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Definition
A seizure is the physical findings or changes in behavior that occur after an episode of abnormal electrical activity in the brain.
See also:
- Generalized tonic clonic seizure
- Partial (focal) seizure
- Petit mal (absence) seizure
- Epilepsy
- Fever (febrile) convulsions (seizures in children with high fever)
Alternative Names
Secondary seizures; Reactive seizures; Seizure - secondary; Seizure - reactive
Considerations
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:
- 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 or down 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.
Common Causes
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:
- Tumors (such as brain tumor) or other structural brain lesions (such as bleeding in the brain)
- Traumatic brain injury, stroke, or a transient ischemic attack (TIA)
- Stopping alcohol after drinking heavily on most days
- Illnesses that cause the brain to deteriorate
- Dementia such as Alzheimer's disease
- Problems that are present from before birth (congenital brain defects)
- Injuries to the brain that occur during labor or at the time of birth
- Low blood sugar or sodium levels in the blood
- Kidney or liver failure
- Use of cocaine, amphetamines, or certain other recreational drugs
- Stopping certain drugs, such as barbiturates and benzodiazepines, after taking them for a period of time.
- Infections (brain abscess, meningitis, encephalitis, neurosyphilis, or AIDS)
- Phenylketonuria (PKU) can cause seizures in infants
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Reviewer Info: 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) ; ADAM Health Illustrated Encyclopedia, 03/29/2009 |
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