Poststroke seizures in the elderly.

Strokes are the most common cause of epilepsy in the elderly. Seizures after an acute stroke have been estimated to occur in 5% to 10% of cases. A distinction between early and late seizures should be made. Early seizures are more common, occur very early in the evolution of the stroke, and tend to be focal motor, brief, and isolated. They are likely to be the result of an acute local brain metabolic alteration induced by the cerebrovascular event, and once these derangements are reversed, seizures disappear. Epilepsy usually does not follow early seizures, but the risk is probably increased. Late seizures occur months to years after the stroke and are probably due to structural brain abnormalities leading to the development of an epileptic focus. The majority of these cases develop epilepsy. The risk of seizures is markedly increased when the cerebrovascular event involves the cerebral cortex. Deep-seated hemispheric or infratentorial lesions rarely produce seizures or epilepsy. It is possible that hemorrhagic stroke carries a higher incidence of seizures, but the issue remains controversial. It has also been suggested that embolic infarction has a higher incidence of seizures that does thrombotic infarction, but definitive evidence is lacking. The presence of seizures in an acute stroke does not seem to correlate with the size of the lesion, functional outcome, or mortality. Prophylactic treatment with antiepileptic drugs is probably not indicated in most types of strokes, except for subarachnoid hemorrhage after a ruptured intracranial aneurysm. When early seizures develop, treatment is indicated but may not be necessary for a prolonged period of time. If late seizures develop, chronic anticonvulsant therapy is recommended.