A preterm very low birth weight male neonate with refractory hypoglycemia and hyperinsulinemia and hyperammonemia: A rare case report

Introduction: Hypoglycemia is an important metabolic complication in neonates, more so in newborns with perinatal risk factors. Physiological immaturity of gluconeogenesis, lipolysis coupled with hyperinsulinemia contributes to hypoglycemia in small for gestational age (SGA) neonates. Persistent hyperinsulinemic hypoglycemia of infancy (PHHI), a hyperinsulinemic condition is an important differential diagnosis for intractable and refractory hypoglycemia. Hyperinsulinemichyperammonemia (HI/HA) syndrome, a rare autosomal dominantly inherited disorder, is the second most common cause for hyperinsulinemichypoglycemia in infancy. Both symptomatic as well as asymptomatic hypoglycemia involves the occipital cortex leading to cortical blindness, necessitating early etiological diagnosis and prompt intervention. We report a preterm male neonate with rare manifestations of refractory hypoglycemia, hyperinsulinemia and hyperammonemia. Case Report: A 30 weeks, 1300 grams male neonate, born by C-section had respiratory distress, requiring mechanical ventilation (MV) for 10 days. On 11th day of life, neonate developed recurrent apneic episodes along with jitteriness and seizures. Initial evaluation revealed low blood sugar levels which persisted despite high glucose infusion rate (GIR 12 mg/kg/min). There was hyperammonemia (serum NH3 levels 273 μg/dL) along with hyperinsulinemia. However, the serum cortisol, thyroid, growth hormone levels and blood lactate were normal. Similarly, metabolic screening for inborn errors of metabolism (IEM) was normal. Abdominal imaging with ultrasound and contrast-enhanced computed tomography (CT) scan did not reveal pancreatic hyperplasia. Persistent hypoglycemia, hyperinsulinemia along with hyperammonemia could suggest hyperammonemic hyperinsulinemic syndrome in this neonate. The infant responded to oral diazoxide. Conclusion: We report a preterm, very low birth weight (VLBW) male neonate with refractory hypoglycemia and hyperinsulinemia and hyperammonemia, which responded to diazoxide.