Today we discussed a case of myocarditis in a young patient with a prior history. Myocarditis typically presents in a patient with some kind of preceding viral prodrome, followed by symptoms either suggestive of pericarditis found to have an associated troponin elevation or typical anginal symptoms. 

1. What are the typical etiologies of myocarditis? They generally fall into 3 categories, infectious, inflammatory, or hypersensitivity. A very thorough differential can be found in Table 1 of the following paper: Circulation. 2006;113:876-890.)

2. When do you biopsy myocarditis? See the figure below from JACC 2016; 68: 2348. Biopsy is, in general, received for very severe cases, or those associated with arrhythmia, or those associated with a systemic disease that could affect the heart.

3. How do you treat myocarditis? Supportive care and usual HFrEF therapy is the mainstay. In viral negative, inflammation positive myocarditis, a combination of prednisone and azathioprine can be considered. Prednisone mono therapy has been used as well in viral positive inflammatory myocarditis. Giant cell myocarditis is typically treated with a combination of cyclosporine and prednisone.