Seizure disorders

A diagnosis of epilepsy is made when a person experiences two or more unprovoked seizures, i.e. seizures without an immediate precipitating event such as fever, a blow to the head, active brain infection, or metabolic disturbance. Epileptic seizures result from abnormal electrical discharges which may be confined to a part of the brain or involve the entire cortex. The diagnostic classification system initially developed by the Commission on Classification and Terminology of the International League Against Epilepsy (1989) reflects both the manner in which the seizure begins (partial versus generalized) and the effects of the abnormal discharge (see Table 8.1). Approximately 1% of children in the United States are diagnosed with epilepsy by age 20 (Epilepsy Foundation of America, 2002). The risk of developing seizures peaks during the first two years of life but declines over the childhood years (Camfield & Camfield, 1997). Epilepsy may develop as the result of or in association with a wide variety of medical conditions, as indicated in Table 8.2. Typically, the diagnosis of epilepsy is based on behavior during the seizure and the characteristics of the electroencephalogram (EEG). For some children, the EEG will be abnormal only during the seizure event. An accurate description of the seizure by observers, and in some cases by the child experiencing the event, becomes essential in making the diagnosis. M.dical and family history may facilitate identification of etiology.