Tonic-clonic seizures, formerly known as “grand mal” seizures, are the most visible and recognized type of seizure. These involve uncontrolled convulsions and other muscle movements. They usually don’t last more than a few minutes, but often happen with epilepsy and sometimes cause severe problems and injuries.
A tonic-clonic seizure is a type of seizure that causes strong muscle movements on both sides of your body, including convulsions. These are typically the best known and easiest to recognize seizures because of these movements.
Tonic-clonic seizures were formerly known as “grand mal” seizures, from the French phrase meaning “great illness.” The term “tonic-clonic” refers to the two phases of these seizures, with the initial tonic phase involving widespread tensing up of muscles in your arms and legs and then the clonic phase involving convulsions.
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A tonic-clonic seizure has some similarities in name or symptom to other types of seizures. Those others include:
Everyone can have seizures, but some people can have them more easily. Seizures tend to happen most commonly in children and adults over 65.
Tonic-clonic seizures happen in about 25% of all people with seizures. Overall, 11% of people in the U.S. will have a seizure at some point in their life, and up to 3% of people will receive an epilepsy diagnosis during their lifetime. Seizures also make up about 1% of emergency room visits in the U.S.
A seizure is a malfunction in how your brain cells (neurons) send and relay electrical signals. A seizure causes affected neurons to fire electrical signals uncontrollably to other nearby neurons, causing the malfunction to spread.
Tonic-clonic seizures are generalized seizures, which means this type of seizure affects both sides of your brain. These seizures make you pass out and affect muscles throughout your body, causing convulsions, shaking and other kinds of uncontrollable muscle movements.
Status epilepticus happens when a seizure lasts for more than five minutes, or another seizure starts before you recover from the first. Status epilepticus is a life-threatening medical emergency and can cause permanent brain damage or death.
Close to 98% of seizures last under five minutes. Anything that can cause seizures can also cause status epilepticus with tonic-clonic seizures (see the Causes and Symptoms section of our main Seizure article).
IMPORTANT NOTE: If you’re with someone who has a seizure that lasts more than five minutes or has a second seizure without enough time to recover from the first, you need to call 911 (or your local emergency services number) immediately. The longer that status epilepticus lasts, the harder it is for healthcare providers to stop the seizure causing it. Long-lasting status epilepticus is also more likely to cause brain damage or death.
Tonic-clonic seizures are usually what people think of when they think about seizures and epilepsy. The symptoms are usually more severe and easier to spot and happen in the following phases:
Many people often experience a period before a seizure where they feel or know it’s going to happen. That lead-up time before the seizure, known as prodrome (rhymes with “dome”), can sometimes include what’s known as an “aura.” An aura happens when seizure activity starts to affect certain parts of your brain.
Generalized seizures, including tonic-clonic seizures, don’t have auras on their own. However, focal seizures — which affect only one side of your brain — can turn into generalized tonic-clonic seizures if the seizure spreads to the other half of your brain. That means an aura before a focal seizure can act as a warning that a tonic-clonic seizure could happen next.
Auras can involve the following symptoms:
Conditions and circumstances that can lead to tonic-clonic seizures include:
When diagnosing a seizure, healthcare providers will also try to determine if a seizure had a provoked or unprovoked cause.
No, tonic-clonic seizures aren’t contagious. However, you can spread conditions like infections that cause them (but none of these will definitely cause a seizure). Also, some conditions that cause seizures are genetic (you can inherit them from your parents, or your children can inherit them from you).
Your healthcare provider, usually a neurologist, can often diagnose a tonic-clonic seizure based on the symptoms. Because you pass out during a tonic-clonic seizure, you might only recall how you felt before and after the seizure. In those cases, your healthcare provider may ask someone who was with you to describe what happened.
If you see someone having a seizure, especially one involving a lot of muscle tension, convulsions or shaking and thrashing, a healthcare provider might ask you to describe what you saw. What you describe to them can be very helpful and make the diagnosing process much easier.
Several possible tests can help diagnose (or rule out) tonic-clonic seizures. Some of the most likely tests include:
While diagnosing epilepsy, healthcare providers will look for a focal point, a part of your brain where your seizures usually or always start. Finding a focal point can make a big difference in the treatments you receive.
Injuries are common with tonic-clonic seizures, either from passing out, clenching your jaw or if you collide with any nearby objects during the seizure. If healthcare providers suspect other injuries or complications from these seizures, they might want to run tests other than those listed above. Your healthcare provider is the best person to tell you (or someone who can make medical decisions for you) what kind of tests they recommend for your particular case and why.
Tonic-clonic seizures usually stop on their own, and there’s no reason to treat them directly while they’re happening. An exception is if you have status epilepticus, which is when a seizure lasts longer than 5 minutes, or you don’t recover fully from a seizure before having another.
The possible treatments related to seizures also depend on what caused the seizure in the first place. If you had a provoked seizure, treating or curing the underlying condition that caused the seizure should stop the seizures from happening. If the underlying cause isn’t curable or treatable, healthcare providers will try to reduce how often your seizures happen or how severe they are.
Healthcare providers also typically recommend against treating first-time unprovoked seizures. That’s because there’s no certainty that another will happen, which would make treatment unnecessary.
Healthcare providers can use your medical history and tests like EEG, CT scan or MRI scan to determine if you have a higher risk of having another seizure.
The treatments for all types of seizures vary widely, which is also true for epilepsy that specifically causes tonic-clonic seizures. For some people, one medication is enough to treat their seizures. For others, a combination of medications and treatments is necessary.
Possible treatments for tonic-clonic seizures due to epilepsy include:
The possible side effects and complications of the stated treatments depend on the treatments themselves, your health history and conditions, and the type of epilepsy you have. Your healthcare provider can tell you more about the possible side effects or complications. They can also tell you any possible concerns to watch for and how you can minimize how any of these affect you.
You shouldn’t try to self-diagnose or treat any kind of seizure. That’s because seizures are often a sign of very serious medical conditions that affect your brain. Tonic-clonic seizures also cause you to pass out, which means you’re not aware of what happens during the seizure itself, so there’s no way of knowing what happened to you during the time you were unconscious.
If you or a loved one have a first-time seizure, seeing a healthcare provider is extremely important. A qualified provider can look for any signs of a seizure, as well as conditions that could cause them.
If you’re with someone who’s having a seizure, there are several things you can do as part of seizure first aid. Some dos and don’ts include:
The recovery time depends on the specific treatment(s) and the condition that caused your seizure. Your healthcare provider can provide more information about what you can and should expect, including how long you’ll need to recover and when you should start feeling better.
Seizures can happen to anyone under the right circumstances, so seizures aren’t completely preventable. However, some people can have seizures more easily, so you can take certain proactive steps to lower your risk of them happening.
The best things you can do to reduce your risk of having a seizure include:
About half of the people who have an unprovoked seizure will have another, and about 75% of those who have a second seizure will have more. That’s why healthcare providers often diagnose epilepsy and recommend starting anti-epilepsy medications after a second unprovoked seizure.
For those who start medication, it might take trying more than one medication or combination of medications. If medications don’t help, there are still other treatments that could make your seizures happen less often or make them less severe.
Stopping provoked seizures depends on whether or not the underlying condition or problem causing them is treatable or curable. Many people who have provoked seizures don’t have them as long as the underlying problem is gone and doesn’t return.
Epilepsy is a life-long condition because it’s not curable. However, it’s possible to treat the underlying cause of the seizures in some cases. When this works, your case is “in remission” as long as you’re seizure-free.
With provoked tonic-clonic seizures, the prognosis depends on the underlying condition. The prognosis is usually better if the condition is treatable and you quickly get treatment. Your healthcare provider is the best person to tell you the prognosis for your case and what you can do to help yourself. They can tailor that information to your needs and circumstances and direct you to other providers and resources for additional help.
Provoked seizures that happen with permanent or severe conditions, such as cancer or permanent brain damage, are sometimes treatable but usually have a lower chance of a good outcome because of why they’re happening. A positive outlook is also less likely for seizures due to genetic and congenital conditions (which you’re born with).
The outlook for unprovoked seizures depends on several factors. These include the underlying condition, the severity of your seizures, how often you have them and whether or not treatments help.
Sudden unexpected death in epilepsy (SUDEP) is a rare condition that can affect anyone with epilepsy but is less likely with treatment. The risk of SUDEP is 1 in 150 for people with untreated epilepsy, while the risk for those with treated epilepsy is 1 in 1,000.
Experts don’t fully understand why SUDEP happens yet. For now, the best available explanation is that it happens due to heart or breathing problems that are possible with seizures.
If you’ve experienced a single tonic-clonic seizure in the past, it’s a good idea to know what to do if you have another. You should also see your healthcare provider as soon as possible if you have another seizure or develop a condition that could cause one.
If your healthcare provider diagnoses you with epilepsy, there are several things you can do to help yourself and manage this condition.
You should go to the emergency room if you have any event that makes you pass out, and you don’t know what caused it. While many people have others around to see them have a first-time seizure, many don’t. If you’re alone and you have what you think is a first-time seizure, you should see your healthcare provider right away.
Calling an ambulance after a seizure is often unnecessary if the person knows they have epilepsy. However, they may need medical attention if they have injuries from the seizure.
If you’re with someone who has a seizure, you should keep in mind the following:
People with epilepsy can often still have children. However, many anti-epilepsy medications aren’t safe to take during pregnancy because many disrupt how a baby develops in your uterus.
Fortunately, other medications can serve as temporary alternatives during part or all of a pregnancy. Your healthcare provider is the best person to talk to about this and can either guide you directly or refer you to a specialist who can.
A note from Cleveland Clinic
Tonic-clonic seizures are the most visible — and often most feared — type of seizure. While these seizures are often scary for the people who have or witness them, most of these only last a few minutes. While they can happen for many reasons, these seizures often go away on their own, especially with treatment of the underlying condition causing them. There are also many different ways of treating these seizures when they happen with epilepsy. With effective treatment, many people with these seizures — even those with epilepsy — can live fulfilling, happy and rewarding lives.
Last reviewed by a Cleveland Clinic medical professional on 04/13/2022.
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