Neonatal Hypoglycemia

A term male infant was born after an uneventful pregnancy to a 28-year-old gravida I woman who had no evidence of hyperglycemia and no chronic diseases. The infant had Apgar scores of 7 and 9 at 1 and 5 minutes, respectively. His growth parameters were in the normal range, with weight at the 60th percentile, head circumference at the 50th percentile, and length at the 50th percentile. The baby was taken to the well baby nursery, examined and bathed, and then taken to the mother for nursing at about 2 hours of age. He appeared slightly jittery at that time and was not very interested in nursing or very aware. A blood glucose concentration of 1.39 mmol/L (25 mg/dL) was obtained using a One Touch instrument. The baby was fed 25 mL of 5% dextrose in water. The blood glucose concentration obtained 1 hour later was 2.22 mmol/L (40 mg/dL), and the baby nursed for about 5 minutes at each breast with apparent satisfaction. Jitteriness and “lack of interest” were improved. Normal nursery routine was followed, with no comment in the chart by the nursing staff about the infant’s feeding or behavior until the second day of life when he again appeared jittery and fussy. Glucose concentration at that time was 1.11 mmol/L (20 mg/dL). The infant was fed by breast or bottle (routine 20 kcal/oz house formula) alternating every 2 hours, and clinical signs improved. One Touch glucose concentrations obtained over the next 24 hours were variable, but overall the concentration increased, with a predischarge, preprandial value of 2.78 mmol/L (50 mg/dL). The family failed to return to the hospital clinic the next day, but did see their primary care physician on the fifth day of life at which time the infant acted hungry, was noted to be “very active,” and weighed 113.4 g more than birthweight. At 2 weeks of life, the parents noted the infant to be very fussy and jittery and to experience staring spells. At a local emergency department, he was noted to have lost weight, appeared somnolent but fussy when aroused, and started having tonicclonic jerking movements of all extremities. A “glucose concentration” was less than 0.55 mmol/L (10 mg/dL). The infant was treated with intravenous glucose, and the apparent seizure resolved. Over the next several weeks, the infant returned to the emergency department several times with similar episodes. When finally examined by the primary care physician, the infant had gained 283.5 g and appeared “puffy.” An “office glucose concentration” was 1.94 mmol/L (35 mg/ dL). The infant was referred to a pediatric endocrinologist, who noted that the infant’s weight was approaching the 90th percentile, there was definite hepatomegaly, and the infant appeared “apathetic.” In the hospital, several serum glucose concentrations were measured at less than 2.22 mmol/L (40 mg/ dL), with plasma insulin concentrations all greater than 144 pmol/L (20 mcU/mL). The infant was treated with diazoxide with only limited success over the next 3 months. Development continued but was “slow.” He was treated in the local emergency department three times for tonicclonic seizures, all requiring intravenous glucose to correct severe hypoglycemia. At 5 months of age, the infant underwent a subtotal pancreatectomy. While recovering, he had a severe, prolonged seizure and was noted to be in shock, requiring two rounds of resuscitation. Escherichia coli meningitis was diagnosed and treated successfully. At 1 year of age, the infant showed little developmental gain from 6 months of age. At 5 years of age, he exhibited extremely poor growth, had diabetes mellitus that necessitated insulin treatment, and required pancreatic enzyme replacement with feedings to treat malabsorptive diarrhea. He was almost completely deaf and had marked developmental delay. His parents sought legal counsel, claiming that the treating physicians in the birth hospital failed to diagnose a “hyperinsulinism” condition that then led to delayed diagnosis and treatment, followed by severe neurologic damage. Questions to consider (feel free to send in your answers to these questions and any questions of your own for the “experts” to consider and discuss about this case): 1. What is the likely diagnosis for this infant’s hypoglycemia? 2. What diagnostic tests could have been done in the birth hospital to determine whether the infant had