- What is epilepsy? What is a seizure?
Epilepsy, which is sometimes called a seizure disorder, is a disorder of the brain. A person is diagnosed with epilepsy when they have had two or more seizures.
A seizure is a short change in normal brain activity.
Seizures are the main sign of epilepsy. Some seizures can look like staring spells. Other seizures cause a person to fall, shake, and lose awareness of what’s going on around them.
Usually, a seizure lasts from a few seconds to a few minutes. It depends on the type of seizure.
What are the major types of seizures?
Sometimes it is hard to tell when a person is having a seizure. A person having a seizure may seem confused or look like they are staring at something that isn’t there. Other seizures can cause a person to fall, shake, and become unaware of what’s going on around them.
Seizures are classified into two groups.
- Generalized seizures affect both sides of the brain.
- Focal seizures affect just one area of the brain. These seizures are also called partial seizures.
A person with epilepsy can have more than one kind of seizure. Read more about types of seizures and what they look like.
Not always. Seizures can also happen because of other medical problems. These problems include:
- A high fever.
- Low blood sugar.
- Alcohol or drug withdrawal.
What causes epilepsy?
Epilepsy can be caused by different conditions that affect a person’s brain. Some known causes include:
- Brain tumor.
- Brain infection from parasites (malaria, neurocysticercosis), viruses (influenza, dengue, Zika), and bacteria.
- Traumatic brain injury or head injury.
- Loss of oxygen to the brain (for example, during birth).
- Some genetic disorders (such as Down syndrome).
- Other neurologic diseases (such as Alzheimer’s disease).
For 2 in 3 people, the cause of epilepsy is unknown. This type of epilepsy is called cryptogenic or idiopathic.
Read more about the causes of epilepsy in the National Institute of Neurological Disorders and Stroke publication: Seizures and Epilepsy: Hope Through Researchexternal icon.
Epilepsy is one of the most common conditions affecting the brain.
When counting both children and adults in the United States:
- About 5.1 million people in the United States have a history of epilepsy.
- About 3.4 million people in the United States have active epilepsy.