[Epidemiology and etiology of status epilepticus]

Establishing the incidence and frequency of status epilepticus (SE) is difficult because of differences in definition, problems of diagnosing nonconvulsive SE and, above all, the diversity of study populations. There are differences involved in studying the frequency of SE in a population of epileptics, in a sample of all patients seen at a single hospital or by a specific department, or in the general population. It is estimated that SE is suffered annually by 50 out of 100,000 inhabitants in the general population, 0.2% of hospital patients, 3.5% of patients admitted to an intensive care unit, and from 2 to 10% of epileptic patients. These figures increase if only children are considered. Age and history of epilepsy must be taken into account in order to determine the cause of SE. SE often appears in a context of no known prior history of epilepsy, particularly in the elderly. The cause remains undetected in approximately one third of SE cases. Among the most common symptomatic causes in the adult are cerebral vascular disease and toxic-metabolic disorders.