Acute myocarditis in children: current concepts and management.

The spectrum of presentation of pediatric myocarditis ranges from minor flu-like illness with chest pain to acute cardiogenic shock in a previously healthy child. A major change in the diagnostic evaluation of myocarditis is a shift in focus away from endomyocardial biopsy and histologic confirmation toward cardiac MRI for noninvasive diagnosis and prognostication of acute myocarditis. Cardiac MRI may be particularly useful in pediatric patients, considering the risks associated with biopsy in children. Some of the MRI characteristics seen in pediatric patients with acute myocarditis also may serve as predictors of outcome. The approach to managing myocarditis varies according to the severity of presentation; it is primarily supportive while spontaneous recovery of cardiac function is awaited. For subacute heart failure, the mainstay of therapy is still supportive management with oral heart failure medications such as angiotensin-converting enzyme inhibitors, beta-blockers, and diuretics. Acute myocarditis presenting with severe symptomatology, termed fulminant myocarditis, has a high recovery rate. Aggressive supportive care, including mechanical circulatory support, is indicated in fulminant myocarditis. With the increasing availability of and experience with paracorporeal pulsatile mechanical assist devices for children, more and more young patients are being bridged to transplantation or recovery. Despite promising results from several uncontrolled pediatric studies using immunosuppressive and/or immunomodulating therapy with intravenous gamma-globulin, the translation of these results into a recommended, routine therapy for pediatric myocarditis has been complicated by the high rate of spontaneous improvement of myocarditis with supportive care and the lack of demonstrable benefit for such therapies in blinded, randomized, placebo-controlled trials in adult myocarditis. Further clinical studies are necessary to define the possible utility of immunosuppressive, immunomodulatory, and antiviral therapy. Heart transplantation remains the final therapeutic option for children with myocarditis and intractable severe heart failure.