Convulsion: An abnormal, involuntary contraction of the muscles most typically seen with certain seizure disorders. The term convulsion is sometimes used as a synonym for seizure, but not all seizures are characterized by convulsions. A person having convulsions appears to be shaking rapidly and without control. Other possible causes of convulsions include fever, meningitis, drug or alcohol abuse, poisoning, hypoglycemia, and head injury.
Reviewed on 5/13/2016