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AMC CAT MCQ study materials
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AMC CAT MCQ practice questions

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Question 1Medicine

A 58-year-old man has crushing central chest pain radiating to the left arm, and an ECG shows ST elevation in leads II, III and aVF. Which coronary artery is most likely occluded?

  1. Right coronary artery Correct answer.
  2. Left circumflex artery
  3. Left anterior descending artery
  4. Left main coronary artery

Explanation

ST elevation in the inferior leads II, III and aVF localises injury to the inferior wall, which is supplied by the right coronary artery in most people. The LAD supplies the anterior wall, and the circumflex supplies the lateral wall. Recognizing the territory guides urgent reperfusion decisions.

Question 2Medicine

Which finding on arterial blood gas is the primary abnormality in acute respiratory acidosis?

  1. Raised bicarbonate with raised pH
  2. Reduced bicarbonate with reduced pH
  3. Reduced arterial pH with raised carbon dioxide Correct answer.
  4. Raised arterial pH with reduced carbon dioxide

Explanation

Acute respiratory acidosis arises from alveolar hypoventilation, so carbon dioxide accumulates and pH falls. Bicarbonate is only minimally elevated initially because renal compensation takes days. A raised bicarbonate with raised pH would instead indicate metabolic alkalosis.

Question 3Medicine

A 24-year-old woman has recurrent episodes of palpitations, sweating and tremor with documented hypertension. Which biochemical test is the most appropriate initial screen for phaeochromocytoma?

  1. Serum cortisol
  2. Plasma free metanephrines Correct answer.
  3. Urinary 5-HIAA
  4. Serum aldosterone-to-renin ratio

Explanation

Phaeochromocytomas secrete catecholamines, which are metabolised to metanephrines, so plasma free metanephrines provide a highly sensitive screening test. Cortisol assesses adrenal cortical function, and the aldosterone-to-renin ratio screens for primary aldosteronism. Urinary 5-HIAA is used for carcinoid syndrome.

Question 4Medicine

Which organism is the most common cause of community-acquired pneumonia in adults?

  1. Klebsiella pneumoniae
  2. Mycoplasma pneumoniae
  3. Staphylococcus aureus
  4. Streptococcus pneumoniae Correct answer.

Explanation

Streptococcus pneumoniae remains the single most frequently isolated pathogen in community-acquired pneumonia and classically causes lobar consolidation. Mycoplasma is common in younger adults but less frequent overall, and Staphylococcus aureus is more typical of post-influenza or hospital-acquired infection. Klebsiella is associated with alcohol misuse and aspiration.

Question 5Medicine

A patient has a serum sodium of 118 mmol/L and has developed confusion over two days. Which initial management step is most appropriate?

  1. Fluid restriction alone without electrolyte monitoring
  2. Rapid correction with hypertonic saline to normal sodium within four hours
  3. Immediate dialysis regardless of symptoms
  4. Hypertonic saline with careful limits on the rate of correction Correct answer.

Explanation

Symptomatic severe hyponatraemia requires hypertonic saline, but correction must be limited, typically to around 8-10 mmol/L in the first 24 hours, to avoid osmotic demyelination. Overly rapid correction is the key danger. Asymptomatic or mild cases may be managed with fluid restriction instead.

Question 6Medicine

Which feature best distinguishes an absence seizure from a focal impaired-awareness seizure?

  1. Presence of an aura before the event
  2. Unilateral motor automatisms
  3. Brief impairment of consciousness with immediate recovery and no postictal confusion Correct answer.
  4. Postictal drowsiness lasting hours

Explanation

Absence seizures cause abrupt, brief loss of awareness, usually seconds, with immediate return to normal and no postictal phase. Focal impaired-awareness seizures often have an aura and are followed by postictal confusion. The electroencephalogram also differs, showing generalised three-hertz spike-and-wave activity in absence epilepsy.

Question 7Medicine

A 32-year-old woman has a painful red eye with photophobia, a constricted pupil and ciliary flush. Which diagnosis is most likely?

  1. Anterior uveitis Correct answer.
  2. Bacterial conjunctivitis
  3. Acute angle-closure glaucoma
  4. Corneal abrasion

Explanation

Anterior uveitis classically presents with a painful red eye, photophobia, a small pupil and ciliary flush, often with reduced visual acuity. Acute angle-closure glaucoma usually has a fixed mid-dilated pupil and markedly raised pressure. Conjunctivitis is typically painless with a normal pupil.

Question 8Medicine

Which laboratory pattern is most consistent with iron-deficiency anaemia?

  1. Low ferritin with high total iron-binding capacity Correct answer.
  2. High ferritin with low total iron-binding capacity
  3. Normal ferritin with low total iron-binding capacity
  4. High ferritin with high total iron-binding capacity

Explanation

Iron deficiency depletes stored iron, so ferritin falls, and the liver increases transferrin production, raising total iron-binding capacity. Anaemia of chronic disease shows the opposite pattern, with normal or high ferritin and low binding capacity. Ferritin is an acute-phase reactant, so it should be interpreted alongside inflammatory markers.

Question 9Medicine

A 70-year-old man has sudden painless loss of vision in one eye and a pale retina with a cherry-red spot at the macula. Which diagnosis is most likely?

  1. Central retinal artery occlusion Correct answer.
  2. Retinal detachment
  3. Vitreous haemorrhage
  4. Central retinal vein occlusion

Explanation

Central retinal artery occlusion causes sudden painless visual loss with a pale, oedematous retina and a cherry-red spot where the fovea is spared. It is an ophthalmological emergency associated with embolic disease and vasculitis. Retinal vein occlusion instead produces a blood-and-thunder appearance with haemorrhages.

Question 10Medicine

Which mechanism best explains the development of kernicterus in a neonate?

  1. Immune-mediated destruction of hepatocytes
  2. Deposition of unconjugated bilirubin in the basal ganglia Correct answer.
  3. Deposition of bile salts in the skin
  4. Accumulation of conjugated bilirubin in the liver

Explanation

Kernicterus results from unconjugated bilirubin crossing the immature blood-brain barrier and depositing in the basal ganglia and brainstem nuclei, causing neurological damage. Conjugated bilirubin is water-soluble and does not cross the barrier in the same way. Risk is highest with severe haemolytic disease of the newborn.

Question 11Medicine

A 45-year-old woman has weight gain, cold intolerance, constipation and a raised thyroid-stimulating hormone with a low free thyroxine. Which is the most appropriate initial treatment?

  1. Carbimazole
  2. Radioiodine ablation
  3. Levothyroxine Correct answer.
  4. Propranolol alone

Explanation

The picture is primary hypothyroidism, treated with levothyroxine replacement titrated to thyroid-stimulating hormone. Carbimazole and radioiodine are treatments for hyperthyroidism. Propranolol controls adrenergic symptoms of thyrotoxicosis but does not correct hypothyroidism.

Question 12Medicine

Which finding is most characteristic of diabetic ketoacidosis?

  1. Blood glucose below 11 mmol/L with normal ketones
  2. Arterial pH above 7.45 with raised bicarbonate
  3. Metabolic acidosis with raised ketones and a raised anion gap Correct answer.
  4. Metabolic alkalosis with hypokalaemia

Explanation

Diabetic ketoacidosis is defined by hyperglycaemia, ketonaemia and a high-anion-gap metabolic acidosis. Insulin deficiency drives lipolysis and ketone production, and dehydration worsens the acidosis. Total body potassium is depleted even when serum potassium appears normal or high.

Question 13Medicine

A patient with cirrhosis develops confusion, asterixis and a raised ammonia level. Which precipitant should be sought first in the history?

  1. Recent immunisation
  2. Increased dietary fibre
  3. Regular moderate exercise
  4. Recent gastrointestinal bleeding Correct answer.

Explanation

Hepatic encephalopathy is commonly precipitated by gastrointestinal bleeding, because blood protein in the gut is broken down to ammonia. Other triggers include infection, constipation, dehydration and sedative drugs. Identifying and correcting the precipitant is as important as lactulose therapy.

Question 14Medicine

Which antibody is most strongly associated with systemic lupus erythematosus and carries high specificity for the disease?

  1. Anti-smooth muscle antibody
  2. Anti-double-stranded DNA antibody Correct answer.
  3. Anti-mitochondrial antibody
  4. Anti-histone antibody

Explanation

Anti-double-stranded DNA antibodies are highly specific for systemic lupus erythematosus, and titres may correlate with disease activity, particularly nephritis. Anti-histone antibodies are associated with drug-induced lupus. Anti-mitochondrial antibodies indicate primary biliary cholangitis.

Question 15Medicine

A 60-year-old man has a sudden severe headache described as the worst of his life. Which investigation is the most appropriate first-line test if he is stable and presents within six hours?

  1. Carotid Doppler ultrasound
  2. Lumbar puncture immediately
  3. Non-contrast CT head Correct answer.
  4. MRI brain with gadolinium

Explanation

A non-contrast CT head is the first-line investigation for suspected subarachnoid haemorrhage and is highly sensitive within the first six hours. If the CT is negative and clinical suspicion persists, lumbar puncture for xanthochromia is performed after 12 hours from onset. MRI and vascular imaging are used selectively.

Question 16Medicine

Which feature most strongly suggests a diagnosis of irritable bowel syndrome rather than inflammatory bowel disease?

  1. Symptoms relieved by defecation with no weight loss Correct answer.
  2. Elevated faecal calprotectin
  3. Nocturnal diarrhoea waking the patient
  4. Iron-deficiency anaemia

Explanation

Irritable bowel syndrome is a functional disorder diagnosed on symptom criteria, with pain relieved by defecation and no alarm features such as weight loss, anaemia or nocturnal symptoms. Raised faecal calprotectin and iron-deficiency anaemia suggest organic inflammation. Alarm features warrant further investigation.

Question 17Medicine

Which drug is the first-line treatment for a patient with newly diagnosed hypertension and no comorbidities, according to most guidelines?

  1. An alpha blocker
  2. An ACE inhibitor
  3. A loop diuretic
  4. A thiazide-like diuretic or calcium channel blocker Correct answer.

Explanation

For most patients with uncomplicated hypertension, a thiazide-like diuretic or a dihydropyridine calcium channel blocker is first-line, especially in older adults. ACE inhibitors are preferred when there is diabetes or chronic kidney disease with proteinuria. Alpha blockers and loop diuretics are reserved for specific indications.

Question 18Medicine

A 28-year-old woman has a deep vein thrombosis and is found to have a prolonged activated partial thromboplastin time that does not correct with mixing. Which condition should be suspected?

  1. Haemophilia A
  2. Vitamin K deficiency
  3. Von Willebrand disease
  4. Lupus anticoagulant Correct answer.

Explanation

A lupus anticoagulant prolongs phospholipid-dependent clotting tests in vitro and does not correct on mixing because it is an inhibitor, yet it is paradoxically associated with thrombosis. Haemophilia and von Willebrand disease cause bleeding rather than thrombosis. Vitamin K deficiency affects the extrinsic pathway and causes bleeding.

Question 19Medicine

Which mechanism explains the therapeutic effect of metformin in type 2 diabetes?

  1. Inhibition of intestinal alpha-glucosidase
  2. Blockade of renal sodium-glucose cotransport
  3. Reduction of hepatic gluconeogenesis and improved insulin sensitivity Correct answer.
  4. Stimulation of insulin secretion from pancreatic beta cells

Explanation

Metformin reduces hepatic glucose production and improves peripheral insulin sensitivity without stimulating insulin release, so it rarely causes hypoglycaemia. Sulfonylureas stimulate beta cells, acarbose inhibits alpha-glucosidase, and SGLT2 inhibitors block renal glucose reabsorption. Lactic acidosis is a rare but serious adverse effect.

Question 20Medicine

A 3-year-old child has a barking cough, inspiratory stridor and a hoarse voice following a coryzal illness. Which diagnosis is most likely?

  1. Croup Correct answer.
  2. Foreign body aspiration
  3. Bronchiolitis
  4. Epiglottitis

Explanation

Croup, usually caused by parainfluenza virus, produces subglottic oedema with a barking cough, stridor and hoarseness. Epiglottitis causes high fever, drooling and a muffled voice with a rapidly toxic child. Bronchiolitis affects infants with wheeze and crackles, and foreign body aspiration is typically sudden in onset.

Question 21Medicine

Which finding is most consistent with nephrotic syndrome?

  1. Sterile pyuria with flank pain
  2. Hyperkalaemia with metabolic acidosis
  3. Heavy proteinuria with hypoalbuminaemia and oedema Correct answer.
  4. Haematuria with hypertension and oliguria

Explanation

Nephrotic syndrome is defined by heavy proteinuria, hypoalbuminaemia, oedema and hyperlipidaemia, reflecting glomerular podocyte injury. The nephritic picture instead features haematuria, hypertension and oliguria. Distinguishing the two guides investigation and management.

Question 22Medicine

Which organism is most commonly implicated in peptic ulcer disease associated with chronic gastritis?

  1. Clostridium difficile
  2. Campylobacter jejuni
  3. Helicobacter pylori Correct answer.
  4. Escherichia coli

Explanation

Helicobacter pylori colonises the gastric mucosa and causes chronic gastritis, predisposing to duodenal and gastric ulcers and to gastric adenocarcinoma. Eradication with proton pump inhibitor-based triple therapy reduces recurrence. Campylobacter and Clostridium difficile cause diarrhoeal illness instead.

Question 23Medicine

A 65-year-old woman has proximal muscle weakness and a raised creatine kinase with a heliotrope rash and Gottron papules. Which diagnosis is most likely?

  1. Dermatomyositis Correct answer.
  2. Myasthenia gravis
  3. Polymyalgia rheumatica
  4. Hypothyroidism

Explanation

Dermatomyositis causes proximal inflammatory myopathy with characteristic skin signs: a violaceous heliotrope rash around the eyes and Gottron papules over the knuckles. Creatine kinase is raised. It is associated with underlying malignancy, so age-appropriate cancer screening is warranted.

Question 24Medicine

Which sequence correctly describes the passage of filtrate through the nephron?

  1. Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct Correct answer.
  2. Collecting duct, distal tubule, loop of Henle, proximal tubule, Bowman's capsule
  3. Proximal tubule, Bowman's capsule, loop of Henle, collecting duct, distal tubule
  4. Bowman's capsule, loop of Henle, proximal tubule, distal tubule, collecting duct

Explanation

Filtrate enters Bowman's capsule, passes through the proximal convoluted tubule, descends the loop of Henle, then passes through the distal tubule into the collecting duct. Most reabsorption occurs in the proximal tubule. The collecting duct fine-tunes water and electrolyte balance under hormonal control.

Question 25Medicine

A 52-year-old man has progressive dysphagia to solids and liquids, weight loss and a normal barium swallow. Which diagnosis should be considered most strongly?

  1. Oesophageal stricture
  2. Achalasia Correct answer.
  3. Gastro-oesophageal reflux disease
  4. Oropharyngeal dysphagia

Explanation

Achalasia causes progressive dysphagia to both solids and liquids due to failure of lower oesophageal sphincter relaxation, often with regurgitation and weight loss. A mechanical stricture typically causes dysphagia to solids first. Manometry is the diagnostic test of choice.

Question 26Medicine

Which electrolyte disturbance is most commonly seen in a patient with prolonged vomiting from gastric outlet obstruction?

  1. Hypokalaemic hypochloraemic metabolic alkalosis Correct answer.
  2. Hypernatraemic hyperchloraemic metabolic acidosis
  3. Hypokalaemic hyperchloraemic metabolic acidosis
  4. Hyperkalaemic hyperchloraemic metabolic acidosis

Explanation

Gastric juice is rich in hydrogen and chloride ions, so vomiting removes acid and chloride, generating a metabolic alkalosis with low serum chloride. Renal compensation in the face of volume depletion causes potassium wasting in the urine, producing hypokalaemia. The combination of low potassium, low chloride and raised bicarbonate is the classic pattern.

Question 27Medicine

A 24-year-old man develops a widespread itchy urticarial rash, wheeze and hypotension minutes after a wasp sting. Which drug should be given first?

  1. Intravenous chlorphenamine
  2. Intramuscular adrenaline Correct answer.
  3. Oral prednisolone
  4. Nebulised salbutamol

Explanation

Anaphylaxis is treated first with intramuscular adrenaline into the anterolateral thigh, because it reverses vasodilatation, bronchospasm and mucosal oedema. Antihistamines and steroids are adjuncts that do not treat airway or circulatory compromise. Bronchodilators help wheeze but do not correct hypotension.

Question 28Medicine

Which organism is the most frequent cause of community-acquired pneumonia requiring hospital admission in adults?

  1. Haemophilus influenzae
  2. Streptococcus pneumoniae Correct answer.
  3. Mycoplasma pneumoniae
  4. Staphylococcus aureus

Explanation

Streptococcus pneumoniae remains the commonest identified pathogen in community-acquired pneumonia across all severities. It typically produces a lobar consolidation with high fever and a productive cough. The other organisms cause a smaller proportion of cases, although Mycoplasma is more prominent in younger adults.

Question 29Medicine

A 55-year-old man has exertional chest tightness that is relieved within minutes by rest. Which investigation is most appropriate to confirm the diagnosis?

  1. Transthoracic echocardiography
  2. 24-hour ambulatory ECG
  3. CT coronary angiography Correct answer.
  4. Exercise tolerance testing

Explanation

Stable angina is best evaluated with CT coronary angiography or functional stress imaging to demonstrate coronary artery disease. The test chosen depends on pretest probability and local availability. Resting tests such as echocardiography or ambulatory ECG do not reliably show reversible ischaemia.

Question 30Medicine

Which finding on arterial blood gas is expected in a patient with an acute exacerbation of asthma?

  1. Respiratory acidosis with a high carbon dioxide
  2. Metabolic acidosis with a high bicarbonate
  3. Respiratory alkalosis with a low carbon dioxide Correct answer.
  4. Metabolic alkalosis with a low chloride

Explanation

In acute asthma, increased respiratory drive causes hyperventilation, which lowers the arterial carbon dioxide and raises the pH, producing a respiratory alkalosis. A normal or rising carbon dioxide in a distressed asthmatic signals fatigue and impending respiratory failure. Metabolic disturbances are not the primary pattern.

Question 31Medicine

Which vaccine is contraindicated in a patient who is severely immunocompromised?

  1. Recombinant hepatitis B vaccine
  2. Live attenuated influenza vaccine Correct answer.
  3. Tetanus-diphtheria booster
  4. Inactivated influenza vaccine

Explanation

Live attenuated vaccines can replicate in the host and cause disseminated infection when cellular immunity is impaired, so they are avoided in severe immunosuppression. Inactivated, toxoid and recombinant vaccines are safe because they cannot replicate. Influenza vaccination is still recommended in immunocompromised patients, but with the inactivated formulation.

Question 32Medicine

A 68-year-old woman has sudden-onset right arm weakness and facial droop that began 90 minutes ago. Blood glucose is normal and CT head shows no haemorrhage. Which treatment is indicated?

  1. Subcutaneous low-molecular-weight heparin
  2. Intravenous thrombolysis with alteplase Correct answer.
  3. Intravenous aspirin alone
  4. Oral warfarin loading

Explanation

Acute ischaemic stroke within the thrombolysis window, with haemorrhage excluded and no contraindication, is treated with intravenous thrombolysis to restore perfusion. Antiplatelet therapy is started after the thrombolysis decision and is not a substitute for reperfusion. Anticoagulation is not used acutely for stroke treatment.

Question 33Medicine

Which feature on history most strongly suggests a diagnosis of migraine rather than tension-type headache?

  1. Pain that is unchanged by climbing stairs
  2. Bilateral pressing tightness without nausea
  3. Unilateral throbbing pain worsened by routine activity Correct answer.
  4. Headache lasting 30 minutes with no photophobia

Explanation

Migraine is characterised by unilateral, pulsating pain of moderate to severe intensity that is aggravated by routine physical activity and accompanied by nausea or photophobia. Tension-type headache is typically bilateral, pressing and not worsened by activity. The duration and lack of associated features also favour tension-type headache.

Question 34Medicine

A 30-year-old woman has recurrent episodes of palpitations, sweating and anxiety with documented hypertension. Which biochemical test is the most appropriate initial screen?

  1. Serum thyroid-stimulating hormone
  2. Plasma renin and aldosterone ratio
  3. Serum cortisol after overnight dexamethasone
  4. Plasma free metanephrines Correct answer.

Explanation

Paroxysmal palpitations, sweating and headache with hypertension suggest phaeochromocytoma, for which plasma free metanephrines are the most sensitive initial test. Cortisol testing investigates Cushing syndrome, and renin-aldosterone testing investigates primary aldosteronism. Thyroid function is reasonable but less specific for this episodic presentation.

Question 35Medicine

Which mechanism best explains the bradycardia and hypotension seen after carotid sinus massage?

  1. Increased circulating catecholamines from the adrenal medulla
  2. Increased vagal tone to the sinoatrial and atrioventricular nodes Correct answer.
  3. Direct sympathetic stimulation of the sinoatrial node
  4. Blockade of beta-adrenergic receptors in the myocardium

Explanation

Carotid sinus baroreceptors signal via the glossopharyngeal nerve to the brainstem, which increases vagal outflow to the heart. The result is slowing of sinoatrial firing and delayed atrioventricular conduction, with reduced sympathetic tone causing vasodilatation. This reflex is exaggerated in carotid sinus hypersensitivity.

Question 36Medicine

Which finding is most characteristic of a pleural effusion on physical examination?

  1. Stony dull percussion note with reduced breath sounds Correct answer.
  2. Bronchial breathing with increased vocal resonance
  3. Hyperresonant percussion note with absent breath sounds
  4. Fine inspiratory crackles at both bases

Explanation

Fluid in the pleural space conducts sound poorly, producing a stony dull percussion note, reduced breath sounds and decreased tactile vocal fremitus over the effusion. Hyperresonance suggests air such as a pneumothorax, while bronchial breathing and increased resonance suggest consolidation. Crackles indicate alveolar or interstitial disease.

Question 37Medicine

A 40-year-old woman has a butterfly-shaped facial rash, arthralgia and a positive antinuclear antibody test. Which additional test is most specific for confirming the diagnosis?

  1. Antimitochondrial antibody
  2. Anti-double-stranded DNA antibody Correct answer.
  3. Anti-smooth muscle antibody
  4. Rheumatoid factor

Explanation

Anti-double-stranded DNA antibodies are highly specific for systemic lupus erythematosus and correlate with disease activity, particularly lupus nephritis. Antinuclear antibody is sensitive but not specific. Rheumatoid factor and the other autoantibodies relate to different conditions.

Question 38Medicine

Which pattern of jaundice is expected in a patient with a common bile duct stone?

  1. Normal bilirubin with isolated raised unconjugated bilirubin
  2. Raised unconjugated bilirubin with normal alkaline phosphatase
  3. Raised conjugated bilirubin with normal alkaline phosphatase
  4. Raised conjugated bilirubin with raised alkaline phosphatase and gamma-glutamyl transferase Correct answer.

Explanation

Biliary obstruction impairs excretion of conjugated bilirubin and induces cholestatic enzymes, so conjugated bilirubin, alkaline phosphatase and gamma-glutamyl transferase all rise. Unconjugated hyperbilirubinaemia reflects haemolysis or impaired conjugation, not obstruction. Isolated enzyme changes without raised bilirubin occur in early or partial obstruction.

Question 39Medicine

Which organism is the most common cause of acute bacterial meningitis in adults?

  1. Listeria monocytogenes
  2. Haemophilus influenzae type b
  3. Streptococcus pneumoniae Correct answer.
  4. Neisseria meningitidis

Explanation

Streptococcus pneumoniae is the leading cause of bacterial meningitis in adults beyond the neonatal period. Neisseria meningitidis is important in adolescents and young adults, and Listeria is more common at the extremes of age or in immunocompromised patients. Hib meningitis has become rare since conjugate vaccination.

Question 40Medicine

A 22-year-old woman has a history of recurrent panic attacks. Which feature best distinguishes a panic attack from a generalised anxiety disorder episode?

  1. Persistent worry lasting most days for six months
  2. Abrupt onset reaching peak intensity within minutes Correct answer.
  3. Symptoms confined to social situations
  4. Gradual build-up of tension over several hours

Explanation

Panic attacks are defined by a sudden surge of intense fear that peaks within minutes and is accompanied by physical symptoms such as palpitations and breathlessness. Generalised anxiety disorder involves pervasive worry present on most days for at least six months. Social anxiety is situationally triggered rather than spontaneous.

Question 41Medicine

Which medication is the first-line treatment for a patient with schizophrenia who has persistent auditory hallucinations?

  1. Lorazepam
  2. Risperidone Correct answer.
  3. Lithium carbonate
  4. Sertraline

Explanation

Second-generation antipsychotics such as risperidone are first-line for the positive symptoms of schizophrenia, including hallucinations and delusions. Lithium is a mood stabiliser used mainly in bipolar disorder, and SSRIs treat depression and anxiety. Benzodiazepines provide short-term sedation only.

Question 42Medicine

A 45-year-old man has a body mass index of 33 and a fasting plasma glucose of 6.8 mmol/L on two occasions. Which diagnosis is most appropriate?

  1. Normal glucose tolerance
  2. Impaired fasting glucose Correct answer.
  3. Type 2 diabetes mellitus
  4. Impaired glucose tolerance

Explanation

A fasting plasma glucose between 6.1 and 6.9 mmol/L defines impaired fasting glucose, a form of prediabetes. Diabetes requires a fasting value of 7.0 mmol/L or more, or a diagnostic oral glucose tolerance test or HbA1c. Impaired glucose tolerance is defined by the two-hour value on an oral glucose tolerance test.

Question 43Medicine

Which mechanism explains the action of a loop diuretic such as furosemide?

  1. Inhibition of aldosterone receptors in the collecting duct
  2. Blockade of sodium channels in the distal convoluted tubule
  3. Inhibition of carbonic anhydrase in the proximal tubule
  4. Inhibition of the sodium-potassium-chloride cotransporter in the thick ascending limb Correct answer.

Explanation

Loop diuretics block the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle, reducing the medullary concentration gradient and producing powerful natriuresis. This also causes loss of calcium and magnesium. Aldosterone antagonists act in the collecting duct and thiazides act in the distal tubule.

Question 44Medicine

A 70-year-old woman has a fractured neck of femur after a fall. Which finding suggests the fracture is pathological rather than traumatic?

  1. A fracture line through the femoral neck in healthy bone
  2. A single fall from standing height
  3. A history of a high-energy road traffic collision
  4. A lytic lesion with cortical destruction on radiography Correct answer.

Explanation

Pathological fractures occur through bone weakened by tumour, infection or metabolic disease, and imaging shows a lytic or sclerotic lesion with cortical destruction. A fracture through normal bone after significant trauma is traumatic. A low-energy fall in osteoporotic bone is a fragility fracture, which is distinct from a pathological lesion.

Question 45Medicine

Which nerve is most commonly injured during a difficult forceps delivery, causing weakness of the deltoid and biceps?

  1. Median nerve at the wrist
  2. Upper trunk of the brachial plexus Correct answer.
  3. Radial nerve in the spiral groove
  4. Lower trunk of the brachial plexus

Explanation

Traction on the shoulder during delivery injures the upper trunk of the brachial plexus, producing Erb palsy with weakness of abduction and external rotation of the shoulder and flexion of the elbow. The lower trunk injury affects the hand and is associated with breech delivery. Distal nerve injuries are unrelated to shoulder traction.

Question 46Medicine

Which feature on a blood film is most suggestive of a microangiopathic haemolytic anaemia?

  1. Schistocytes Correct answer.
  2. Target cells
  3. Howell-Jolly bodies
  4. Basophilic stippling

Explanation

Microangiopathic haemolysis results from red cells being fragmented as they pass through damaged small vessels or fibrin strands, producing schistocytes. Target cells suggest liver disease or thalassaemia, and Howell-Jolly bodies indicate hyposplenism. Basophilic stippling is seen in lead poisoning and other disorders.

Question 47Medicine

A 60-year-old man has painless haematuria. Which investigation is the most appropriate first step to identify a bladder cause?

  1. Urine cytology alone
  2. Renal ultrasound
  3. Intravenous urography
  4. Cystoscopy Correct answer.

Explanation

Painless visible haematuria in an older adult raises concern for urothelial malignancy, and cystoscopy allows direct visualisation and biopsy of the bladder. Imaging of the upper tract is also arranged, but cystoscopy is the key test for bladder lesions. Urine cytology alone is insufficiently sensitive to exclude cancer.

Question 48Medicine

Which vitamin deficiency is most strongly associated with neural tube defects in the developing fetus?

  1. Vitamin K
  2. Vitamin D
  3. Vitamin B12
  4. Folic acid Correct answer.

Explanation

Periconceptional folic acid supplementation reduces the risk of neural tube defects such as spina bifida and anencephaly. The neural tube closes in the first four weeks of gestation, so supplementation must begin before conception. The other vitamins are not linked to neural tube closure.

Question 49Medicine

A 35-year-old man has sudden severe testicular pain with a high-riding testis and absent cremasteric reflex. What is the most appropriate immediate action?

  1. Scrotal support and analgesia with outpatient review
  2. Immediate antibiotic therapy
  3. Urgent surgical exploration Correct answer.
  4. Transillumination and reassurance

Explanation

Testicular torsion is a surgical emergency, and the diagnosis should be made clinically with urgent exploration and bilateral fixation rather than delayed imaging. Loss of the cremasteric reflex and a high-riding testis are classic. Antibiotics treat epididymo-orchitis, which is a different diagnosis.

Question 50Medicine

Which finding best supports a diagnosis of acute appendicitis in a young adult?

  1. Diffuse abdominal pain relieved by defecation
  2. Migratory pain from the umbilicus to the right iliac fossa Correct answer.
  3. Periumbilical pain with profuse watery diarrhoea
  4. Right upper quadrant pain radiating to the shoulder

Explanation

Appendiceal inflammation initially produces vague periumbilical visceral pain that localises to the right iliac fossa as the parietal peritoneum becomes involved. Rebound tenderness and guarding often accompany this shift. Pain relieved by defecation and diarrhoea suggest colonic or infective causes instead.