Tonic-Clonic Seizure

 Tonic-clonic seizures, previously known as grand mal seizures, are characterized by both stiffness and jerking motions.

A generalized tonic-clonic seizure is a disturbance in the functioning of both sides of your brain. A seizure that starts by affecting one side of your brain but spreads to involve both sides is called a focal to bilateral tonic-clonic seizure.

The disturbance is caused by an atypical spread of electrical signals through the brain. Often this will result in signals being sent to your muscles, nerves, or glands. The spread of these signals in your brain can make you lose consciousness and have severe muscle contractions.

Seizures, specifically tonic-clonic seizures, are commonly associated with epilepsy. According to the Centers for Disease Control and Prevention (CDC)Trusted Source, about 5.1 million people in the United States have a history of epilepsy, and about 3.4 million have active epilepsy.

However, a seizure could also occur because you have a high fever, head injury, or low blood sugar. Sometimes, people may have a seizure if their body has developed a dependence on a substance and they stop using it.

one-time seizure that’s not related to epilepsy could happen at any stage of your life. These seizures are normally brought about by a triggering event that temporarily alters your brain functioning.

If you have epilepsy, you might begin to have tonic-clonic seizures in late childhood or adolescence. This type of seizure is rarely seen in children under 2 years old.

A tonic-clonic seizure may be a medical emergency. This depends in part on your history of epilepsy or other health conditions.

Tonic-clonic seizures get their name from their two distinct stages.

Typically, in the tonic stage of the seizure, your muscles stiffen, you lose consciousness, and you may fall down.

The clonic stage consists of rapid muscle contractions, which are sometimes called convulsions. Your limbs and face will appear to jerk rapidly as your muscles convulse.

If you have a tonic-clonic seizure, symptoms may include:

  • a strange feeling or sensation, which is called an aura
  • screaming or crying out involuntarily
  • losing control of your bladder and bowels either during or after the seizure
  • a severe headache after the seizure
  • passing out and waking up feeling confused or sleepy

After you have a tonic-clonic seizure, you might feel confused or sleepy for several hours before recovering.

Tonic-clonic seizures usually last 1­ to 3 minutes, according to the Epilepsy Foundation.

If you see someone having a tonic-clonic seizure, take the actions below:

  • Make sure that there’s nothing in their mouth and that their airway isn’t obstructed.
  • Clear around them so there are no sharp or hard objects nearby.
  • Place something soft, such as a pillow, under their head.
  • Place them on their side.
  • Loosen any restrictive clothing or accessories, such as a belt.
  • Remove their eyeglasses.
  • Time the seizure or seizures.

Tonic-clonic seizures tend to resolve on their own. If the seizure lasts longer than 5 minutes, it’s considered a medical emergency. Call 911 or your local emergency services.

Also seek immediate medical attention if someone:

  • is having their first seizure
  • has been injured during the seizure
  • has a cluster of seizures
  • has three seizures in a row and doesn’t regain consciousness in between the seizures
  • has a preexisting medical condition, such as diabetes or heart disease
  • is pregnant

If you have a history of tonic-clonic seizures, some steps you can take to ensure your safety include:

All seizures are caused by unusual electrical activity in the brain.

The onset of tonic-clonic seizures could be related to a variety of health conditions. Some of the more severe conditions include a brain tumor or a ruptured blood vessel in your brain, which can cause a stroke.

Other potential causes of a tonic-clonic seizure include:

Sometimes, doctors aren’t able to determine what causes the onset of seizures.

All types of seizures essentially have the same risk factors.

You may be at a higher risk for having seizures, including tonic-clonic seizures, if you have a family history of epilepsy. Other factors that could increase your chances of having a tonic-clonic seizure include:

  • having abnormal results on a neurological exam
  • certain genetic conditions or neurological disorders
  • history of seizures with a fever
  • brain injury related to a head trauma
  • stroke
  • infection
  • an electrolyte imbalance due to other medical conditions
  • misuse of drugs or alcohol

Triggers for seizures include:

  • sleep deprivation
  • loud music
  • flickering lights
  • fever
  • menstrual cycle

There are several ways to diagnose epilepsy or the cause of a seizure.

Medical history

Your doctor will ask you questions about other seizures or medical conditions you’ve had. They might ask the people who were with you during the seizure to describe what they saw.

Your doctor might also ask you to remember what you were doing immediately before the seizure happened. This helps to determine what activity or behavior may have triggered the seizure.

Your doctor may also want to know:

  • which over-the-counter or prescription medications you’re currently taking
  • if you’ve been sick recently
  • the time of day the seizure occurred
  • whether you had a headache after the seizure
  • if your muscles ached after the seizure

Neurological exam

Your doctor will perform simple tests to check your balance, coordination, and reflexes. They’ll assess your muscle tone and strength. They’ll also judge how you hold and move your body and whether your memory and judgment seem abnormal.

Blood tests

Your doctor may order blood tests to look for medical problems that could influence the onset of a seizure. A complete blood count (CBC) or blood culture may be used to help identify conditions such as infection.

Medical imaging

Some types of brain scans can help your doctor monitor your brain function. This could include an electroencephalogram (EEG), which shows the patterns of electrical activity in your brain. It could also incorporate MRI, which provides a detailed picture of certain parts of your brain.

If someone is unable to receive an MRI, a CT scan may be performed instead. CT scans are less detailed than MRIs, though.

If you’ve had one tonic-clonic seizure, it may have been an isolated event that doesn’t require treatment. Your doctor could decide to monitor you for further seizures before beginning a long-term course of treatment.

Antiepileptic drugs

Most people manage their seizures through medication.

The Food and Drug Administration (FDA) has approved many medications for the treatment of tonic-clonic seizures, including:

You’ll probably start off with a low dose of one drug. Your doctor will gradually increase the dose as needed. Some people require more than one medication to treat their seizures.

It may take time to determine the most effective dose and type of medication for you.


Brain surgery may be an option if medications aren’t successful in helping you manage your seizures. This option may be more effective for focal seizures that affect one part of the brain than for ones that are generalized.

Supplemental treatments

There are multiple types of supplemental or alternative treatments for tonic-clonic seizures.

Vagus nerve stimulation (VNS) therapy involves the implantation of an electrical device that automatically stimulates the vagus nerve in your neck.

Responsive neurostimulation (RNS) is a trademarked program by the company NeuroPace. The RNS System monitors electrical activity in the brain and sends stimulation to the brain when it suspects a seizure or unusual electrical activity. Like VNS, it requires an implanted electrical device.

In deep brain stimulation (DBS), electrodes are added to a part of the brain known as the thalamus. The DBS device delivers either constant or occasional stimulation (unlike RNS, which only sends stimulation when a seizure is detected). The goal of DBS is to modulate certain brain circuits, which should ultimately help prevent or decrease the frequency of seizures.

These three therapies are intended for people with refractory, or drug-resistant, epilepsy. They’re used in addition to seizure medications.

Eating a ketogenic diet, which is high in fat and low in carbohydrates, is also believed to help some people reduce certain types of seizures.

Seizures aren’t well understood. In some cases, it may not be possible for you to prevent a seizure if your seizures don’t appear to have a specific trigger.

You can take steps in your daily life to help prevent seizures:

People who are pregnant should have proper prenatal care. This helps to avoid complications that could contribute to the development of a seizure disorder in the fetus.

After childbirth, it’s important to have your child immunized against diseases that can negatively affect their central nervous system and contribute to seizure disorders.

Having a tonic-clonic seizure due to a one-time trigger may not affect you in the long term.

People with seizure disorders can often live a full and productive life. This is especially true if their seizures are managed through medication or other treatments.

It’s important to continue using your seizure medication as prescribed by your doctor. Suddenly stopping your medication could cause your body to undergo prolonged or repeated seizures, which can be life threatening.

In rare cases, people with tonic-clonic seizures that aren’t managed by medication can sometimes die suddenly. This is called SUDEP, or sudden unexpected death in epilepsy. It’s believed to be caused by a disturbance in your heart’s rhythm as a result of muscle convulsions.

If you have a history of seizures, some everyday activities may not be safe for you. Having a seizure while swimming, bathing, or driving, for example, could be life threatening. Talk with a doctor before attempting these activities.

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