Nonsymptomatic generalized epilepsy in children younger than six years: Excellent prognosis, but classification should be reconsidered after follow-up: The Dutch study of epilepsy in childhood

Purpose: To assess the prognosis and the accuracy of the epilepsy classification in young children with nonsymptomatic generalized epilepsy. Methods: Of the cohort of the Dutch Study of Epilepsy in Childhood (n = 466), all children younger than 6 years with a diagnosis of idiopathic (IGE) or cryptogenic (CGE) generalized epilepsy either at intake (n = 108) and/or after 2 years of follow-up (n = 102) were included. The number of reclassifications after 2 years was determined, and the reasons for reclassification were analyzed. All children receiving a diagnosis of IGE or CGE at 2 years were followed up for 5 years to study their outcome in terms of terminal remission (TR). Data on their level of intellectual functioning were collected at the start of this analysis. Results: The epilepsy syndrome was reclassified in 17 children. In 14 of them, the seizure type also was reclassified, and in three, the course of the epilepsy determined the new epilepsy type. Two other children had a reclassification of their seizure types without a change of the epilepsy type. Many children were categorized as having IGE not otherwise specified. In all probability, this is a heterogeneous group, containing patients with various epilepsy syndromes, with generalized tonic-clonic seizures as a common hallmark. Of the 102 children with IGE or CGE at 2 years of follow-up, 75% had a TR of >6 months after 2 years, and 85% a TR of greater than or equal to1 year after 5 years. Conclusions: In a fair proportion of children with nonsymptomatic generalized epilepsy in this age group, it is not possible to classify firmly the epilepsy and/or the seizures immediately after the intake. Instead, they are reclassified during the course of the disease. This and the apparent heterogeneity of the category IGE not otherwise specified point to inherent drawbacks of the current International League Against Epilepsy (ILAE) classification of epilepsy and epileptic syndromes. The prognosis of IGE at this young age is generally excellent.