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Causes of Epilepsy

Medically Reviewed by Carol DerSarkissian, MD on October 14, 2021

Epilepsy is a general term for the tendency to have seizures. Epilepsy is usually diagnosed only after a person has had more than one seizure.

When identifiable, the causes of epilepsy usually involve some form of injury to the brain. For most people, though, epilepsy's causes aren't known.

What Are Seizures?

A seizure occurs when a burst of electrical impulses in the brain escape their normal limits. They spread to neighboring areas and create an uncontrolled storm of electrical activity. The electrical impulses can be transmitted to the muscles, causing twitches or convulsions.

What Are the Types of Seizures?

There are two types of seizures:

Focal seizures. These seizures involve abnormal activity in just one part of your brain. You may lose consciousness, or you may stay alert when you have them.

  • Without loss of consciousness. These seizures may just change your emotions, or alter your sense of sight, smell, taste, or sound. You might also jerk an arm or a leg without meaning to, or feel tingling, dizziness, or see flashing lights.
  • With loss of consciousness. During these seizures, you aren’t quite aware of your surroundings as usual. You may stare into space, or move repetitively by chewing, rubbing your hands, or walking in circles.

Generalized seizures. This type of seizure tends to involve all the parts of your brain. There are six kinds of generalized seizures:

  • Absence seizures happen mostly in children and involve small movements such as lip smacking or eye blinking.
  • Tonic seizures make you stiffen the muscles in your arms, legs, back and sometimes fall down as a result.
  • Atonic seizures take away your muscle control. They’re also called drop seizures, because they can make you collapse onto the floor.
  • Clonic seizures often make you repeat jerking movements in your neck, face, and arms.
  • Myoclonic seizures involve short, twitching and jerking motions in your arms and legs.
  • Tonic-clonic seizures, which used to be called grand-mal seizures, can make you lose consciousness, stiffen your whole body, and shake. You may also bite your tongue or lose control of your bladder.

What Are the Causes of Epilepsy?

There are around 180,000 new cases of epilepsy each year. About 30% occur in children. Children and elderly adults are the ones most often affected.

There is a clear cause for epilepsy in only a minority of the cases. Typically, the known causes of seizure involve some injury to the brain. Some of the main causes of epilepsy include:

Family history. Genes play a big part. As many as 40% of all epilepsy cases happen because the person with it has a genetic makeup that makes them more likely to get it. There isn’t just one gene behind epilepsy. In fact, some experts think there may be as many as 500.

If you have a parent or a sibling with epilepsy, you have a higher chance of getting it than someone who doesn't. Doctors aren’t sure how it’s passed down, but they think it may have something to do with a gene mutation that affects nerve cells in the brain. It’s also possible to have this mutation and never get epilepsy.

Experts think the combination of genetics and something else, like a medical condition, may be to blame.

Injury before, during, or soon after birth. Any problems with brain development in the womb or in early infancy raise the chance of epilepsy. Brain damage can happen to babies in the womb for many reasons, including:

  • An infection in the mother
  • Poor nutrition
  • Too little oxygen

If there are problems during birth, or if a baby is born with brain defects, this can also bring on epilepsy.

Head or brain trauma. Either can trigger seizures. Sometimes they go away. If they do, you don't have epilepsy. However, if they continue, that's a sign that you have post-traumatic epilepsy, or PTE. It can also happen during birth. You may not get epilepsy until long after your brain injury -- sometimes years later.

Brain conditions. Most cases of epilepsy in people older than 35 happen because of brain damage from a stroke or even after brain surgery. Other brain problems that can trigger epilepsy include:

  • Tumor
  • Blood vessel problems, like the hardening of your brain’s arteries
  • Stroke
  • Alzheimer’s disease
  • Tuberous sclerosis, a genetic condition that can cause growths in the brain.

Infectious diseases. Conditions caused by a viral or bacterial infection can cause epilepsy, too, especially if they infect your brain. Some common culprits are:

Developmental disorders. It could be caused by how the brain itself developed in the womb. Certain disorders raise your chance of epilepsy, including:

In up to 70% of all cases of epilepsy in adults and children, no cause can be discovered.

What Are the Causes of Seizures

Although the underlying causes of epilepsy are usually not known, certain factors are known to provoke seizures in people with epilepsy. Avoiding these triggers can help you avoid seizures and live better with epilepsy:

  • Missing medication doses
  • Heavy alcohol use
  • Cocaine, ecstasy, or other illegal drugs
  • Lack of sleep
  • Other medicines that interfere with seizure medications
  • Flashing lights, images, and repetitive patterns may cause seizures in persons with photosensitive seizure disorder.

For about 1 in 2 women with epilepsy, seizures tend to occur more around the time of menstrual periods. Changing or adding certain drugs before menstrual periods can help.

WebMD Medical Reference

Sources

SOURCES:

Epilepsy.com: "What Causes Epilepsy?"

Epilepsy Foundation: "Causes."

Mayo Clinic: “Epilepsy.”

National Institute of Neurological Disorders and Stroke: “The Epilepsies and Seizures: Hope Through Research.”

University of Chicago Medicine: “Epilepsy.”

American Academy of Family Physicians: “Epilepsy.”

Cedars-Sinai: “Epilepsy.”

Medscape: “Posttraumatic Epilepsy.”

Epilepsy Society: “Causes of Epilepsy.”

Epileptic Disorders: “Epilepsy in children with Down syndrome.”

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