[Risk factors in recurrent febrile seizures]

Febrile convulsions are the most frequent type of seizures in children under 6 years old. They usually have a good prognosis. Only a few of these children will later suffer from non-febrile seizures. The low risk of non-febrile seizures and important side-effects of antiepileptic drugs have limited the use of continuous prophylaxis in children with recurrent febrile seizures.

Our aim has been to identify the main factors that imply a higher risk for recurrent febrile convulsions and also to identify the frequency of antiepileptic prophylactic medication in our area.

We have carried out a protocoled study in children which were sent consecutively and with no previous selection to a reference electroencephalography (EEG) outpatient unit in Murcia with the clinical diagnosis of febrile convulsions. Data included have been: sex, actual age and age at the time of the first seizure, total number of seizures, family and personal history of either febrile seizures or epilepsy, EEG findings, treatment and side-effects. Data collection was accomplished between September 1991 and June 1993. A total of 509 patients have been included.

A 34% of the children had suffered two or more seizures. Children with recurrent seizures were younger at onset (16.7 vs 21 months) and had more often family history of febrile seizures (40.6% vs 28%) and epilepsy (21.5% vs 12.5%). 60% of the children who had family history of febrile seizures of epilepsy and who suffered the first episode before the age of 16 months had recurrent febrile convulsions.

An age under 16 months at the moment of the first convulsion and the existence of family history of febrile seizures or epilepsy increase the risk of recurrent febrile seizures.