Epilepsy: epidemiology, classification and natural history

Epilepsy is a paroxysmal disorder in which a person has two or more seizures. A seizure results from an abnormal electrical discharge and the clinical manifestations vary greatly. The peak incidence is in younger and older people. Childhood febrile convulsions occur in about 5% of the population, and there is a 2–5% lifetime prevalence for one or more seizures. Two-thirds of patients go into remission. The minority are refractory and need reassessment of both the diagnosis and management. Epilepsy is associated with at least twice the standardized mortality ratio. In the economically disadvantaged world epilepsy is even more common, compounded by far fewer resources to deal with it. The different patterns and causation are summarized.