Risk factors for subsequent epilepsy after febrile convulsions.

To evaluate the risk of subsequent epilepsy after febrile convulsions and the long-term prognosis of such patients, the risk factors for afebrile seizures following initial febrile convulsions were studied in 154 hospitalized children: 122 with simple febrile convulsions and 32 with complex features of febrile convulsions. The mean follow-up period was 7 years 2 months (range, 4 yr - 11 yr 2 mo). Nineteen patients (12.3%) developed subsequent epilepsy in the follow-up period. The seizure types in patients with subsequent epilepsy following febrile convulsions included generalized seizures in seven patients, complex partial seizures in five patients, partial seizures evolving to secondary generalized seizures in six patients and benign childhood epilepsy with centrotemporal spike in one patient. The occurrence of epilepsy was strongly associated with complex features of febrile convulsions, pre-existing neurodevelopmental abnormalities, family history of epilepsy, and abnormal electroencephalographic findings. However, the number of recurrences of febrile convulsions, sex, family history of febrile convulsions, age of onset and long-term prophylactic use of anticonvulsants for febrile convulsions were not significant factors for subsequent epilepsy. This study demonstrates the importance of identifying the risk factors for subsequent afebrile seizures after febrile convulsions.