A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain.
The term "seizure" is often used interchangeably with "convulsion." During convulsions a person has uncontrollable shaking that is rapid and rhythmic, with the muscles contracting and relaxing repeatedly. There are many different types of seizures. Some have mild symptoms without shaking.
It may be hard to tell if someone is having a seizure. Some seizures only cause a person to have
. These may go unnoticed.
Specific symptoms depend on which part of the brain is involved. Symptoms occur suddenly and may include:
Brief blackout followed by a period of
(the person cannot remember for a short time)
Changes in behavior, such as picking at one's clothing
Drooling or frothing at the mouth
Eye movements
Grunting and snorting
Loss of bladder or bowel control
Mood changes, such as sudden anger, unexplainable fear, panic, joy, or laughter
Shaking of the entire body
Sudden falling
Tasting a bitter or metallic flavor
Teeth clenching
Temporary stop in breathing
Uncontrollable muscle spasms with twitching and jerking limbs
Symptoms may stop after a few seconds or minutes, or continue for up to 15 minutes. They rarely continue longer.
The person may have warning symptoms before the attack, such as:
Fear or anxiety
(feeling as if you are spinning or moving)
Visual symptoms (such as flashing bright lights, spots, or wavy lines before the eyes)
Seizures of all types are caused by abnormal electrical activity in the brain.
Causes of seizures can include:
Abnormal levels of sodium or glucose in the blood
Brain infection, including
and
Brain injury that occurs to a baby during labor or childbirth
Brain problems that occur before birth (congenital brain defects)
(a rare cause)
(particularly in
)
Heat illness (
)
High
(PKU), which can cause seizures in infants
Poisoning
Street drugs, such as angel dust (PCP), cocaine, and amphetamines
Toxin buildup in the body due to liver or
Very high blood pressure (
)
Venomous bites and stings (such as a
)
Withdrawal from
or certain medicines after using it for a long time
Sometimes, no cause can be found. This is called an idiopathic seizures. They are usually seen in children and young adults, but can occur at any age. There may be a family history of epilepsy or seizures.
If seizures continue repeatedly after any underlying problem is treated, the condition is called epilepsy.
Most seizures stop by themselves. But during a seizure, the person can be hurt.
When a seizure occurs, the main goal is to protect the person from injury:
Try to prevent a fall. Lay the person on the ground in a safe area. Clear the area of furniture or other sharp objects.
Cushion the person's head.
Loosen tight clothing, especially around the neck.
Turn the person on their side. If vomiting occurs, this helps make sure that the vomit is not inhaled into the lungs.
Look for a medical ID bracelet with seizure instructions.
Stay with the person until they recover or until professional medical help arrives.
Things friends and family members should not do:
Do not restrain (try to hold down) the person.
Do not place anything between the person's teeth during a seizure (including your fingers).
Do not attempt to hold the person's tongue.
Do not move the person unless they are in danger or near something hazardous.
Do not try to make the person stop convulsing. They have no control over the seizure and are 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.
Do not start CPR unless the seizure has clearly stopped and the person is not breathing or has no pulse.
If a baby or child has a seizure during a high fever, cool the child slowly with lukewarm water. Do not place the child in a cold bath. Call your child's health care provider and ask what you should do next. Also, ask if it is OK to give the child acetaminophen (Tylenol) once they are awake.
Call 911 or the local emergency number if:
This is the first time the person has had a seizure
A seizure lasts more than 2 to 5 minutes
The person does not awaken or have normal behavior after a seizure
Another seizure starts soon after a seizure ends
The person had a seizure in water
The person is pregnant, injured, or has diabetes
The person does not have a medical ID bracelet (instructions explaining what to do)
There is anything different about this seizure compared to the person's usual seizures
Report all seizures to the person's provider. The provider may need to adjust or change the person's medicines.
A person who has had a new or severe seizure is usually seen in a hospital emergency room. The provider will try to diagnose the type of seizure based on the symptoms.
Tests will be done to check for other medical conditions that cause seizures or similar symptoms. This may include fainting,
transient ischemic attack (TIA)
or stroke,
,
, sleep disturbances, and other possible causes.
Tests that may be ordered include:
Blood and urine tests
of the head or
of the head
(usually not in the emergency room)
(spinal tap)
Further testing is needed if a person has:
A new seizure without a clear cause
Epilepsy (to make sure the person is taking the right amount of medicine)
Secondary seizures; Seizure - secondary; Convulsions; Epileptic seizure
Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley's and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 100.
Krumholz A, Wiebe S, Gronseth GS, et al. Evidence-based guideline: management of an unprovoked first seizure in adults: report of the Guideline Development Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology.2015;84(16):1705-1713. PMID: 25901057
pubmed.ncbi.nlm.nih.gov/25901057/
. Updated January 17, 2023.
Maciel CB, Elie-Turrene M-C. Seizure. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 92.
Mikati MA, Tchapyjnikov D, Rathke KM. Seizures in childhood. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 633.
Wiebe S. The epilepsies. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 372.
Updated by: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.