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What is a seizure?

When your brain's electrical system doesn't work properly, a seizure can occur. Usually, your brain cells fire electrical impulses in a particular way. Certain factors can make those electrical impulses fire erratically. This can result in a "short circuit" in your brain that causes a seizure.


Although the exact cause of a seizure can't always be pinpointed, a healthcare provider should always evaluate you the first time you have a seizure. It’s important to know if you have an underlying health condition, such as epilepsy, that needs to be treated to prevent future seizures.

Seizures are classified by type and each has different symptoms. You may have a seizure that lasts for under a minute and causes no lasting effects, or a seizure that lasts for a few minutes and causes symptoms that last for a short time. Or you may have a seizure that lasts much longer and can be a medical emergency.

Seizures are often grouped by the amount of brain tissue involved. These are the major types of seizures:

  • Partial seizures
  • Spasms in infants
  • Absence seizures, or petit mal seizures 
  • Myoclonic seizures
  • Atonic seizures
  • Generalized tonic-clonic or grand mal seizures

Usually, a first seizure happens before age 25.

What causes seizures?

Seizures can be a sign of epilepsy, but they can happen for other reasons as well.

Why the brain suddenly misfires and causes a seizure is not usually known. Sometimes head injuries, drug use or drug withdrawal, or health conditions such as a tumor, high fever, brain infection, or an abnormal structure in the brain may be responsible for seizures.

What are the symptoms of seizures?

Symptoms can vary widely based on the type and severity of the seizure. These are common symptoms:

  • Staring blankly
  • Repetitive motions, such as smacking your lips
  • Uncontrollable movement of the eyes
  • Loss of consciousness
  • Loss of bladder or bowel control 
  • Convulsions and jerking
  • Tremors or twitching
  • Confusion

How are seizures diagnosed?

Your healthcare provider will first make sure that you're getting enough oxygen, that all of your vital signs are normal and healthy, and that there are no signs that the seizure is still happening. The main goal of the evaluation is to figure out if your symptoms were actually caused by a seizure and, if so, why the seizure occurred.

To make a diagnosis, your healthcare provider may do:

  • Complete neurological exam
  • Blood work and other lab tests to look for abnormalities in blood sugar and other factors
  • Imaging tests of the brain, such as an MRI or CT scan
  • Electroencephalogram, to test your brain's electrical activity


Your provider will also ask questions to find out if any of these factors may be responsible for the seizure:

  • Drug or alcohol use
  • Injury to the head
  • High fever or infection
  • Genetic abnormality

How are seizures treated?

A single seizure might not require any treatment. If the cause of the seizure can be found (such as an infection or fever), treating the underlying cause might prevent further seizures.

These are some common treatments to help prevent further seizures:

  • A special high-fat, low-carbohydrate diet called the ketogenic diet (often suggested for children)
  • Medicines to control electrical activity in the brain
  • Surgery to repair abnormalities in the brain
  • Vagus nerve stimulation, which delivers electrical impulses to the brain

When should I call my healthcare provider?

If you or a child has a seizure, see a healthcare provider immediately for an evaluation. Your healthcare provider may be able to find a health problem or abnormality that caused the seizure and recommend treatment.

Key points about seizures

  • Seizures occur when the electrical impulses of the brain fire erratically. There are many types of seizures, and each can cause different kinds of symptoms, ranging from slight body movements to loss of consciousness and convulsions.
  • There are many possible causes of seizures, including head injuries, drugs, and different health conditions, but often the cause of the seizure can't be determined.
  • First seizures need to be evaluated by a healthcare provider to look for possible underlying causes. If needed, medicines, surgery, or other treatments can often help prevent further seizures so that they don't interfere with your life.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Dozier, Tennille, RN, BSN, RDMS
Online Medical Reviewer: Shelat, Amit, MD
Date Last Reviewed: 9/1/2016
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