A type of seizure which causes a sudden loss of consciousness followed immediately by a generalized convulsion in which extremities become stiff, then jerk rhythmically. Formerly know as grand mal seizure.
A tonic-clonic seizure begins with the tonic phase, which often involves a fall to the floor, stiffening of the limbs, and clenching of teeth. This is followed by the clonic phase, which presents itself as the violent rhythmic jerking of the limbs and torso. Previously know as grand mal seizure.