Seizure recurrence after a 1st unprovoked seizure: an extended follow-up.

We followed 208 patients identified on the day of their 1st unprovoked seizure for a mean duration of 4 years. Seizures recurred in 64. Recurrence risks were estimated to be 14%, 29%, and 34% at 1, 3, and 5 years following the 1st episode. A history of previous neurologic insult (remote symptomatic) was associated with a 2.5-fold increased risk of recurrence. Among idiopathic cases, a sibling with epilepsy, a generalized spike and wave EEG, or a history of acute symptomatic seizure increased risk for recurrence. Among remote symptomatic cases, status epilepticus, a prior acute symptomatic seizure, or Todd's paresis increased risk. Depending upon clinical features, recurrence risk at 5 years following a 1st seizure ranged from 23% to 80%. Treatment with anticonvulsant medication was not associated with a decrease in recurrence risks.