Concussive convulsions: emergency department assessment and management of a frequently misunderstood entity.

Immediate concussive convulsions are an unusual but dramatic sequela to head injuries. Previously believed to be an epileptic phenomenon, they are now thought to be a brief traumatic functional decerebration that results from loss of cortical inhibition. With concussive convulsions generally occurring within seconds of head impact and lasting up to several minutes, patients are initially in a tonic phase, followed by a clonic convulsion. A postictal phase is generally brief if it occurs at all with these episodes. Patients with isolated concussive convulsions have no evidence of structural brain injury as assessed with neuroimaging studies or physical examination. Neuropsychological testing often demonstrates transient cortical dysfunction consistent with the concussive episode. The long-term outcome for patients with isolated concussive convulsion is universally good, with no long-term neurologic sequelae and no increased incidence of early or late posttraumatic epilepsy. Emergency department management should focus on evaluation of the associated concussive injury. The concussive convulsion requires no specific therapy, and antiepileptic medication is not indicated.