A case report of nonrheumatic myocarditis following group G streptococcus pharyngitis

Infectious myocarditis commonly presents following viral illness. Patients with myocarditis are at increased risk of cardiomyopathy, cardiogenic shock, and ventricular tachyarrhythmias. However, due to the rarity of post-bacterial myocarditis, less is known about the presentation, treatment, and prognosis of patients in this sub-population. In particular, myocarditis attributed to group G streptococcus is exceedingly rare. This report describes a 22-year-old man who presented to the hospital with 2 days of chest pain following group G streptococcal pharyngitis. Cardiac magnetic resonance imaging demonstrated focal myocardial hyperintensity on T2W imaging with corresponding elevated T2 values on T2 mapping compatible with myocardial edema. The delayed enhancement imaging showed subepicardial delayed enhancement involving the basal and mid-lateral walls, thereby fulfilling both T1 and T2 Lake Louise criteria consistent with myocarditis. He was treated with 3 months of colchicine. Interval echocardiogram and cardiac magnetic resonance imaging demonstrated improvement, and he was cleared for exercise 3 months post-diagnosis. This case adds to the limited literature on group G streptococcus-associated myocarditis. Close cardiology follow-up, including repeat echocardiogram, cardiac magnetic resonance imaging, and symptom review were key to the successful management of this case.