Bilateral tonic-clonic seizure
Bilateral tonic-clonic seizure is a type of seizure that involves the entire body. It is also called grand mal seizure. The terms generalized seizure, convulsion, or epilepsy are most often associated with bilateral tonic-clonic seizures.
Convulsion
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...

Epilepsy
Epilepsy is a brain disorder in which a person has repeated seizures over time. Seizures are episodes of uncontrolled and abnormal electrical activi...

Causes
Seizures result from electrical overactivity in the brain. Bilateral tonic-clonic seizures may occur in people of any age. They can occur once (single episode). Or, they can occur as part of a repeated, chronic illness (epilepsy). Some seizures are due to psychological problems (psychogenic or non-epileptic).
Epilepsy - Animation
Having a brain seizure can be a terrifying experience. If you have a seizure more than once, you may have epilepsy, a problem with electrical activity in your brain. So, what causes epilepsy? For most people, the brain sends electrical signals throughout the body efficiently, in a coordinated way. In epilepsy, however, the normal pattern of electrical activity becomes disturbed. This causes the brain to be too excitable, or jumpy, and it sends out abnormal signals. The result is repeated seizures that can happen at any time. Epilepsy seizures usually begin between ages 5 and 20, but they can happen at any age. Common causes include Stroke, or a mini-stroke called transient ischemic attack; Dementia, or loss of brain function, such as Alzheimer's disease; Traumatic brain injury; Infections in the brain; Brain problems you are born with; or perhaps, a Brain tumor. Some people with epilepsy may have simple staring spells, while others have violent, uncontrollable shaking and loss of consciousness. Before each seizure, some people may have strange sensations, such as tingling, smelling an odor that isn't really there, or emotional changes. This is called an aura. Your doctor will perform a number of tests to find out if epilepsy is causing your seizures. One test, an electroencephalogram or EEG, checks your brain's electrical activity. Other tests can take detailed pictures of the part of your brain that is causing your seizures. Your doctor will most likely start treating your epilepsy with medication. These medicines, called anticonvulsants, may reduce the number of seizures you have in the future. Sometimes, changing the diet of a child with epilepsy can help prevent seizures. Your doctor will probably talk to you about making some changes in your life, such as reducing your stress, getting more sleep, and avoiding alcohol and recreational drugs. Surgery to remove a brain tumor or abnormal blood vessels or brain cells may make the seizures stop. For many people, epilepsy is a lifelong problem, and they'll always need to take anti-seizure medicines. There is a very low risk of sudden death with epilepsy. However, you, or someone else, can be seriously injured if you have a seizure while driving or operating equipment. If your seizures are uncontrolled, you should not drive.
Symptoms
Many people with generalized bilateral tonic-clonic seizures have an aura with one or more symptoms before the seizure such as:
- Vision, taste, smell, or sensory changes.
- Seeing, smelling, or sometimes hearing things that are not there (hallucinations).
Hallucinations
Hallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.
Read Article Now Book Mark Article - Dizziness or other symptoms.
Dizziness
Dizziness is a term that is often used to describe 2 different symptoms: lightheadedness and vertigo. Lightheadedness is a feeling that you might fai...
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Some people have a focal onset seizure (only affecting one part of the body) that becomes a bilateral tonic-clonic seizure.
The seizures often result in rigid muscles (tonic phase). This is followed by violent muscle contractions (clonic phase). Other symptoms that occur during the seizure may include:
Muscle contractions
Muscle cramps are when a muscle gets tight (contracts) without you trying to tighten it, and it does not relax. Cramps may involve all or part of on...

- Biting the cheek or tongue
- Clenched teeth or jaw
- Loss of urine or stool control (incontinence)
-
Stopped breathing or difficulty breathing
Difficulty breathing
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
ImageRead Article Now Book Mark Article - Blue skin color (cyanosis)
Blue skin color
A bluish color to the skin or mucous membrane is usually due to a lack of oxygen in the blood. The medical term is cyanosis.
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After the seizure, the person may have:
- Confusion
Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
ImageRead Article Now Book Mark Article - Drowsiness or sleepiness that lasts for 1 hour or longer (called the post-ictal state)
Drowsiness
Drowsiness refers to feeling more sleepy than normal during the day. People who are drowsy may fall asleep when they do not want to or at times whic...
ImageRead Article Now Book Mark Article - Loss of memory (amnesia) about the seizure episode
- Headache
Headache
A headache is pain or discomfort in the head, scalp, or neck. Serious causes of headaches are rare. Most people with headaches can feel much better...
ImageRead Article Now Book Mark Article - Weakness of one side of the body for a few minutes to a few hours following seizure (called Todd paralysis)
Exams and Tests
Your health care provider will perform a physical exam. This will include a detailed check of the brain and nervous system.
An electroencephalogram (EEG) will be done to check the electrical activity in the brain. People with seizures often have abnormal electrical activity seen on this test. In some cases, the test shows the area in the brain where the seizures start. The brain may appear normal after a seizure or between seizures.
Electroencephalogram
An electroencephalogram (EEG) is a test to measure the electrical activity of the brain.

Blood and urine tests may also be ordered to check for other health problems that may be causing the seizures.
Head CT or MRI scan may be done to find the cause and location of the problem in the brain.
Head CT
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.

MRI
A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...

Treatment
Treatment for tonic-clonic seizures includes medicines, changes in lifestyle for adults and children, such as activity and diet, and sometimes surgery. Your provider can tell you more about these options.
Treatment
Epilepsy is a brain disorder in which a person has repeated seizures over time. Seizures are episodes of uncontrolled and abnormal electrical activi...

Adults
You have epilepsy. People with epilepsy have seizures. A seizure is a sudden brief change in the electrical and chemical activity in the brain. Aft...
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Your child has epilepsy. People with epilepsy have seizures. A seizure is a sudden brief change in the electrical and chemical activity in the brai...
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Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 100.
Kanner AM, Ashman E, Gloss D, et al. Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs I: Treatment of new-onset epilepsy: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2018;91(2):74-81. PMID: 29898971 pubmed.ncbi.nlm.nih.gov/29898971/.
Mikati MA, Tchapyjnikov D, Rathke KM. Seizures in childhood. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 633.
Wiebe S. The epilepsies. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 372.