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Question 1
Correct
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A newborn baby girl is delivered vaginally to a 19-year old female, however with complications due to cephalopelvic disproportion. Upon examination by the attending paediatrician, there is a notable 'claw hand' deformity of the left, and sensory loss of the ulnar aspect of the left distal upper extremity.
What is the most probable diagnosis of the case above?Your Answer: Klumpke’s palsy
Explanation:Klumpke palsy, named after Augusta Dejerine-Klumpke, is a neuropathy involving the lower brachial plexus. In contrast, the more common Erb–Duchenne palsy involves the more cephalic portion of the brachial plexus C5 to C6. The brachial plexus is a bundle of individual nerves that exit between the anterior and middle scalene muscles in the anterior lateral and basal portion of the neck. Although the most common anatomical presentation of the brachial plexus is between the anterior and middle scalene, there are variations, with the most common being penetration of the anterior scalene. The main mechanism of injury to the lower brachial plexus is hyper-abduction traction, and depending on the intensity, it will lead to signs and symptoms consistent with a neurological insult.
The most common aetiology resulting in Klumpke palsy is a hyper-abduction trauma to the arm that has enough intensity to traction the lower brachial plexus. Trauma during birth can cause brachial plexus injuries, but again hyper-abduction and traction forces to the upper extremity are usually present.
The history presented by the patient usually depicts a long axis hyper-abduction traction injury with high amplitude and velocity. The typical patient presentation is a decrease of sensation along the medial aspect of the distal upper extremity along the C8 and T1 dermatome. The patient might also present myotome findings that can range from decreasing muscular strength to muscular atrophy and positional deformity. For example, if the neurological damage has led to muscular atrophy and tightening, the patient may present with a claw hand. This deformity presents a finger and wrist flexion. The patient may also describe the severe pain that starts at the neck and travels down the medial portion of the arm. One other sign of a lower brachial plexus injury is Horner syndrome; because of its approximation to the T1 nerve root, it may damage the cephalic sympathetic chain. If this happens, the patient will develop ipsilateral ptosis, anhidrosis, and miosis.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 2
Correct
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A patient with rash is examined. He has some redness of the skin that blanches when finger pressure is applied.
What is the best description of this rash that you have found on examination?Your Answer: Erythema
Explanation: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.
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 diameter
Purpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 3
Correct
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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: 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 4
Correct
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The average BP reading on ambulatory blood pressure monitoring for a 59-year-old Caucasian man is 152/96 mmHg (ABPM).
The first-line drug treatment for this patient would be which of the following? Please only choose ONE answer.Your Answer: Amlodipine
Explanation:An ambulatory blood pressure reading of >150/95 is classified as stage 2 hypertension, according to the NICE care pathway for hypertension, and the patient should be treated with an antihypertensive drug.
A calcium-channel blocker, such as amlodipine, would be the most appropriate medication for a 59-year-old Caucasian man.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 5
Incorrect
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Identify the type of graph described below:
This graph is a useful tool for evaluating the performance of diagnostic tests and more generally for evaluating the accuracy of a statistical model (e.g., logistic regression, linear discriminant analysis) that classifies subjects into 1 of 2 categories, diseased or non diseased. The closer the graph is to the upper left corner, which represents 100% sensitivity and 100% specificity, the more accurate the diagnostic test.Your Answer: Kaplan-Meier plot
Correct Answer: ROC curve
Explanation:Receiver-operating characteristic (ROC) analysis was originally developed during World War II to analyse classification accuracy in differentiating signal from noise in radar detection. Recently, the methodology has been adapted to several clinical areas heavily dependent on screening and diagnostic tests, in particular, laboratory testing, epidemiology, radiology, and bioinformatics. ROC analysis is a useful tool for evaluating the performance of diagnostic tests and more generally for evaluating the accuracy of a statistical model (e.g., logistic regression, linear discriminant analysis) that classifies subjects into 1 of 2 categories, diseased or non diseased. Its function as a simple graphical tool for displaying the accuracy of a medical diagnostic test is one of the most well-known applications of ROC curve analysis.
The closer the ROC curve is to the upper left corner, which has 100% sensitivity and 100% specificity, the higher the overall accuracy of the diagnostic test.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 6
Correct
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What is the primary mode of action of Enoxaparin?
Your Answer: Inhibits factor Xa
Explanation:Heparin acts as an anticoagulant by enhancing the inhibition rate of clotting proteases by antithrombin III impairing normal haemostasis and inhibition of factor Xa. Low molecular weight heparins have a small effect on the activated partial thromboplastin time and strongly inhibit factor Xa. Enoxaparin is derived from porcine heparin that undergoes benzylation followed by alkaline depolymerization.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 7
Correct
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A foot drop is a sign of damage to which of the following nerves?
Your Answer: Deep fibular nerve
Explanation:The deep fibular nerve was previously referred to as the anterior tibial nerve.
It starts at the common fibular nerve bifurcation, between the fibula and the proximal part of the fibularis longus. Damage to this nerve can cause foot drop or loss of dorsiflexion since this nerve controls the anterior leg muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 8
Incorrect
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Which of the following causes increased aldosterone secretion:
Your Answer: Hyperosmolarity
Correct Answer: Decreased blood volume
Explanation:Decreased blood volume stimulates the secretion of renin (because of decreased renal perfusion pressure) and initiates the renin-angiotensin-aldosterone cascade. Angiotensin-converting enzyme (ACE) inhibitors block the cascade by decreasing the production of angiotensin. Hyperosmolarity stimulates antidiuretic hormone (ADH) [not aldosterone] secretion. Hyperkalaemia, not hypokalaemia, directly stimulates aldosterone secretion by the adrenal cortex. ANP inhibits renin secretion, thereby inhibiting the production of angiotensin and aldosterone.
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This question is part of the following fields:
- Physiology
- Renal
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Question 9
Correct
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Which of the following medications can block the effect of adrenaline?
Your Answer: Beta-blockers
Explanation:Beta-blockers may reduce the response to adrenaline in the treatment of anaphylactic reactions.
Noncardioselective beta-blockers in particular can antagonize the broncho dilating and cardio stimulatory effects of adrenaline by blocking beta-2 adrenergic receptors in the smooth muscles of the bronchial tree and in the heart muscles.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 10
Correct
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If a lesion is observed in Broca's area, which function is expected to become affected?
Your Answer: Formation of words
Explanation:The primary functions of the Broca area are both language production and comprehension. While the exact role in the production is still unclear, many believe that it directly impacts the motor movements to allow for speech. Although originally thought to only aid in speech production, lesions in the area can rarely be related to impairments in the comprehension of language. Different regions of the Broca area specialize in various aspects of comprehension. The anterior portion helps with semantics, or word meaning, while the posterior is associated with phonology, or how words sound. The Broca area is also necessary for language repetition, gesture production, sentence grammar and fluidity, and the interpretation of others’ actions.
Broca’s aphasia is a non-fluent aphasia in which the output of spontaneous speech is markedly diminished and there is a loss of normal grammatical structure. Specifically, small linking words, conjunctions, such as and, or, and but, and the use of prepositions are lost. Patients may exhibit interjectional speech where there is a long latency, and the words that are expressed are produced as if under pressure. The ability to repeat phrases is also impaired in patients with Broca’s aphasia. Despite these impairments, the words that are produced are often intelligible and contextually correct. In pure Broca’s aphasia, comprehension is intact.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 11
Incorrect
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The ECG of a patient presenting with a history of intermittent palpitations has a prolonged QT interval.
Which of these can cause prolongation of the QT interval on the ECG?Your Answer: Hyperkalaemia
Correct Answer: Hypomagnesaemia
Explanation:The causes of a prolonged QT interval include:
Hypomagnesaemia
Hypothermia
Hypokalaemia
Hypocalcaemia
Hypothyroidism
Jervell-Lange-Nielsen syndrome (autosomal dominant)
Romano Ward syndrome (autosomal recessive)
Ischaemic heart disease
Mitral valve prolapse
Rheumatic carditis
Erythromycin
Amiodarone
Quinidine
Tricyclic antidepressants
Terfenadine
Methadone
Procainamide
Sotalol -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 12
Correct
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Regarding aciclovir, which of the following statements is INCORRECT:
Your Answer: Aciclovir eradicates herpes simplex virus from the body.
Explanation:Aciclovir is active against herpesviruses but does not eradicate latent virus.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 13
Correct
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Which of the following is NOT a common side effect of adenosine:
Your Answer: Yellow vision
Explanation:Common side effects of adenosine include:
Apprehension
Dizziness, flushing, headache, nausea, dyspnoea
Angina (discontinue)
AV block, sinus pause and arrhythmia (discontinue if asystole or severe bradycardia occur) -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 14
Correct
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Question 15
Correct
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Which of the following statements about sickle cell disease is TRUE:
Your Answer: Hand-foot syndrome is frequently a first presentation of the disease.
Explanation:Hand-foot syndrome in children is typically the first symptom of the disease, produced by infarction of the metaphysis of small bones. The disease is inherited as an autosomal recessive trait. By adulthood, the spleen has usually infarcted. Infection with the B19 parvovirus is usually followed by an aplastic crisis. Thrombocytopenia is caused by splenic sequestration.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 16
Correct
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Regarding the foetal oxygen-haemoglobin dissociation curve, which of the following statements is CORRECT:
Your Answer: The HbF dissociation curve lies to the left of that for HbA.
Explanation:Foetal haemoglobin (HbF) has a higher affinity for oxygen than adult haemoglobin (HbA) because it’s gamma chains bind 2,3-DPG less avidly than beta chains of HbA. The HbF dissociation curve lies to the left of that for HbA. In the placenta PCO2moves from the foetal to the maternal circulation, shifting the maternal curve further right and the foetal curve further left (the double Bohr effect). The higher affinity of HbF relative to HbA helps transfer oxygen from mother to foetus. Therefore even through blood returning from the placenta to the foetus in the umbilical vein has a PO2of only about 4 kPa, its saturation is 70%. Oxygen transport in the foetus is also helped by a high Hb of about 170 – 180 g/L.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 17
Correct
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A 59-year-old man presents to the emergency room with chest pain. The cardiology team recently discharged him. He underwent a procedure and was given several medications, including abciximab, during his stay. Which of the following statements about abciximab is correct?
Your Answer: It is a glycoprotein IIa/IIIb receptor antagonist
Explanation:Abciximab (ReoPro) is a glycoprotein IIb/IIIa receptor antagonist that is a chimeric monoclonal antibody. It is primarily used during and after coronary artery procedures such as angioplasty to inhibit platelet aggregation.
It’s approved for use as a supplement to heparin and aspirin in high-risk patients undergoing percutaneous transluminal coronary intervention to prevent ischaemic complications. Only one dose of abciximab should be given (to avoid additional risk of thrombocytopenia).
Before using, it is recommended that baseline prothrombin time, activated clotting time, activated partial thromboplastin time, platelet count, haemoglobin, and haematocrit be measured. 12 and 24 hours after starting treatment, haemoglobin and haematocrit should be measured again, as should platelet count 2-4 hours and 24 hours after starting treatment.
When used for high-risk patients undergoing angioplasty, the EPIC trial(link is external)found that abciximab reduced the risk of death, myocardial infarction, repeat angioplasty, bypass surgery, and balloon pump insertion.The use of abciximab is contraindicated in the following situations:
Internal bleeding is present.
Within the last two months, you’ve had major surgery, intracranial surgery, or trauma.
Stroke in the previous two years
Intracranial tumour
Aneurysm or arteriovenous malformation
Haemorrhagic diathesis is a type of haemorrhagic diathesis.
Vasculitis
Retinopathy caused by hypertensionThe following are some of the most common abciximab side effects:
Manifestations of bleeding
Bradycardia
Back ache
Pain in the chest
Vomiting and nausea
Pain at the puncture site
Thrombocytopenia -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 18
Incorrect
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Coagulative necrosis is typically seen in which of the following:
Your Answer: Malignant hypertension
Correct Answer: Myocardial infarction
Explanation:Coagulative necrosis is the most common form of necrosis characterised by the loss of cell nuclei, but with general preservation of the underlying architecture. Dead tissue is macroscopically pale and firm. This is the classic pattern seen in myocardial infarction.Liquefactive necrosis leads to complete loss of cellular structure and conversion into a soft, semi-solid mass. This is typically seen in the brain following cerebral infarction.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.Gangrenous necrosis is necrosis with putrefaction of tissues due to exposure to air (dry gangrene) or infection (wet gangrene).
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 19
Incorrect
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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: Sodium valproate
Correct 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. Ataxia
2. Drug-induced lupus
3. Hirsutism
4. Pruritic rash
5. Megaloblastic anaemia
6. Nystagmus -
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 20
Incorrect
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Langhans giant cells, seen in granulomatous inflammation. are:
Your Answer: Specialised dendritic cells found in skin
Correct Answer: Multinucleated cells formed from fusion of epithelioid cells
Explanation:A granuloma is a collection of five or more epithelioid macrophages, with or without attendant lymphocytes and fibroblasts; epithelioid macrophages are altered macrophages which have turned themselves over to becoming giant phagocytosing and killing machines, they often fuse to become multinucleate (Langhans) giant cells.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 21
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 lumbricals
O– Opponens pollicis
A– Abductor pollicis
F– 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 22
Correct
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From which of the following cell types are platelets derived?
Your Answer: Megakaryocytes
Explanation:Synthesis of platelets occurs in the bone marrow by fragmentation of megakaryocytes cytoplasm, derived from the common myeloid progenitor cell. The average time for differentiation of the human stem cell to the production of platelets is about 10 days. The major regulator of platelet formation is thrombopoietin and 95% of this is produced by the liver. Normal platelet count is 150 – 450 x 109/L and the normal lifespan of a platelet is about 10 days. Usually about one-third of the marrow output of platelets may be trapped at any one time in the normal spleen.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 23
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 24
Incorrect
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A 30-year-old man suffers from an open femoral shaft fracture after being involved in a road traffic accident. As a consequence of his injury, the nerve that was damaged innervates the popliteus muscle.
In which of the following nerves is the popliteus muscle innervated by?Your Answer: Femoral nerve
Correct Answer: Tibial nerve
Explanation:The popliteus muscle is innervated by the tibial nerve (L4, 5 and S1).
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 25
Correct
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Question 26
Correct
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In the resus area of your Emergency Department, you are called to a VF cardiac arrest.
During an adult VF arrest, which of the following points should be treated with adrenaline?Your Answer: After the 3 rd shock, once chest compressions have been resumed
Explanation:In non-shockable (PEA/asystole) cardiac arrests, adrenaline should be given as soon as circulatory access is gained. The dose is 1 mg via IV or IO (10 mL of 1:10,000 or 1 mL of 1:1000).
Once chest compressions have been resumed after the third shock in a shockable (Vf/pVT) cardiac arrest, adrenaline should be administered. The dosage is one milligram (10 mL of 1:10,000 or 1 mL of 1:1000)
It should be given every 3-5 minutes after that (i.e. alternate loops) and without interrupting chest compressions.
Systemic vasoconstriction is caused by the alpha-adrenergic effects of adrenaline, which raises coronary and cerebral perfusion pressures.Adrenaline’s beta-adrenergic effects are inotropic (increased myocardial contractility) and chronotropic (increased heart rate), and they can increase coronary and cerebral blood flow. However, concomitant increases in myocardial oxygen consumption and ectopic ventricular arrhythmias (especially in the absence of acidaemia), transient hypoxemia due to pulmonary arteriovenous shunting, impaired microcirculation, and increased post-cardiac arrest myocardial dysfunction may offset these benefits.
Although there is no evidence of long-term benefit from its use in cardiac arrest, the improved short-term survival reported in some studies justifies its use.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 27
Incorrect
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A possible diagnosis of Cushing's illness is being investigated in an overweight patient with resistant hypertension. A CRH (corticotropin-releasing hormone) test is scheduled.
Which of the following statements about corticotropin-releasing hormone is correct?Your Answer: It is stored in the posterior pituitary
Correct Answer: It is produced by cells within the paraventricular nucleus of the hypothalamus
Explanation:Corticotropin-releasing hormone (CRH) is a neurotransmitter and peptide hormone. It is generated by cells in the hypothalamic paraventricular nucleus (PVN) and released into the hypothalamo-hypophyseal portal system at the median eminence through neurosecretory terminals of these neurons. Stress causes the release of CRH.
The CRH is carried to the anterior pituitary through the hypothalamo-hypophyseal portal system, where it activates corticotrophs to release adrenocorticotropic hormone (ACTH). Cortisol, glucocorticoids, mineralocorticoids, and DHEA are all produced in response to ACTH.
Excessive CRH production causes the size and quantity of corticotrophs in the anterior pituitary to expand, which can lead to the creation of a corticotrope tumour that generates too much ACTH.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 28
Correct
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A young male has presented to you with respiratory depression and small pupils on examination. You diagnose opioid overdose and immediately start therapy with Naloxone.
Which of the following statements is TRUE regarding naloxone?Your Answer: It can be given by a continuous infusion if repeated doses are required
Explanation:Naloxone is a short-acting, specific antagonist of mu(μ)-opioid receptors. It is used to reverse the effects of opioid toxicity.
It can be given by a continuous infusion if repeated doses are required and the infusion rate is adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.
Naloxone has a shorter duration of action (6-24 hours) than most opioids and so close monitoring according to the respiratory rate and depth of coma and repeated injections are necessary. When repeated doses are needed in opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours.
An initial dose of 0.4 to 2 mg can be given intravenously and can be repeated at 2 to 3-minute intervals to a maximum of 10mg.
If the intravenous route is inaccessible, naloxone can be administered via an IO line, subcutaneously (SQ), IM, or via the intranasal (IN) route.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 29
Correct
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Regarding basophils, which of the following statements is INCORRECT:
Your Answer: They are the second most common type of granulocyte.
Explanation:Basophils are only occasionally seen in normal peripheral blood comprising < 1% of circulating white cells. However, they are the largest type of granulocyte. They have many dark cytoplasmic granules which overlie the nucleus and contain heparin and histamine. They have immunoglobulin E (IgE) attachment sites and their degranulation is associated with histamine release. Basophils are very similar in both appearance and function to mast cells.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 30
Incorrect
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All of the following statements are considered true regarding likelihood ratios, except:
Your Answer: They provide a way to estimate the pre-test probabilities of having a condition
Correct Answer: A likelihood ratio less than 1 indicates that the result is associated with the presence of the disease
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 31
Incorrect
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Which of the following statements is correct with regards to insulin receptors?
Your Answer: Insulin has its intracellular effects via the increased production of cAMP.
Correct Answer: Insulin has its intracellular effects via activation of tyrosine kinase.
Explanation:Most cells have insulin receptors present on them which can be sequestered into the cell to inactivate them. These receptors consist of two extracellular alpha subunits which contain the insulin-binding site and two transmembrane beta subunits. Because insulin is a polypeptide hormone, it must act via cell surface receptors as it is unable to readily cross the cell membrane. On binding to the receptor, the beta subunit of insulin autophosphorylation, which activates tyrosine kinase. As a result, there is an intracellular cascade of phosphorylation, causing a translocation of the glucose transporter GLUT4 and GLUT-1 to the plasma membrane of the affected cell. This facilitates glucose entry.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 32
Correct
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A patient presents to your clinic with fever of unknown origin. His blood results shows a markedly elevated C-Reactive Protein (CRP) level.
Which of these is responsible for mediating the release of CRP?
Your Answer: IL-6
Explanation:C-reactive protein (CRP) is an acute phase protein produced by the liver hepatocytes. Its production is regulated by cytokines, particularly interleukin 6 (IL-6) and it can be measured in the serum as a nonspecific marker of inflammation.
Although a high CRP suggest an acute infection or inflammation, it does not identify the cause or location of infection.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 33
Correct
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A patient with a central line in situ for the past 10 days now has erythema surrounding the catheter insertion site and shows signs of sepsis. You suspect line sepsis.
Which of these antibacterial agents would be most appropriate to prescribe for this patient?Your Answer: Vancomycin
Explanation:The current recommendation by NICE and the BNF is to use vancomycin as first-line in treatment of septicaemia related to vascular catheter. A broad-spectrum antipseudomonal beta-lactam antibiotic should be added to vancomycin if a Gram-negative sepsis is suspected especially in an immunocompromised patient.
In any patient that has had a central venous catheter in situ for a period longer than a week, it should be suspected as the source of sepsis.
The features suggesting the vascular catheter as the source of infection include:
Presence of the catheter before onset of fever.
The absence of another identifiable source of infection.
Presence of inflammation or purulent material at the insertion site or along the tunnel.
An immunocompetent patient without any underlying disease developing bacteraemia (or fungaemia). -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 34
Incorrect
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A six-year-old boy presents with coryzal symptoms that have persisted for more than two weeks. He was born and raised in the Middle East. His mother claims he has been tired and has complained of various 'aches and pains.' On examination, you find splenomegaly and enlarged cervical lymph nodes. His legs and arms are covered in petechiae.
In this case, what is the most likely diagnosis?Your Answer: Henoch-Schonlein purpura
Correct Answer: Acute lymphoblastic leukaemia (ALL)
Explanation:ALL is the most common leukaemia in children, with a peak incidence between the ages of 2 and 5.
ALL has a wide range of clinical symptoms, but many children present with an acute illness that resembles coryza or a viral infection. ALL also has the following features:
Weakness and sluggishness all over
Muscle, joint, and bone pain that isn’t specific
Anaemia
Petechiae and unexplained bruising
Oedema
Lymphadenopathy
HepatosplenomegalyThe following are typical features of a full blood count in patients with ALL:
Anaemia (normocytic or macrocytic)
Leukopenia affects about half of the patients (WCC 4 x 109/l).
Around 25% of patients have leucocytosis (WCC > 10 x 109/l).
Around 25% of patients have hyperleukocytosis (WCC > 50 x 109/l).
Thrombocytopaenia -
This question is part of the following fields:
- Haematology
- Pathology
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Question 35
Incorrect
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In the small intestine, there is a deep gap between each villus that leads to the crypt of Lieberkühn, a tubular intestinal gland.
What is the primary function of these glands?
Your Answer: Production of an acidic intestinal juice
Correct Answer: Production of an alkaline intestinal juice
Explanation:In the small intestine, there is a deep gap between each villus that leads to the crypt of Lieberkühn, a tubular intestinal gland. These glands create an alkaline intestinal juice that is a mixture of water and mucus with a pH of 7.4-7.8. Intestinal juice is released in a volume of 1-2 litres per day in response to distention of the small intestine or the irritating effects of chyme on the intestinal mucosa.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 36
Incorrect
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One of your patients is undergoing resuscitation and is in septic shock. The intensive care outreach team arrives to assess them and determines that a dobutamine infusion should be started.
Which of the following receptors does dobutamine primarily affect?Your Answer: Dopamine receptors
Correct Answer: Beta-1 receptors
Explanation:Dobutamine is a synthetic isoprenaline derivative that is used to provide inotropic support to patients with low cardiac output caused by septic shock, myocardial infarction, or other cardiac conditions.
Dobutamine is a sympathomimetic drug that stimulates beta-1 adrenergic receptors in the heart to produce its primary effect. As a result, it has inotropic properties that increase cardiac contractility and output. It also has a small amount of alpha1- and beta-2-adrenergic activity.
A summary of the mechanism and effects of different inotropic agents is shown below:
Inotrope
Mechanism
Effects
Adrenaline (epinephrine)
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Noradrenaline (norepinephrine)
Mainly alpha-agonist;
Beta-1 and -2 agonist at increasing doses
Vasoconstriction;
Some increased cardiac output
Dopamine
Dopamine agonist at low doses;
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Dobutamine
Mainly beta-1 agonist
Increased cardiac output -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 37
Correct
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A 30-year-old woman is transfused following a diagnosis of anaemia secondary to heavy vaginal bleeding. She complains of feeling hot and cold during transfusion of the second unit and her temperature is 38.5ºC. Prior to the transfusion, her temperature was 37ºC. She has no other symptoms.
Which of these transfusions reactions most likely occurred?Your Answer: Febrile transfusion reaction
Explanation:Febrile transfusion reactions presents with an unexpected temperature rise (≥ 38ºC or ≥ 1ºC above baseline, if baseline ≥ 37ºC) during or shortly after transfusion. It is usually an isolated finding and the fever is accompanied by chills and malaise occasionally.
Allergic reaction is commonly caused by foreign plasma proteins but may be due to anti-IgA. Allergic type reactions usually present with urticaria, pruritus, hives. Associations include laryngeal oedema or bronchospasm.
Acute haemolytic reaction aka immediate haemolytic transfusion reaction presents with fever, chills, pain at transfusion site, nausea, vomiting, dark urine and feeling of ‘impending doom’. Often, it occurs due to ABO incompatibility.
Transfusion-associated circulatory overload (TACO) presents as acute or worsening respiratory distress within 6 hours of transfusion of a large volume of blood. It is common in patients with diminished cardiac reserve or chronic anaemia. Elderly patients, infants and severely anaemic patients are particularly susceptible. Clinical features of TACO include: Acute respiratory distress, Tachycardia, Hypertension, Acute/worsening pulmonary oedema on chest X-ray. The BNP is usually raised to at least 1.5 times the pre-transfusion baseline.
Transfusion-related lung injury (TRALI) is a form of acute respiratory distress caused by the donor plasma containing antibodies against the patient’s leukocytes. It is defined as hypoxia and bilateral pulmonary oedema that occurs within 6 hours of a transfusion in the absence of other causes of acute lung injury. Clinical features include Breathlessness, cough, frothy sputum, hypertension or hypotension, hypoxia and fever. Chest X-ray shows multiple perihilar nodules with infiltration of the lower lung fields.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 38
Correct
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Which of the following statements is correct with regards to Hodgkin's lymphoma?
Your Answer: Most patients present with painless asymmetrical lymphadenopathy, with cervical nodes involved most commonly.
Explanation:Lymphoma is a cancer of the lymphatic system, which is part of the body’s germ-fighting network. They are a group of diseases that are caused by malignant lymphocytes. These malignant cells accumulate in lymph nodes and other lymphoid tissue, giving rise to the characteristic clinical feature of lymphadenopathy.
They can be subdivided into Hodgkin lymphoma (HL) which are characterised by the presence of Reed-Sternberg cells, and non-Hodgkin lymphoma (NHL).
Characteristics of HL include:
1. can present at any age but is rare in children and has a peak incidence in young adults,
2. almost 2:1 male predominance.
3. presents with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes.
4. cervical node involvement in 60-70% of cases,
5. axillary node involvement in 10-15%
6. inguinal node involvement in 6-12%.
7. modest splenomegaly during the course of the disease in 50% of patients
8. may occasionally have liver enlargement
9. bone marrow failure involvement is unusual in early disease.
Approximately 85% of patients are cured, but the prognosis depends on age, stage and histology.
Two well‐known but rare symptoms in HL are alcohol‐induced pain and pruritus. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 39
Incorrect
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A 21-year-old student presents to the minors area of your Emergency Department with a laceration on his external nose that occurred during sparring in a kickboxing class. The area is bleeding profusely and will require suturing. Pressure is being applied. The laceration extends through some of the nasal muscles.
Motor innervation of the nasal muscles of facial expression is provided by which of the following ? Select ONE answer only.Your Answer: Trigeminal nerve
Correct Answer: Facial nerve
Explanation:The facial nerve (the labyrinthine segment) is the seventh cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.
Motor innervation of the nasal muscles of facial expression is provided by the facial nerve (CN VII). -
This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 40
Correct
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A 43-year old male is taken to the Emergency Room for a lacerated wound on the abdomen, situated above the umbilicus. A short segment of the small bowel has herniated through the wound.
Which of these anatomic structures is the most superficial structure injured in the case above?Your Answer: Camper’s fascia
Explanation:The following structures are the layers of the anterior abdominal wall from the most superficial to the deepest layer:
Skin
Fatty layer of the superficial fascia (Camper’s fascia)
Membranous layer of the superficial fascia (Scarpa’s fascia)
Aponeurosis of the external and internal oblique muscles
Rectus abdominis muscle
Aponeurosis of the internal oblique and transversus abdominis
Fascia transversalis
Extraperitoneal fat
Parietal peritoneum -
This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 41
Incorrect
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Action potentials are transmitted from myocyte to myocyte via which of the following:
Your Answer: Purkinje fibres
Correct Answer: Gap junctions
Explanation:Action potentials are transmitted to adjacent myocytes via gap junctions.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 42
Incorrect
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Carbon dioxide is transported in the blood approximately:
Your Answer: 60% as bicarbonate ions, 20% as carbamino compounds and 20% dissolved in plasma
Correct Answer: 60% as bicarbonate ions, 30% as carbamino compounds and 10% dissolved in plasma.
Explanation:Carbon dioxide is transported in the blood from tissues to the lungs in three ways as bicarbonate ions (60%), as carbamino compounds with proteins (30%) or simply dissolved in plasma (10%).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 43
Incorrect
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Which of the following is NOT an advantage of a case-control study used to identify past exposure to a risk factor in patients with a disease:
Your Answer: Relative quick, cheap and easy to perform
Correct Answer: Can directly measure absolute and relative risk of a disease
Explanation:Advantages:relatively quickrelatively cheap and easy to performparticularly suitable for studying associations between an exposure and an outcome when the outcome is uncommon or if the outcome occurs decades after exposurea wide range of risk factors can be investigated in each studyDisadvantages:subject to recall biasunlike in a whole population study, absolute risk cannot be quantifiedtemporal relationship between exposure and outcome can be difficult to establishunsuitable for rare risk factorsprone to confounding
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 44
Incorrect
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Which of the following classes of drugs may predispose to lithium toxicity:
Your Answer: Statins
Correct Answer: Thiazide diuretics
Explanation:Excretion of lithium may be reduced by thiazide diuretics, NSAIDs, and ACE inhibitors thus predisposing to lithium toxicity. Loop diuretics also cause lithium retention but are less likely to result in lithium toxicity.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 45
Correct
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Your consultant decides to use ketamine for a patient requiring procedural sedation in the Emergency Department. At what receptor does ketamine primarily act:
Your Answer: NMDA receptor
Explanation:In contrast to most other anaesthetic agents, ketamine is a NMDA (N-methyl-D-aspartate) receptor antagonist. It is a non-competitive antagonist of the calcium-ion channel in the NMDA receptor. It further inhibits the NMDA-receptor by binding to its phencyclidine binding site. Ketamine also acts at other receptors as an opioid receptor agonist (analgesic effects), as an muscarinic anticholinergic receptor antagonist (antimuscarinic effects) and by blocking fast sodium channels (local anaesthetic effect).
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 46
Correct
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A 33 year old lady with a known nut allergy was having dinner at a Thai restaurant. She suddenly complained of lip and tongue swelling and difficulty breathing and is brought to ED by ambulance with suspected anaphylaxis. She received intramuscular adrenaline in the ambulance.
The most appropriate doses of the second line treatments for anaphylaxis are which of the following?Your Answer: 10 mg chlorphenamine and 200 mg hydrocortisone
Explanation:Second line drugs to reduce the severity and duration of anaphylactic symptoms are intravenous or intramuscular chlorpheniramine and hydrocortisone. The recommended dose is 10 mg chlorpheniramine and 200 mg hydrocortisone in adults.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 47
Incorrect
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A 29-year-old volunteer returns from a recent trip to the middle east with profuse watery diarrhoea. You make a diagnosis of cholera and organize a hospital admission for rehydration with intravenous fluids.
What is the mechanism of action of cholera toxin?
Your Answer: Inhibition of the enzyme phosphodiesterase
Correct Answer: ADP-ribosylation of the G regulatory protein
Explanation:Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.
The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl.
The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.
Incubation period is between 2 and 5 days, but can be as short as just a few hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 48
Correct
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In patients requiring oxygen, who are at risk of hypercapnic respiratory failure, oxygen saturations should be maintained at:
Your Answer: 88 - 92%
Explanation:A lower target of 88 – 92% oxygen saturation is indicated for patients at risk of hypercapnic respiratory failure e.g. patients with COPD. Until blood gases can be measured, initial oxygen should be given using a controlled concentration of 28% or less, titrated towards the SpO2 of 88 – 92%. The aim is to provide the patient with enough oxygen to achieve an acceptable arterial oxygen tension without worsening carbon dioxide retention and respiratory acidosis.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 49
Incorrect
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Lidocaine's antiarrhythmic mode of action is as follows:
Your Answer: Blocks open Na+ channels
Correct Answer: Blocks inactivated Na+ channels
Explanation:Lidocaine is a class 1B antidysrhythmic; combines with fast Na channels and thereby inhibits recovery after repolarization, resulting in decreasing myocardial excitability and conduction velocity. However, in ischaemic areas, where anoxia causes depolarisation and arrhythmogenic activity, many Na+ channels are inactivated and therefore susceptible to lidocaine.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 50
Incorrect
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Haemophilia B results from a deficiency in:
Your Answer: Factor VIII
Correct Answer: Factor IX
Explanation:Haemophilia B is a bleeding disorder caused by a deficiency of clotting factor IX. It is the second commonest form of haemophilia, and is rarer than haemophilia A. Haemophilia B tends to be similar to haemophilia A but less severe. The two disorders can only be distinguished by specific coagulation factor assays.
The incidence is one-fifth of that of haemophilia A. Laboratory findings demonstrate prolonged APTT, normal PT and low factor IX.
Haemophilia B inherited in an X-linked recessive fashion, affecting males born to carrier mothers.
There is also a variation called Leyden, in which factor IX levels are below 1% until puberty, when they rise, potentially reaching as high as 40-60% of normal. This is thought to be due to the effects of testosterone at puberty. -
This question is part of the following fields:
- Haematology
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
