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A seizure is a sudden change in behavior due to abnormal electrical activity in the brain.


There are a wide variety of possible symptoms of seizures, depending on what parts of the brain are involved. Many types of seizures cause loss of awareness and some cause twitching or shaking of the body.

However, some seizures may be hard to notice because they consist of staring spells that can easily go unnoticed. Occasionally, seizures can cause temporary changes in sensation or vision.

Seizures are classified as involving a small part of the brain (focal) and then spreading, or as involving the whole brain (generalized). Focal seizures can be "simple" (there is no change in memory or awareness) or "complex" (there is loss of memory or a change in awareness) . Seizures may also be classified as generalized (whole body affected) or focal (only one part or side of the body is affected).

Epilepsy is a chronic disorder with recurrent seizures. Some types of epilepsy run in families.

See also:

Symptoms of seizures come on suddenly, over just seconds to a minute, and include:

  • Change in consciousness, so that you can't remember some period of time
  • Change in emotion, like unexplainable fear, panic, joy, or laughter
  • Change in sensation of the skin, usually spreading over the arm, leg, or trunk
  • Changes in vision, including flashing lights, or (rarely) hallucinations (seeing things that aren't there)
  • Loss of muscle control and falling, often very suddenly
  • Muscle movement such as twitching that might spread up an arm or leg
  • Muscle tension/tightening that causes twisting of the body, head, arms or legs
  • Tasting a bitter or metallic flavor

Symptoms may stop after a few minutes, or continue for 15 minutes. They rarely continue longer.

Shaking of the entire body when it occurs should last a few minutes and stop within 5 minutes.


Some of the more common causes of seizures include:

Developmental problems, genetic conditions present at birth, or injuries near the time of birth (seizures usually begin in infancy or early childhood):

  • Brain injury (see:Injury or trauma to the head)
    • early seizures (within 2 weeks of injury) don't necessarily mean that a seizure disorder (epilepsy) will develop
    • most common in young adults
    • seizures usually begin within 2 years after injury

Metabolic abnormalities (problems with the body's chemistry) can happen at any age and can result from:

  • Complications of diabetes
  • Kidney failure and uremia (the toxic accumulation of wastes in the body)
  • Liver failure
  • Nutritional deficiencies
  • Phenylketonuria (PKU) -- this can cause seizures in infants)
  • Use of cocaine, amphetamines, alcohol, or certain other recreational drugs
  • Withdrawal from alcohol
  • Withdrawal from drugs, particularly barbiturates and benzodiazepines

Other causes include:

  • Infections
    • acute, severe infections of any part of the body
    • brain abscess
    • brain infections such as meningitis and encephalitis can produce seizures
    • can happen in people of all ages
    • chronic infections (such as neurosyphilis)
      • complications of AIDS or other immune disorders
      • may be a reversible cause of seizures (not continue)
  • Tumors (see:brain tumor) and brain lesions (such as bleeding in the brain)
    • may affect any age person but are most common after age 30
    • may lead to generalized (tonic-clonic) seizures
    • partial (focal) seizures are most common to start with

Home Care

If someone who has never had a seizure before had one, call 9-1-1 immediately.

People with epilepsy should always wear a medical alert tag.

Most seizures stop by themselves. However, a person having a generalized seizure may be injured; breathe food, fluid, or vomit into the lungs; or not get enough oxygen. During a generalized seizure, it is important to protect the person from injury. Turn the person on his or her side, so that any vomit is expelled. See seizure first aid.

After a generalized seizure, most people go into a deep sleep. Don't prevent the person from sleeping. He or she will probably be disoriented, or possibly agitated for awhile after awakening.

Stay with the person until recovery or until you have professional medical help. Meanwhile, monitor their pulse, rate of breathing, and blood pressure.

  • DO NOT give the person anything by mouth until the convulsions have stopped and the person is fully awake and alert.
  • DO NOT move the person unless he or she is in danger or near something hazardous.
  • DO NOT place anything between the person's teeth during a seizure (including your fingers). You can break the person's teeth, or the object, if you do.
  • DO NOT restrain the person.
  • DO NOT try to make the person stop convulsing. He or she can't control the seizure and is not aware of what is happening at the time.

Some people with epilepsy may have a vagal nerve stimulator implanted in their chest. Activating this device at the beginning of a seizure may shorten or stop a seizure. Other people may have been prescribed medication to administer rectally during a seizure. Never try to administer anything (even medications) by mouth.

When to Contact a Medical Professional

If this is the first time someone has ever had a seizure, or if this is an unusually long seizure in someone who has a seizure disorder, call 9-1-1 immediately. These symptoms can be caused by life-threatening conditions, such as a stroke or meningitis.

Report all seizures (even a mild one) to the health care provider. If the patient is known to have epilepsy or recurrent seizures, their doctor should be notified so that medications can be adjusted or other instructions given.

What to Expect at Your Office Visit

The doctor will perform a physical examination and ask questions to help understand the cause of the seizures, such as:

  • Are there any risk factors (such as recent head injury)?
  • Did it occur or start on one side of the body?
  • Did the person remain awake and aware (maintain consciousness) during the seizure?
  • How long did the seizure last?
  • How often do the seizures happen?
  • Was there movement of the muscles and if so, what was the pattern?
  • Was there any warning (aura) of the seizures?
  • Were there any other symptoms present (visual changes, abnormal smells)?

The following tests may be performed:

Instructions for taking any prescribed medications should be strictly followed. Family members should observe and record any seizures to ensure the person gets proper treatment.

People with uncontrolled seizures should not drive. Each state has a different law that determines which people with a history of seizures are allowed to drive. People with uncontrolled seizures also should avoid activities where loss of awareness would cause great danger, such as climbing to high places, biking, and swimming alone.


Good habits may help to control seizures. Because sleep deprivation, stress, and a poor diet can contribute to increased seizures, good sleep habits, stress reduction, proper exercise, and sound nutrition may help.

There is no specific way to prevent seizures. Use helmets when appropriate to prevent head injury. This will lessen the likelihood of a brain injury and subsequent seizures. Avoid recreational drugs. People with epilepsy should take medication as directed and avoid excessive amounts of alcohol.


Foldvary-Schaefer N, Wyllie E. Epilepsy. In: Goetz, CG. Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 52.

Krumholz A, Wiebe S, Gronseth G, et al. Practice parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007;69(21):1991-2007.

Pollack CV Jr. Seizures. In: Marx, JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 6th ed. Philadelphia, PA: Mosby Elsevier; 2006: chap 100.

Spenser SS. Seizures and Epilepsy. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 426.

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Review Date: 5/29/2008
Reviewed By: Daniel B. Hoch, MD, PhD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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