The time taken to develop intractability of epilepsy was determined prospectively in a cohort of 613 children followed in the Connecticut Study for a median of 9.7 years and reported by researchers from Northern Illinois University, DeKalb, IL; University of California Los Angeles, CA; Yale Medical School, New Haven, CT; and Albert Einstein College of Medicine, Bronx, NY. Intractability was defined in two ways: 1) 2 drugs failed, 1 seizure/month (average) for 18 months (stringent definition), and 2) failure of 2 drugs. Delayed intractability was defined as 3 or more years after epilepsy diagnosis. Intractability (stringent form) developed in 83 children (13.8%), and the 2-drug definition of intractability was met by 142 (23.2%). Intractability was delayed in 26 (31.3%) children meeting stringent and in 39 (27.5%) meeting the 2-drug definition. Intractability varied with the epilepsy syndrome and was delayed more often in focal than catastrophic (including encephalopathic) epilepsies (stringent: 46.2 vs 14.3%, p=0.003; 2-drug: 40.3 vs 2.2%, p<0.0001). Early remission preceded delayed intractability in 65.4 to 74.3% of cases. After developing intractability, 20.5% entered remission, and 13.3% were seizure-free at last follow-up. Referral to surgery may be delayed for 20 or more years, because of this interim period of remission. [1]

COMMENT. In the earlier Dutch study of 453 children with newly diagnosed epilepsy followed prospectively for 5 years [2], significant variables for the worst outcome group included a symptomatic or cryptogenic etiology, early age at onset, and a history of febrile seizures. Of 108 (24%) patients with a terminal remission (TS) of <1 year, 27 had intractable seizures at 5 years. Of patients receiving 2 or more AEDs, almost 60% had a TR5 >1 year. AEDs were successfully withdrawn in 227 (59%). The course of epilepsy was constantly favorable in 51%, steadily poor in 17%, remitting after intractability in 25%, and deteriorating in 6% (Ped Neur Briefs August 2004;18:57-59).