Seizure recurrence after a first generalized tonic-clonic seizure, in children, adolescents and young adults.

A sample of 78 patients (32 females and 46 males) who had a first unprovoked generalized tonic-clonic seizure between the age of 3 and 21 years was studied prospectively. Duration of follow-up was 2-10 years (mean 5.2 years). A second seizure occurred in 69.2% (54 of 78), most commonly (38 of 54, 70.37%) in the first three months after the first seizure. There were no significant differences in the total number of relapses among various aetiological groups. For idiopathic aetiology, seizure recurrence was significantly more common if the first seizure occurred during sleep (24 of 29, 82.75%) than in the waking state (5 of 13, 17.25%). The second seizure occurred in the same state, i.e. night sleep or awake in 72.2% (39 of 54) of patients. The presence of epileptiform patterns in the first two EEGs in the waking state or in sleep was significantly associated with a highly increased risk of seizure recurrence.