Evidence of late-onset infantile spasms

To underline the unusual but possible occurrence of epileptic spasms (ES) in children >1 year of age.

Cases in whom onset of spasms occurred after 1 year of age were identified through a retrospective review of the records of all patients referred for ES to the Saint-Vincent de Paul Hôpital (Paris) and American Memorial Hospital (Reims) between 1974 and 1994.

Eighteen cases were identified among the 734 children referred for ES, 18 cases were identified where spasm onset time ranged from 12 to 38 months of age. In 1/3 of the cases, the diagnosis was suspected from the onset of clinical manifestations; in the remaining 2/3, diagnosis was delayed by a mean 6 months (range, 2-25 months). Neurobehavioral regression affected two-thirds of the patients. Modified hypsarrhythmia was present in 11 patients; all but one exhibited major and diffuse spike- and slow-wave activity. EEG abnormalities were detected in the frontal areas in 11 patients. Spasms were cryptogenic in 9 patients. Steroids were administered to 13 patients; these controlled the spasms in 6 patients. Outcome was favorable for both seizures; cognition favorable in only 2 of the 18 patients.

Beginning after the first year of life, ES, or late-onset infantile spasms, are distinct from early Lennox-Gastaut syndrome, although etiology, prognosis and treatment are similar to that for the classical infantile spasms.