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What are the Signs of a Tonic-Clonic Seizure?

D. Jeffress
D. Jeffress

A tonic-clonic seizure is a common, potentially severe type of generalized seizure that involves forceful muscle contractions and loss of consciousness and memory. Most tonic-clonic seizures last for about one to three minutes, though it is possible for an attack to last up to 30 minutes or for several seizures to occur in a short period of time. The first signs of a tonic-clonic seizure are typically a shrill cry followed by a collapse to the ground. Within a few seconds, a sufferer starts to convulse violently and uncontrollably. An individual who witnesses another person having a seizure should contact emergency medical services immediately.

The exact symptoms of a tonic-clonic seizure can be different for different people. For many, a phenomenon called an aura precedes an attack. An aura can be a strange tingling feeling, an odd smell or taste, or a visual hallucination. Aura symptoms typically arise a few minutes or seconds before a seizure, and there is usually no way to stop the impending attack.

The first stage of the seizure, the tonic stage, involves a sudden loss of consciousness.
The first stage of the seizure, the tonic stage, involves a sudden loss of consciousness.

The first stage of the actual seizure, the tonic stage, involves a sudden loss of consciousness and a tightening of most or all of the muscles in the body. Many sufferers let out screams just as their seizures set in because their vocal cord muscles forcefully contract. Stiff leg muscles cause people to fall down, and contractions in the throat and mouth can lead to bitten tongues and shallow or absent breathing. The skin and lips also may appear blue due to a lack of oxygen.

Using illicit drugs can increase an individual's risk of having a tonic-clonic seizure.
Using illicit drugs can increase an individual's risk of having a tonic-clonic seizure.

The tonic stage typically lasts about 15 seconds, followed by the clonic stage. Muscles begin to unpredictably relax and contract, causing the limbs and neck to jerk in a violent, rhythmic pattern. Bowel and bladder incontinence are common during a tonic-clonic seizure. After a few minutes, jerking stops and consciousness slowly begins to return. The sufferer usually feels very weak, confused, and sleepy for several hours. Massive headaches can occur after a tonic-clonic seizure as well.

Long-term bulimia may cause seizures.
Long-term bulimia may cause seizures.

It is important to call for help and provide assistance for a person who is having a tonic-clonic seizure. Trying to grab and restrain the sufferer during the attack can be dangerous, so a bystander should instead try to remove nearby objects such as chairs and tables to help avoid injury to jerking limbs. Once violent movements stop, the sufferer should be moved onto his or her side to promote better breathing. Emergency responders can assess the situation when they arrive and provide additional first aid if necessary.

Discussion Comments

anon295436

I really wish you didn't have that sentence in the article: "An individual who witnesses another person having a seizure should contact emergency medical services immediately."

For those of us who have regular seizures, the last thing we want to do is make a trip to the ER every time we have a seizure. Our son has one to three seizures each night (in spite of being on several medications and a special diet) -- believe me, we are not running down to the ER each night.

If you observe a seizure, the best thing to do is ease the person to their side, remove anything that could hurt the person if they bump into it, and try to get some sort of padding under the head. As long as the person comes out of the seizures within three minutes, and unless there is some sort of injury as a result of the seizure, it is NOT necessary to call 911. However, someone does need to stay with the person during the post-ictal stage, which may last 30 minutes or more, as they might be confused during this time.

A trip to the ER has actually been disastrous in the case of some with epilepsy. One person I know was rushed to the ER, and they were trying to hold him down (which is not what you do when someone is having a seizure), but in his confused state, he was fighting them off, and the ER staff ended up called the police who arrested him for assault. He ended up in a jail cell while he was still post-ictal, which could have been very dangerous.

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    • The first stage of the seizure, the tonic stage, involves a sudden loss of consciousness.
      By: Igor Normann
      The first stage of the seizure, the tonic stage, involves a sudden loss of consciousness.
    • Using illicit drugs can increase an individual's risk of having a tonic-clonic seizure.
      By: aaabbc
      Using illicit drugs can increase an individual's risk of having a tonic-clonic seizure.
    • Long-term bulimia may cause seizures.
      By: Sylvie Bouchard
      Long-term bulimia may cause seizures.
    • A prolonged, high fever may cause seizures in babies.
      By: fred goldstein
      A prolonged, high fever may cause seizures in babies.
    • Seizures may occur as a result of severe trauma to the brain.
      By: Verity Johnson
      Seizures may occur as a result of severe trauma to the brain.