Risk of recurrence of seizures following single unprovoked idiopathic seizure

A prospective study was conducted to look for various factors that could predict the risk of recurrence of a single unprovoked idiopathic seizure. Seventy six patients with a history of single episode of seizure ultimately completed the study and the data regarding age, sex, duration of seizure, time of occurrence of the ictus, interval between onset and referral, family history of seizure and alcohol consumption were analysed. All patients of symptomatic epilepsy and those with an abnormal scan were excluded. The patients were randomized into two groups, one of which received anti epileptic medication and the other did not. All patients underwent electroencephalography (EEG). Twenty two (M=16, F=6) of the 76 patients (M=56, F=20) had a recurrence of seizure. The duration of seizure at initial presentation was 10.1 +/- 5.2 min. in the recurrence group and 6.5 +/- 4.1 min. in the non-recurrence group. Twelve of the 16 patients with an abnormal EEG had a recurrence whereas only 10 of the 60 patients with a normal EEG had a recurrence (p <0.001). Of the treated cases (n=36), only 4 had a recurrence compared to 18 of the untreated cases (n=40) (p <0.002). Eighteen of the 22 cases having a recurrence did so within three months. Six of the cases with family history of seizure (n=10) had a recurrence, whereas only 16 of the cases without family history of seizure (n=16) had a recurrence (p <0.05). Patients of a single unprovoked idiopathic seizure with a normal CT scan are less likely to have a recurrence if the duration of seizure at presentation is short, EEG is normal, more than 3 months have passed since the first seizure and if treatment has been started. Family history of seizures does have a moderately significant bearing, but alcohol intake does not increase the chances of seizure.