Febrile convulsions in 220 children--neurological sequelae at 12 years follow-up.

We report a 12-year follow-up study of children with febrile convulsions (FCs). The National General Practice Study of Epilepsy (NGPSE) is a large prospective community-based cohort study of 1,195 patients of all ages from first presentation with an identified seizure. Two hundred and twenty children with a first febrile convulsion were identified from the above study between 1984 and 1987. Children were prospectively followed up to ascertain subsequent seizures, neurological problems and treatment. Two hundred and seven patients were followed for a minimum of 8.4 years (median 11.2 years). In the FC cohort, 6% of the children developed subsequent epilepsy, which compares with a population risk of about 1.4%. Ten percent had neurological sequelae. Eleven percent of the children had received medication to prevent recurrence of FC, and in one third of these cases, this was for simple FCs. Using a time-dependent covariate Cox proportional hazards model, the number of FCs was associated with an increased risk of epilepsy (hazard ratio 2.48; 95% confidence limits, CL 1.68, 3.65) up to a limit of 4. A statistically significant association between occurrence of complex FC and subsequent epilepsy was not found, but a review of other studies quantified the odds ratio for epilepsy after a complex first FC as 3.4 (95% CL 2.1, 5.4). Epilepsy is a significant if infrequent sequel to FCs. Factors associated with subsequent epilepsy are the number of FCs or a complex first FC. Overtreatment of this condition continues.