Myocarditis and pericarditis — formative SAQs

SAQ 1 — Acute chest pain with a raised troponin (10 marks, 15 minutes)

A nine-year-old boy presents to the emergency department one week after a febrile respiratory illness with central chest pain, breathlessness on walking and palpitations. He is tachycardic at 130 beats per minute with a gallop rhythm, a respiratory rate of 40, cool peripheries and a capillary refill of four seconds. The high-sensitivity troponin is markedly raised. The electrocardiogram shows widespread ST-segment and T-wave changes with occasional ventricular ectopic beats. The echocardiogram shows a moderately impaired left ventricular ejection fraction with global hypokinesis and a trivial pericardial effusion. A diagnosis of acute myocarditis is made. ^[1]

a) Outline your diagnostic reasoning, naming the three bedside investigations that anchor the diagnosis and the role of cardiac magnetic resonance. (3 marks) ^[3]

b) Describe your immediate and stepwise management, including where this child should be managed, the activity-restriction advice and the role (if any) of intravenous immunoglobulin and corticosteroids. (5 marks) ^{[1] [6]}

c) Twenty-four hours later the child becomes hypotensive, oliguric and cold, with a rising lactate and sustained ventricular tachycardia. What has happened, and what is the definitive intervention that reverses the course? (2 marks) ^[8]