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.
Seizures occur in girls and boys at an equal rate and are more common before the age of 15 and after age 65. For now, there is no way to screen for a seizure disorder before it develops. However, avoiding head injuries -- such as by wearing a helmet while riding a bicycle -- can reduce the risk of acquiring a seizure disorder.
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
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
In this article
This information is produced and provided by the National
Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National
Institute via the Internet web site at http://
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WebMD Medical Reference from Healthwise
March 12, 2014
This information is not intended to replace the advice of a doctor.
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