Myocarditis

Myocarditis

This is an acute inflammatory condition that can have an infectious, toxic or autoimmune aetiology

Myocarditis can complicate many infections in which inflammation may be due directly to infection of the myocardium
or the effects of circulating toxin

Viral infections are the most common causes, such as Coxsackie
influenza A and B
. Myocarditis may occur several weeks after the initial viral symptoms and susceptibility is increased by corticosteroid treatment, immunosuppression, radiation, previous myocardial damage and exercise.

Toxic aetiologies include
drugs, which may directly injure the myocardium (e.g. cocaine, lithium and anti-cancer drugs, such as doxorubicin) (e.g.penicillins and sulphonamides, lead and carbon monoxide).

Occasionally, autoimmune conditions, such
as systemic lupus erythematosus and rheumatoid arthritis, are associated with myocarditis

Clinical features and investigations

Myocarditis can be classified by four distinct clinical presentations:
• Fulminant myocarditis follows a viral prodrome or influenza-like illness, and results in severe heart failure or cardiogenic shock