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Question 1
Incorrect
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Which of the following statements about lithium treatment is FALSE:
Your Answer: A serum-lithium concentration of 0.4 – 1 mmol/litre is therapeutic.
Correct Answer: Concomitant treatment with NSAIDs decreases serum-lithium concentration.
Explanation:Lithium levels are raised by NSAIDs because renal clearance is reduced. Lithium is a small ion (74 Daltons) with no protein or tissue binding and is therefore amenable to haemodialysis. Lithium is freely distributed throughout total body water with a volume of distribution between 0.6 to 0.9 L/kg, although the volume may be smaller in the elderly, who have less lean body mass and less total body water. Steady-state serum levels are typically reached within five days at the usual oral dose of 1200 to 1800 mg/day. The half-life for lithium is approximately 18 hours in adults and 36 hours in the elderly.Lithium is excreted almost entirely by the kidneys and is handled in a manner similar to sodium. Lithium is freely filtered but over 60 percent is then reabsorbed by the proximal tubules.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 2
Incorrect
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A 58-year-old male has cellulitis of his left leg. Because he is allergic to penicillin, you start him on erythromycin.What is erythromycin's mechanism of action?
Your Answer: Inhibition of cell wall synthesis
Correct Answer: Inhibition of protein synthesis
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolide antibiotics. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and thereby protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered to the infection site as a result.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 3
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 4
Correct
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The following all cause a right shift in the oxygen dissociation curve EXCEPT for:
Your Answer: Foetal haemoglobin
Explanation:A decreased affinity of haemoglobin for oxygen (and hence increased ease of dissociation), shown by a right shift in the oxygen dissociation curve, is caused by a fall in pH, a rise in PCO2(the Bohr effect) and an increase in temperature. These changes occur in metabolically active tissues such as in exercise, and encourage oxygen release. The metabolic by-product 2,3-diphosphoglycerate (2,3 -DPG) also causes a right shift; 2, 3 -DPG may also be raised in chronic anaemia, chronic lung disease, or at high altitude. Foetal haemoglobin (HbF) binds 2, 3 -DPG less strongly than does adult haemoglobin (HbA), and so the HbF dissociation curve lies to the left of that for HbA, reflecting its higher oxygen affinity. This helps transfer oxygen from mother to foetus.
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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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Regarding carbon dioxide transport in the blood, which of the following statements is CORRECT:
Your Answer: Carbon dioxide is formed from the dissociation of bicarbonate ions.
Correct Answer: Deoxygenated haemoglobin acts as a buffer for H+ ions.
Explanation:CO2generated in the tissues and water combine to form carbonic acid which readily dissociates to form HCO3-and H+. The first part of this reaction is very slow in plasma, but is accelerated dramatically by the enzyme carbonic anhydrase present in red blood cells. Bicarbonate is therefore formed preferentially in red cells, from which it freely diffuses down its concentration gradient into plasma where it is transported to the lungs. The red cell membrane is impermeable to H+ions which remain in the cell. To maintain electroneutrality, Cl-ions diffuse into the cell to replace HCO3-, an effect known as the chloride shift. Deoxygenated haemoglobin acts as a buffer for H+, allowing the reaction to continue.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 6
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: 10 mcg lidocaine hydrochloride
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 7
Incorrect
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Following a decrease in extracellular volume, which of the following is a reaction to enhanced sympathetic innervation of the kidney:
Your Answer: Inhibit release of ADH
Correct Answer: Release of renin
Explanation:The RAS pathway begins with renin cleaving its substrate, angiotensinogen (AGT), to produce the inactive peptide, angiotensin I, which is then converted to angiotensin II by endothelial angiotensin-converting enzyme (ACE). ACE activation of angiotensin II occurs most extensively in the lung. Angiotensin II mediates vasoconstriction as well as aldosterone release from the adrenal gland, resulting in sodium retention and increased blood pressure.
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This question is part of the following fields:
- Physiology
- Renal
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Question 8
Correct
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A 30-year-old male presents with easy bruising and bleeding gums, feeling very tired lately, and recurrent chest infections over the past few months. He had glandular fever approximately 6 months ago and feels that his symptoms started after that. His full blood count today is as follows: Hb 6.3 g/dl (11.5-14 g/dl) MCV 90 fl (80-100 fl) WCC 2.0 x 10 9 /l (4-11 x 10 9 /l) Platelets 15 x 10 9 /l (150-450 x 10 9 /l)The SINGLE most likely diagnosis is?
Your Answer: Aplastic anaemia
Explanation:Aplastic anaemia is a life-threatening failure of haemopoiesis characterised by pancytopenia and hypocellular bone marrow. It is rare and patients present with features of recurrent infections secondary to (leukocytopenia), increased bleeding tendency (secondary to thrombocytopenia) and anaemia. In aplastic anaemia, there is damage to the bone marrow and the haematopoietic stems cells leading to pancytopenia.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 9
Correct
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A 70-year-old patient develops bacteraemia following peripheral cannulation.Which of these bacteria is the most likely cause of the infection?
Your Answer: Staphylococcus epidermidis
Explanation:The commonest implicated organisms in hospital-acquired bacteraemia following cannulation are Staphylococcus aureus and Staphylococcus epidermidis. The risk is directly proportional to the length of time in-situ. Peripheral cannula should be replaced after 48 hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 10
Correct
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A 63 year old lady presents to ED with a persistent cough and red currant jelly sputum. She has a history of chronic alcohol abuse and has an X-ray which demonstrates a cavitating pneumonia. The most likely causative pathogen is:
Your Answer: Klebsiella pneumoniae
Explanation:One of the results of Klebsiella pneumoniae is pneumonia that is usually a very severe infection. It is characterised by thick, bloody sputum (red currant jelly sputum), and is associated with complications like lung abscess, cavitation, necrosis, empyema and pleural effusions.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 11
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: The wrist flexors
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 12
Correct
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Which of the following best describes the therapeutic effect of calcium gluconate when used in treatment for hyperkalaemia:
Your Answer: Reduces cardiac cell membrane excitability
Explanation:Calcium resonium is an ion-exchange resin that exchanges sodium for potassium as it passes through the intestine, leading to excretion of potassium from the body. Salbutamol and insulin act to increase intracellular uptake of K+ via Na-K ATP pump. Sodium bicarbonate acts to correct acidosis and thus promotes intracellular uptake of K+. Calcium gluconate acts to protect the cardiac membrane and has no effect on serum K+ levels.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 13
Correct
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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: 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 14
Incorrect
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The most common cause of anaemia worldwide is which of the following?
Your Answer:
Correct Answer: Iron deficiency anaemia
Explanation:The most common cause of microcytic anaemia and of any anaemia worldwide is iron deficiency anaemia.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 15
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 16
Incorrect
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A 66-year-old male was admitted from the Emergency Department due to severe pain in the left forearm and hand, refractory to pain medication along with pallor and hypothermia of the affected limb. Ultrasound doppler showed an arterial embolism. Circulation was restored after vascular surgery, but there was extensive, irreversible muscle damage. How will the muscle heal from an injury of this type?
Your Answer:
Correct Answer: Diffuse formation of fibrous tissue
Explanation:Once muscle tissue is damaged, there will be healing via diffuse formation of fibrous tissue, especially due to the widespread ischemia. Callus formation takes place in the healing of bone, not muscle. Organised scar formation occurs when a lacerated wound is approximated by sutures so that primary intention wound healing can occur. Liquefaction degeneration occurs following ischemia in the brain. Volkmann’s ischemic contracture may occur, but it is not the primary type of healing that will take place but rather the effect of the fibrous scar formation.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 17
Incorrect
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Question 18
Incorrect
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Since the fluid that enters the loop of Henle is isotonic, what is its estimated osmolality?
Your Answer:
Correct Answer: 300 mOsm
Explanation:The loop of Henle connects the proximal tubule to the distal convoluted tubule and lies parallel to the collecting ducts. It is consists of three major segments, the thin descending limb, the thin ascending limb, and the thick ascending limb. The segments are differentiated based on structure, anatomic location, and function. The main action of the loop of Henle is to recover water and sodium chloride from urine. The liquid entering the loop of Henle is a solution of salt, urea, and other substances traversed along by the proximal convoluted tubule, from which most of the dissolved components are needed by the body, particularly glucose, amino acids, and sodium bicarbonate that have been reabsorbed into the blood. This fluid is isotonic. Isotonic fluids generally have an osmolality ranging from 270 to 310 mOsm/L. With the fluid that enters the loop of Henle, it is estimated to be 300 mOsm/L. However, after passing the loop, fluid entering the distal tubule is hypotonic to plasma since it has been diluted during its passage.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 19
Incorrect
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A patient presents with a gastrointestinal infection. Which of the following microbes attaches to gut mucosa via a specialised sucking disc:
Your Answer:
Correct Answer: Giardia lamblia
Explanation:Giardia lambliainfection occurs through the ingestion of dormant microbial cysts in contaminated water, food or via faceo-oral transmission via poor hygiene.Following ingestion of the cysts, the trophozoite emerges to an active state of feeding and motility. After the feeding stage they undergo asexual replication through longitudinal binary fission.They attach to the intestinal wall via a specialised sucking disc. The mechanism for diarrhoea in giardiasis remains unknown but could possibly be due to direct cytotoxicity.Giardial trophozoites and cysts pass through the digestive system in the faeces and are excreted. While the trophozoites may be found in the faeces, only the cysts are adapted for long-term survival outside the host.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 20
Incorrect
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When the pulmonary artery is completely blocked, what is the ventilation over perfusion ratio for the area that it supplies?
Your Answer:
Correct Answer: Infinity
Explanation:The ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the matching ventilation and perfusion. A pulmonary artery carries deoxygenated blood from the right side of the heart to the lungs. When a large pulmonary embolus completed blocked a pulmonary artery the alveoli were ventilated but not perfused at all, then the V/Q ratio would be infinity.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 21
Incorrect
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Regarding the lacrimal apparatus, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Lacrimal fluid is drained from the eyeball through the lacrimal punctum.
Explanation:Lacrimal fluid is drained from the eyeball through the lacrimal punctum.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 22
Incorrect
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Which of the following statements about neutrophils is TRUE:
Your Answer:
Correct Answer: Neutrophils are typically the first immune cell to arrive to a site of injury.
Explanation:Neutrophils are the most numerous peripheral blood leukocytes, accounting for 50-70 percent of all circulating white cells. Neutrophils have a compact nucleus with two to five lobes and a pale cytoplasm with an irregular shape containing numerous fine pink-blue or grey-blue granules. The granules are classified as primary, which emerges during the promyelocyte stage, and secondary, which develop at the myelocyte stage and predominate in the mature nucleus.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 23
Incorrect
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Which of the following is an action of glucagon:
Your Answer:
Correct Answer: Stimulates glycogenolysis
Explanation:Glucagon is a peptide hormone that is produced and secreted by alpha cells of the islets of Langerhans, which are located in the endocrine portion of the pancreas. The main physiological role of glucagon is to stimulate hepatic glucose output, thereby leading to increases in glycaemia. It provides the major counter-regulatory mechanism to insulin in maintaining glucose homeostasis.Hypoglycaemia is the principal stimulus for the secretion of glucagon but may also be used as an antidote in beta-blocker overdose and in anaphylaxis in patients on beta-blockers that fail to respond to adrenaline. Glucagon then causes:GlycogenolysisGluconeogenesisLipolysis in adipose tissueThe secretion of glucagon is also stimulated by:AdrenalineCholecystokininArginineAlanineAcetylcholineThe secretion of glucagon is inhibited by:InsulinSomatostatinIncreased free fatty acidsIncreased urea productionGlycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released by this process is used to form ATP and NADH. Glycolysis is inhibited by glucagon, and glycolysis and gluconeogenesis are reciprocally regulated so that when one cell pathway is activated, the other is inactive and vice versa.Glucagon has a minor effect of enhancing lipolysis in adipose tissue. Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into glycerol and free fatty acids. It makes fatty acids available for oxidation.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 24
Incorrect
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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 25
Incorrect
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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 26
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 27
Incorrect
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A 62 year old man has sustained a penetrating injury to the submandibular triangle. On examination, his tongue is weak and when protruded deviates to the left. Which of the following nerves has most likely been injured:
Your Answer:
Correct Answer: Left hypoglossal nerve
Explanation:Damage to the hypoglossal nerve results in weakness of the tongue, with deviation of the tongue towards the weak side on protrusion.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 28
Incorrect
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A patient has a cardiac output of 4.8 L/min and a heart rate of 80 bpm, therefore their stroke volume is:
Your Answer:
Correct Answer: 60 mL
Explanation:Cardiac output (CO) = Stroke volume (SV) x Heart rate (HR). Therefore SV = CO/HR = 4.8/80 = 0.06 L = 60 mL.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 29
Incorrect
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A 68-year-old man with BPH presents to the emergency department in significant pain secondary to urinary retention. What is the location of the neuronal cell bodies that are responsible for urinary bladder discomfort sensation?
Your Answer:
Correct Answer: Dorsal root ganglia of spinal cord levels S2, S3 and S4
Explanation:The activation of stretch receptors with visceral afferents relayed through the pelvic nerve plexus and into the pelvic splanchnic nerves causes bladder pain. The sensory fibres of spinal nerves S2 – S4 enter the dorsal root ganglia.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 30
Incorrect
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Damage to this nerve affects the flexor digitorum longus.
Your Answer:
Correct Answer: Tibial nerve
Explanation:Like all muscles in the deep posterior compartment of the leg, flexor digitorum longus muscle is innervated by branches of the tibial nerve (root value L5, S1 and S2) which is a branch of sciatic nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
