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]

SAQ 2 — Recurrent pericarditis in an adolescent (10 marks, 15 minutes)

A fifteen-year-old girl presents with her third episode in eight months of sharp, pleuritic central chest pain that eases when she sits forward. She is febrile at 38.2 degrees Celsius. A loud three-component pericardial friction rub is audible at the left sternal edge. The electrocardiogram shows diffuse concave ST elevation with PR-segment depression. The echocardiogram shows a moderate circumferential pericardial effusion without tamponade physiology. Her previous episodes were treated with a non-steroidal anti-inflammatory drug alone and recurred on cessation. [12]

a) What is the diagnosis, and what are the characteristic bedside and electrocardiographic findings that support it? (3 marks) [2] [13]

b) Outline the medical management of this episode and the strategy to prevent further recurrence, including the specific drug regimen, its duration, and the class of drug to avoid in a first idiopathic episode and why. (4 marks) [13] [14]

c) Three hours later her blood pressure falls, her jugular venous pressure rises and she develops a pulsus paradoxus. What complication has developed, and what is the immediate management? (3 marks) [15]