Childhood-onset epilepsy with and without preceding febrile seizures.

OBJECTIVE: To identify characteristics in children with epilepsy that differ between those who did versus did not have a history of preceding febrile seizures.
BACKGROUND: Febrile seizures precede epilepsy in 10 to 15% of children. Little is known about the specific types of epilepsy associated with febrile seizures.
METHODS: In a community-based, prospectively identified cohort of children, the association between prior febrile seizures and characteristics of the children's epilepsy (seizure type, epilepsy syndrome, age at onset, underlying etiology, family history) were examined for 524 of the children who were aged > or =1 year at onset of epilepsy.
RESULTS: Seventy-three (13.9%) had febrile seizures. Children with febrile seizures were more likely to have a first-degree or a second-higher-degree relative with febrile seizures and less likely to have childhood absence epilepsy and absence seizures compared with children without febrile seizures. This was especially true for simple febrile seizures. There was no specific association with localization-related forms of epilepsy. Complex, but not simple, febrile seizures were associated with younger age at onset of epilepsy. There was no evidence that focal or prolonged febrile seizures were associated with localization-related epilepsy or temporal lobe epilepsy per se. Of the three children whose initial MRIs demonstrated hippocampal atrophy, none had a history of febrile seizures.
CONCLUSIONS: At the time of diagnosis, febrile seizures are not specifically related to temporal lobe epilepsy or localization-related epilepsy in general. A genetic component for febrile seizures is suggested by its positive associations with family history, especially for simple febrile seizures. Complex febrile seizures represent an underlying age-dependent susceptibility.