Decerebrate posturing misinterpreted as seizure activity.

Sudden onset of tonic muscular contraction and loss of consciousness is most often caused by an epileptic seizure. In a seizure, however, the tonic muscular contraction is usually followed by interrupted jerking movements. When the motor pattern remains one of tonic contraction, a different underlying mechanism implying a separate differential diagnosis and therapeutic plan must be considered. Failure to make this distinction clearly may lead to neurologic catastrophe.