First seizures in adults.

A seizure is a clinical manifestation of presumed or proved abnormal electrical activity in the brain. A first seizure can range from a fleeting subjective experience such as déjà vu or a twitch (myoclonic jerk) through to a tonic-clonic convulsion. Some seizuremanifestations overlap with normal phenomena. A single seizure may be provoked (with an acute precipitant that may or may not recur) or unprovoked (idiopathic or of unknown cause). Epilepsy is defined as more than one seizure. This article focuses on the diagnosis of first seizures and differentiation from their “mimics” in adults. The diagnosis is correct in only two thirds of cases or less and relies almost exclusively on the clinical history. Information for patients, particularly regarding risks of recurrence, investigation and treatment, driving, and mortality, will be discussed. This review uses older seizure terminology, 11 as this is better understood by most readers and succinctly conveys important clinical concepts. Where the revised terminology differs, this is noted in the text and the supplementary table. How common are first seizures?