Symptoms of Seizures

  • Warning symptoms (known as an aura) prior to a seizure: sensations of strange odors, sounds, sights, or feelings; feeling of déjà vu; nausea. Each person generally has a consistent aura, although aura sensations vary widely from person to person.
  • Petit mal or absence seizure: loss of awareness and lack of responsiveness; staring; twitching of the arm or head.
  • Grand mal seizure: loss of consciousness; muscle rigidity followed by twitching or jerking; loss of bladder and bowel control. Most grand mal seizures are not preceded by an aura. After the seizure: no memory of the event; confusion; sleepiness; headache.
  • Focal seizure: uncontrollable twitching of one part of the body, such as the hand, which may spread to nearby muscles or the entire body. The patient may remain conscious during a focal seizure.
  • Temporal lobe seizure: loss of awareness; sudden, bizarre behavior, such as laughing or becoming angry for no apparent reason; repetitive lip smacking, chewing motions, or picking at clothes. Temporal lobe seizures may be preceded by an aura lasting a few seconds.
  • Febrile seizure: rapid rise or fall in body temperature; loss of consciousness; muscle convulsions characteristic of a grand mal seizure. A febrile seizure is usually an isolated event that does not recur.

What Is a Seizure?

Seizures are alterations in neurologic function resulting from bursts of abnormal electrical activity in the brain. In normal brain function, electrical charges flow from one neuron to the other along pathways that establish orderly patterns of thought and behavior.

Seizures are initiated by the sudden onset of repetitive, synchronized discharges from many neurons that can cause radical changes in consciousness, sensation, and muscle control. The many different types of seizures can be grouped into two broad categories: generalized and partial (or focal).

In generalized seizures, abnormal electrical activity may occur anywhere in the brain, while in partial seizures, abnormal activity is isolated to one area of the brain. Perhaps the best-known type of generalized seizure is the grand mal seizure: sudden loss of consciousness followed by violent full-body convulsions lasting several minutes. The patient has no memory of the event and is usually confused and drowsy for some time afterward. The petit mal seizure—another type of generalized seizure—is characterized by a blank look, staring, and loss of awareness, but not muscle convulsions. Like the grand mal, there is typically no memory of the event afterward. An untreated person may experience hundreds of petit mal seizures daily, each one lasting only a few seconds. However, these are only two of many different types of seizures.

Partial (or focal) seizures may trigger isolated, localized movements—such as chewing, lip smacking, or swallowing—or merely produce odd sensations, such as transient prickling or numbness. Disorders producing recurrent seizures are known as the epilepsies; seizures may also occur as one-time events, such as those triggered by high fevers in children.

Epilepsy occurs in approximately 1 to 2 percent of the population. Generally, seizures last a few seconds to a few minutes at a time. Prolonged grand mal seizures (status epilepticus), or those that recur in rapid succession, require emergency medical treatment.

Although there is generally no cure, epilepsy can usually be controlled with a variety of anticonvulsant medications. Children with petit mal epilepsy often outgrow it as they reach late adolescence and young adulthood. For other types of seizures, anticonvulsant medication can often be discontinued after a patient has been seizure-free for two to five years. Finally, brain surgery is an option if seizures are severe or resistant to medication. After surgery, seizures may subside completely or almost completely, and mental functioning is often improved.

What Causes Seizures?

  • Sudden, explosive, highly synchronized firing of neurons in the brain—the cause of which is unidentifiable in about half of all cases
  • Brain damage due to prior head trauma, such as an automobile accident, sports injury, or a fall
  • Withdrawal from alcohol, illicit drugs, or anticonvulsant medication
  • Brain tumor or stroke
  • Infection of the brain or its surrounding tissues (see Meningitis and Encephalitis)
  • High fevers, which commonly cause seizures in children under age five (febrile seizure)
  • Congenital brain damage due to illness, injury, or infection during pregnancy that affects the development of the fetal nervous system
  • Chemical imbalances such as low blood sugar, calcium, or sodium levels, or severe vitamin deficiency
  • Conditions that affect the central nervous system, such as cerebral palsy and multiple sclerosis
  • Sleep deprivation or physical stress

Prevention of Seizures

There is no known way to prevent epilepsy, but medications can control seizures in most cases.

Diagnosis of Seizures

  • Patient history and physical examination
  • Electroencephalogram (EEG)—In this procedure, electrodes are attached to the patient’s head to measure electrical activity in the brain. A series of EEGs may be taken over a period of time to obtain a complete picture of brain activity.
  • Skull x-ray; CT (computed tomography), PET (positron-emission tomography), or SPECT (single-photon emission computed tomography) scans of the brain; or MRI (magnetic resonance imaging) may be ordered.
  • Proper diagnosis of the type of seizure is important for selecting the most appropriate drug treatment.

How to Treat Seizures

  • Do not try to restrain someone having a seizure. If the person falls, try to ease the descent to the ground. Move objects out of the way to prevent accidental injury, then stand aside. Do not try to insert your fingers into the mouth of someone having a seizure; contrary to popular belief, people do not swallow their tongues during seizures, and attempting to force their mouth open may cause injury to them or you. After muscle convulsions have ceased, roll the person to one side to prevent choking on fluids or vomit. When the person regains consciousness, offer reassurance. The person may need to sleep for a while after a seizure.
  • Treatment is unnecessary for seizures caused by high fevers in children.
  • Anticonvulsant medications, such as carbamazepine, phenytoin, phenobarbital, valproate, gabapentin, tiagabine, topiramate, lamotrigine, ethosuximide, clonazepam, and primidone, may be prescribed.
  • Brain surgery may be advised in severe cases to remove tumors, scar tissue, or vascular malformations, or to interrupt paths of abnormal electrical activity.

When to Call a Doctor

  • Call a doctor if you or your child suffers a seizure for the first time.
  • Emergency—Call an ambulance if a seizure lasts for more than five minutes, or if the person has another seizure before regaining consciousness.

Publication Review By: the Editorial Staff at

Published: 10 Aug 2010

Last Modified: 15 Dec 2014