Pediatric myocarditis: emergency department clinical findings and diagnostic evaluation

The goal was to determine, in children with myocarditis, the frequency of various presenting symptoms and the sensitivity of clinical and laboratory investigations routinely available in the emergency department.

We performed a retrospective review of all patients < 18 years of age who were diagnosed as having myocarditis at our institution between May 2000 and May 2006 and who initially presented to an emergency department. Patients were categorized as having definite myocarditis (positive endomyocardial biopsy results) or probable myocarditis (diagnosis assigned by a pediatric cardiologist on the basis of history, physical examination, and investigation results in the absence of an endomyocardial biopsy or in the presence of negative biopsy results). All patients were assigned a predominant category of symptoms at presentation on the basis of criteria defined a priori.

There were 16 cases of definite myocarditis and 15 cases of probable myocarditis. The age distribution was nonnormal, with peaks among children < or = 3 years and > or = 16 years of age. Of 14 patients who were seen by a physician before being diagnosed with myocarditis, 57% were originally diagnosed as having pneumonia or asthma. Thirty-two percent of patients presented with predominantly respiratory symptoms, 29% had cardiac symptoms, and 6% had gastrointestinal symptoms. Although evidence of cardiac dysfunction was frequently present in the form of respiratory distress, only a minority of children had evidence of hepatomegaly or abnormal cardiac examination results. The sensitivities of electrocardiograms and chest radiographs as screening tests were 93% and 55%, respectively. Among laboratory tests studied, aspartate aminotransferase measurement was the most sensitive (sensitivity: 85%).

Children with myocarditis present with symptoms that can be mistaken for other types of illnesses; respiratory presentations were most common. When clinical suspicion of myocarditis exists, chest radiography alone is an insufficient screening test. All children should undergo electrocardiography. Aspartate aminotransferase testing may be a useful adjunctive investigation.