Myocarditis in children: diagnosis and management

Historically, myocarditis was diagnosed by findings on endomyocardial biopsy. Although still considered to be the reference standard, this approach has become uncommon in pediatrics. Cardiac magnetic resonance imaging can also be used to make a diagnosis, but its use is also limited in pediatrics due to the frequent need for sedation among other logistical and technical requirements. In current practice, the diagnosis of myocarditis in children for the purpose of deciding whether to treat is largely clinical, guided by noninvasive clinical findings. Preceding fever, constitutional, respiratory, and gastrointestinal symptoms, and hepatomegaly are common presenting signs and symptoms that are frequently mistaken for non-cardiac issues. Arrythmias and specific ECG findings can also accompany myocarditis. Cardiac biomarkers including troponin and BNP are frequently elevated and can help provide prognostic information. Infectious workup is an important part of the diagnosis of myocarditis, and recent studies have shown Parvovirus B19 and HHV6 to be the most common causes of viral myocarditis in pediatrics. Echocardiography is key to the clinical diagnosis, yet findings of myocarditis can be quite variable. The hallmark of treatment for myocarditis in children is supportive care including ionotropic support and heart failure therapies, with prompt initiation of mechanical circulatory support for cardiogenic shock or compromising arrhythmias. Some combination of steroids and IVIG are also frequently used to slow the injurious inflammatory response involved with myocarditis, yet this remains an area of debate. Future treatments may include additional immunomodulatory therapies, but further studies are needed.