Early onset, non-rheumatic, group A streptococcal-associated myocarditis

Group A streptococcal (GAS) tonsillitis is reported as an uncommon cause of acute non-rheumatic fever (non-RF) myocarditis. The aim of this research was to study the occurrence, diagnosis, management and prognosis of this condition.

We conducted a retrospective computerised search through medical records of patients admitted to our tertiary medical center between 1998-2016 with the diagnosis of either acute rheumatic fever or non-RF streptococcal myocarditis based on criteria we developed and review the relevant literature from 1973-2016.

We identified 283 cases diagnosed with acute myocarditis. Eight patients with non-RF GAS-myocarditis were identified, 7 of whom were men. Average age was 28.5 (22-35) years, and average latency period between onset of sore throat and chest pain 4.8 (3-10) days. Most patients presented with ST-segment elevations on the ECG and 2 underwent coronary catheterisation with presumed diagnosis of myocardial infarction. Three patients had heart failure, as documented by echocardiogram. All patients were treated with antibiotics and 6 patients received non-steroidal anti-inflammatory drugs (NSAIDs). All patients recovered with no evidence of heart failure a few months after the initial infection. One patient had a recurrent episode.

Non-RF GAS myocarditis typically affects healthy young males and represents about 3% of all hospitalised patients with myocarditis. These patients may be mistakenly diagnosed with an acute rheumatic fever or myocardial infarction. The prognosis in generally good following treatment with antibiotics and possibly NSAIDs.