Tonic-Clonic (Grand Mal) Seizure


A tonic-clonic seizure, also called a grand mal seizure, causes violent muscle contractions and loss of consciousness. These are the types of seizures most people know about, and what they usually picture when they think about seizures in general.

They are the most common type of generalized seizure, or seizure that affects the whole body.

The muscles of the arms and legs stiffen during the first part of the seizure, called the tonic part. Then, the muscles of the arms, legs and face begin to jerk during the second phase of the seizure, known as the clonic part. Some patients may only experience one part of the seizure. Others may experience both.

Tonic-clonic seizures last between one and three minutes. Any seizure lasting longer than 5 minutes will need medical attention.


Symptoms of a tonic-clonic seizure may include:

  • Stiff muscles
  • Loss of consciousness
  • A cry or groan
  • Jerking of the arms or legs
  • Loss of bladder or bowel control
  • Limited or even stopped breathing
  • Blue lips
  • Arched back

After the seizure the patient may experience:

  • Confusion
  • Feeling sleepy or drowsy for 1 hour or longer (post-ictal state)
  • Loss of memory (amnesia) about the seizure episode
  • Headache
  • Weakness of one side of the body for a few minutes to a few hours (Todd paralysis)

Causes and Risk Factors

These seizures are usually caused by epilepsy. They are also linked to other conditions, such as:


A detailed description of what happened during your seizure is important to making a correct diagnosis. Your doctor will likely need to speak to a witness who has seen your seizures, as people tend to go unconscious during grand mal seizures.

The doctor will also perform a neurological exam. These examinations look at the muscles, including reflexes, muscle tone, and strength. They also look at how you walk, balance, coordination and posture.

One of the most useful tools for diagnosis an electroencephalogram (EEG). This records electrical activity in the brain. The EEG can record unusual spikes or waves in electrical activity patterns. Different types of epilepsy can be identified with these patterns.

Magnetic resonance imaging (MRI) and computed tomography (CT) scans may be used to look at the cause and the location within the brain. The scans can show scar tissue, tumors or structural problems in the brain.


Correct treatment can help reduce or prevent seizures. In some cases, treatment can help patients to remain free of seizures for the rest of their lives.

Factors that affect treatment include:

  • Frequency of the seizures
  • Severity of seizures
  • Patient's age
  • Patient's overall health
  • Patient's medical history

Anti-seizure (or anti-epileptic) medications can be highly effective. It may take a few tries to get the right drug and right amount. Your doctor will work with you to monitor side effects and find the best treatment.

Surgery may not be an option for some tonic-clonic seizures. This is because surgery often focuses on treating the area of the brain where the seizure starts. For generalized seizures it is difficult to pinpoint where the seizures start in the brain.

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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