Tonic-clonic seizure


A tonic-clonic seizure, previously called a grand mal seizure, is a dramatic event characterized by a sudden loss of consciousness and intense muscle contractions. It is the type most commonly associated with seizures in the public imagination. This type of seizure typically begins with a burst of electrical activity in one area of the brain, either as a focal onset that can spread and generalize throughout the brain, affecting behavior and movement globally. During the tonic phase, muscles throughout the body tense up, causing the individual to fall if standing, followed by the clonic phase where muscles begin to contract and relax rhythmically.

Tonic-clonic seizures are often associated with epilepsy, but they can also be triggered by other medical conditions such as severe hypoglycemia, high fever, or stroke. The initial tonic phase results in the stiffening of limbs, while the subsequent clonic phase leads to convulsive movements. These seizures are easily identifiable due to these pronounced physical symptoms.

Although many individuals may experience a tonic-clonic seizure at some point, it does not necessarily indicate a chronic condition. For those with recurrent seizures, ongoing management typically includes anti-seizure medications aimed at reducing the frequency and severity of future episodes. For others, a single seizure may not require further treatment unless subsequent episodes occur.


When most people think about seizures and epilepsy, they normally think of tonic-clonic seizures. The following phases are when the symptoms occur, and they are often more severe and noticeable:

  • Tonic phase: This phase usually lasts between 10 and 20 seconds. You may pass out and all of your muscles, particularly your arms and legs, stiffen up, giving the impression that you are raising your tummy and arching your back. You could cry out as your breathing muscles try to expel air out of your lungs. Falling or clenching your teeth and biting your tongue might result in injuries.
  • Clonic phase: This phase often last little more than a minute or two. Convulsions, or full-body spasms or shaking, are a characteristic of this phase. You may also froth at the mouth. Convulsions often weaken and slow throughout this period before ending. As this phase comes to an end, you may find yourself unable to control your intestines and bladder, which might result in you having to poop or urinate.
  • Post-seizure recovery: This may last longer than 30 minutes or longer. Most people wake up from a seizure and feel exactly the same as they did before. You may frequently have headaches, soreness in your muscles, or confusion. In more severe situations, such as when you experienced status epilepticus, it might take you far longer to wake up.

Some tonic-clonic seizure patients, although not all, have the following signs and symptoms:

  • Confusion: When a tonic-clonic seizure occurs, the patient is frequently confused. It’s known as postictal confusion.
  • Fatigue: It is typical to feel sleepy following a tonic-clonic seizure.
  • Headache: A tonic-clonic seizure may be followed by headaches.
  • Loss control of bowel and bladder: This might occur either during or after a seizure.
  • Scream: A seizure may start and some people may scream out at that point.
  • Unresponsiveness: Even when the seizures stop, the patient might not wake up for a few minutes.

Seek immediate medical attention if the patient encounter seizure for the first time or they experience the following:

  • Seizure last longer than five minutes.
  • Patient is not breathing when the seizure stops.
  • Patient stay unconscious even the seizure stops.
  • There is another seizure right away.
  • Having high fever.
  • Heat exhaustion.
  • Pregnant.
  • Medical condition such as diabetes.
  • Patient was injured during the onset of seizure.


Nerve cells in the brain typically communicate by sending chemical and electrical signals through the connections that bind them. Tonic-clonic seizures occur when there is a surge in electrical activity across the surface of the brain, leading to a high rate of simultaneous firing of nerve cells. The precise causes of these changes occurring frequently remain unclear.

Tonic-clonic seizures can occasionally be brought on by underlying medical issues, such as:

  • Infection or injury.
    • History of infections, such as encephalitis or meningitis.
    • Injury caused by previous lack of oxygen.
    • Stroke.
    • Traumatic head injuries.
  • Congenital or developmental factors
    • Brain tumors.
    • Genetic diseases.
    • Improperly formed blood vessels in the brain.
  • Metabolic issues
    • Blood levels of glucose, sodium, calcium or magnesium are extremely low.
  • Withdrawal syndromes
    • Drugs or alcohol withdrawal.
    • Drugs and alcohol (include prescription medications, recreational drugs and even caffeine).

Risk factors

The factors increase the risk for tonic-clonic seizures may include:

  • People over 65 and children are more likely to get seizures.
  • Having a family member with history of seizure disorders.
  • History of any brain trauma, stroke, infections or other causes that may injure the brain.
  • Sleep deprived individuals.
  • Electrolyte imbalance caused by a medical condition.
  • Use of illegal drugs.
  • Heavy alcohol consumption.