Retrospective study of late febrile seizures.

This retrospective study documents the clinical features, electroencephalographic data, and outcome of 50 children with a history of seizures with fever that occurred after 5 years of age. Children with afebrile seizures before the onset of febrile seizures were excluded. Outcome was based on a cross-sectional survey and the follow-up period was 1-13 years. Of the 50 children, 40 had two or fewer febrile seizures after 5 years of age, and febrile seizures did not occur after 10 years of age. Twenty had complex febrile seizures, and 16 had a first-degree relative with febrile seizures. Five developed afebrile seizures, and 18 had educational difficulties. Epileptiform electroencephalographic abnormalities were observed in 22 but were not predictive of later afebrile seizures. Febrile seizures that occur after 5 years of age recur infrequently and cease by 10 years of age. The risk of developing afebrile seizures in this group is small.