Alternative names 

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


There are a wide variety of possible symptoms of seizures, depending on what parts of the brain are affected. Many types of seizures cause loss of consciousness with twitching or shaking of the body. However, some seizures consist of staring spells that can easily go unnoticed. Occasionally, seizures can cause temporary abnormal sensations or visual disturbances.

Seizures can generally be classified as either “simple” (no change in level of consciousness) or “complex” (change in level of consciousness). 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 are hereditary.

See also:

  • Epilepsy  
  • Petit mal seizure  
  • Generalized tonic-clonic seizure (grand mal)  
  • Partial (focal) seizure  
  • Temporal lobe seizure  
  • Fever convulsions (seizures in children with high fever)

Common Causes

Any condition that results in abnormal electrical excitation of the brain may result in a seizure, including:

  • Epilepsy  
  • Injury or trauma to the head  
  • Infection (brain abscess, meningitis)  
  • Brain tumor  
  • Stroke

Also, any medical condition that irritates brain cells may result in a seizure. Common medical conditions that commonly cause seizures include:

  • Hypoglycemia (low blood sugar)  
  • Drug use (especially cocaine or stimulants)  
  • Alcohol withdrawal  
  • Very high fever (fever convulsions in children)

Home Care

People with epilepsy should always wear a medical alert tag.

Most seizures are self-limiting and stop by themselves after various periods of time. However, a person having a seizure may be injured; breathe food, fluid, or vomit into the lungs; or not get enough oxygen. During a 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 convulsion, 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 restrain the person.  
  • DO NOT place anything between the person’s teeth during a seizure (including your fingers).  
  • DO NOT move the person unless he or she is in danger or near something hazardous.  
  • 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.  
  • DO NOT give the person anything by mouth until the convulsions have stopped and the person is fully awake and alert.

Some patients with epilepsy may have a vagal nerve stimulator implanted in their chest. In these persons, a seizure can be halted by activating the device. Other patients may have been prescribed medication to administer rectally during a seizure. Never try to administer anything (even medications) by mouth.

Call your health care provider if

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.

If this is the first time a patient has ever had a seizure, or if this an unusually prolonged seizure for someone known to have a seizure disorder, call for emergency transportation to the hospital. These symptoms may represent a life-threatening condition, such as a stroke or meningitis.

What to expect at your health care provider’s office
The doctor will perform a physical examination and ask questions to help understand the cause of the seizures, such as:

  • Did it occur or start on one side of the body?  
  • Was there movement of the muscles and if so, what was the pattern?  
  • Are there any risk factors (such as recent Head injury)?  
  • Was consciousness maintained during the seizure?  
  • How long did the seizure last?  
  • What are the frequency of the seizures?  
  • Was there any warning (aura) of the seizures?  
  • Were there any other symptoms present (visual changes, abnormal smells)?

The following diagnostic tests may be performed:

  • CT scan of the head or MRI of the head  
  • EEG  
  • Lumbar puncture  
  • Blood tests

Medications are often prescribed. Instructions for taking them should be strictly followed. Family members should observe and record any seizures to ensure the patient gets proper treatment.

People with uncontrolled seizures should not drive. Each state has a different law that determines which patients are allowed to drive. People with seizures also should not swim or bike alone.


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.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

Medical Encyclopedia

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.