The clinical problem of hyperinsulinemic hypoglycemia and resultant infantile spasms.

Hyperinsulinemic hypoglycemia (HH) is a cause of severe hypoglycemia in the newborn and infancy period and is associated with a high risk of neurologic handicap and epilepsy. Infantile spasms after exposure to HH is rare and has been described in only 1 previous report. We report the clinical, biochemical, and neurodevelopmental characteristics of 5 patients with neonatal-onset HH who subsequently developed infantile spasms. All 5 patients had neonatal-onset HH of varying severity and duration. These patients presented with the characteristic ictal pattern of spasms in clusters at a mean age of 6.6 months. Characteristic hypsarrhythmia was noted in only 3 of 5 patients. Structural abnormality was found in only 1 of 4 patients who underwent MRI of the brain. Infantile spasms responded to medical treatment in 3 patients, spasms in 1 patient were refractory to antiepileptic drugs, and treatment duration was insufficient for us to comment on the response in 1 patient. Developmental delay was evident in all of them. In conclusion neonatal HH of varying severity is associated with later (after a latent period) development of infantile spasms. The latent period before the onset of the spasms can be variable; hence, long-term neurodevelopmental follow-up (until 1 year of age) is necessary.