A 67-year-old woman develops painful swelling of the left calf 5 days after hip-replacement surgery. The affected leg is 4 cm larger in circumference than the other leg and is warm and tender. Which diagnosis should be considered most strongly?

A 10-year-old child with congenital heart disease presents with persistent fever, fatigue and a newly changing murmur. Blood cultures are positive. Which complication should be considered if the child suddenly develops focal neurologic weakness?

A 48-year-old man with poor dentition and alcohol misuse develops fever and foul-smelling sputum. Chest imaging shows a thick-walled pulmonary cavity containing an air-fluid level. Which diagnosis is most likely?

A 34-year-old man with a prosthetic heart valve presents with persistent fever, malaise and weight loss. Examination reveals a new regurgitant murmur and splinter hemorrhages. Multiple blood cultures grow the same organism. Which diagnosis is most likely?

A 62-year-old man with a 40-year occupational history of asbestos exposure presents with progressive dyspnea and chest pain. Imaging reveals diffuse pleural thickening and a unilateral pleural effusion. Which diagnosis is most strongly associated with this exposure?

A hospitalized patient with suspected proximal DVT has a high clinical probability based on history and examination. Which investigation is most appropriate to confirm the diagnosis?

A 2-year-old child with cyanotic congenital heart disease becomes deeply cyanosed and breathless while crying. The child instinctively squats after exertion. Examination reveals a harsh systolic murmur. Which diagnosis is most likely?

A 7-year-old child is evaluated for reduced exercise tolerance. Examination reveals a fixed wide splitting of the second heart sound and an ejection systolic murmur over the pulmonary area. Which congenital heart defect is most likely?

A 58-year-old man is found to have blood pressure readings of 166/96 mmHg and 162/94 mmHg at two clinic visits. He is asymptomatic. Before labeling his hypertension as persistently uncontrolled, which principle is most important?

A 71-year-old man with known COPD presents with an acute infective exacerbation and carbon dioxide retention. He requires supplemental oxygen. Which approach is most appropriate?

A term newborn develops profound cyanosis within the first hours of life. Oxygen administration produces little improvement. Echocardiography shows the aorta arising from the right ventricle and the pulmonary artery arising from the left ventricle. Which diagnosis is present?

A 52-year-old man newly diagnosed with hypertension smokes 20 cigarettes daily, is obese and has a sedentary lifestyle. Which counselling strategy is most appropriate alongside pharmacological management?

A 52-year-old man has years of daily productive cough with large volumes of purulent sputum and recurrent chest infections. He occasionally has hemoptysis. Examination reveals coarse inspiratory crackles and clubbing. Which diagnosis is most likely?

A 64-year-old man presents with severe retrosternal chest pain for 90 minutes associated with sweating and nausea. ECG shows ST-segment elevation in leads II, III and aVF. His blood pressure is 105/70 mmHg and there is no contraindication to reperfusion therapy. Which diagnosis best explains this presentation?

A 59-year-old man with known heart failure develops severe breathlessness at rest, widespread inspiratory crackles and hypoxemia. He is sitting upright and coughing frothy sputum. Which complication is most likely?

A 2-year-old child has fever, cough, tachypnea and lower chest-wall indrawing. The child is lethargic and oxygen saturation is 86% on room air. Which feature most strongly indicates the need for urgent hospital-level assessment?

A 68-year-old man with chronic heart failure presents with increasing breathlessness. Echocardiography shows a left ventricular ejection fraction of 30%. Which finding represents systolic ventricular dysfunction?

A 30-year-old man is brought after a road-traffic accident. He is severely breathless and hypotensive. The right hemithorax is hyper-resonant, breath sounds are absent on the right, and the trachea is deviated to the left. Neck veins are distended. What is the most appropriate immediate action?

A 40-year-old man presents with several weeks of fever, weight loss, productive cough and intermittent hemoptysis. He has upper-zone crackles and a chest radiograph showing cavitation. Which investigation is most directly aimed at confirming pulmonary tuberculosis microbiologically?

A patient with a newly diagnosed unilateral pleural effusion undergoes diagnostic thoracentesis. Which investigation of the pleural fluid is most useful for initially distinguishing an exudate from a transudate?

A 65-year-old man with COPD is admitted with increasing cough, purulent sputum and dyspnea. He is using accessory muscles and appears drowsy. ABG shows marked hypercapnia and acidemia despite initial medical therapy. Which complication must be recognized promptly?

A 38-year-old man has cough for 7 weeks, night sweats, weight loss and occasional hemoptysis. Chest radiograph demonstrates an upper-lobe cavitary lesion. Which diagnosis must be strongly suspected?

A patient is suspected of having infective endocarditis. He is hemodynamically stable and has not yet received antibiotics. Which step is most appropriate before starting antimicrobial therapy?

A 62-year-old man presents with progressive dyspnea. Examination shows reduced right-sided chest expansion, stony dull percussion and markedly diminished breath sounds at the right base. Chest radiograph demonstrates blunting of the costophrenic angle with a meniscus. Which diagnosis is most likely?

A 54-year-old woman receiving chemotherapy develops sudden pleuritic chest pain, tachycardia and dyspnea. Oxygen saturation is 87% on room air. Her right calf is swollen. Which diagnosis is most likely?

A 49-year-old man with blood pressure of 220/130 mmHg presents with severe headache, confusion and visual disturbance. Fundoscopy shows retinal hemorrhages and papilledema. Which condition is most likely?

A 15-year-old boy is found to have hypertension in both arms during a school medical examination. Femoral pulses are weak and delayed compared with radial pulses. Blood pressure in the legs is lower than in the arms. Which diagnosis is most likely?

A 66-year-old man with previous myocardial infarction reports progressive exertional dyspnea, three-pillow orthopnea and nocturnal breathlessness. Examination reveals raised JVP, bilateral basal crackles, displaced apex beat and pitting ankle edema. Which diagnosis is most likely?

A child is diagnosed with acute rheumatic fever following documented group A streptococcal pharyngitis. Which long-term strategy is most important for reducing the risk of recurrent rheumatic fever?

A 32-year-old man presents with sharp central chest pain that worsens when lying flat and improves on sitting forward. ECG demonstrates widespread concave ST-segment elevation with PR depression. Which diagnosis is most likely?

A 24-year-old previously healthy man develops chest discomfort, palpitations and progressive dyspnea one week after a viral febrile illness. ECG shows nonspecific ST-T changes and troponin is elevated. Echocardiography demonstrates global left ventricular systolic dysfunction without a regional coronary distribution. Which diagnosis is most likely?

A 3-year-old child presents with fever, barking cough and inspiratory stridor that worsens at night. The child is alert and has no drooling. Which diagnosis is most likely?

A 70-year-old man with hypertension presents with palpitations and mild breathlessness. His pulse is 136/min and irregularly irregular. ECG shows absent discrete P waves with variable R–R intervals. He is hemodynamically stable. Which rhythm is present?

A 28-year-old woman suddenly develops rapid palpitations while at work. ECG demonstrates a regular narrow-complex tachycardia at 190/min. She is alert, blood pressure is 118/76 mmHg, and there is no chest pain or pulmonary edema. Vagal maneuvers fail. Which treatment is most appropriate next?

A 72-year-old man complains of recurrent syncope. His pulse is 32/min. ECG shows regular P waves and regular QRS complexes, but there is no consistent relationship between them. Which conduction abnormality is present?

A 58-year-old man with diabetes and hypertension develops central crushing chest pain while climbing stairs. The pain radiates to his left arm and resolves within 5 minutes of rest. He has had similar episodes for 3 months with a predictable level of exertion. Resting ECG shows no acute ST-segment changes. Which diagnosis is most likely?

A 45-year-old man presents with fever, productive cough, pleuritic chest pain and dyspnea for 3 days. Examination shows bronchial breathing, increased vocal resonance and dullness to percussion over the right lower zone. Which pathological process best explains these findings?

A tall, thin 23-year-old man develops sudden pleuritic chest pain and dyspnea. He is stable. Examination reveals hyper-resonance and reduced breath sounds over the left upper chest. Chest radiograph confirms a small primary spontaneous pneumothorax. Which diagnosis best fits the presentation?

A 56-year-old man is reviewed 6 weeks after an acute myocardial infarction treated with PCI. He has stopped smoking and is clinically stable. Which combination most appropriately represents secondary prevention following myocardial infarction?

A 4-year-old child with unrepaired Tetralogy of Fallot suddenly becomes intensely cyanosed and irritable after crying. The child is tachypneic and assumes a knee-chest posture when helped by the parent. What is the underlying physiological problem during this episode?

A 69-year-old man with severe COPD presents with drowsiness and worsening dyspnea. ABG shows pH 7.28, PaCO₂ 68 mmHg and PaO₂ 52 mmHg. Which acid-base and respiratory abnormality is most likely?

A chest tube has been inserted for a traumatic hemopneumothorax. Which position is generally appropriate for the underwater-seal drainage system during patient care?

A 24-year-old woman has recurrent episodes of wheeze, chest tightness and nocturnal cough that vary from day to day. Spirometry demonstrates airflow obstruction that improves significantly after bronchodilator administration. Which diagnosis is most likely?

A 6-year-old child has recurrent lower respiratory tract infections, chronic productive cough, poor weight gain and bulky foul-smelling stools. The parents report that the child's skin tastes unusually salty. Which diagnosis is most likely?

A 61-year-old woman has recurrent chest pain occurring at rest over the last 24 hours. Each episode lasts 15–20 minutes. ECG during pain demonstrates transient ST-segment depression, while cardiac troponin remains within the reference range on serial testing. Which diagnosis is most likely?

A 5-month-old infant with congenital heart disease has tachypnea, feeding difficulty, sweating during feeding and failure to thrive. Examination demonstrates hepatomegaly and tachycardia. Which clinical syndrome best explains these findings?

A 12-year-old child develops migratory pain and swelling of large joints three weeks after an untreated sore throat. Examination reveals tachycardia and a new apical systolic murmur. Which diagnosis is most likely?

A 62-year-old man develops massive pulmonary embolism. He is hypotensive at 78/46 mmHg, tachycardic and hypoxemic. There is no major contraindication to thrombolysis. Which treatment should be considered because he is hemodynamically unstable?

A 64-year-old man with a previous myocardial infarction presents with gradually worsening dyspnea, orthopnea, ankle swelling and reduced exercise tolerance. Examination shows elevated JVP, displaced apex beat, basal crackles and bilateral pitting edema. Which investigation is most useful for assessing ventricular systolic function and structural cardiac abnormalities?

A 58-year-old woman has progressive dry cough and exertional dyspnea. Examination demonstrates fine end-inspiratory basal crackles and finger clubbing. Pulmonary function testing shows reduced lung volumes with a normal or increased FEV₁/FVC ratio. Which physiological pattern is present?

A 4-month-old infant has poor feeding, sweating during feeds and recurrent respiratory infections. Examination reveals tachypnea and a harsh pansystolic murmur at the left lower sternal border. The infant has poor weight gain. Which congenital lesion is most likely?

A 67-year-old man with a 50-pack-year smoking history reports chronic productive cough and gradually progressive exertional dyspnea. Examination shows a barrel-shaped chest, prolonged expiration and diffusely reduced breath sounds. Spirometry reveals FEV₁/FVC of 52%. Which diagnosis is most likely?

A patient with malignancy develops progressive dyspnea, hypotension, raised JVP and muffled heart sounds. Echocardiography demonstrates a large pericardial effusion with right ventricular diastolic collapse. Which complication has developed?

A 69-year-old heavy smoker reports progressive cough, weight loss and hemoptysis. Chest radiograph shows a right hilar mass. CT confirms a central bronchogenic tumor. Which next step is essential for establishing a definitive histological diagnosis?

A 55-year-old woman with systemic sclerosis develops gradually progressive exertional dyspnea and dry cough. Examination shows fine bibasal crackles. HRCT demonstrates interstitial abnormalities. Which manifestation of systemic disease is most likely present?

A 35-year-old man sustains blunt chest trauma. He becomes tachycardic and hypotensive. Examination reveals reduced movement of the left hemithorax, absent breath sounds and marked dullness to percussion. Which diagnosis is most likely?

A 60-year-old man with diabetes, hypertension and a long smoking history presents with prolonged central chest pressure at rest associated with sweating and vomiting. ECG demonstrates ischemic changes and troponin is elevated. He is stabilized and later asks what will most reduce his risk of another cardiovascular event. Which approach is most appropriate?

A 9-year-old child develops fatigue, tachypnea and palpitations one week after a viral illness. Examination reveals tachycardia out of proportion to fever, gallop rhythm and hepatomegaly. Echocardiography demonstrates global ventricular dysfunction. Which underlying diagnosis is most likely?

A 60-year-old woman with newly diagnosed hypertension is undergoing focused assessment. Which finding most strongly suggests chronic hypertensive target-organ involvement?

A 67-year-old man develops sudden palpitations, dizziness and hypotension following an acute myocardial infarction. ECG shows a regular broad-complex tachycardia at 180/min. His blood pressure is 75/45 mmHg and he is confused. Which immediate management is most appropriate?