A seizure is a sudden burst of electrical activity in the brain. It can cause changes in behavior, movements, feelings and levels of consciousness. Epilepsy is defined as having two or more seizures at least 24 hours apart that don’t have a known cause. But epilepsy doesn’t cause all seizures.

There are many types of seizures. They have a range of symptoms and vary in how much they affect your daily life. Seizure types also vary by where they begin in the brain and how far they spread. Most seizures last from 30 seconds to two minutes. A seizure that lasts longer than five minutes is a medical emergency.

Seizures can happen after a stroke or a head injury. An infection such as meningitis or another illness also may be the cause. But often the cause is not known.

Medicine can manage most seizures, but they can have side effects. Work with your healthcare professional to balance seizure management and medicine side effects.

Symptoms vary based on the type of seizure. They also can range from mild to serious. Seizure symptoms may include:

Most seizures fall into one of two classes called focal or generalized. The classes are based on how and where the brain activity causing the seizure began. If health professionals don’t know how the seizures began, they may say the seizures are of unknown onset.

Focal seizures

Focal seizures result from electrical activity in one area of the brain. This type of seizure can happen with or without passing out, called losing consciousness.

Symptoms of focal seizures may seem like those of other conditions of the brain or nervous system. These other conditions include migraine, mental illness or a condition that affects how the brain manages sleep-wake cycles, called narcolepsy.

Generalized seizures

Seizures that appear to involve all areas of the brain from the time they start are called generalized seizures. Types of generalized seizures include:

Seizure stages

Seizures can have a beginning phase, a middle phase and an end phase. These phases also are called prodrome, ictal and postictal.

When to see a doctor

Seek medical help right away if you have a seizure or if you see someone have a seizure and any of the following happens:

The first time you have a seizure, see a healthcare professional.

Seizures are caused by changes in the way nerve cells in the brain communicate. Nerve cells in the brain create, send and receive electrical impulses. The nerve cells are called neurons. The impulses allow the cells to communicate. Anything that gets in way of the communication pathways can lead to a seizure. Gene changes cause some types of seizures.

Epilepsy is a common cause of seizures. But not everyone who has a seizure has epilepsy. Sometimes the following can cause seizures:

The following increase the risk of having a seizure:

Having a seizure can sometimes lead to complications that can cause danger for you or others. You might be at risk of:

People who have more than one seizure should stay away from things that can cause a seizure, such as:

After a seizure, your healthcare professional reviews your symptoms and medical history and does a physical exam. You may have tests to find the cause of your seizure. Tests also may show how likely it is that you’ll have another seizure.

Tests may include:

Imaging tests may include:

Not everyone who has one seizure has another one. So your healthcare professional may not start treatment unless you’ve had more than one.

The goal in seizure treatment is to find the best therapy that stops seizures with the fewest side effects.

Medications

Treatment of seizures often involves antiseizure medicines. There are many types of antiseizure medicine.

Finding the right medicine and dosage can be hard. Some people try several medicines before finding the right one in the right dosage. Common side effects may include weight changes, dizziness, tiredness and mood changes. Very rarely, more-serious side effects can cause damage to the liver or bone marrow.

A healthcare professional thinks about your condition, how often you have seizures, your age and other factors when choosing which medicine to prescribe. The health professional also reviews other medicines you take to make sure that the antiseizure medicines won’t interact with them.

Dietary therapy

Following a ketogenic diet can improve seizure management. A ketogenic diet is high in fat and very low in carbohydrates. But it can be hard to follow because there’s a small range of foods allowed.

Other versions of a high-fat, low-carbohydrate diet also may be helpful but not work as well. These diets include low glycemic index and Atkins diets. Experts are still studying these diets.

Surgery

If treatment with at least two antiseizure medicines doesn’t work, you might have surgery to stop the seizures. Surgery works best for people who have seizures that always begin in the same place in the brain. Types of surgery include:

Electrical stimulation

If surgeons can’t remove or separate the area of the brain where seizures start, devices that provide electrical stimulation may help. They can work with antiseizure medicines to reduce seizures. Stimulation devices that may offer seizure relief include:

Pregnancy and seizures

People who’ve had seizures most often can have healthy pregnancies. But some medicines used to treat seizures sometimes can cause health conditions that are present at birth.

Valproic acid is a medicine for generalized seizures that has been linked with cognitive issues and neural tube defects, such as spina bifida, in babies. The American Academy of Neurology advises against using valproic acid during pregnancy because of risks to babies.

Talk with your healthcare professional about the risks of antiseizure medicines, including the risk of health conditions present at birth. Make a plan with your health professional before you get pregnant. Pregnancy can change medicine levels.

Some people may need to change the dosage of seizure medicine before or during pregnancy. The goal is to be on the lowest dose of the safest seizure medicine that manages seizures.

Taking folic acid before pregnancy may help prevent some complications related to taking antiseizure medicines while pregnant. Folic acid is in standard prenatal vitamins. Experts suggest that all people of childbearing age take folic acid while taking antiseizure medicines.

Birth control and antiseizure medicines

Some antiseizure medicines keep birth control from working as well. Check with your healthcare professional to see whether your medicine affects your birth control. You may need to try other forms of birth control.

Potential future treatments

Researchers study other therapies that might treat seizures. These include therapies to stimulate the brain without surgery.

One area of research showing promise is MRI-guided focused ultrasound. The therapy involves pointing ultrasound beams, which are sound waves, to an area of the brain that’s causing seizures. The beam creates energy to destroy brain tissue without surgery.

This type of therapy can reach deeper brain structures. It also can focus on a target without damaging the nearby tissue.

Here are some steps you can take to help manage seizures:

Personal safety

Seizures don’t often result in serious injury. But if you have repeated seizures, you might injure yourself. These steps can help you avoid injury during a seizure:

Seizure first aid

It’s helpful to know what to do if you see someone having a seizure. If you’re at risk of having seizures, give this information to family, friends and co-workers. Then they’ll know what to do if you have a seizure.

To help someone during a seizure, take these steps:

Stress due to living with a seizure condition can affect your mental health. Talk with your healthcare professional about your feelings. Look for ways to find help.

At home

Your family members can provide support you may need. Tell them what you know about your seizures. Let them know they can ask you questions. Ask them about their worries. Help family members learn about your condition. Share materials or other resources that your healthcare professional gives you.

At work

Talk with your supervisor about your seizures and how they affect you. Discuss what you need your supervisor or co-workers to do if you have a seizure at work. Talk with your co-workers about seizures. This will help them understand and give you more support.

You’re not alone

Reach out to family and friends. Ask your healthcare professional about local support groups or join an online support community. Don’t be afraid to ask for help. Having a strong support system is vital to living with any medical condition.

Sometimes seizures need medical help right away. So there’s not always time to prepare for an appointment.

But you may see your primary healthcare professional or be sent to a specialist. You might see a specialist trained in brain and nervous system conditions, called a neurologist. Or you might see a neurologist trained in epilepsy, known as an epileptologist.

Here’s some information to help you get ready for your appointment.

What you can do

For seizures, some basic questions to ask include:

Be sure to ask all the questions you have.

What to expect from your doctor

A healthcare professional is likely to ask you questions, such as:

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