Early Detection of Acute Myocarditis in the Pediatric Population Using Clinically Accessible Data

Early diagnosis of acute myocarditis (AMC) is crucial due to its rapid progression and high mortality rate. Initial symptoms such as fever, abdominal pain, and vomiting are nonspecific and pose challenges for clinicians in distinguishing AMC from acute gastroenteritis (AGE).

We retrospectively reviewed the clinical characteristics of seven patients with AMC who were hospitalized at our institution between April 2011 and March 2022. We compared these findings with those of 19 patients with AGE.

The common initial symptoms of patients with AMC included fever, vomiting, abdominal pain, appetite loss, nausea, and fatigue, which did not differ significantly from those in patients with AGE. However, the percentage of diarrhea was significantly lower, whereas the detection rates of tachypnea, tachycardia, gallop rhythms, or cardiomegaly on radiography were higher in the patients with AMC than in those with AGE, respectively. Additionally, patients with AMC exhibited significantly higher serum lactate dehydrogenase (LDH) levels than those with AGE (p = 0.006). LDH demonstrated 71% sensitivity and 100% specificity (area under the curve, 0.857) for predicting AMC when a cutoff value of 459 U/L was used.

Preliminary findings suggest that LDH may serve as a trigger for suspicion of AMC in the pediatric population. Furthermore, combining LDH results with physical examination and chest radiographic findings could be useful for early diagnosis.