Myocarditis: the great pretender

Key words: Myocarditis, Shock, Troponin, Chronic dilated cardiomyopathy

Myocarditis is a rare, but life threatening disease in childhood. It is most often due to common viral infections; less commonly, it may result from bacterial infections, immune mediated diseases or chemotherapy. Myocarditis may present with unspecific symptoms, ranging from respiratory to gastrointestinal ones; a clear hypomobility is the typical sign of myocarditis (“the immobile child”). The diagnosis is based on electrocardiogram and echocardiography, which are always pathologic but unspecific; an X-chest is useful to identify cardiomegaly. Among laboratory tests, the most sensitive element is an increased level of aspartate aminotransferase, while troponin dosage has low specificity and not absolute sensitivity. Endomyocardial biopsy is the gold standard diagnostic test, but it should be performed only in patients who do not respond to usual treatment, because of the high risk of side effects. The mainstay of therapy is supportive therapy for left ventricular dysfunction. The fulminant viral forms usually have initial significant cardiovascular impairment, followed by a complete resolution. On the other hand, a subacute disease might have less initial cardiovascular impairment, but more often can evolve to chronic dilated cardiomyopathy. In this case immunosuppressive therapy could be useful.