes alpha-1 antitrypsin deficiency the more likely diagnosis as biliary atresia does not cause respiratory symptoms. Deficiency of the enzyme alpha-1 antitrypsin causes uninhibited elastase activity and a decrease in elastic tissue. This causes liver cirrhosis leading to an elevation of conjugated bilirubin and emphysema in the lungs.Rhesus disease, hereditary spherocytosis and breast milk jaundice cause an elevation of unconjugated bilirubin thus ruling it out in this case. Breast milk jaundice occurs due to an inability of the newborn to metabolize the proteins in breast milk. Rhesus disease occurs when an Rh negative mother gives birth to an Rh positive baby. The jaundice would have been accompanied by anaemia and oedema. Hereditary spherocytosis occurs due to extravascular haemolysis as defective RBCs are removed by the spleen. The patient would present with jaundice, splenomegaly and possibly an aplastic crisis (if Parvovirus B19 infection).
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 195
Incorrect
-
A 29-year-old volunteer returns from a recent trip to the middle east with profuse watery diarrhoea. You make a diagnosis of cholera and organize a hospital admission for rehydration with intravenous fluids.What is the mechanism of action of cholera toxin?
Your Answer:
Correct Answer: ADP-ribosylation of the G regulatory protein
Explanation:Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl. The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.Incubation period is between 2 and 5 days, but can be as short as just a few hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 196
Incorrect
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Which one of these equations best defines lung compliance?
Your Answer:
Correct Answer: Change in volume / change in pressure
Explanation:Lung compliance is defined as change in volume per unit change in distending pressure. Lung compliance is calculated using the equation:Lung compliance = ΔV / ΔPWhere:ΔV is the change in volumeΔP is the change in pleural pressure.Static compliance is lung compliance in periods without gas flow, and is calculated using the equation:Static compliance = VT / Pplat − PEEPWhere:VT = tidal volumePplat = plateau pressurePEEP = positive end-expiratory pressure
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 197
Incorrect
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Parasympathetic preganglionic neurons originate in which of the following locations:
Your Answer:
Correct Answer: Brainstem and pelvic splanchnic nerves
Explanation:Parasympathetic preganglionic neurones originate in the brainstem from which they run in cranial nerves III, VII, IX and X and also from the second and third sacral segments of the spinal cord. Parasympathetic preganglionic neurones release acetylcholine into the synapse, which acts on cholinergic nicotinic receptors on the postganglionic fibre. Parasympathetic peripheral ganglia are generally found close to or within their target, whereas sympathetic peripheral ganglia are located largely in two sympathetic chains on either side of the vertebral column (paravertebral ganglia), or in diffuse prevertebral ganglia of the visceral plexuses of the abdomen and pelvis. Parasympathetic postganglionic neurones release acetylcholine, which acts on cholinergic muscarinic receptors.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 198
Incorrect
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Regarding pressures and airflow during the normal breathing cycle, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Negative intrapleural pressure causes dynamic compression of the airways.
Explanation:Dynamic compression occurs during forced expiration, when as the expiratory muscles contract, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 199
Incorrect
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Identify the type of graph described below:A graph wherein the frequency distribution is represented by adjoining vertical bars and cases are stacked in adjoining columns. It can be used for continuous quantitative data, such as to analyse outbreak data to show an epidemic curve.
Your Answer:
Correct Answer: Histogram
Explanation:A histogram is used to demonstrate the distribution of continuous quantitative data. It is a very familiar graphical display device for representing the distribution of a single batch of data. The range of the data is divided into class intervals or bins, and the number of values falling into each interval is counted. The histogram then consists of a series of rectangles whose widths are defined by the class limits implied by the binwidths, and whose heights depend on the number of values in each bin. Histograms quickly reveal such attributes of the data distribution as location, spread, and symmetry. If the data are multimodal (i.e., more than one “hump” in the distribution of the data), this is quickly evident as well.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 200
Incorrect
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Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer:
Correct Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response.
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This question is part of the following fields:
- Immune Responses
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
