Hyperinsulinism in a neonate

A male patient was born small for gestational age (SGA) at 33 weeks with a birth weight of 1,663 grams (< 10th percentile) and length 43 cm (10th percentile) to a 38-year-old G5P4 mother by cesarean section due to non-reassuring fetal heart tones. Prior to delivery, his mother experienced decreased fetal movement and decelerations. At birth, he was initially well-appearing and vigorous, with Apgar scores of 7 and 8 at 1 and 5 minutes, respectively. The physical examination was unremarkable--no skin findings, no facial anomalies, good tone, and the anterior fontanelle was soft and flat. The placenta, although noted to be healthy in appearance on prenatal ultrasounds, was atrophic and calcified by gross examination. The patient developed respiratory distress 1 hour after birth and was found to have a blood glucose level of 24 mg/dL. Following an intravenous (IV) bolus of 10% dextrose in water (D10W) of 2 mL/kg, his glucose was 20 mg/dL. He was started on IV fluids with a glucose infusion rate (GIR) of 7.3 mg/kg/minute, with a subsequent rise in blood glucose to 46 mg/dL. Due to prematurity, respiratory distress, and persistent hypoglycemia, a diagnostic evaluation was initiated for possible sepsis, including a complete blood count with differential and platelet count and blood cultures. The patient was started empirically on IV ampicillin and gentamicin. The patient was subsequently found to have thrombocytopenia, hypomagnesemia, and hyponatremia on laboratory evaluation and was transferred to our neonatal intensive care unit (NICU) for further care.