To the Editor:

A 16-year-old female patient presented to the clinic with a 4-day history of fever, headache, and lethargy, and a slight cough that began the night before. She denied sore throat, vomiting, or diarrhea. Her highest temperature was 101.8°F (38.8°C), taken at home the previous day. No one at home had recently been ill. She was up to date on all immunizations, including tetravalent meningococcal conjugate vaccine (Menactra). Her medical history was benign except for chest pain at 12 years of age, when she had a normal heart examination and electrocardiogram.

Physical examination was unremarkable, with normal vital signs and no respiratory distress or cardiac abnormalities. Laboratory studies were obtained, including a complete blood count, Epstein-Barr virus and cytomegalovirus antibody titers, and an influenza nasal swab. The patient was advised to take acetaminophen as needed for fever, increase fluid intake, consume a bland diet, and go to the emergency department if symptoms worsened. Her mother observed that she initially appeared comfortable after returning home, but was found unresponsive that evening. Emergency services were called, and the patient was pronounced dead. The autopsy report was consistent with acute myocarditis secondary to an underlying cardiac abnormality.

Although viral myocarditis is underdiagnosed, it is one of the most common causes of sudden cardiac death in children without previous heart disease.¹ Presentations vary widely, and mild cases may be misdiagnosed as upper respiratory tract infections or gastroenteritis. Viral myocarditis is usually diagnosed later, after the patient becomes seriously ill or after sudden cardiac death. One study estimated that 1 to 2 in every 100,000 children develop viral myocarditis during adolescence.²

Due to possible rapid deterioration, it is imperative to consider myocarditis in children with tachycardia or respiratory distress, neither of which occurred in this case. If myocarditis is on the differential, testing should include an electrocardiogram or echocardiogram, because these are commonly abnormal with this condition.³ Children with myocarditis have over an 80% chance of survival if correctly diagnosed and treated.⁴