Recurrent Episodes of Abdominal Distention.

A 1-month-old nondysmorphic female infant presents with repeated episodes of abdominal distention and irregular stool patterns. Prenatal findings were significant for oligohydramnios at 34 weeks’ gestation. The infant was born at 36 weeks’ gestation with a birthweight of 2,250 g (10th percentile). She had abdominal distention and delayed passage of meconium, which occurred after a saline enema on the 3rd postnatal day and was discharged at 5 days of age. At 11 days of age, she had constipation with abdominal distention, for which she received simethicone drops that resolved her symptoms. At 26 days of age, she was admitted to a community hospital as a result of poor feeding, loose stools, and fever. She had poor perfusion and room air oxygen saturation of 88% at admission. She received intravenous fluid, antibiotics, and inotropes. Her laboratory testing showed a hemoglobin level of 13.9 g/dL (139 g/L), white blood cell count of 7,300/µL (7.3 × 109/L), platelet count of 415 × 103/µL (415 × 109/L), C-reactive protein of 0.6 mg/dL (6 mg/L), sodium of 136 mEq/L (136 mmol/L), potassium of 5 mEq/L (5 mmol/L), chloride of 103 mEq/L (103 mmol/L), and thyroid-stimulating hormone of 4.6 mIU/L. A blood culture was negative and she was presumed to have an infectious enterocolitis. Abdominal ultrasonography showed a fluid-filled distended bowel and a normal relationship of the …