Abstracts

The majority of children who are seizure free on antiepileptic drug (AED) therapy for 2 or more years will remain so when AEDs are discontinued. Few data are available on the long term prognosis of these children and in particular what happens to those whose seizures recur following AED withdrawal. Between 1983 and 1990, 264 children and adolescents (median age 11.9 years) who were seizure free for a minimum of 1 year on their AEDs and who were being withdrawn from AED therapy were enrolled in a prospective study and followed. The cohort has now been followed for a mean of 15.3 years with 10 or more years of follow-up available in 248 (94%). Median age at last follow-up was 27.4 years. The distribution of etiologies was 82 (31%) idiopathic, 85 (32%) cryptogenic and 97 (37%) with remote symptomatic epilepsy. Outcomes analyzed included recurrence of seizures as well as final outcome at last follow-up. To date, 110 subjects have experienced a recurrence. Of these 86 (78%) occurred within 2 years of medication withdrawal, 13 (12%) between 2 and 5 years, 9 (8%) between 5 and 10 years and 2 (2%) more than 10 years after AED withdrawal. At last follow-up 70% of the cohort was seizure free for 10 or more years, 83% were seizure for 5 yrs and 77% were not on AEDs. At last follow-up, 3 (1%) children were still having frequent seizures and 8 (3%) were having occasional seizures (6 on AEDs, 2 off AEDs). Etiology was associated with prognosis. At last follow-up 88% of those with idiopathic etiology, 85% with cryptogenic etiology and 78% of those with remote symptomatic etiology were [gt]5 years seizure free (p = 0.2). However, at last follow-up, 85% of idiopathic, 76% of cryptogenic and 67% of remote symptomatic cases were seizure free for one or more years off AEDs (p [lt] 0.02). There were 5 deaths in the cohort all of which occurred in children with severe neurological abnormalities. Of these 5, one was having frequent seizures but the other 4 were all seizure free for 6 to 11 years (2 on AEDs due to earlier recurrence, 2 off AEDs who never recurred). The majority of children who are withdrawn from AEDs after a seizure free interval have a favorable long term prognosis. Late recurrences occur but are uncommon. The majority of those who do recur will reenter remission though not necessarily as soon as AEDs are restarted. (Supported by grant 1 R01 NS26151 from NINDS)