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Question 1
Correct
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A 7-year-old girl is admitted to the hospital with a persistently high temperature. To help her reduce her fever, you decide to give her paracetamol and ibuprofen.What are the effects of paracetamol and ibuprofen on fever?
Your Answer: Reduction in prostaglandin synthesis
Explanation:Interleukin-1, which is released by leukocytes and acts on the thermoregulatory centre of the hypothalamus, causes fever. Because prostaglandins mediate this process, antipyretics such as NSAIDs, paracetamol, and aspirin reduce prostaglandin levels by inhibiting cyclooxygenase enzymes. Malignant disease secretes interleukins, which cause the B-symptoms seen in lymphoma, for example. Bacterial toxins can also cause interleukins to be produced.Pyrexia of unknown origin (PUO) is defined as a fever of greater than 38.3 degrees Celsius that lasts for more than 2-3 weeks with no clear diagnosis despite extensive investigation.Investigation necessitates a thorough understanding of the conditions that can cause febrile illness, which may be missed during an initial investigation, as well as a thorough history, examination, and investigation centred on that list.Pyrexia of unknown origin has a wide differential diagnosis, which includes:InfectionBacterialPyogenic abscessTuberculosisInfective endocarditisBrucellosisLyme diseaseViralHIV Epstein Barr VirusCytomegalovirusParasiteToxoplasmosisMalignancy LeukaemiaLymphomaRenal cell carcinomaHepatocellular carcinomaVasculitides Still’s diseaseGranulomatosis with polyangiitis (formerly Wegener’s)Systemic lupus erythematosusGiant cell arteritisRheumatoid arthritisPolymyalgia rheumaticaMiscellaneous Drug induced fevers Familial Mediterranean feverThyrotoxicosisInflammatory bowel diseaseSarcoidosisFactitious fever Exaggerated normal circadian fluctuationThe patient might need to be admitted to the hospital for observation and further investigation. Because infection is still a possibility, blood cultures should be repeated on a regular basis, and inflammatory markers should be closely monitored. CT, PET, and MRI imaging have largely replaced diagnostic laparotomy as a diagnostic tool.
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This question is part of the following fields:
- Pathology
- Pathology Of Infections
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Question 2
Correct
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A 7-days-old neonate is taken to the emergency department. She's pyretic, lethargic, and unresponsive, and her fontanelle has bulged. Antibiotics are started, and a lumbar puncture reveals Gram-negative rods. Which pathogen is most likely to be the cause:
Your Answer: Escherichia coli
Explanation:Among neonates, group B streptococci (GBS) are the most commonly identified causes of bacterial meningitis, implicated in roughly 50% of all cases. Escherichia coli(Gram-negative rods) accounts for another 20%. Thus, the identification and treatment of maternal genitourinary infections is an important prevention strategy.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 3
Incorrect
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Which of the following side effects has limited the use of etomidate as an intravenous induction agent:
Your Answer: Hypersensitivity reactions
Correct Answer: Adrenocortical suppression
Explanation:Etomidate causes the least cardiovascular depression of the intravenous induction agents, with only a small reduction in the cardiac output and blood pressure. In the past, etomidate was widely used to induce anaesthesia in the shocked, elderly or cardiovascularly unstable patient. However, more recently it has become less popular as a single induction dose blocks the normal stress-induced increase in adrenal cortisol production for 4 – 8 hours, and up to 24 hours in elderly and debilitated patients. Although no increase in mortality has been identified following a single dose during induction of anaesthesia, the use of etomidate has declined due to a perceived potential morbidity.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 4
Incorrect
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A 15-year-old girl took almost 20 tablets of paracetamol almost 4 hours ago to show anger towards her mother for denying permission to go on a girl's trip. The girl is healthy and has no known comorbids or drug history. Which one of the following is TRUE regarding paracetamol?
Your Answer: Toxicity is primarily due to glutathione production
Correct Answer: It is excreted renally
Explanation:Acetaminophen is an acetanilide derivative and is a widely used non-prescription analgesic and antipyretic medication for mild-to-moderate pain and fever.The route of elimination: Metabolites are mainly excreted in the urine. 90% of the dose administered is excreted within 24 hours. It is thought to work by selectively inhibiting COX-1 receptors in the brain and spinal cord: It is categorized by the FDA as an NSAID as it is believed to selectively inhibit cyclo-oxygenase 3 (COX-3) receptors in the brain and spinal cord. COX-3 is a unique variant of the more known COX-1 and COX-2. It is responsible for the production of prostaglandins in central areas, which sensitizes free nerve endings to the chemical mediators of pain. Therefore, by selectively inhibiting COX-3, paracetamol effectively reduces pain sensation by increasing the pain threshold.Toxicity is primarily due to glutathione production: Acetaminophen metabolism by the CYP2E1 pathway releases a toxic metabolite known as N-acetyl-p-benzoquinoneimine (NAPQI). NAPQI primarily contributes to the toxic effects of acetaminophen. NAPQI is an intermediate metabolite that is further metabolized by fast conjugation with glutathione. The conjugated metabolite is then excreted in the urine as mercapturic acid. High doses of acetaminophen (overdoses) can lead to hepatic necrosis due to depleting glutathione and high binding levels of reactive metabolite (NAPQI) to important parts of liver cells.It has a half-life of 6-8 hours: Acetaminophen can be administered orally, rectally, or intravenously. It is predominantly metabolized in the liver, and the elimination half-life is 1-3 hours after a therapeutic dose. But maybe greater than 12 hours after an overdose.It is primarily metabolized via the cytochrome p450 enzyme system: It is predominantly metabolized in the liver by three main metabolic pathways:1. Glucuronidation (45-55%)2. Sulphate conjugation (30-35%)3. N-hydroxylation via the hepatic cytochrome p450 enzyme system (10-15%)
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 5
Correct
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A 60-year-old man diagnosed with chronic kidney disease has an elevated creatinine level and a reduced glomerular filtration rate (GFR).Which statement concerning glomerular filtration is true?
Your Answer: Creatinine is freely filtered at the glomerulus
Explanation:Glomerular filtration is a passive process. It depends on the net hydrostatic pressure across the glomerular capillaries, the oncotic pressure, and the intrinsic permeability of the glomerulus.The mean values for glomerular filtration rate (GFR) in young adults are 130 ml/min/1.73m2 in males and 120 ml/min/1.73m2in females.The GFR declines with age after the age of 40 at a rate of approximately 1 ml/min/year.The Cockcroft and Gault formula overestimates creatinine in obese patients. This is because their endogenous creatinine production is less than that predicted by overall body weight.Creatinine is used in the estimation of GFR because it is naturally produced by muscle breakdown, not toxic, not produced by the kidney, freely filtered at the glomerulus, not reabsorbed from the nephron, and does not alter GFR.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 6
Correct
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Most of the lymph from vessels that drain the breast is collected in which of the following lymph nodes?
Your Answer: Axillary nodes
Explanation:Lymph is the fluid that flows through the lymphatic system. Axillary lymph nodes are near the breasts. They are often the first location to which breast cancer spreads if it moves beyond the breast tissue. They receive approximately 75% of lymph drainage from the breast via lymphatic vessels, laterally and superiorly. The lymph usually first drains to the anterior axillary nodes, and from here, through the central axillary, apical, and supraclavicular nodes in sequence.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 7
Correct
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The mechanism of action of abciximab is by:
Your Answer: Blocking the binding of fibrinogen to GPIIb/IIIa receptor sites
Explanation:Abciximab is a glycoprotein IIb/IIIa inhibitors and prevents platelet aggregation by blocking the binding of fibrinogen to receptors on platelets.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Correct
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Digoxin is predominantly used for which of the following:
Your Answer: Rate control in persistent and permanent atrial fibrillation
Explanation:Digoxin is most useful for controlling the ventricular response in persistent and permanent atrial fibrillation and atrial flutter. Digoxin is usually only effective for controlling the ventricular rate at rest, and should therefore only be used as monotherapy in predominantly sedentary patients with non-paroxysmal atrial fibrillation. It is now rarely used for rapid control of heart rate, as even with intravenous administration, response may take many hours. Digoxin is reserved for patients with worsening or severe heart failure due to left ventricular systolic dysfunction refractory to combination therapy with first-line agents. Digoxin is contraindicated in supraventricular arrhythmias associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndrome.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 9
Correct
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Which of the following best describes the popliteal artery's course?
Your Answer: After exiting the popliteal fossa terminates at the lower border of the popliteus muscle
Explanation:The popliteal artery divides into the anterior and posterior tibial arteries at the lower border of the popliteus after exiting the popliteal fossa between the gastrocnemius and popliteus muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 10
Correct
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A 35-year-old man, who was feeling unwell after his return from a business trip, was diagnosed with a disease that is known to be transmitted by a vector. Among the following microorganisms, which of the following has a mode of transmission of being vector-borne?
Your Answer: Plasmodium falciparum
Explanation:Plasmodium falciparum is a parasite that is vector-borne which is transmitted by the female Anopheles mosquito.Bordetella pertussis is transmitted through the respiratory tract, via respiratory droplets or direct contact with infectious secretions.Mycobacterium tuberculosis is transmitted via inhalation of infected respiratory droplets.HIV may be transmitted via sexual contact, vertical transmission from mothers to infants, and among injection drug users sharing infected needles, as well as through transfusion of infected blood products.Treponema pallidum transmission normally occurs during direct sexual contact with an individual who has an active primary or secondary syphilitic lesion.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 11
Correct
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A 6-year-old girl is brought to the nephrology clinic by her mother due to facial oedema. Her lab workup shows proteinuria of 7 g/24 hours and serum albumin levels of 15 g/L. A diagnosis of Nephrotic Syndrome is made, and corticosteroid therapy is initiated. Which one of the following is the most likely cause of nephrotic syndrome in this patient?
Your Answer: Minimal change disease
Explanation:Minimal Change Disease is the most common cause of Nephrotic Syndrome in the paediatric population. It may be caused by NSAID use. Electron microscopy shows the fusion of foot processes while light microscopy will appear normal.Focal segmental glomerulosclerosis causes Nephrotic Syndrome in adults. It is associated with Heroin use and HIV infection. There is a limited response to steroids, and the disease progresses to end-stage renal failure in 5-10 years.Diabetic nephropathy occurs after a long period of diabetes due to the deposition of amyloid protein leading to a decrease in glomerular filtration. There is no history of Hepatitis B in this patient and no symptoms of liver disease such as jaundice. Membranous glomerulonephritis would present with features of Nephritic Syndrome. These would be oedema, haematuria; red blood cell casts in the urine and hypertension.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 12
Correct
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A pheochromocytoma is diagnosed in a 38-year-old female who has had episodes of acute sweating, palpitations, and paroxysmal hypertension.Which of the following is the MOST SUITABLE INITIAL TREATMENT?
Your Answer: Alpha-blocker
Explanation:A phaeochromocytoma is a rare functional tumour that develops in the adrenal medulla from chromaffin cells. Extra-adrenal paragangliomas (extra-adrenal pheochromocytomas) are tumours that arise in the sympathetic nervous system’s ganglia and are closely connected to extra-adrenal paragangliomas (extra-adrenal pheochromocytomas). Catecholamines are secreted by these tumours, which generate a variety of symptoms and indications associated with sympathetic nervous system hyperactivity.Hypertension is the most prevalent presenting symptom, which can be continuous or intermittent.Symptoms are usually intermittent, occurring anywhere from many times a day to occasionally. The symptoms of the condition tend to grow more severe and frequent as the disease progresses.The ultimate therapy of choice is surgical resection, and if full resection is done without metastases, hypertension is typically cured.Preoperative medical treatment is critical because it lowers the risk of hypertensive crises during surgery. This is commonly accomplished by combining non-competitive alpha-blockers (such as phenoxybenzamine) with beta-blockers. To allow for blood volume expansion, alpha-blockade should be started at least 7-10 days before surgery. Beta-blockade, which helps to regulate tachycardia and some arrhythmias, can be started after this is accomplished. Hypertensive crises can be triggered if beta-blockade is started too soon.There should also be genetic counselling, as well as a search for and management of any linked illnesses.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 13
Correct
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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: 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 14
Correct
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Chronic myeloid leukaemia is most common in middle-aged and elderly people. It is responsible for 20% of all leukemias.Which of the following statements about CML is NOT TRUE?
Your Answer: Serum B12 is typically low
Explanation:Chronic myeloid leukaemia is most common in middle-aged and elderly people. It is responsible for 20% of all leukemias. The majority of CML patients experience fatigue, weight loss, and excessive sweating.The Philadelphia chromosome is found in over 90% of CML cases. A balanced translocation between chromosomes 9 and 22 is known as the Philadelphia chromosome.Because white cells produce a B12 binding protein, serum B12 levels in CML are typically high.In CML, the neutrophil alkaline phosphatase score is usually low.Almost all patients with CML eventually progress to blast crisis, though this can take up to ten years. If any of the following features are present in a CML patient, a blast crisis is diagnosed:In the blood or bone marrow, there are more than 20% myeloblasts or lymphoblasts.On a bone marrow biopsy, large clusters of blasts were discovered.CML can be treated with tyrosine kinase inhibitors like imatinib and dasatinib if a chloroma (a solid tumour made up of myeloblasts that grows outside of the bone marrow) is present.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 15
Correct
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A 34-year-old male presents to the Emergency Department with the complaint of palpitations and difficulty breathing, which started suddenly half an hour ago. His ECG shows findings of supraventricular tachycardia. You attempt vagal manoeuvres but cannot convert them back to sinus rhythm. Therefore, drug therapy is necessary to terminate the arrhythmia. Adenosine cannot be used in this patient because of a contra-indication listed in his medical record. Which one of the conditions listed below would be a contraindication in this case?
Your Answer: Asthma
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:
- Cardiovascular Pharmacology
- Pharmacology
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Question 16
Correct
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A patient presents with nausea, anorexia, jaundice and right upper quadrant pain. A diagnosis of acute hepatitis B is suspected.Which of the following blood results is most suggestive of an acute hepatitis B infection? Select ONE answer only.
Your Answer: HBsAg positive, IgM anti-HBc positive
Explanation:Hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, that is the first serologic marker to appear in a new acute infection.It can be detected as early as 1 week and as late as 9 weeks. It can be detected in high levels in serum during acute or chronic hepatitis B virus infection. The presence of HBsAg indicates that the person is infectious. The body normally produces antibodies to HBsAg as part of the normal immune response to infection. HBsAg is the antigen used to make hepatitis B vaccine.Hepatitis B surface antibody (anti-HBs) indicates recovery and immunity from the hepatitis B virus infection. Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B.Total hepatitis B core antibody (anti-HBc): Appears at the onset of symptoms in acute hepatitis B and persists for life. The presence of anti-HBc indicates previous or ongoing infection with hepatitis B virus in an undefined time frame. It is not present following hepatitis B vaccination.IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates recent infection with hepatitis B virus (<6 months). Its presence indicates acute infection.The following table summarises the presence of hepatitis B markers according to each situation:Susceptible to infection:HBsAg = NegativeAnti-HBc = NegativeAnti-HBs = NegativeImmune due to natural infection:HBsAg = NegativeAnti-HBc = PositiveAnti-HBs = PositiveImmune due to vaccination:HBsAg = NegativeAnti-HBc = NegativeAnti-HBs = PositiveAcute infection:HBsAg = PositiveAnti-HBc = PositiveAnti-HBs = NegativeIgM anti-HBc = PositiveChronic infection:HBsAg = PositiveAnti-HBc = PositiveAnti-HBs = NegativeIgM anti-HBc = Negative
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 17
Correct
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The 'pump handle' movement of the thoracic wall describes which of the following movements:
Your 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 18
Correct
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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: 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 19
Correct
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Which of the following leukaemias is most common in children in the UK:
Your Answer: Acute lymphoblastic leukaemia
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. There is a secondary rise after the age of 40 years. 85% of cases are of B-cell lineage and have an equal sex incidence; there is a male predominance for the 15% of T-cell lineage.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 20
Correct
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Among the following microorganisms, which is considered to be transmitted by invasion of intact skin?
Your Answer: Leptospira spp.
Explanation:Rodents and domestic animals are the primary reservoirs for the Leptospira spp, although other animals, including cows, horses, mongooses, and frogs, can also harbour the leptospires. Humans may be directly infected from animal urine or indirectly by contact with soil or water that is contaminated with urine from infected animals. Infected humans can shed leptospires in urine for up to 11 months, infected cows for 3.5 months, infected dogs for 4 years, and infected rodents possibly for their entire lifetime.The organisms enter the host through mucous membranes or abraded skin. The incubation period ranges from 5 to 14 days.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 21
Incorrect
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Regarding an avulsion fracture, a sudden contraction of which muscle may lead to fracture of the head of the fibula?
Your Answer: Semimembranosus
Correct Answer: Biceps femoris
Explanation:Avulsion fractures of the fibular head are rare and are so-called the arcuate signal. The “arcuate signal” is used to describe an avulsed bone fragment related to the insertion site of the tendon of the biceps femoris associated with the arcuate complex, which consists of the fabellofibular, popliteofibular, and arcuate ligaments. Such lesions are typically observed in direct trauma to the knee with excessive varus and internal rotation forces or indirect trauma with the same direction of the force.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 22
Correct
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At the start of the cardiac cycle, towards the end of diastole, all of the following statements are true EXCEPT for:
Your Answer: The semilunar valves are open.
Explanation:At the start of the cardiac cycle, towards the end of diastole, the whole of the heart is relaxed. The atrioventricular (AV) valves are open because the atrial pressure is still slightly greater than the ventricular pressure. The semilunar valves are closed, as the pressure in the pulmonary artery and aorta is greater than the ventricular pressures. The cycle starts when the sinoatrial node (SAN) initiates atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 23
Incorrect
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Damage to this nerve affects the flexor digitorum longus.
Your Answer: Deep peroneal nerve
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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Question 24
Correct
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A 39-year-old man with a long history of depression presents after intentionally overdoing his heart medication. Verapamil immediate-release 240 mg is the tablet he takes for this condition, he says. He took the pills about 30 minutes ago, but his wife discovered him right away and rushed him to the emergency room.Which of the following is a verapamil toxicity?
Your Answer: Negative inotropy
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 following summarises the toxicity of calcium-channel blockers:Cardiac effectsVascular smooth muscle tone affectsMetabolic effectsExcessive negative inotropy: myocardial depressionNegative chronotropy: sinus bradycardiaNegative dromotropy: atrioventricular node blockadeDecreased afterloadSystemic hypotensionCoronary vasodilationHypoinsulinaemiaCalcium channel blocker-induced insulin resistance
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 25
Correct
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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: 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 26
Correct
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The tetanus vaccination contains inactivated tetanus toxoid, which induces the body to produce protective antibodies. How do these antibodies protect the body from tetanus?
Your Answer: Neutralise the protein exotoxin of C. tetani
Explanation:C. Tetanospasmin, an exotoxin produced by tetani, is responsible for the neurotoxic consequences of tetanus. The tetanus vaccination contains inactivated tetanus toxoid, which induces the body to produce protective antibodies that neutralize the tetanus toxin. It induces active immunization against Clostridium tetani exotoxin via toxoid-induced Ab generation.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 27
Correct
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A 25-year-old guy who has had a knee-high plaster cast on his left leg for the past 5 weeks arrives at the emergency department complaining of numbness on the dorsum of his left foot and an inability to dorsiflex or evert his foot. You know that his symptoms are due to fibular nerve compression. Where is the fibular nerve located?
Your Answer: Neck of fibula
Explanation:Dorsiflexion and eversion of the foot are innervated by the deep fibular nerve and the superficial fibular nerve, respectively. The common fibular nerve runs obliquely downward along the lateral border of the popliteal fossa (medial to the biceps femoris) before branching at the neck of the fibula. Thus, it is prone to being affected during an impact injury or fracture to the bone or leg. Casts that are placed too high can also compress the fibular nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 28
Correct
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Which of the following statements is incorrect regarding the electron transfer system?
Your Answer: The electron transfer system occurs in anaerobic respiration.
Explanation:The electron transfer system is responsible for most of the energy produced during respiration. The is a system of hydrogen carriers located in the inner mitochondrial membrane. Hydrogen is transferred to the electron transfer system via the NADH2molecules produced during glycolysis and the Krebs cycle. As a result, a H+ion gradient is generated across the inner membrane which drives ATP synthase. The final hydrogen acceptor is oxygen and the H+ions and O2 combine to form water.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 29
Correct
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A 64-year-old woman had a humerus midshaft fracture due to tripping on a curb and falling on her left arm. She might also have damaged which of the following structures?
Your Answer: Radial nerve and deep brachial artery
Explanation:The radial nerve and brachial artery are most likely to be damaged in humerus fractures. They are tethered together to the bone and cannot withstand the forces applied to it as a result of the displacement.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 30
Incorrect
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A 79-year-old male had a humeral shaft fracture during a road traffic accident and is being followed up in a fracture clinic. He complains of inability to use the limb 6 months after the injury. X-rays of that arm shows non union of his fracture.All the following are responsible for this non-union EXCEPT?
Your Answer: Infection
Correct Answer: Osteoporosis
Explanation:An imbalance between bone resorption and formation is Osteoporosis. In normal bone, formation and resorption are roughly equal, and the density of bone matrix remains constant but there is more resorption in osteoporosis and the matrix density reduces and bones become weaker. Fractures are more likely to occur but healing is unaffected. Non-union of a fracture occurs when the two sides of a fracture fail to unite after 6 months. Causes include: infection, movement at the fracture site, avascular necrosis, tissue interposed between the fracture and gross misalignment.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 31
Correct
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Which of the following drugs used in the management of hyperkalaemia does not affect serum potassium levels:
Your Answer: Calcium gluconate
Explanation:Calcium gluconate is given to antagonise cardiac cell membrane excitability to reduce the risk of arrhythmias. It has no effect on serum potassium levels unlike the alternative drugs listed above.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 32
Incorrect
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Identify the type of graph described below:This graph is a scatter plot of the effect estimates from individual studies against some measure of each study's size or precision.
Your Answer: Forest plot
Correct Answer: Funnel plot
Explanation:A funnel plot is a scatter plot of the effect estimates from individual studies against some measure of each study’s size or precision. The standard error of the effect estimate is often chosen as the measure of study size and plotted on the vertical axis with a reversed scale that places the larger, most powerful studies towards the top. The effect estimates from smaller studies should scatter more widely at the bottom, with the spread narrowing among larger studies. In the absence of bias and between study heterogeneity, the scatter will be due to sampling variation alone and the plot will resemble a symmetrical inverted funnel. A triangle centred on a fixed effect summary estimate and extending 1.96 standard errors either side will include about 95% of studies if no bias is present and the fixed effect assumption (that the true treatment effect is the same in each study) is valid.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 33
Correct
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A 5-year-old girl is brought into the Paediatric ER for acute seizures. She has been convulsing for the past 18 minutes now and was already two doses of lorazepam in the ambulance. Now, you prepare a phenytoin infusion to abolish the seizures. According to the APLS algorithm, what dose of phenytoin is advised for a convulsing child at this stage?
Your Answer: 20 mg/kg over 20 minutes
Explanation:Advanced paediatric life support (APLS) recommends phenytoin as the first choice for second-line anticonvulsant in a patient that continues to seize ten minutes after the second dose of the first-line anticonvulsant (benzodiazepine). (step 3 of the APLS algorithm)The recommended dose of phenytoin infusion is up at 20 mg/kg over 20 minutes. If the patient has already taken phenytoin as maintenance therapy or is allergic to phenytoin, then a phenobarbitone infusion should be set up at 20 mg/kg over 30-60 minutes.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 34
Correct
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A 38-year-old woman presented to the emergency room after an incident of slipping and falling onto her back and left hip. Upon physical examination, it was noted that she has pain on hip flexion, but normal hip adduction. Which of the following muscles was most likely injured in this case?
Your Answer: Sartorius
Explanation:The hip adductors are a group of five muscles located in the medial compartment of the thigh. These muscles are the adductor longus, adductor brevis, adductor magnus, gracilis, and pectineus.The hip flexors consist of 5 key muscles that contribute to hip flexion: iliacus, psoas, pectineus, rectus femoris, and sartorius.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 35
Correct
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Which of the following is NOT a function of antibodies:
Your Answer: Act as antigen receptors on T lymphocytes
Explanation:Antibodies: Neutralise toxins and prevent attachment of pathogensTarget, opsonise or agglutinate (clump together) antigens for phagocytosisActivate the complement cascade (leading to lysis or opsonisation of the pathogen)Act as antigen receptors on B lymphocytesActivate antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells or T cytotoxic cellsProvide mucosal immunity (IgA-mediated)Stimulate degranulation of mast cells (IgE and IgG mediated)Provide passive immunity to the newborn (through transplacental passage of IgG and secretion of IgA in breast milk)
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 36
Incorrect
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Which of the following is NOT mainly characterised by intravascular haemolysis:
Your Answer: Haemolytic transfusion reactions
Correct Answer: Beta-Thalassaemia
Explanation:Causes of intravascular haemolysis:Haemolytic transfusion reactionsG6PD deficiencyRed cell fragmentation syndromesSome severe autoimmune haemolytic anaemiasSome drug-and infection-induced haemolytic anaemiasParoxysmal nocturnal haemoglobinuria
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This question is part of the following fields:
- Haematology
- Pathology
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Question 37
Incorrect
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Regarding the refractory period, which of the following statements is INCORRECT:
Your Answer: Hyperpolarisation occurs due to delayed closure of K + channels.
Correct Answer: Action potentials can occur in the relative refractory period but the amplitude of the action potential is smaller.
Explanation:Following the action potential, Na+channels remain inactive for a time in a period known as the absolute refractory period where they cannot be opened by any amount of depolarisation. Following this there is a relative refractory period where the temporary hyperpolarisation (due to delayed closure of rectifier K+channels) makes the cell more difficult to depolarise and an action potential can be generated only in response to a larger than normal stimulus. The refractory period limits the frequency at which action potentials can be generated, and ensures that, once initiated, an action potential can travel only in one direction. An action potential is an all or nothing response so the amplitude of the action potential cannot be smaller.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 38
Incorrect
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What is the effect of a positive inotrope on the Starling curve:
Your Answer: Causes a leftward shift along the curve
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 39
Correct
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Regarding bicarbonate handling by the proximal tubule, which of the following statements is CORRECT:
Your Answer: For each H + secreted into the lumen, one Na + and one HCO 3 - is reabsorbed into the plasma.
Explanation:About 80% of bicarbonate is reabsorbed in the proximal tubule. HCO3-is not transported directly, tubular HCO3-associates with H+secreted by epithelial Na+/H+antiporters to form carbonic acid (H2CO3) which readily dissociates to form carbon dioxide and water in the presence of carbonic anhydrase. CO2and water diffuse into the tubular cells, where they recombine to form carbonic acid which dissociates to H+and HCO3-. This HCO3-is transported into the interstitium largely by Na+/HCO3-symporters on the basolateral membrane (and H+is secreted back into the lumen). 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.
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This question is part of the following fields:
- Physiology
- Renal
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Question 40
Correct
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Regarding linear relationships between two variables, what does a positive correlation coefficient indicate:
Your Answer: The two variables are directly proportional
Explanation:A positive correlation coefficient means that the two variables are directly proportional e.g. height and weight in healthy growing children.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 41
Correct
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A 54-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.Which of the following is the patient's preferred drug treatment?
Your Answer: 25% of the mean arterial pressure over the first hour
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 42
Correct
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By which of the following is mean arterial pressure (MAP) primarily determined?
Your Answer: Total peripheral resistance and cardiac output
Explanation:Mean arterial pressure (MAP) = Cardiac output (CO) x Total peripheral resistance (TPR). Cardiac output is dependent on the central venous pressure (CVP). CVP, in turn, is highly dependent on the blood volume. Any alterations of any of these variables will likely change MAP.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 43
Correct
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Which of the following best describes the typical rash of measles:
Your Answer: The typical rash of measles is maculopapular, starting behind the ears and spreading downwards to the trunk.
Explanation:A prodromal 2 – 4 day coryzal illness (fever, cough, conjunctivitis, irritability) normally occurs associated with Koplik’s spots (small white papules found on the buccal mucosa near the first premolars), before a morbilliform maculopapular rash appears, first behind the ears and then spreading downwards to whole body.The rash peels off or fades about about 7 – 10 days. The chickenpox rash is characterised by a maculopapular rash progressing to vesicles and then crusting over. Scarlet fever is characterised by a sandpaper like rash associated with a strawberry tongue.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 44
Incorrect
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A 50-year-old man presents with signs and symptoms of an anaphylactic reaction. His GP had recently given him a new medication.Which one of these is the most likely medication responsible for the drug-induced anaphylactic reaction?
Your Answer: Ibuprofen
Correct Answer: Penicillin
Explanation:The most common cause of drug-induced anaphylaxis is penicillin.The second commonest cause are NSAIDs. Other drugs associated with anaphylaxis are ACE inhibitors and aspirin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 45
Correct
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A new test is being developed to diagnose chlamydia. 1000 people aged 15 – 35 years attending a GUM clinic undergo the new test and the current gold standard nucleic acid amplification test (NAAT) to confirm the diagnosis. Of the 1000 people, 250 are diagnosed with chlamydia. Of the patients diagnosed with chlamydia, 240 test positive with the new diagnostic test and of the patients not diagnosed with chlamydia, 150 test positive with the new diagnostic test. What is the positive predictive value of this test:Chlamydia YesChlamydia NoTotalPositive testa= 240b = 150390Negative testc = 10d = 600610Total2507501000
Your Answer: 0.62
Explanation:Positive predictive value (PPV) is the proportion of individuals with a positive test result who actually have the disease.Positive predictive value (PPV) = a/(a+b) = 240/390 = 0.62 = 62%This means there is a 62% chance, if the test is positive, that the patient actually has chlamydia.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 46
Correct
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A 71-year-old man treated with antibiotics for a chest infection returns with a profuse, offensive smelling diarrhoea. A diagnosis of Clostridium difficile diarrhoea is made after investigations.Which antibiotic is associated with the greatest risk of causing Clostridium Difficile diarrhoea?
Your Answer: Ciprofloxacin
Explanation:Clostridium difficile, a Gram-positive, anaerobic, spore forming bacteria is present in the gut of approximately 3% of healthy adults (2012 UK HPA estimates). Following use of broad spectrum antibiotics, which alter normal gut flora, Clostridium difficile infection (CDI) occurs. About 80% of Clostridium Difficile infections are seen in people over the age of 65 and its main clinical features are:Abdominal cramps, severe bloody and/or watery diarrhoea, offensive smelling diarrhoea, and fever. CDI is the most severe consequence of antibiotic treatment and is a major cause of morbidity and mortality. Risk for CDI has been found to be greatest with clindamycin followed by fluoroquinolones Tetracyclines are not associated with risk for CDI.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 47
Correct
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Regarding dermatophytes, which of the following statement is CORRECT:
Your Answer: Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings.
Explanation:Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings depending on the site of infection. The lesions of ringworm typically have a dark outer ring with a pale centre. Tinea capitis is ringworm affecting the head and scalp. Spread is via direct skin contact. Treatment is usually topical, oral antifungals are reserved for refractory infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 48
Correct
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A 70-year-old man has a resting tremor, rigidity, bradykinesia, and a shuffling gait. Parkinson's disease is caused by one of the following mechanisms:
Your Answer: Loss of dopaminergic neurons in the substantia nigra
Explanation:Parkinson’s disease (PD) is one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years and causing progressive disability that can be slowed but not halted, by treatment. The 2 major neuropathologic findings in Parkinson’s disease are loss of pigmented dopaminergic neurons of the substantia nigra pars compacta and the presence of Lewy bodies and Lewy neurites. See the images below.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 49
Correct
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In the treatment of hypertensive episodes in pheochromocytoma, which of the following medication types is administered as first-line management:
Your Answer: Alpha-blockers
Explanation:The first line of management in controlling blood pressure and preventing intraoperative hypertensive crises is to use a combination of alpha and beta-adrenergic inhibition. In phaeochromocytoma, alpha-blockers are used to treat hypertensive episodes in the short term. Tachycardia can be managed by the careful addition of a beta-blocker, preferably a cardioselective beta-blocker, once alpha blockade has been established. Long term management of pheochromocytoma involves surgery.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 50
Incorrect
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Which of the following is an example of discrete data:
Your Answer: Disease staging system
Correct Answer: Number of children
Explanation:Discrete data is quantitative data that can only take whole numerical values e.g. number of children, number of days missed from work.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 51
Correct
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Regarding endothelin-1, which of the following statements is INCORRECT:
Your Answer: Endothelin-1 release is inhibited by noradrenaline.
Explanation:Endothelin-1 (ET-1) is an extremely potent vasoconstrictor peptide which is released from the endothelium in the presence of many other vasoconstrictors, including angiotensin II, antidiuretic hormone (ADH) and noradrenaline, and may be increased in disease and hypoxia.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 52
Correct
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A patient presents with a rash for dermatological examination. A large area of purplish discolouration of the skin that measures 2 cm in diameter and does not blanch when pressure is applied is seen .What is the best description of this rash that you have found on examination?
Your Answer: Ecchymoses
Explanation:Ecchymosis are discolouration of the skin or mucous membranes caused by extravasation of blood. They are usually red or purple in colour and measure greater than 1 cm in diameter and do not blanch on applying pressure. A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin. Petechiae are discolouration of the skin measuring less than 3 mm in diameterPurpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.Erythema is redness of the skin or mucous membranes caused by hyperaemia of superficial capillaries caused by skin injury, infection or inflammation. Erythema blanches when pressure is applied whereas ecchymosis, purpura and petechiae do not.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 53
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: A positive p24 antigen test
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 54
Correct
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Question 55
Incorrect
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A 46-year-old male who is suffering from a chest infection. You decide to start giving the patient antibiotics, however he is allergic to penicillin. You consult with one of your co-workers about the best choice of antibiotic to give. From the following choices, which is considered an example of bacteriostatic antibiotic?
Your Answer: Ciprofloxacin
Correct Answer: Trimethoprim
Explanation:Antibiotics that are bactericidal kill bacteria, while antibiotics that are bacteriostatic limit their growth or reproduction. The antibiotics grouped into these two classes are summarized in the table below:Bactericidal antibioticsBacteriostatic antibioticsVancomycinMetronidazoleFluoroquinolone, such as ciprofloxacinPenicillins, such as benzylpenicillinCephalosporin, such as ceftriaxoneCo-trimoxazoleTetracyclines, such as doxycyclineMacrolides, such as erythromycinSulphonamides, such as sulfamethoxazoleClindamycinTrimethoprimChloramphenicol
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 56
Incorrect
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Which of these statements about the monospot test is true?
Your Answer: It is an example of an indirect Coombs type test
Correct Answer: It can be positive in rubella
Explanation:Infectious mononucleosis can be diagnosed using specific EBV antibodies and a variety of unrelated non-EBV heterophile antibodies.Heterophile antibodies:About 70-90% of patients with EBV infectious mononucleosis produce antibodies against an antigen produced in one species that react against antigens from other species called heterophile antibodies. False positives can be seen with rubella, hepatitis, SLE, malaria, toxoplasmosis, lymphoma and leukaemia. These antibodies can be detected by two main screening tests:The monospot test uses horse red blood cells. It agglutinates in the presence of heterophile antibodies.Paul-Bunnell test uses sheep red blood cells. The blood agglutinates in the presence of heterophile antibodies.EBV-specific antibodies:Patients can remain heterophile-negative after six weeks and are then considered to be heterophile-negative and should be tested for EBV-specific antibodies. EBV-specific antibodies test are helpful if a false positive heterophile antibody test is suspected.The indirect Coombs test is used to detect in-vitro antibody-antigen reactions. It is typically used in antenatal antibody screening and in preparation for blood transfusion.Heterophile antibody tests are generally not positive in the incubation period of infectious mononucleosis (4-6 weeks) before the onset of symptoms.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 57
Correct
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A 26-year-old woman is currently 9 weeks pregnant. Upon interview and history taking, she mentioned that she visited a friend whose child had just been diagnosed with slapped cheek disease.If the mother contracts an illness during pregnancy, which among the following is not known to cause fetal abnormalities?
Your Answer: Hepatitis A
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)toxoplasmosis, (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:
- Microbiology
- Specific Pathogen Groups
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Question 58
Incorrect
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Regarding NSAIDs, which of the following statements is CORRECT:
Your Answer: Mefenamic acid has very potent anti-inflammatory properties.
Correct Answer: Diclofenac is contraindicated in people with ischaemic heart disease.
Explanation:Due to their increased risk of cardiovascular adverse events, coxibs and diclofenac are contraindicated in people with ischaemic heart disease, cerebrovascular disease, peripheral arterial disease and mild, moderate, or severe heart failure. Other NSAIDs are only contraindicated in people with severe heart failure. Selective inhibition of COX-2 is associated with less gastrointestinal intolerance. In single doses NSAIDs have analgesic activity comparable to that of paracetamol, therefore given their side effect profile, paracetamol is preferred, particularly in the elderly. Pain relief starts soon after taking the first dose and a full analgesic effect should normally be obtained within a week, whereas an anti-inflammatory effect may not be achieved (or may not be clinically assessable) for up to 3 weeks. Mefenamic acid has only very mild anti-inflammatory properties.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 59
Incorrect
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A trauma victim who has been intubated is tachycardic, hypotensive, and has a poor urine output. You feel she is dehydrated and decide to use a central venous catheter to help you manage her. As part of this, you keep an eye on the waveform of central venous pressure (CVP).Which of the following cardiac cycle phases corresponds to the CVP waveform's 'a wave'?
Your Answer: Early systole
Correct Answer: End diastole
Explanation:The pressure measured in the right atrium or superior vena cava is known as central venous pressure (CVP). In a spontaneously breathing subject, the usual CVP value is 0-8 cmH2O (0-6 mmHg).The structure of the CVP waveform is as follows:The CVP’s components are listed in the table below:Component of the waveformThe cardiac cycle phase.mechanical eventmechanical event Diastole Atrial contractiona wave C wave v waveEarly systoleThe tricuspid valve closes and bulges Late Systole Filling of the atrium with systolic blood x descenty descentMid systoleRelaxation of the atrium Early diastoleFilling of the ventricles at an early stage
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 60
Correct
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A 55-year-old female is urgently rushed into the Emergency Department as she complains of chest pain that is worse on breathing, shortness of breath, palpitations, and haemoptysis. She undergoes a CT pulmonary angiogram, which reveals a large pulmonary embolus. She is immediately started on heparin and shifted to the acute medical ward.Which of the following does heparin activate?
Your Answer: Antithrombin III
Explanation:Heparin works by binding to and activating the enzyme inhibitor antithrombin III. Antithrombin III inactivates thrombin (factor IIa) by forming a 1:1 complex with thrombin. The heparin-antithrombin III complex also inhibits factor Xa and some other proteases involved with clotting. The heparin-ATIII complex can also inactivate IX, XI, XII, and plasmin.Heparin is a polymer of glycosaminoglycan. It occurs naturally and is found in mast cells. Clinically, it is used in two forms:1. Unfractionated: widely varying polymer chain lengths2. Low molecular weight: Smaller polymers only Heparin is not thrombolytic or fibrinolytic. It prevents the progression of existing clots by inhibiting further clotting. The lysis of existing clots relies on endogenous thrombolytics.Heparin is used for:1. Prevention and treatment of venous thromboembolism2. Treatment of disseminated intravascular coagulation3. Treatment of fat embolism4. Priming of haemodialysis and cardiopulmonary bypass machines
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 61
Correct
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A patient with history of weight loss and diarrhoea was found out to have Giardia lamblia in her stool since returning from a holiday to Nepal.Which of the following statements is considered true regarding the life cycle of Giardia lamblia?
Your Answer: Trophozoites attach to the intestinal wall via a specialised sucking disc
Explanation:Cysts are resistant forms and are responsible for transmission of giardiasis. Both cysts and trophozoites can be found in the faeces (diagnostic stages). The cysts are hardy and can survive several months in cold water. Infection occurs by the ingestion of cysts in contaminated water, food, or by the faecal-oral route (hands or fomites). In the small intestine, excystation releases trophozoites (each cyst produces two trophozoites).Trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk.Encystation occurs as the parasites transit toward the colon. The cyst is the stage found most commonly in non diarrheal faeces.Because the cysts are infectious when passed in the stool or shortly afterward, person-to-person transmission is possible. While animals are infected with Giardia, their importance as a reservoir is unclear.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 62
Incorrect
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Regarding Escherichia coli, which of the following statements is INCORRECT:
Your Answer: E.coli O157 strain is implicated in the development of haemolytic uraemic syndrome.
Correct Answer: It is a predominant member of the normal flora of the skin.
Explanation:Escherichia coli is a Gram-negative bacilli that is an important member of the intestinal flora. It is the most common cause of UTI in adults (about 70 – 95% of cases), followed by Staphylococcus saprophyticus (about 5 – 10% of cases), and an important cause of neonatal meningitis. E. coli O157 strain is implicated in the development of dysentery associated with haemolytic uraemic syndrome characterised by haemolytic anaemia, thrombocytopenia and acute renal failure.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 63
Incorrect
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As part of his angina treatment, a 68-year-old man is prescribed a beta blocker. He starts having nightmares and has trouble sleeping soon after starting the beta-blocker.Which of the beta blockers listed below is the most likely to be in his system?
Your Answer: Sotalol
Correct Answer: Propranolol
Explanation:The beta-adrenoceptors in the heart, peripheral vasculature, bronchi, pancreas, and liver are blocked by beta-adrenoceptor blocking drugs (beta blockers).Beta blockers come in a wide range of strengths, with the choice largely determined by the disease being treated and the patient’s unique circumstances. The intrinsic sympathomimetic activity, lipid solubility, duration of action, and cardioselectivity of beta blockers all differ.Some beta blockers are lipid (lipophilic) soluble, while others are water soluble (hydrophilic). Drugs that are more lipid-soluble are absorbed faster from the gut, undergo more first-pass metabolism, and are eliminated faster. They’re also more likely to get into the brain and cause central effects like insomnia and nightmares. Propranolol, pindolol, labetalol, and metoprolol are examples of lipid-soluble beta blockers. Beta blockers that are water-soluble are less likely to enter the brain and are more resistant to first-pass metabolism. They are excreted by the kidneys, and in renal impairment, dosage reduction is frequently required. Atenolol, nadolol, celiprolol, and sotalol are examples of water-soluble beta blockers.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 64
Correct
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Which statement concerning aerosol transmission is true?
Your Answer: They can be spread via ventilation systems in hospitals
Explanation:Aerosols are airborne particles less than 5 µm in size containing infective organisms. They usually cause infection of both the upper and/or lower respiratory tract.The organisms can remain suspended in the air for long periods and also survive outside the body. They can be transmitted through the ventilation systems and can spread over great distances. Some examples of organisms transmitted by the aerosol route include: Varicella zoster virus, Mycobacterium tuberculosis and measles virus
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 65
Correct
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A 17-year-old male presenting in the department has a history of C3 deficiency.C3 deficiency is associated with all of the following EXCEPT?
Your Answer: Hereditary angioedema
Explanation:C1-inhibitor deficiency is the cause of hereditary angioedema not C3 deficiency,All the other statements are correct
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 66
Correct
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Na+ is reabsorbed via the Na+/K+/2Cl-symporter in which part of the loop of Henle?
Your Answer: Thick ascending limb
Explanation:In the thick ascending limb is the part of the loop of Henle in which there is active reabsorption of Na+and Cl- ions from the tubular fluid. This occurs via the Na+/K+/2Cl-symporter on the apical membrane. This mechanism is by:1. Na+ions are transported across the basolateral membrane by Na+pumps and the Cl-ions by diffusion. 2. K+leaks back into the tubular fluid via apical ROMK K+channels which creates a positive charge. 3. This positive charge drives the reabsorption of cations (Na+, K+, Ca2+, Mg2+) through paracellular pathways. 4. Due to the thick ascending limb being impermeable to water, the tubular fluid osmolality is reduced by ion reabsorption, the interstitial fluid osmolality is increased, and an osmotic difference is created.
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This question is part of the following fields:
- Physiology
- Renal
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Question 67
Correct
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A 42-year-old patient with worsening epigastric pain has been referred to you by a GP. The patient has been taking omeprazole for a month, but her symptoms are getting worse.Which of the following is NOT a well-known side effect of proton pump inhibitor treatment?
Your Answer: Pelvic fracture
Explanation:Proton pump inhibitors (PPIs) have a variety of side effects, including:Vomiting and nauseaPain in the abdomenFlatulenceDiarrhoeaConstipationHeadachePPIs have been linked to a significant increase in the risk of focal tachyarrhythmias (link is external).Low serum magnesium and sodium levels have been linked to long-term use of PPIs, according to the US Food and Drug Administration (link is external).Long-term PPI use has also been linked to an increased risk of fracture, according to epidemiological evidence (link is external). Observational studies have discovered a slight link between hip, wrist, and spine fractures. However, there is no link between the two and an increased risk of pelvic fracture. For this reason, the MHRA recommends that patients at risk of osteoporosis who take PPIs maintain an adequate calcium and vitamin D intake.
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This question is part of the following fields:
- Gastrointestinal Pharmacology
- Pharmacology
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Question 68
Correct
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A 67-year-old female presents with a history of morning stiffness and arthritis of her hand joints. She is being investigated for rheumatoid arthritis.Which test is most sensitive and specific for this diagnosis?
Your Answer: Anti-CCP
Explanation:Anti-cyclic citrullinated peptide (anti-CCP) is an antibody present in 60-80% of rheumatoid arthritis patients. It is measured by enzyme-linked immunosorbent assay (ELISA). It may be present years before the onset of the disease and is associated with a more severe disease course.While most patients with anti-CCP antibodies are also positive for rheumatoid factor (RF), RF antibody is not specific for rheumatoid arthritis as it can occur in patients with other conditions such as infections and other autoimmune conditions.ESR, antinuclear antibodies(ANA) and Synovial fluid examination are not specific for rheumatoid arthritis.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 69
Correct
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A patient is diagnosed with a Klebsiella infection.Which SINGLE statement regarding Klebsiella infections is true?
Your Answer: Klebsiella spp are an important cause of ventilator-associated pneumonia
Explanation:Klebsiellais a genus of non-motile,Gram-negative, rod-shaped bacteriawith a prominent polysaccharide-based capsule. They are routinely found in the nose, mouth and gastrointestinal tract as normal flora, however, they can also behave as opportunistic pathogens.Infections with Klebsiella spp. areusually nosocomial. They are an important cause of ventilator-associated pneumonia (VAP), urinary tract infection, wound infection and bacteraemia. Outbreaks of infections with Klebsiellaspp. in high-dependency units have been described and are associated with septicaemia and high mortality rates. Length of hospital stay and performance of invasive procedures are risk factors forKlebsiellainfections.Primary pneumonia withKlebsiella pneumoniaeis a rare,severe, community-acquired infection associated with a poor outcome.Klebsiella rhinoscleromatis causes a progressive granulomatous infection of the nasal passages and surrounding mucous membranes. This infection is mainly seen in the tropics.Klebsiella ozanae is a recognised cause of chronic bronchiectasis.Klebsiella organisms are resistant to multiple antibiotics including penicillins. This is thought to be a plasmid-mediated property. Agents with high intrinsic activity againstKlebsiellapneumoniaeshould be selected for severely ill patients. Examples of such agents include third-generation cephalosporins (e.g cefotaxime), carbapenems (e.g. imipenem), aminoglycosides (e.g. gentamicin), and quinolones (e.g. ciprofloxacin). These agents may be used as monotherapy or combination therapy. Aztreonam may be used in patients who are allergic to beta-lactam antibiotics.Species with ESBLs (Extended spectrum beta-lactamase) are resistant to penicillins and also cephalosporins such as cefotaxime and ceftriaxone.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 70
Correct
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Caseous necrosis is typically seen in which of the following:
Your Answer: Tuberculosis
Explanation:Caseous necrosis is most commonly seen in tuberculosis. Histologically, the complete loss of normal tissue architecture is replaced by amorphous, granular and eosinophilic tissue with a variable amount of fat and an appearance reminiscent of cottage cheese.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 71
Correct
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Question 72
Incorrect
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An analytical cohort study aimed to determine a relationship between intake of dietary calcium and incidence of hip fractures among post-menopausal women. The following are the data obtained from the study:No. of post-menopausal women who took Calcium: 500No. of post-menopausal women who took Calcium and suffered a hip fracture: 10No. of post-menopausal women who took placebo: 500No. of post-menopausal women who took placebo and suffered a hip fracture: 25Compute for the absolute risk reduction of a hip fracture.
Your Answer: None of the other options
Correct Answer: 0.03
Explanation:Absolute risk reduction (ARR) is computed as the difference between the absolute risk in the control group (ARC) and the absolute risk in the treatment group (ART).ARR = ARC-ARTARR = (25/500) – (10/500)ARR = 0.03
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This question is part of the following fields:
- Evidence Based Medicine
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Question 73
Correct
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Which of the following body location is the appropriate site to apply pressure when performing a carotid sinus massage?
Your 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 74
Correct
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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 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 75
Correct
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On which of the following is preload primarily dependent?
Your Answer: End-diastolic volume
Explanation:Preload refers to the initial stretching of the cardiac myocytes before contraction. It is therefore related to muscle sarcomere length. The sarcomere length cannot be determined in the intact heart, and so, other indices of preload are used, like ventricular end-diastolic volume or pressure. The end-diastolic pressure and volume of the ventricles increase when venous return to the heart is increased, and this stretches the sarcomeres, which increase their preload.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 76
Incorrect
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A 30-year old male is taken to the emergency room after suffering a blunt trauma to the abdomen. He is complaining of severe abdominal pain, however all his other vital signs remain stable. A FAST scan is performed to assess for hemoperitoneum.If hemoperitoneum is present, it is most likely to be observed in which of the following areas?
Your Answer: Spleen
Correct Answer: Liver
Explanation:The Focused Assessment with Sonography in Trauma (FAST) is an ultrasound protocol developed to assess for hemoperitoneum and hemopericardium. Numerous studies have demonstrated sensitivities between 85% to 96% and specificities exceeding 98%.The FAST exam evaluates four regions for pathologic fluid: (1) the right upper quadrant, (2) the subxiphoid (or subcostal) view, (3) the left upper quadrant, and (4) the suprapubic region.The right upper quadrant (RUQ) visualizes the hepatorenal recess, also known as Morrison’s pouch, the right paracolic gutter, the hepato-diaphragmatic area, and the caudal edge of the left liver lobe. The probe is positioned in the sagittal orientation along the patient’s flank at the level of the 8 to 11 rib spaces. The hand is placed against the bed to ensure visualization of the retroperitoneal kidney. The RUQ view is the most likely to detect free fluid with an overall sensitivity of 66%. Recent retrospective evidence suggests the area along the caudal edge of the left lobe of the liver has the highest sensitivity, exceeding 93%.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 77
Correct
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A patient presents with an adducted eye at rest which cannot abduct past the midline, which of the following cranial nerves is most likely to be affected:
Your Answer: Abducens nerve
Explanation:Abducens nerve palsies result in a convergent squint at rest (eye turned inwards) with inability to abduct the eye because of unopposed action of the rectus medialis. The patient complains of horizontal diplopia when looking towards the affected side. With complete paralysis, the eye cannot abduct past the midline.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 78
Correct
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A patient presents with a history of renal problems, generalised weakness and palpitations. Her serum potassium levels are measured and come back at 6.2 mmol/L. An ECG is performed, and it shows some changes that are consistent with hyperkalaemia.Which of the following ECG changes is usually the earliest sign of hyperkalaemia? Select ONE answer only.
Your Answer: Peaked T waves
Explanation:Hyperkalaemia causes a rapid reduction in resting membrane potential leading to increased cardiac depolarisation and muscle excitability. This in turn results in ECG changes which can rapidly progress to ventricular fibrillation or asystole. Very distinctive ECG changes that progressively change as the K+level increases:K+>5.5 mmol/l – peaked T waves (usually earliest sign of hyperkalaemia), repolarisation abnormalitiesK+>6.5 mmol/l – P waves widen and flatten, PR segment lengthens, P waves eventually disappearK+>7.0 mmol/l – Prolonged QRS interval and bizarre QRS morphology, conduction blocks (bundle branch blocks, fascicular blocks), sinus bradycardia or slow AF, development of a sine wave appearance (a pre-terminal rhythm)K+>9.0 mmol/l – Cardiac arrest due to asystole, VF or PEA with a bizarre, wide complex rhythm.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 79
Incorrect
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Cryptococcus neoformans is primarily transmitted by which of the following routes:
Your Answer: Respiratory droplet spread
Correct Answer: Inhalation of spores
Explanation:Cryptococcus neoformans is found in bird droppings and transmission is by inhalation of spores, thus the lung is the primary site of infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 80
Correct
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Question 81
Incorrect
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Regarding cytotoxic T cells, which of the following statements is CORRECT:
Your Answer: They form the majority of the circulating T-cell population.
Correct Answer: They kill target cells by inducing cell apoptosis.
Explanation:CD8+ T-cells (Cytotoxic T cells)Recognise antigen only in association with HLA Class I molecules (found on all nucleated cells; present endogenous antigens such as those found in cells infected by viruses or intracellular bacteria.)Comprise about 25% of peripheral T-cellsResponsible for cytotoxic killing of target cells
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 82
Correct
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Regarding hepatitis C, which of the following statements is INCORRECT:
Your Answer: Anti-HCV IgG antibodies are diagnostic of acute infection.
Explanation:Anti-HCV IgG antibodies indicate exposure to hepatitis C but this could be acute, chronic or resolved infection. If the antibody test is positive, HCV RNA should be tested for, which if positive indicates that a person has current infection with active hepatitis C.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 83
Correct
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A 25-year-old patient requires procedural sedation for reduction of an open fracture of his tibia and fibula. You plan on using ketamine as the sedative agent.Ketamine works as a result of action on what type of receptor? Select ONE answer only.
Your Answer: N-methyl-D-aspartate (NMDA)
Explanation:Ketamine is the only anaesthetic agent available that has analgesic, hypnotic, and amnesic properties. When used correctly it is a very useful and versatile drug.Ketamine acts by non-competitive antagonism of the NMDA receptor Ca2+ channel pore and also inhibits NMDA receptor activity by interaction with the phencyclidine binding site.Ketamine can be used intravenously and intramuscularly. The intramuscular dose is 10 mg/kg, and when used by this route, it acts within 2-8 minutes and has a duration of action of 10-20 minutes. The intravenous dose is 1.5-2 mg/kg administered over a period of 60 seconds. When used intravenously, it acts within 30 seconds and has a duration of action of 5-10 minutes. Ketamine is also effective when administered orally, rectally, and nasally.Ketamine causes tachycardia, an increase in blood pressure, central venous pressure, and cardiac output, secondary to an increase in sympathetic tone. Baroreceptor function is well maintained, and arrhythmias are uncommon.The main disadvantage to the use of ketamine is the high incidence of hallucinations, nightmares, and other transient psychotic effects. These can be reduced by the co-administration of a benzodiazepine, such as diazepam or midazolam.The main side effects of ketamine are:Nausea and vomitingHypertensionNystagmusDiplopiaRash
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 84
Correct
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In ventricular myocytes, the plateau phase of the action potential comes about through which of the following:
Your Answer: Opening of voltage-gated Ca 2+ channels
Explanation:After the intial upstroke of the action potential, Na+channels and currents rapidly inactivate, but in cardiac myocytes, the initial depolarisation activates voltage-gated Ca2+channels (slow L-type channels, threshold approximately – 45 mV) through which Ca2+floods into the cell. The resulting influx of Ca2+prevents the cell from repolarising and causes a plateau phase, that is maintained for about 250 ms until the L-type channels inactivate. The cardiac AP is thus much longer than that in nerve or skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 85
Correct
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Which of the following decreases activation of vitamin D:
Your Answer: Chronic renal failure
Explanation:Calcium deficiency (low Ca2+ diet or hypocalcemia) activates 1-alpha-hydroxylase in the cells of the renal proximal tubule which catalyses the conversion of vitamin D to its active form, 1,25-dihydroxycholecalciferol. Increased parathyroid hormone (PTH) and hypophosphatemia also stimulate the enzyme. Chronic renal failure is associated with a constellation of bone diseases, including osteomalacia caused by failure of the diseased renal tissue to produce the active form of vitamin D.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 86
Correct
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A 45-year-old man, a known case of epilepsy, visits his neurologist with complaints of red, swollen gums.Which of the following medications is most likely responsible for his symptoms?
Your Answer: Phenytoin
Explanation:Phenytoin is a commonly used antiepileptic drug. A well-recognized side-effect of phenytoin is gingival enlargement and occurs in about 50% of patients receiving phenytoin. It is believed that reduced folate levels may cause this, and evidence suggests that folic acid supplementation may help prevent this in patients starting phenytoin. As evidence suggests, drug-induced gingival enlargement may also improve by substituting with other anticonvulsant drugs and reinforcing a good oral hygiene regimen. Surgical excision of hyperplastic gingiva is often necessary to correct the aesthetic and functional impairment associated with this condition to manage it successfully.Phenytoin is also the only anticonvulsant therapy associated with the development of Dupuytren’s contracture.Other side effects are:1. Ataxia2. Drug-induced lupus3. Hirsutism4. Pruritic rash5. Megaloblastic anaemia6. Nystagmus
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 87
Correct
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Identify the type of graph described below:A graph that is a useful summary of a set of bivariate data (two variables), usually drawn before working out a linear correlation coefficient or fitting a regression line.
Your Answer: Scatterplot
Explanation:A scatterplot is a useful summary of a set of bivariate data (two variables), usually drawn before working out a linear correlation coefficient or fitting a regression line. It gives a good visual picture of the relationship between the two variables, and aids the interpretation of the correlation coefficient or regression model. Each unit contributes one point to the scatterplot, on which points are plotted but not joined. The resulting pattern indicates the type and strength of the relationship between the two variables.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 88
Correct
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A 70-year-old patient diagnosed with Cushing's syndrome, has a history of weight gain, hypertension, and easy bruising.Which of the following statements about Cushing's syndrome is NOT true?
Your Answer: Menorrhagia is a common feature
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.Iatrogenic corticosteroid injection is the most prevalent cause of Cushing’s syndrome.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.Insulin resistance causes hyperglycaemia, which is a frequent symptom. Insulin resistance can produce acanthosis nigricans in the axilla and around the neck, as well as other skin abnormalities.In contrast to menorrhagia, elevated testosterone levels are more likely to produce amenorrhoea or oligomenorrhoea. Infertility in women of reproductive age can also be caused by high androgen levels.A dexamethasone suppression test or a 24-hour urine free cortisol collection can both be used to establish the existence of Cushing’s syndrome.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 89
Correct
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A 45-year old man presented to the emergency room with complains of chest pain and breathlessness. Upon history taking and examination, it was discovered that he had a right-sided spontaneous pneumothorax and had a failed attempt at pleural aspiration. The pneumothorax is still considerable in size, but he remains breathless. A Seldinger chest drain was inserted but it started to drain frank blood shortly after. Which of the following complications is most likely to have occurred?
Your Answer: Intercostal artery laceration
Explanation:Injury to the intercostal artery (ICA) is an infrequent but potentially life-threatening complication of all pleural interventions. Traditional anatomy teaching describes the ICA as lying in the intercostal groove, protected by the flange of the rib. This is the rationale behind the recommendation to insert needles just above the superior border of the rib. Current recommendations for chest drain insertion suggest that drains should be inserted in the ‘safe triangle’ in order to avoid the heart and the mediastinum and be above the level of the diaphragm. The safe triangle is formed anteriorly by the lateral border of the pectoralis major, laterally by the lateral border of the latissimus dorsi, inferiorly by the line of the fifth intercostal space and superiorly by the base of the axilla. Imaging guidance also aids in the safety of the procedure.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 90
Incorrect
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One of the following pathogens is a conditional pathogen:
Your Answer: Treponema pallidum
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 91
Correct
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An 80-year-old woman with history of hypertension, diabetes, and ischemic stroke, presents with left-sided hemiplegia of the face, tongue, and limbs and right-sided deficits in motor eye activity. A CT scan was ordered and showed a right-sided stroke. Branches of which of the following arteries are most likely implicated in the case?
Your Answer: Basilar artery
Explanation:Weber syndrome is a midbrain stroke characterized by crossed hemiplegia along with oculomotor nerve deficits and it occurs with the occlusion of the median and/or paramedian perforating branches of the basilar artery. Typical clinical findings include ipsilateral CN III palsy, ptosis, and mydriasis (such as damage to parasympathetic fibres of CN III) with contralateral hemiplegia.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 92
Correct
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A 71-year-old man treated with antibiotics for a chest infection returns with a profuse, offensive smelling diarrhoea. A diagnosis of Clostridium difficile diarrhoea is made after investigations.The action most effective at minimizing spread to other patients is?
Your Answer: Hand washing
Explanation:Clostridium difficile, a Gram-positive, anaerobic, spore forming bacteria is present in the gut of approximately 3% of healthy adults (2012 UK HPA estimates). Following use of broad spectrum antibiotics, which alter normal gut flora, Clostridium difficile associated diarrhoea (CDAD) occurs.Alcohol hand gel is not effective against Clostridium Difficile spores. Hand washing with soap and water is very essential for healthcare workers who come in contact with it.Wearing an apron and gloves, and isolation to a side room are important contact precautions. They are, however, ineffective if hand washing is neglected.Although oral vancomycin is the first-line treatment for C. difficile associated diarrhoea, it will not limit patient to patient spread.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 93
Correct
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Which of the following muscles inserts into the patella?
Your Answer: The quadriceps femoris complex
Explanation:The quadriceps femoris muscle translates to “four-headed muscle” from Latin. It bears this name because it consists of four individual muscles; rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. Out of all four muscles, only the rectus femoris crosses both the hip and knee joints. The others cross only the knee joint. These muscles differ in their origin, but share a common quadriceps femoris tendon which inserts into the patella. The function of the quadriceps femoris muscle is to extend the leg at the knee joint and to flex the thigh at the hip joint.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 94
Correct
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A 33-year-old woman demonstrates right-sided superior homonymous quadrantanopia upon visual field testing. A diagnosis of a brain tumour has been established.Which of the following anatomical points in the visual pathway has the lesion occurred?
Your Answer: Lower optic radiation
Explanation:Homonymous quadrantanopia is not a disease; it is a clinical finding that points towards a lesion of the optic radiations coursing through the temporal lobe.Homonymous superior quadrantanopia is caused by damage to the contralateral inferior parts of the posterior visual pathway: the inferior optic radiation (temporal Meyer loop), or the inferior part of the occipital visual cortex below the calcarine fissure.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 95
Incorrect
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How does an action potential in the motor end plate rapidly spread to the central portions of the muscle cells?
Your Answer: Pores in the plasma membrane
Correct Answer: Transverse tubules
Explanation:When the concentration of intracellular Ca2+rises, muscle contraction occurs. The pathway of an action potential is down tube-shaped invaginations of the sarcolemma called T-tubules (transverse tubules). These penetrate throughout the muscle fibre and lie adjacent to the terminal cisternae of the sarcoplasmic reticulum. The voltage changes in the T-tubules result in the opening of sarcoplasmic reticulum Ca2+channels and there is there is release of stored Ca2+into the sarcoplasm. Thus muscle contraction occurs via excitation-contraction coupling (ECC) mechanism.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 96
Incorrect
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Which of the following neurotransmitter and receptor combinations is present at the neuromuscular junction:
Your Answer: Noradrenaline acting at beta receptors
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 97
Correct
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Mast cells play a significant part in which of the following?
Your Answer: Allergic disease
Explanation:Mast cells play a central role in the response to allergen challenges. The activation of mast cells results in both an early and a delayed phase of inflammation. Mast cells have been implicated in both physiologic and pathogenic processes. Mast cells are important in defence against some bacteria and viruses and contribute to defence against parasites. They are key effector cells in both innate and acquired immunity and are capable of inducing and amplifying both types of responses. Specifically, mast cells are capable of detecting microbial products through surface pattern recognition receptors, and they are involved in the recruitment of other leukocytes, containment of bacterial infections, and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 98
Correct
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A 65-year-old female presents to the Emergency Department with complaints of chest pain pointing to angina. A dose of glyceryl trinitrate (GTN) was administered, rapidly resolving her symptoms. Unfortunately, she develops a side-effect of the drug.Which one of the following is the side effect she is most likely to have developed?
Your Answer: Flushing
Explanation:Angina pectoris is the most common symptom of ischemic heart disease and presents with chest pain relieved by rest and nitro-glycerine. Nitrates are the first-line treatment to relieve chest pain caused by angina. The commonly used nitrates are: 1. Glyceryl trinitrate 2. Isosorbide dinitrate Side effects to nitrate therapy are common especially The most common side effects are:1. Headaches2. Feeling dizzy, weak, or tired3. Nausea4. Flushing The serious but less likely to occur side effects are:1. Methemoglobinemia (rare)2. Syncope3. Prolonged bleeding time4. Exfoliative dermatitis5. Unstable angina6. Rebound hypertension7. ThrombocytopeniaDry eyes, bradycardia, and metabolic acidosis have not been reported.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 99
Correct
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Which of the following is NOT an advantage of a cohort study used to investigate the relationship between exposure to a risk factor and a future outcome:
Your Answer: Particularly suitable for rare diseases
Explanation:Advantages: ideal for studying associations between an exposure and an outcome when the exposure is uncommon, the time sequence of events can be assessed, they can provide information on a wide range of disease outcomes, the absolute and relative risk of disease can be measured directly, they can give a direct estimation of disease incidence ratesDisadvantages: costly and can take long periods of time if the outcome is delayed, subject to subject-selection and loss to follow-up bias, large sample size required for rare outcome of interest so it is not useful for rare diseases, prone to confounding
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 100
Incorrect
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You review an 18-months-old child who seems to be having a reaction following an immunisation she took earlier in the day.Which statement concerning immunity and vaccination is true?
Your Answer: Vaccination induces passive adaptive immunity
Correct Answer: The strongest immunological response is seen with natural immunity
Explanation:Vaccination induces ACTIVE adaptive immunity. Actively acquired immunity involves the development of an immune response either due to vaccination or natural exposure to a pathogen and leads to long-lasting resistance to infection.Immediate protection is achieved with injection of immunoglobulin. The protection is transient lasting only a few weeks and is useful as post-exposure prophylaxis. Passively acquired immunity usually leads to short-lasting resistance to infection because it does not involve a host immune response. With inactivated bacteria, a series of primary vaccinations is usually required to induce an adequate immune response. In most cases, boosters are required to sustain adequate immunity.
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This question is part of the following fields:
- General Pathology
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
