A 7-week-old girl presents to the ED with respiratory distress. She has had increasingly labored breathing over the past several hours without accompanying fever, cough, or rhinorrhea. During evaluation, she develops apnea and requires intubation. Chest radiography demonstrates diffuse bilateral opacities. Echocardiography reveals dilated cardiomyopathy. During a 2-week hospitalization, her clinical status and cardiac function gradually improve on medical therapy.
Her cardiac function normalizes within months of discharge. Laboratory evaluation and endomyocardial biopsy do not identify a cause for her cardiomyopathy. Viral titers are negative. During this interval, she is noted to have nystagmus. Dilated ophthalmologic examination and MRI of the head yield normal results.
An attempt is made to take her off angiotensin-converting enzyme inhibitors at 1 month of age. However, after the withdrawal of medications, her cardiac function decreases but normalizes within 4 weeks of reinitiation of the medication.
At 3 years of age, the patient has slightly...