CLINICAL HISTORY.—A 5-week-old boy was admitted to the hospital because of irritability, anorexia, and an episode of apnea. The mother's pregnancy was uneventful, and the patient weighed 3.4 kg (7 lb 5 oz) at birth. Three days after birth he was discharged from the nursery in good health.
Two days prior to the present admission he was seen in the Out Patient Department, where he was irritable and having difficulty breathing. Symptomatic therapy was prescribed, and the parents were asked to return in 48 hours. On their return, the infant weighed 2.9 kg (6 lb 6 oz), was pale and severely dehydrated. During the physical examination he had an episode of apnea, so he was admitted to the hospital. Laboratory studies revealed the following values: hemoglobin, 8.4 mg/100 cc; blood urea nitrogen (BUN), 66 mg/100 cc; blood glucose, 292 mg/100 cc; sodium, 113 mEq/liter; potassium, 5 mEq/liter; chloride, 103