A 15-month-old boy presented with tachypnea and rales on examination after a mild upper-respiratory tract infection. Pregnancy and delivery were normal. An intermittent nonproductive cough developed at approximately age 5 months that did not improve with bronchodilators. At age 12 months, intercostal retractions, crackles, and wheezes were noted. The retractions continued despite nebulized bronchodilators and oral corticosteroids. The family history was negative for cystic fibrosis, asthma, or cardiovascular disease. There was one smoker and one dog in the home, but no woodburning stove or fireplace.
Laboratory findings were as follows: sweat chloride, normal; arterial oxygen saturation, 96%; hemoglobin, 130 g/L; prothrombin time, 11.3 seconds; activated partial thromboplastin time, 25.0 seconds; and erythrocyte sedimentation rate (Wintrobe method), 4 mm/h. Titers of respiratory viruses in serum were nondiagnostic.
A chest roentgenogram (Fig 1) and angiogram (Fig 2) were obtained.
An electrocardiogram demonstrated possible right ventricular hypertrophy. An echo-Doppler study demonstrated normal anatomy