Myocarditis describes inflammation of the myocardium. There are a wide range of underlying causes. It should be particularly considered in younger patients who present with chest pain.

Causes

• viral: coxsackie B, HIV
• bacteria: diphtheria, clostridia
• spirochaetes: Lyme disease
• protozoa: Chagas' disease, toxoplasmosis
• autoimmune
• drugs: doxorubicin

PC

• usually young patient with an acute history
• fever
• chest pain
• dyspnoea
• arrhythmias

Examination findings are non-specific. Signs of heart failure may be evident (along with S3 and S4 gallops). If pericarditis is associated, auscultation can reveal a pericardial friction rub.

Investigations

• bloods
  • ↑ inflammatory markers in 99%
  • ↑ cardiac enzymes
  • ↑ BNP
• ECG
  • tachycardia
  • arrhythmias
  • ST/T wave changes including ST-segment elevation and T wave inversion