The classification (database) of etiologies of the epilepsies is divided into four main categories.
Definitions
1. Idiopathic epilepsy—defined here as an epilepsy of predominately genetic or presumed genetic origin and in which there is no gross neuroanatomic or neuropathologic abnormality. Included here are epilepsies of presumed multigenic or complex inheritance, but for which currently the genetic basis has not been elucidated.
2. Symptomatic epilepsy—defined here as an epilepsy of an acquired or genetic cause, associated with gross anatomic or pathologic abnormalities, and/or clinical features, indicative of underlying disease or condition. We thus include in this category developmental and congenital disorders where these are associated with cerebral pathologic changes, whether genetic or acquired (or indeed cryptogenic) in origin. Also included are single gene and other genetic disorders in which epilepsy is
only one feature of a broader phenotype with other cerebral or systemic effects.
3. Provoked epilepsy—defined here as an epilepsy in which a specific systemic or environmental factor is the predominant cause of the seizures and in which there are no gross causative neuroanatomic or neuropathologic changes. Some ‘‘provoked epilepsies’’ will have a genetic basis and some an acquired basis, but in many no inherent cause can be identified. The reflex epilepsies are
included in this category (which are usually genetic) as well as the epilepsies with a marked seizure precipitant.
4. Cryptogenic epilepsy—defined here as an epilepsy of presumed symptomatic nature in which the cause has not been identified. The number of such cases is diminishing, but currently this is still an important category, accounting for at least 40% of adult-onset cases of epilepsy.
