Clinical Problem Solving Flashcards

A 45-year-old woman presents with sudden onset severe headache she describes as 'the worst headache of her life.' A CT head is normal. What is the most appropriate next investigation?

Answer: Lumbar puncture for xanthochromia

A normal CT does not exclude subarachnoid hemorrhage; lumbar puncture looking for xanthochromia is required when clinical suspicion remains high.

A 68-year-old man with COPD has an ABG showing pH 7.32, PaCO2 58 mmHg, PaO2 52 mmHg, and HCO3 28 mEq/L. What is the correct interpretation?

Answer: Type II respiratory failure with compensatory metabolic alkalosis

Elevated PaCO2 with low PaO2 defines Type II respiratory failure, and the raised bicarbonate reflects chronic renal compensation for the respiratory acidosis.

A 25-year-old woman reports 3 months of fatigue, unintentional weight loss, heat intolerance, and palpitations. Lab results show an undetectable TSH and elevated free T4. What is the most likely diagnosis?

Answer: Hyperthyroidism (Graves' disease)

Suppressed TSH with elevated free T4 is consistent with primary hyperthyroidism, and Graves' disease is the most common cause in young women.

A 55-year-old man reports chest pain radiating to the jaw on exertion that resolves with rest. His resting ECG is normal. What is the most appropriate next investigation?

Answer: Exercise tolerance test (ETT)

Classic exertional angina with a normal resting ECG warrants an exercise tolerance test to provoke ischemic changes under stress.

A 30-year-old woman at 32 weeks gestation presents with a blood pressure of 158/104 mmHg, 2+ proteinuria on dipstick, and a severe headache. What is the most likely diagnosis?

Answer: Pre-eclampsia

New hypertension after 20 weeks with significant proteinuria and symptoms such as headache defines pre-eclampsia.

A 70-year-old man develops sudden painless loss of vision in his right eye, describing it as a 'curtain coming down.' Fundoscopy reveals a pale retina with a cherry-red spot at the macula. What is the diagnosis?

Answer: Central retinal artery occlusion

Sudden painless monocular visual loss with a pale infarcted retina and cherry-red spot at the fovea is the classic presentation of central retinal artery occlusion.

A 40-year-old woman has recurrent episodes of palpitations. ECG during an episode shows a regular narrow complex tachycardia at 180 bpm with P waves visible just after the QRS complexes. What is the most likely diagnosis?

Answer: AV nodal re-entrant tachycardia (AVNRT)

Regular narrow complex tachycardia with retrograde P waves immediately after the QRS is the hallmark of AVNRT, the most common paroxysmal supraventricular tachycardia.