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Question 1
Correct
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What is the mechanism of action of captopril:
Your Answer: Angiotensin-converting enzyme inhibitor
Explanation:Captopril is an angiotensin-converting enzyme (ACE) inhibitor, which inhibits the conversion of angiotensin I to angiotensin II.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 2
Incorrect
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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:
Correct 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 3
Incorrect
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A 24-year-old man goes to the emergency department with a fever, headache, and swollen parotid glands that are excruciating. You have a suspicion that it is mumps. Which of the following nerves is causing the discomfort the patient is experiencing:
Your Answer:
Correct Answer: Auriculotemporal nerve
Explanation:The auriculotemporal nerve is irritated by mumps, which results in significant discomfort due to inflammation and swelling of the parotid gland, as well as the stretching of its capsule. Compression caused by swallowing or chewing exacerbates pain.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 4
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:
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 5
Incorrect
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Which of the following is diagnostic for acute hepatitis B infection:
Your Answer:
Correct Answer: anti-HBc IgM
Explanation:Anti-HBc IgM antibodies are diagnostic for acute hepatitis B infection. Anti-HBc IgG antibodies indicate previous exposure, either chronic state or cleared infection. HBsAg is also positive in acute infection but is not diagnostic as this remains positive in chronic infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 6
Incorrect
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Regarding ciprofloxacin, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Ciprofloxacin decreases plasma concentrations of theophylline.
Explanation:Ciprofloxacin increases plasma concentrations of theophylline. There is an increased risk of convulsions when quinolones are given with NSAIDs or theophylline. There is an increased risk of tendon damage when quinolones are given with corticosteroids. Quinolones are known to increase the QT-interval and should not be taken with concomitantly with other drugs that are known to cause QT-interval prolongation. There is an increased risk of myopathy when erythromycin or clarithromycin are taken with simvastatin or atorvastatin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 7
Incorrect
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Regarding Hodgkin lymphoma, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Some patients may complain alcohol-induced nodal pain and pruritus
Explanation:Lymphomas are a group of diseases caused by malignant lymphocytes that accumulate in lymph nodes and other lymphoid tissue and cause the characteristic clinical feature of lymphadenopathy. The major subdivision of lymphomas is into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) and this is based on the histological presence of Reed-Sternberg cells present in HL. Hodgkin lymphoma can present at any age but is rare in children and has a peak incidence in young adults. There is an almost 2 : 1 male predominance. Most patients present with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes. Cervical nodes are involved in 60-70% of cases, axillary nodes in 10-15% and inguinal nodes in 6-12%. Modest splenomegaly occurs during the course of the disease in 50% of patients; the liver may also be enlarged. Bone marrow failure involvement is unusual in early disease. The prognosis depends on age, stage and histology, but overall approximately 85% of patients are cured. Alcohol‐induced pain and pruritus are two well‐known but rare symptoms in HL.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 8
Incorrect
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The percentage of patients with hepatitis B that develop chronic infection is about:
Your Answer:
Correct Answer: 10%
Explanation:With hepatitis B, about 90% of people will develop lifelong immunity after clearing the infection. Chronic hepatitis develops in about 10% of patients and this may be complicated by cirrhosis or hepatocellular carcinoma. There is a very high risk of chronic infection and hepatocellular carcinoma when there is congenital infection. The risk of this in healthy adults is only about 5%.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 9
Incorrect
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How does abciximab mediate its antiplatelet effect:
Your Answer:
Correct Answer: It is a GPIIb/IIIa inhibitor.
Explanation:Abciximab, eptifibatide and tirofiban are GPIIb/IIIa inhibitors, inhibiting platelet aggregation by preventing the binding of fibrinogen, von Willebrand factor and other adhesive molecules.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 10
Incorrect
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A 14-year-old female is brought to the Emergency Room by her mother after a fall from a tree in which she injured her elbow. An elbow fracture is suspected based on the examination findings, and she is given Entonox for analgesia as her elbow is set in a cast.
Which one of the following statements regarding this drug is true?Your Answer:
Correct Answer: It can cause inhibition of vitamin B12 synthesis
Explanation:Entonox is a mixture of 50% Oxygen and 50% nitrous oxide and is given in an inhaled form as a quick form of analgesia. Entonox causes non-competitive inhibition of NMDA (N-methyl-D-aspartate) receptors, which are a subtype of the glutamate receptor.
It is stored in blue and white cylinders and administered via a pressure regulator and demand valve. The administration of this medicine reduces pain and anxiety in paediatric and dental procedures ands during labour.
Effects are apparent after 20 seconds, and peak action occurs after 3 to 5 minutes as it is a drug with a rapid onset and the patient will also recover rapidly from its effects. Entonox is widely used as it does not accumulate in the body and does not cause many side effects. However, a notable side effect is the inhibition of Vitamin B12 synthesis.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 11
Incorrect
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Which one of these equations best defines lung compliance?
Your Answer:
Correct Answer: Change in volume / change in pressure
Explanation:Lung compliance is defined as change in volume per unit change in distending pressure.
Lung compliance is calculated using the equation:
Lung compliance = ΔV / ΔP
Where:
ΔV is the change in volume
ΔP is the change in pleural pressure.Static compliance is lung compliance in periods without gas flow, and is calculated using the equation:
Static compliance = VT / Pplat − PEEP
Where:
VT = tidal volume
Pplat = plateau pressure
PEEP = positive end-expiratory pressure -
This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 12
Incorrect
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Regarding the penis, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The corpus spongiosum is ventral in the erect penis.
Explanation:Because the anatomical position of the penis is erect, the paired corpora cavernosa are defined as dorsal in the body of the penis and the single corpus spongiosum as ventral. The nerves and vessels lie superficial to the corpus cavernosum. The urethra lies within the corpus spongiosum.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 13
Incorrect
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All of the following statements are considered true regarding randomized control trials, except:
Your Answer:
Correct Answer: They can eliminate the need for further studies
Explanation:Meta-analysis is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis. The examination of variability or heterogeneity in study results is also a critical outcome.
The benefits of meta-analysis include a consolidated and quantitative review of a large, and often complex, sometimes apparently conflicting, body of literature. The specification of the outcome and hypotheses that are tested is critical to the conduct of meta-analyses, as is a sensitive literature search.Important medical questions are typically studied more than once, often by different research teams in different locations. In many instances, the results of these multiple small studies of an issue are diverse and conflicting, which makes the clinical decision-making difficult. The need to arrive at decisions affecting clinical practise fostered the momentum toward evidence-based medicine. Evidence-based medicine may be defined as the systematic, quantitative, preferentially experimental approach to obtaining and using medical information. Therefore, meta-analysis, a statistical procedure that integrates the results of several independent studies, plays a central role in evidence-based medicine.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 14
Incorrect
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A patient presents with a laceration on his hand and wrist that has cut the nerve that innervates opponens pollicis.
The opponens pollicis muscle is innervated by which of the following nerves? Select ONE answer only.Your Answer:
Correct Answer: The recurrent branch of the median nerve
Explanation:Opponens pollicis is a small, triangular muscle that forms part of the thenar eminence. It originates from the flexor retinaculum and the tubercle of trapezium bone and inserts into the whole length of the first metacarpal bone on its radial side.
Opponens pollicis is innervated by the recurrent branch of the median nerve and receives its blood supply from the superficial palmar arch.
The main action of opponens pollicis is to flex the first metacarpal bone at the carpometacarpal joint, which opposes the thumb towards the centre of the palm. It also medially rotates the first metacarpal bone at the carpometacarpal joint. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 15
Incorrect
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Which of the following medications may lessen warfarin's anticoagulant effect:
Your Answer:
Correct Answer: Phenytoin
Explanation:Phenytoin will decrease the level or effect of warfarin by affecting hepatic/intestinal enzyme CYP3A4 metabolism.
Metronidazole will increase the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism.
NSAIDs, when given with Warfarin, increase anticoagulation. -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 16
Incorrect
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All of the following statements are incorrect about insulin except:
Your Answer:
Correct Answer: Proinsulin is cleaved into insulin and C peptide.
Explanation:Proinsulin is synthesised as a single-chain peptide. A connecting peptide (C peptide) within storage granules is removed by proteases to yield insulin.
Insulin:
1. is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds.
2. is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas.
3. release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin. However, most output is driven by the rise in plasma glucose concentration that occurs after a meal.
4. effects are mediated by the receptor tyrosine kinase. -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 17
Incorrect
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Regarding fibrinolytics, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Fibrinolytic drugs act as thrombolytics by directly degrading the fibrin mesh and so breaking up thrombi.
Explanation:Fibrinolytic drugs act as thrombolytics by activating plasminogen to form plasmin, which degrades fibrin and so breaks up thrombi.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 18
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:
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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Question 19
Incorrect
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The flow of ions across a cell membrane causes electrical activity in biological tissues. Excitable tissues are specialized tissues that may generate a significant electrical signal called an action potential, which is followed by a refractory period.
Which set of ion channels is responsible for the refractory period?Your Answer:
Correct Answer: Sodium channels
Explanation:A refractory period follows each action potential. The absolute refractory time and the relative refractory period are two divisions of refractory periods. Because the sodium channels seal after an AP, they enter an inactive state during which they cannot be reopened regardless of membrane potential, this time occurs.
The sodium channels slowly come out of inactivation during the relative refractory period that follows. During this time, a stronger stimulus than that required to initiate an action potential can excite the cell. The strength of the stimulus required early in the relative refractory period is relatively high, and it steadily decreases as more sodium channels recover from the inactivation of the refractory period.
Nodes of Ranvier are periodic holes in a myelinate axon when there is no myelin and the axonal membrane is exposed. There are no gated ion channels in the portion of the axon covered by the myelin sheath, but there is a high density of ion channels in the Nodes of Ranvier. Action potentials can only occur at the nodes as a result of this.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 20
Incorrect
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An ambulance transports a 23-year-old woman who has taken a witnessed overdose of her mother's diazepam tablets. She has no significant medical history and does not take any medications on a regular basis.
In this case, what is the SINGLE MOST APPROPRIATE FIRST DRUG TREATMENT?Your Answer:
Correct Answer: Flumazenil IV 200 μg
Explanation:Flumazenil is a benzodiazepine antagonist that can be helpful in some overdose situations. It works quickly (in less than a minute), but the effects are fleeting, lasting less than an hour. The dose is 200 micrograms every 1-2 minutes with a maximum dose of 3 milligrams per hour.
Flumazenil should be avoided by patients who are addicted to benzodiazepines or who take tricyclic antidepressants because it can cause withdrawal symptoms. It can cause seizures or cardiac arrest in these situations.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 21
Incorrect
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Superficial fibular nerve palsy results in which of the following clinical features:
Your Answer:
Correct Answer: Loss of eversion of the foot
Explanation:Damage to the superficial fibular nerve results in loss of eversion of the foot and loss of sensation over the lower anterolateral leg and the dorsum of the foot.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 22
Incorrect
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Compliance is decreased by all but which one of the following:
Your Answer:
Correct Answer: Aging
Explanation:Factors increasing compliance:
Old age
EmphysemaFactors decreasing compliance:
Pulmonary fibrosis
Pulmonary oedema
Atelectasis
Extremes of lung volumes (at higher lung volumes the compliance of the lung becomes less as the lung becomes stiffer) -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 23
Incorrect
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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:
Correct 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 24
Incorrect
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A 70-year-old man presents with right-sided hemiplegia and loss of joint position sense, vibratory sense, and discriminatory touch. Upon further physical examination, it was observed that her tongue deviates to the left-hand side. An MRI and CT scan was ordered and results showed that he was suffering a left-sided stroke.
Which of the following is considered the best diagnosis for the case presented above?Your Answer:
Correct Answer: Medial medullary syndrome
Explanation:Medial medullary syndrome is a form of stroke that affects the medial medulla of the brain. It is caused by a lesion in the medial part of the medulla, which is due to an infraction of vertebral arteries and/or paramedian branches of the anterior spinal artery.
It is characterized by contralateral paralysis of the upper and lower limb of the body, a contralateral decrease in proprioception, vibration, and/or fine touch sensation, paresthesias or less commonly dysesthesias in the contralateral trunk and lower limb, and loss of position and vibration sense with proprioceptive dysfunction. Ipsilateral deviation of the tongue due to ipsilateral hypoglossal nerve damage can also be seen.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 25
Incorrect
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Regarding postural hypotension, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Postural hypotension usually causes a reflex bradycardia.
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 26
Incorrect
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A 20-year-old male who is a known patient of sickle cell disease presents to the Emergency Room with a sustained erection that is extremely painful.
Out of the following clinical syndromes, which one does this patient most likely have?Your Answer:
Correct Answer: Priapism
Explanation:Sickling of red blood cells can lead to several different clinical syndromes. If the sickling occurs in the corpora cavernosa, it can lead to a sustained, painful erection of the penis, referred to as priapism. One of the complications is long-term impotence. It is important to seek a urological opinion immediately in this case, but in the interim, treat with perineal ice packs and walk up and down the stairs.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 27
Incorrect
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All of the following statements are considered true regarding likelihood ratios, except:
Your Answer:
Correct Answer: If less than one, indicates that the information increases the likelihood of the suspected diagnosis
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.
A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 28
Incorrect
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Which of the following muscles is NOT involved in depression of the mandible:
Your Answer:
Correct Answer: Masseter
Explanation:Depression of the mandible is generated by the digastric, geniohyoid, mylohyoid and lateral pterygoid muscles on both side, assisted by gravity. The lateral pterygoid muscles are also involved as this movement also involves protraction of the mandible. The masseter muscle is a powerful elevator of the mandible.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 29
Incorrect
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A patient presents with pain in the wrist and a tingling in the hand. On examination Tinel's test is positive and you diagnose carpal tunnel syndrome. Regarding the carpal tunnel, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The tendons of the flexor digitorum profundus, flexor digitorum superficialis and flexor pollicis longus lie within a single synovial sheath.
Explanation:Free movement of the tendons in the carpal tunnel is facilitated by synovial sheaths, which surround the tendons. All of the tendons of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) are contained within a single synovial sheath with a separate sheath enclosing the tendon of the flexor pollicis longus (FPL).
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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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How is filtered K+mainly reabsorbed in the thick ascending limb of the loop of Henle:
Your Answer:
Correct Answer: Secondary active transport via Na + /K + /2Cl - cotransporter
Explanation:Around 30% of filtered K+is reabsorbed in the thick ascending limb of the loop of Henle, primarily via the luminal Na+/K+/2Cl-cotransporter, but there is also significant paracellular reabsorption, encouraged by the positive potential in the tubular lumen.
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This question is part of the following fields:
- Physiology
- Renal
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SESSION STATS - PERFORMANCE PER SPECIALTY
