Myocarditis as the initial presentation of Epstein-Barr virus infection in a 17-year-old male patient

Case

A 17-year-old male patient contacted the on-call family physician with a complaint of sudden-onset, throbbing, bilateral shoulder and arm pain that woke him from sleep, without a clear trigger or any focal neurologic symptoms. He had taken ibuprofen once without any relief. He also described slight discomfort in the upper chest, bilaterally near the collarbone, and central back pain. He reported a recent upper respiratory tract infection and had a residual mild cough, but no other respiratory symptoms or sore throat. The patient was also experiencing generalized weakness and reduced appetite.

The medical history of the patient was relevant only for a diagnosis of attention deficit disorder for which he was taking methylphenidate. He was active in sports without any recent hospitalizations or substantial illness. Although the patient was initially advised to attend the clinic for assessment, he presented to the pediatric emergency department owing to considerable concern about his pain.

On examination, the patient was afebrile with normal vital signs, and findings of cardiovascular, respiratory, and neurologic examinations were normal. He was noted to have a slight cervical lymphadenopathy and mild left upper quadrant abdominal tenderness. Based on the initial assessment, he was believed to have a nonspecific viral illness, but a workup was initiated.

Laboratory investigations revealed normal complete blood count, electrolyte levels, and creatinine level, but a troponin I level of 14 762 ng/L (normal level < 30.9 ng/L) and a creatine kinase level of 747 U/L (normal level 55 to 370 U/L), as well as slight elevations in liver enzyme levels (Table 1). A 12-lead electrocardiogram (ECG) showed normal sinus rhythm and the rSR’ pattern in lead V₁, suggesting right ventricular conduction delay and early repolarization (Figure 1). Findings of a chest x-ray scan were normal. Transthoracic echocardiography was performed, findings of which showed good biventricular systolic function with no regional wall abnormalities and no pericardial effusion. Ultrasound of the abdomen was not performed.

In the emergency department, he received 1000 mg of acetaminophen and 162.5 mg of acetylsalicylic acid. He was assessed by a cardiologist and was discharged home with ibuprofen for pain control. In follow-up, he was seen by another cardiologist who made a diagnosis of myocarditis, presumed to be viral in cause.

When he was seen 5 days later in the family medicine clinic, his pain had markedly improved, with complete resolution of chest and back pain but some persistence of the bilateral shoulder and arm pain with movement. He also continued to complain of generalized fatigue. On examination at that time, he had persistent cervical lymphadenopathy but no other findings. He presented again 2 days later with a worsening sore throat and was found to have increased lymphadenopathy, tonsillar hypertrophy, and exudates. Repeat bloodwork showed a normal white blood cell count with a slight increase in lymphocytes, a return of troponin I and creatine kinase to normal levels, and continued mild elevation of liver enzyme levels (Table 1). Findings of a throat swab culture were negative for streptococcus, but mononuclear spot test results for EBV were positive.

The final diagnosis made was EBV infection with initial presentation as myocarditis, followed 1 week later by the more typical picture of infectious mononucleosis.

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Figure 1.

Patient’s electrocardiogram on initial presentation to the pediatric emergency department showing normal sinus rhythm and the rSR’ pattern in lead V₁, suggesting right ventricular conduction delay and early repolarization