Distribution of epilepsy syndromes in a cohort of children prospectively monitored from the time of their first unprovoked seizure

Purpose: To assess the distribution of epilepsy syndromes and their stabili ty in children. Methods: A cohort of 407 children with a first unprovoked seizure was prosp ectively recruited and followed up for a mean of 9.4 years. Etiology and ep ilepsy syndromes were classified by using the International League Against Epilepsy (ILAE) guidelines in the 182 children with two or more seizures. C lassification was done both at time of second seizure and at last follow-up . Two-year terminal remission also was analyzed by etiology and epilepsy sy ndrome. Results: Etiology of epilepsy syndromes was idiopathic in 45 (25%), cryptog enic in 89 (49%), and remote symptomatic in 48 (26%). In the initial classi fication, 114 (63%) children had a localization-based epilepsy syndrome inc luding idiopathic in 26, cryptogenic in 34, and symptomatic based on locali zation or etiology in 54. Twenty-one (12%) children had a generalized epile psy syndrome, including 19 with primary generalized epilepsy. Forty-seven ( 26%) cases were in the category of undetermined if focal or generalized. At last follow-up, there was a change in either etiology (n = 16) or the fina l epilepsy syndrome classification (n = 33) or both (n = 15) in 34 (19%) ca ses. At time of last follow-up, 144 (79%) of the children with epilepsy wer e in 2-year terminal remission, and 108 (59%) were in 2-year terminal remis sion without medications. Factors associated with a favorable prognosis inc luded an idiopathic or cryptogenic etiology and having a localization-based idiopathic epilepsy syndrome. Conclusions: After two seizures, childhood-onset epilepsy can be classified by etiology and epilepsy syndrome. Prognosis is favorable in the majority of cases. However, the apparent syndrome may change with longer follow-up. The ability to classify these cases early in the clinical course is importa nt if they are to be used for prognostic purposes.