Severe transient hyperinsulinaemic hypoglycaemia: two neonates without predisposing factors and a review of the literature

We report on transient hyperinsulinism (HI), presenting as severe congenital HI, in two neonates born without intrauterine growth restriction, maternal diabetes, perinatal asphyxia or Rhesus/platelet isoimmunisation. The neonates developed early (<6 h of life), symptomatic, non-ketotic hypoglycaemia (0-0.66 mmol/l), associated with elevated insulin levels (40-200 mU/l), and required high glucose infusion rates (22-24 mg/kg per min) to maintain normoglycaemia. However, both babies were diazoxide-sensitive and did not require glucose infusions beyond 2 weeks of life. Neither neonate had elevated serum ammonia levels or evidence of a metabolic disorder. Conclusion. Transient hyperinsulinism can occur in newborns delivered uneventfully without significant perinatal complications. The unusual sensitivity to medical treatment in these cases of neonatal-onset hyperinsulinaemic hypoglycaemia underscores the importance of careful medical management of severe congenital hyperinsulinism. Careful consideration of the indication and if necessary, timing and extent of pancreatectomy is required, while maintaining euglycaemia to protect the developing brain.