What Is a 'Grand Mal' Seizure?

These seizures can make person shake and jerk for up to three minutes, but recovery can take hours.

When you think of a seizure, chances are a grand mal seizure is the first thing that comes to mind. It's the type of seizure that can cause a person to fall down, shake and jerk, and even lose consciousness.

But the term "grand mal seizure"—which technically means "big illness" in French—is actually an outdated one: In 2017, the International League Against Epilepsy (ILAE) came up with new ways to describe and classify seizures. What was once known as a "grand mal seizure" is now called a "tonic-clonic seizure," according to the Epilepsy Foundation. ("Grand mal seizure" and "tonic-clonic seizure" will be used interchangeably throughout this article.)

Despite the new name, grand mal seizure is often the term people are most familiar with (some healthcare providers even continue to use it in medical settings, especially if they don't specialize in seizures). Regardless of what you know them as—grand mal seizures or tonic-clonic seizures—here's what you need to know about them, including their main causes and how long they typically last.

What Is a Grand Mal Seizure? Here’s What to Know, According to Experts
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What Is a Grand Mal Seizure?

A grand mal seizure is an example of a generalized onset motor seizure or a generalized tonic-clonic seizure. This means that the seizure starts on both sides of the brain. In some cases, however, tonic-clonic seizures can start on just one side of the brain (aka, a focal seizure), before spreading to both sides. The Epilepsy Foundation specifically calls this type of seizure a bilateral tonic-clonic seizure.

Phases of a Grand Mal Seizure

Grand mal seizures typically have two phases: a tonic (stiffening) phase, followed by a clonic (jerking) phase—that's what has given them their current, more up-to-date name.

  • Tonic phase: This phase comes first and causes the muscles in a person's body to stiffen. In this phase, a person can lose consciousness and fall to the floor. They may also let out a cry or a groan due to air being forced past their vocal cords, and they may bite their tongue or inside of their cheek.
  • Clonic phase: The tonic phase is followed by the clonic phase when a person's arms and legs begin to jerk "rapidly and rhythmically." This bending and relaxing tend to happen at the elbow, knee, and hip joints. It can last for a few minutes before slowly coming to a stop.

Keep track of how long the seizure lasts. Call 911 if a seizure lasts more than 5 minutes or if the person gets injured during the seizure.

What Are the Symptoms of a Grand Mal Seizure?

During a grand mal seizure, someone may also lose control of their bladder or bowels—this happens when the body relaxes. If the person is having trouble breathing, they may also begin to take on a "dusky" or blue hue to their face.

Sometimes people describe the warning signs and symptoms of a grand mal seizure as an aura. These generally happen just before the seizure and can include a range of abnormal sensations, like anxiety, nausea, vertigo, and other sensory changes.

Symptoms of a Grand Mal Seizure may include:

  • Vision, taste, smell, or sensory changes
  • Hallucinations
  • Dizziness before the seizure
  • Muscles stiffening
  • Biting the cheek or tongue
  • Clenched teeth or jaw
  • Loss of urine or stool control (incontinence)
  • Stopped breathing or difficulty breathing
  • Blue skin color

How Long Does a Grand Mal Seizure Last?

A grand mal seizure usually lasts between one and three minutes. After that, a person's consciousness can slowly return, but recovery after a grand mal seizure can take considerably longer. Many people report feeling sleepy, confused, anxious, or agitated for hours after the fact.

If a seizure goes on for longer than five minutes—or if a person has three seizures in a row without regaining consciousness between them—they need emergency medical attention. In this case, the person is experiencing something known as status epilepticus. There are two types: convulsive status epilepticus and nonconvulsive status epilepticus.

Though both types require medical treatment, nonconvulsive status epilepticus may be hard to recognize. In the case of convulsive status epilepticus, medical treatment must be started as soon as possible—typically through oxygen, intravenous fluids, medications, and continuous EEG (electroencephalogram) monitoring. Sometimes, people may even be put into a coma to get the seizures to stop.

What Causes a Grand Mal Seizure?

Like all seizures, a grand mal or tonic-clonic seizure happens when there's overactivity or a sudden surge of electrical activity in the brain. They can occur once as a single episode. But more typically, grand mal seizures occur repeatedly in an individual with epilepsy. Some seizures are due to psychological conditions.

Other times the cause isn't known, and the seizure seems to happen randomly.

"We always try to figure out the cause because it's more satisfying to know why someone is having seizures, of course," Vikram Rao, MD, PhD, an associate professor of neurology at the University of California, San Francisco, told Health. "But in many cases, we actually never do. It's not at all uncommon for there to be no obvious explanation."

Who Is More At Risk of Grand Mal Seizures?

Bilateral tonic-clonic seizures may occur in people of any age.

Someone's risk of grand mal depends on several factors related to epilepsy waves or patterns seen on the EEG (electroencephalogram) and the results of a neurological exam.

  • Children who have had tonic-clonic seizures and have a normal EEG and neurological exam have a 70% chance of being seizure-free without medication.
  • Children who have had tonic-clonic seizures and have epilepsy waves on their EEG or an abnormal exam have a 30% chance of being seizure-free off the medicine.
  • Children who have generalized onset tonic-clonic seizures are more likely to come off seizure medicine and do well than children with tonic-clonic seizures that begin in one side of the brain (focal to bilateral).

Can You Die From a Grand Mal Seizure?

It's rare to die from a seizure, but it can happen. Grand mal seizure death is usually due to a condition called sudden unexpected death in epilepsy (SUDEP). It kills more than one out of 1,000 people with epilepsy each year.

SUDEP is a bit of a medical mystery—some experts believe the seizure causes breathing difficulties or an irregular heart rhythm, which results in death. People with severe epilepsy and/or those with poorly controlled seizures are considered to be at higher risk of SUDEP.

That's why a treatment plan is so important for people who have seizures. "When patients are understandably reluctant to take more medicine, consider a surgery evaluation, etc., I fully understand," said Dr. Rao.

"But one thing we do to impress on them the urgency of being aggressive with treatment is talk about SUDEP. We say, 'This is what we're trying to avoid. So maybe we should push on and not be satisfied until we have full control of the seizures.'"

How Are Grand Mal Seizures Diagnosed?

The specific characteristics of a tonic-clonic seizure make it relatively easy for healthcare providers to diagnose—sometimes, they can do so with access to a cell phone video or written account of the incident. EEG or other tests may also help confirm a diagnosis or determine a cause.

How Are Grand Mal Seizures Treated?

Daily medications—anti-seizure medications (ASMs) and anti-epileptic drugs (AEDs)—are one way to help people manage seizures. It may take some time for someone to find a medication that works well for them.

There are also medications called "rescue medications" which are to be taken when someone has more seizures than usual or to prevent further seizures (specifically tonic-clonic seizures) from happening. There are very specific instructions on how to take these medications so they should be used with caution and under a doctor's surveillance.

Dietary changes may also be used in conjunction with medications—the keto diet specifically was first meant to help manage epilepsy in children and adults. And certain surgeries or devices (vagus nerve stimulators or responsive neurostimulators) may be used if epilepsy doesn't respond to medications.

A Quick Review

A grand mal seizure, or a generalized tonic-clonic seizure, is a seizure that usually starts in both sides of the brain. Grand mal seizures typically have two phases: a tonic (stiffening) phase, followed by a clonic (jerking) phase—that's what has given them their current, more up-to-date name.

Like all seizures, a grand mal or tonic-clonic seizure happens when there's overactivity or a sudden surge of electrical activity in the brain.

Medications, diet, and certain surgeries or devices may be used to treat grand mal seizures. As with many conditions, it may take some time for someone to find a treatment that works well for them.

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6 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. International League Against Epilepsy (ILAE). ILAE classification of the epilepsies: Position paper of the ILAE Commission for Classification and Terminology.

  2. Epilepsy Foundation. Types of Seizures.

  3. Epilepsy Foundation. Tonic-clonic Seizures.

  4. Medline Plus. Bilateral tonic-clonic seizure.

  5. Epilepsy Foundation. Status Epilepticus.

  6. Centers for Disease Control and Prevention (CDC). Sudden Unexpected Death in Epilepsy (SUDEP).

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