Tonic-clonic seizures — sometimes called grand mal seizures — may come on suddenly and cause muscle stiffness, involuntary jerking or shaking movements, and loss of consciousness. They are caused by abnormal electrical activity in the brain and can affect people of any age. While some patients may have no warning symptoms prior, others may have a prodrome or aura they recognize at the start of a seizure.
UPMC epilepsy experts provide advanced care for tonic-clonic seizures, including first-line treatment with antiseizure medication. If seizures continue despite medications, our neurologists will work with our neurosurgery experts to discuss surgical options to reduce seizure activity.
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What Are Tonic-Clonic Seizures?
Tonic-clonic seizures — sometimes called grand mal seizures — may come on suddenly and cause muscle stiffness, involuntary jerking or shaking movements, and loss of consciousness. They are caused by abnormal electrical activity in the brain and can affect people of any age. While some patients may have no warning symptoms before a seizure, others may have a prodrome or aura they recognize at the start of a seizure.
Is a tonic-clonic seizure serious?
Yes. Tonic-clonic seizures can be dangerous because they cause loss of consciousness, often resulting in falls, which can lead to injuries and accidents. They are most dangerous when they occur at night during sleep. If left untreated, they can cause serious complications and affect your quality of life.
What are the types of tonic-clonic seizures?
There are two types of tonic-clonic seizures, including:
- Focal-to-bilateral tonic-clonic seizure — Occurs when abnormal electrical activity begins in one region of your brain and spreads to the other side.
- Generalized tonic-clonic seizure — Occurs when abnormal electrical activity happens at the same time on both sides of your brain.
How common are tonic-clonic seizures?
Tonic-clonic seizures affect approximately 20% to 25% percent of people with epilepsy.
What causes a tonic-clonic seizure?
Tonic-clonic seizures are caused by abnormal electrical activity in your brain. Researchers aren’t sure what causes the abnormal electrical signals, but they can sometimes be triggered by underlying health conditions.
What triggers tonic-clonic seizures?
Tonic-clonic seizures may be triggered by:
- Autoimmune disorders.
- Brain injuries or disorders, such as tumors, head injuries, or neurodegenerative diseases.
- Changes to blood flow or circulation caused by ruptured aneurysms, abnormal heart rhythms (arrhythmia), stroke, or high blood pressure in pregnancy (eclampsia).
- Fevers.
- High or low blood sugar.
- Infections, such as encephalitis, meningitis, or sepsis.
- Lack of sleep.
- Poisoning, including inhaled poisons like carbon monoxide or ingested poisons like heavy metals.
- Stress.
- Alcohol, recreational drug use, or withdrawal.
Tonic-clonic seizure risk factors
Tonic-clonic seizures can occur in anyone at any age.
You may be at higher risk if you:
- Experience high levels of stress or lack of sleep.
- Have a history of brain injury.
- Have underlying health conditions that could trigger seizures.
- Misuse alcohol, prescription medication, or recreational drugs.
Complications of tonic-clonic seizures
Tonic-clonic seizures may cause complications, including:
- Cognitive impairment.
- Heart disease.
- Injuries from falling.
- Mental health problems, such as anxiety and depression.
- Sleep problems.
Serious complications of tonic-clonic seizures may include:
- Status epilepticus — Long-lasting seizures or seizures that occur one after another.
- Sudden unexplained death in epilepsy (SUDEP) — A rare condition that causes sudden death without a clear cause in people with epilepsy, often during sleep.
How can I prevent tonic-clonic seizures?
Seizures can affect anyone, so you may not be able to prevent them.
However, you may be able to reduce your risk by:
- Avoiding misuse of alcohol, prescription medications, or drugs.
- Avoiding known or possible seizure triggers.
- Getting timely treatment for infections.
- Managing chronic health conditions.
- Wearing head protection when recommended to reduce the risk of head injury.
What Are the Signs and Symptoms of Tonic-Clonic Seizures?
Most tonic-clonic seizures last only a few minutes. Tonic-clonic seizures typically have two phases with distinct symptoms.
Phases include:
- Tonic phase — Lasts 10 to 30 seconds and causes sudden stiffening of muscles. Most people groan or yell, fall to the ground, and lose consciousness. Injuries from falling and other accidents are very common.
- Clonic phase — Lasts one to three minutes and causes involuntary jerking or shaking movements (convulsions). You may bite your tongue or lose bowel or bladder control.
After the seizure is over, you may:
- Feel disoriented or confused.
- Feel tired.
- Have a headache.
- Have sore muscles.
When should I see a doctor about my tonic-clonic seizure symptoms?
If you have a tonic-clonic seizure for the first time, you should dial 911 or ask someone to take you to the nearest hospital Emergency Department. If a seizure lasts longer than five minutes, dial 911.
If you have already been diagnosed with seizures and they are changing or getting worse, you should schedule an appointment with your provider right away.
How Do You Diagnose Tonic-Clonic Seizures?
To diagnose tonic-clonic seizures, your doctor will perform a physical examination and review your symptoms and medical history. Your doctor may also order tests to confirm your diagnosis or rule out other problems.
What to expect during your visit
During your visit, your provider will:
- Ask you about your symptoms.
- Order tests.
- Perform a physical and neurological exam.
- Review your medical history.
Tests to diagnose tonic-clonic seizures
Your provider may order tests to confirm your diagnosis or rule out other conditions, including:
- Blood tests — Checks for infections and abnormalities.
- Cerebral spinal fluid analysis (spinal tap or lumbar puncture) — Involves inserting a needle into your lower back to collect a sample of cerebrospinal fluid (CSF) for analysis in a lab.
- Electromyography (EMG) — Checks for abnormal electrical activity in your brain that may cause seizures.
- Magnetic resonance imaging (MRI) — Creates images of your brain to look for damaged or abnormal areas.
- Video-EEG monitoring — Uses EEG in combination with video monitoring to capture physical symptoms during seizures or episodes of concern.
- Neurological examination — A noninvasive physical exam to check your reflexes, balance, movement, memory, and ability to think.
Tonic-clonic seizure prognosis
Your prognosis after a tonic-clonic seizure diagnosis depends on the cause and severity of your condition. In many cases, tonic-clonic seizures can be controlled with antiseizure medications. However, if medications aren’t effective, surgical options to treat your seizures may be pursued.
When seizures start in childhood, it is possible to eventually outgrow them. Several factors may play a role in this, and your provider will inform you if they believe this to be a possibility.
How Do You Treat Tonic-Clonic Seizures?
The goals of tonic-clonic seizure treatment are to reduce seizure frequency, minimize treatment-related side effects, and improve quality of life.
Treatment options may include:
Lifestyle changes
If you and your epilepsy care team can identify triggers that lead to tonic-clonic seizures, you may be able to make lifestyle changes to reduce the number of seizures you experience. Identifying and treating the underlying cause of your seizures, such as a brain tumor or uncontrolled blood sugar, may prevent further seizures.
Dietary changes
Your provider may recommend following a specialized, high-fat, low-carbohydrate diet, such as the ketogenic diet, to help manage seizures in certain circumstances.
Medications for epilepsy
Medications are first-line treatment for tonic-clonic seizures and help to control them in most people with epilepsy. Your provider will work with you to identify the medication or combination of medications that work best for you with minimal side effects.
Surgery to treat epilepsy
Tonic-clonic seizures continue in at least one-third of people even with antiseizure medication(s).
Epilepsy surgery may be an effective option if:
- Medication side effects are not tolerated.
- At least two different medications have not been effective at controlling seizures.
UPMC neurosurgeons offer a range of surgical options for people with epilepsy, including:
Diagnostic surgery
Also known as intracranial monitoring or stereo-EEG, this procedure helps neurosurgeons pinpoint the origin of seizures within the brain. UPMC neurosurgeons use the ROSA® (robotic stereotactic assistance) Robotic System to perform minimally invasive procedures for epilepsy and movement disorders with greater accuracy.
Neurosurgical procedures
Neurosurgical procedures for epilepsy include:
- Craniotomy for resection of seizure focus — Involves surgically removing the abnormal brain tissue causing seizures.
- Laser ablation — Minimally invasive surgery using focused heat to destroy the abnormal brain tissue causing seizures.
Other less commonly performed surgeries include multiple subpial transections (MST), corpus callosotomy, and other procedures that reduce abnormal electrical impulses in the brain.
Neuromodulation device implantation
Your neurosurgeon may recommend a procedure to implant a neuromodulation device that sends electrical impulses to your brain. These impulses regulate or disrupt abnormal electrical signals and reduce seizures.
Procedures include:
- Deep brain stimulation (DBS) — Implantation of electrodes in the brain to directly deliver electrical impulses that can reduce seizure activity.
- Vagus nerve stimulation (VNS) — Implantation of a device in the chest that delivers electrical impulses to the vagus nerve in your neck to prevent or disrupt seizures.
- Responsive neurostimulation (RNS®) — Implantation of a device within the skull and electrodes within the brain that can detect seizure activity and respond with electrical stimulation to disrupt seizures
Why Choose UPMC for Tonic-Clonic Seizure Care?
When you choose UPMC for tonic-clonic seizure care, you will receive:
- Multidisciplinary care — Our team of neurologists, epileptologists, and neurosurgeons can work together to develop a customized epilepsy treatment plan that helps you manage seizures and minimize treatment side effects for medication-resistant epilepsy.
- Access to advanced clinical trials — Our team participates in national, multicenter clinical trials evaluating new epilepsy treatments, allowing you to contribute to research that advances seizure disorder care.
- Expert neurosurgery care — People with medication-resistant epilepsy can access cutting-edge, minimally invasive neurosurgery treatment options that may help reduce seizures and restore quality of life.
