Medical Encyclopedia


Medical Encyclopedia

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Contents of this page:

Alternative Names   

Secondary seizures; Reactive seizures; Seizure - secondary; Seizure - reactive

Definition    Return to top

A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain.

See also:

Considerations    Return to top

There are a wide variety of possible symptoms of seizures, depending on what parts of the brain are involved. Many, if not all, 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.

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

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.

Causes    Return to top

A seizure may be related to a temporary condition, such as exposure to drugs, withdrawal from certain drugs, a high fever, or abnormal levels of sodium or glucose in the blood. If the repeated seizures do not happen again once the underlying problem is corrected, the person does not have epilepsy.

In other cases, injury to the brain (for example, stroke or head injury) causes brain tissue to be abnormally excited.

In some people, a problem that is passed down through families (inherited) affects nerve cells in the brain, which leads to seizures. In these cases, the seizures happen spontaneously, without an immediate cause, and repeat over time. This is epilepsy.

Idiopathic seizures are chronic seizures that occur without an identifiable cause. They usually begin between ages 5 and 20, but can occur at any age. The person can have a family history of epilepsy or seizures.

Other more common causes of seizures include:

Home Care    Return to top

If someone who has never had a seizure before had one, call 911 or your local emergency number immediately.

Persons 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 the side, so that any vomit leaves the body and does not enter the lungs. See: Seizure first aid

After a generalized seizure, most people go into a deep sleep. Do not prevent the person from sleeping. The person will probably be disoriented, or possibly agitated for awhile after awakening.


If a person has repeated or prolonged seizures without regaining consciousness or returning to normal behavior, the body may develop a severe lack of oxygen. This an emergency situation - seek immediate medical help.


Treat any injuries from bumps or falls. Record details of the seizure to report to the person's primary health care provider. You should note the following details:

When to Contact a Medical Professional    Return to top

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 911 or your local emergency number 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 person 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    Return to top

Often, a person who has had a new or severe seizure will be seen in an emergency room, rather than a doctor's office.

The health care provider will try to diagnose the type of seizure based on the symptoms.

Other medical conditions that can cause a seizure or similar symptoms will be ruled out. Disorders that may cause similar symptoms include fainting, TIA or stroke, rage or panic attacks, migraine headaches, sleep disturbances, and conditions that cause loss of consciousness.

The following tests may be done:

The need for further tests or treatment depends on a number of factors.

Prevention    Return to top

Instructions for taking any prescribed medications should be strictly followed. Family members should observe and record any seizure information to make sure the person gets proper treatment.

Good health 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 all 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.

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.

References    Return to top

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.

Update Date: 3/29/2009

Updated by: Reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Previously reviewed by Daniel B. Hoch, MD, PhD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. (5/29/2008)

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