Recurrent fulminant non-rheumatic streptococcal myocarditis proven by endomyocardial biopsy and autopsy

A 42-year-old man with a history of acute myocarditis after streptococcal pharyngitis developed recurrent fulminant myocarditis. Endomyocardial biopsy revealed myocyte degeneration, interstitial edema, and neutrophil infiltration. The patient's cardiac function deteriorated rapidly, and he died despite mechanical circulatory support. Autopsy revealed neutrophil infiltration, interstitial edema, and micro-abscesses containing masses of streptococci and neutrophilic phagocytosis within the myocardium. The patient did not meet the diagnostic criteria for acute rheumatic fever; thus, he was diagnosed with non-rheumatic streptococcal myocarditis. Non-rheumatic streptococcal myocarditis rarely recurs, but it can be fulminant upon recurrence. Learning objective: We report a rare case of recurrent fulminant non-rheumatic streptococcal myocarditis. Endomyocardial biopsy and autopsy revealed neutrophil infiltration and micro-abscesses containing bacterial masses of streptococci and neutrophilic phagocytosis in the myocardium. The patient did not meet the diagnostic criteria for acute rheumatic fever; thus, he was diagnosed with non-rheumatic streptococcal myocarditis. Non-rheumatic streptococcal myocarditis rarely recurs, but it can be fulminant upon recurrence.