Tonic-Clonic (Grand Mal) Seizure

Tonic-clonic seizures, formerly known as grand mal seizures, cause stiff muscles, involuntary jerking movements and a loss of consciousness. Abnormal electrical activity in your brain causes them.

It involves passing out and shaking uncontrollably. It can be scary to witness, and even more uncomfortable to experience. This is because you’re at high risk of injury when you fall. And afterward, you may feel confused or disoriented when you wake up.

These events are often unpredictable, but a healthcare provider can help you manage them and stay safe.

Tonic-clonic seizure types

There are two types based on the location in your brain:

• Generalized tonic-clonic seizure: Abnormal electrical activity happens on both sides of your brain at the same time.
• Focal to bilateral tonic-clonic seizure: Abnormal electrical activity starts on one side of your brain and spreads to the other.

Symptoms of a tonic-clonic seizure

When most people picture a seizure, a tonic-clonic seizure is likely the one they think about. Symptoms are easier to spot and happen in the following phases:

• Tonic (10 to 30 seconds): A groan or yell, sudden stiffening of muscles causing you to fall and loss of consciousness
• Clonic (30 to 60 seconds): Full-body rhythmic muscle jerks (convulsions) or shaking, sometimes with a loss of bladder and bowel control

You may bite your cheek or tongue during the seizure. This could cause bloody saliva. Fall injuries are also common as you lose consciousness.

When it’s over, you may wake up with:

• A headache
• Confusion
• Fatigue
• Sore muscles

Tonic-clonic seizure causes

A surge of electrical activity in your brain causes a tonic-clonic seizure. The reason why this happens is unknown.

Normally, brain cells (neurons) use electrical and chemical signals to send messages. But during a seizure, the signals go out of control and spread too fast. This sudden burst of activity leads to symptoms.

Tonic-clonic seizures may be a symptom of epilepsy. Epilepsy means you have unprovoked seizures often. You may have seizures with or without an epilepsy diagnosis.

Several conditions have also been known to cause tonic-clonic seizures:

• Blood flow and circulation: Aneurysms, arrhythmias, stroke, eclampsia
• Brain injuries or changes: Concussion, traumatic brain injury, brain tumor, diseases that slowly damage your brain (degenerative diseases)
• Imbalances: High blood sugar (hyperglycemia) or low blood sugar (hypoglycemia), lack of oxygen
• Infections or immune responses: Encephalitis, meningitis, sepsis, certain autoimmune conditions
• Poisoning: Carbon monoxide poisoning, heavy metal poisoning
• Substances: Substance use disorder, withdrawal
• Triggers: Fever (children), sleep deprivation, stress

Complications of a tonic-clonic seizure

Complications may include:

• Cognitive impairment
• Heart disease
• Mental health conditions, like anxiety and depression
• Sleep disorders

A seizure that lasts over five minutes (status epilepticus) is an emergency. Without quick treatment, it can cause brain damage or even death.

How doctors diagnose a tonic-clonic seizure

A healthcare provider will make a diagnosis after a physical exam and a review of your symptoms. Because you passed out, you may not remember what happened. Your provider may ask someone who was with you to describe what they saw.

What tests diagnose a tonic-clonic seizure?

Testing may confirm a diagnosis or rule out conditions with similar symptoms. These may include:

• Blood tests
• CT scan
• Electroencephalogram (EEG)
• MRI
• Spinal tap (lumbar puncture)

These tests can also help your provider determine the best treatment option to manage symptoms.

How is a tonic-clonic seizure treated?

Most seizures stop on their own within minutes. To prevent choking, you can roll the person onto their side. This helps them keep breathing. Call emergency services if it lasts longer than five minutes.

To manage tonic-clonic seizures long term, a healthcare provider may recommend:

• Treatment to manage any underlying conditions
• Daily antiseizure medications

If seizures don’t respond to medical management, an epilepsy specialist may assess you to see if you’re a candidate for:

• Starting a low- or no-carb (ketogenic) diet
• Having epilepsy surgery
• Using devices that help control brain signals (deep brain stimulation or vagus nerve stimulation)

Medication for treating tonic-clonic seizures

Common anti-seizure medications may include:

• Clobazam
• Lamotrigine
• Levetiracetam
• Topiramate
• Valproic acid

Each medication comes with possible side effects. Your provider will discuss these with you so you know what to expect.

When should I see my healthcare provider?

If you’re undergoing treatment, you’ll have regular check-ins with your provider to see how well it’s working. They may run tests to monitor your brain activity periodically. Be sure to tell them about any side effects you experience.

If you have a seizure for the first time, contact 911 or your local emergency services number.

What can I expect if I have a tonic-clonic seizure?

After the first seizure, you’re more likely to have another. But sometimes, it can be a one-off (where you only have one and no more after that). Your provider can help treat any underlying conditions that may be triggering symptoms or recommend options to manage the seizures themselves. This may reduce how often they happen or how severe they are.

Your provider can also suggest ways to make your home safer, like padding sharp corners or using non-slip rugs. You can wear a medical ID bracelet, too, to inform others if you have an unexpected seizure. Providers can connect you with support if complications arise.