Diagnosis and management of hyperinsulinaemic hypoglycaemia of infancy.

Hyperinsulinaemic hypoglycaemia is a cause of persistent hypoglycaemia in the neonatal and infancy periods. Prompt recognition and management of patients with hyperinsulinaemic hypoglycaemia are essential, if brain damage and long-term neurological sequelae are to be avoided. Hyperinsulinaemic hypoglycaemia can be transient, prolonged, or persistent (congenital). Advances in the fields of molecular biology, genetics, and pancreatic beta-cell physiology are beginning to provide novel insights into the mechanisms causing congenital forms of hyperinsulinism. So far mutations in six different genes have been described that lead to unregulated insulin secretion. The histological differentiation of focal and diffuse congenital hyperinsulinism has radically changed the surgical approach to this disease. Until recently, highly invasive investigations were performed to localize the focal lesion, but recent experience with (18)F-L-dopa positron emission tomography scanning suggests that this technique is highly sensitive for differentiating diffuse from focal disease as well as for accurately locating the focal lesion. Despite recent advances, the genetic basis of congenital hyperinsulinism is still unknown in about 50% of the patients, and the management of medically unresponsive diffuse disease remains a real challenge.