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Epilepsy Health Center

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Epilepsy: Generalized Tonic-Clonic Seizures - Topic Overview

Generalized tonic-clonic (grand mal) seizures are the easiest seizures to recognize. They happen most often in people with generalized epilepsy of unknown cause.

A generalized tonic-clonic seizure begins with a sudden loss of consciousness. During the first 15 to 30 seconds of the seizure, the entire body stiffens as the muscles contract. The back and neck are arched. Sometimes the person may cry out as the vocal cords contract and air is released from the lungs. The person may turn blue because he or she isn't breathing. This is the tonic phase of the seizure.

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Seizure Prevention

If you have epilepsy, avoiding possible triggers -- such as lack of sleep, flashing lights, video games, use of heroin or cocaine, and abrupt withdrawal from medications or alcohol -- may prevent or reduce seizures. People with diabetes may help prevent seizures triggered by low blood sugar levels by closely monitoring blood sugar.

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During the next 30 to 45 seconds, the muscles jerk (convulse) in a rhythmic pattern. This is the clonic phase of the seizure. While the muscles are jerking, the person may bite his or her tongue or lose bladder or bowel control.

An entire seizure lasts 1 to 2 minutes. After the seizure, the person will be unresponsive at first but will gradually wake up in 10 to 30 minutes. The person may be sleepy, confused, or dazed. The person may also feel tired, weak, or moody and may have a headache and muscle aches for the next 24 hours.

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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