MSRA MSRA Clinical Reasoning 2 — Questions and Answers
Question 1: A 4-year-old child presents with fever, stridor, and a 'barking cough' that is worse at night. What is the most likely diagnosis?
- Epiglottitis
- Croup (laryngotracheobronchitis) (Correct answer)
- Foreign body aspiration
- Bacterial tracheitis
Correct answer: Croup (laryngotracheobronchitis)
A barking cough with stridor that worsens at night in a young child is the hallmark presentation of croup, typically caused by parainfluenza virus.
Question 2: A 25-year-old male presents with acute onset monoarthritis of the right knee, urethral discharge, and conjunctivitis following a gastrointestinal infection. What is the likely diagnosis?
- Septic arthritis
- Reactive arthritis (Correct answer)
- Gonococcal arthritis
- Gout
Correct answer: Reactive arthritis
The triad of arthritis, urethritis, and conjunctivitis following an enteric or urogenital infection is diagnostic of reactive arthritis (formerly Reiter's syndrome).
Question 3: A 68-year-old woman with known atrial fibrillation presents with sudden left-sided weakness and facial droop lasting 45 minutes before fully resolving. What is the most appropriate next step?
- Reassure and discharge
- Start aspirin and review in 2 weeks
- Admit urgently using the ABCD2 score and fast-track TIA pathway (Correct answer)
- Order an MRI in outpatient clinic
Correct answer: Admit urgently using the ABCD2 score and fast-track TIA pathway
A TIA in a patient with AF carries high early stroke risk; same-day neurovascular assessment and urgent investigation are mandatory under the fast-track TIA pathway.
Question 4: A 50-year-old male presents with central crushing chest pain radiating to the left arm, diaphoresis, and nausea. ECG shows ST elevation in V1–V4. What is the immediate priority?
- Oral nitrates and observation
- Primary PCI within 90–120 minutes (Correct answer)
- IV heparin and thrombolytics if PCI unavailable within 120 min
- CABG
Correct answer: Primary PCI within 90–120 minutes
Anterior STEMI requires primary percutaneous coronary intervention (PCI) as the first-line reperfusion strategy, targeting a door-to-balloon time within 90–120 minutes.
Question 5: A neonate at 24 hours of life develops jaundice. Total bilirubin is markedly elevated. What is the most important cause to exclude first?
- Breast milk jaundice
- Physiological jaundice
- Haemolytic disease of the newborn (Correct answer)
- Gilbert's syndrome
Correct answer: Haemolytic disease of the newborn
Jaundice in the first 24 hours is always pathological; haemolytic disease of the newborn due to Rh or ABO incompatibility must be excluded urgently to prevent kernicterus.
Question 6: A 72-year-old woman presents with confusion, polyuria, and severe hypercalcaemia (Ca²⁺ 3.8 mmol/L). She has a history of non-small cell lung cancer. What is the mechanism?
- Primary hyperparathyroidism
- Vitamin D toxicity
- PTHrP secretion by tumor (Correct answer)
- Sarcoidosis
Correct answer: PTHrP secretion by tumor
Hypercalcaemia of malignancy in lung cancer is most commonly mediated by parathyroid hormone-related peptide (PTHrP) secreted by the tumor cells.
MSRA MSRA Clinical Reasoning 2
A 4-year-old child presents with fever, stridor, and a 'barking cough' that is worse at night.
What is the most likely diagnosis?