Abstracts

Rationale: The natural history of new onset epilepsy is not well-established. Retrospective studies have reported short-term rates of seizure (SZ) freedom. We examined the pattern of SZ occurrence or remission and long-term outcome in new onset epilepsy. Methods: Monthly SZ rates from patients with new-onset epilepsy were prospectively collected from patients followed in the UVA Epilepsy Clinic from June 2000 to May 2008. Analysis was limited to patients followed for > 1 year, who had SZ frequency rates acquired on at least 3 occasions, and were 5 years old or greater. Other data collected included demographics, SZ type, epilepsy syndrome, and etiology. SZ frequency of each SZ type was plotted over time. Patterns of SZ occurrence were divided into 6 categories: 1) SZ free immediately after starting an AED, 2) SZ free after a delay of less than 1/3 of the duration of follow-up, 3) seizure-free with breakthrough SZs less than 1/3 of the duration of follow-up, 4) progressive decrease in SZ frequency but not SZ free, 5) continued occurrence of SZs, and 6) period of SZ freedom followed by recurrence. Categories 1-3 were considered “well controlled”. Adults (age >18) and children (age 5-18) were analyzed separately. Results: A total of 114 patients were analyzed, with mean current age of 24.6 years. Patients were followed for a mean of 4.3 years and 13.1 visits, and currently taking 1.3 AEDs. Age was 5-18 in 51%, 19-49 in 37% and >49 in 12%. Overall, 74% of adults and children were eventually well-controlled but in 26% SZs continued to occur. The mean current SZ frequency was 6.4 per month. The most common SZ pattern in adults was immediate SZ freedom (25%), followed closely by SZ freedom with breakthroughs (27%) and delayed SZ freedom (20%), while less common were continuous SZs throughout the follow-up period (15%) and progressively decreasing SZ frequency (13%); a period of SZ freedom followed by recurrence did not occur. Children followed the same general hierarchy of SZ patterns as adults but immediate SZ freedom was more common (47%) and breakthroughs (19%) and delayed SZ freedom (14%) were less common, while continuous SZs were nearly identical (15%), and progressive decreasing SZ frequency (3%) was less common, while a period of SZ freedom followed by recurrence occurred in 7%. The differences between adults and children did not quite reach statistical significance (p=0.053). Conclusions: Three-fourths of patients with new-onset epilepsy will be well controlled relatively soon after onset. Although many patients, especially children, will be SZ free immediately after starting an AED, a substantial subset will have a relatively short delay before achieving SZ freedom. Long-term SZ freedom is likely even among patients with occasional breakthrough SZs. This implies that early after starting the first treatment for epilepsy, a short period of SZs or the occurrence of breakthrough SZs does not imply refractoriness to all therapies. However, patients who do not have a substantial period of SZ freedom relatively early in their course are unlikely to have long-term SZ freedom.