Epilepsy (EP-i-lep-see) is a condition of the nervous system characterized by recurrent seizures that affect a person's awareness, movements, or sensations temporarily. Epileptic seizures occur when powerful, rapid bursts of electrical energy interrupt the normal electrical patterns of the brain. Some cases of epilepsy are hereditary (run in families), but scientists do not know the cause of epilepsy in most other cases.
In a normal brain, millions of tiny electrical charges pass between nerve cells and all parts of the body. Usually these cells fire in an orderly and controlled manner, but this is not the case with epilepsy. In the brain of a person with epilepsy, nerve cells in parts of the brain fire simultaneously and repeatedly, sending out powerful, rapid electrical charges that disrupt the brain's normal function. During a seizure such as the one experienced by Erin, brain cells can fire at up to four times their normal rate, temporarily affecting how a person behaves, moves, thinks, or feels.
Many people with epilepsy can sense they are about to have a seizure by something called an aura. An aura is a strange feeling—often of unease, anxiety, or discomfort—that may be accompanied by sensing or seeing flickering lights. Despite these warning signals, people with epilepsy still cannot stop the oncoming seizure.
Anyone can have seizures, but they are usually few and far between. A person with epilepsy, in contrast, has many more seizures and experiences them over a longer period of time. For a person with epilepsy, many conditions that affect the brain can trigger a seizure. These triggers include hormonal changes, such as those that occur during women's menstrual cycle * or pregnancy; hunger, exhaustion, or sleep deprivation; and rhythmic patterns of sound, touch, or light (particularly strobe lights). In many cases, an epileptic seizure is not a medical emergency. However, if a person goes into something called status epilepticus, during which a seizure lasts longer than 30 minutes or two seizures follow one another rapidly, his or her life may be in danger and onlookers should summon medical assistance at once.
Because of the way a person appears during or after a seizure, others sometimes mistakenly believe the person is drunk, drugged, or has a mental health issue. Epileptic seizures have different symptoms or characteristics depending on where the seizure begins in the brain and how the electrical discharge spreads across the brain. Epileptic seizures fall in three categories: generalized, partial, and other.
Generalized seizures affect nerve cells throughout the cerebral cortex * (the cauliflower-like outer portion of the brain) or across the entire brain. The most common generalized seizures are generalized tonic–clonic seizures and absence seizures:
Partial seizures are contained within one region of the cerebral cortex. Types of partial seizures include the following:
There are two other types of mild seizures: febrile seizures and Jacksonian seizures.
Most people with epilepsy lead normal, active lives, although they must follow a few safety restrictions. People with epilepsy must be free of seizures for a period of time specified by their home state before they are permitted to drive. Laws prohibit people with uncontrolled seizures from driving a car.
A person with a seizure disorder should avoid working in jobs that involve heights, dangerous machinery, or underwater environments. To avoid the risk of drowning during a seizure, taking showers is safer than taking baths, and swimming in a pool or lake with other people is safer than swimming alone.
People with epilepsy are also at risk for depression. In part, the depression may stem from loss of mobility or from the effects of prejudice at school or at work. Prejudice results when people fear a condition and do not understand it. Children with epilepsy may become depressed if their parents become overly protective and prevent them from engaging in normal childhood activities. Depression is a particular problem among adolescents, who may refuse to take their medication on schedule and, therefore, may run the risk of additional seizures. In addition, alcohol consumption makes people who have epilepsy more susceptible to seizures, and the combination of alcohol and anticonvulsant medications can be deadly. Understanding the facts about epilepsy and providing a positive environment in which treatment becomes a part of everyday life can help people with epilepsy and their families.
Epilepsy is not uncommon and is most often seen in young children or older adults. According to the Epilepsy Foundation, about 1 in 100 people in the United States has had a single, unprovoked seizure or has been diagnosed with epilepsy. It is not contagious.
Because not every person who has a seizure necessarily has epilepsy, doctors must determine the cause of the seizure by a physical exam and medical history, including descriptions of seizures that have already occurred. Doctors assess risk factors such as sleep deprivation and alcohol use, as well as possible head injuries, childhood seizures, or family history of seizures.
Physicians also want to know whether the patient has experienced an aura, because experiencing an aura helps confirm the seizure is a brain disorder and establishes its location. Doctors also ask about the nature of the movements the person made during a seizure.
If patients have indeed experienced an epileptic seizure, doctors then try to identify the type of seizure. The first tool doctors use is an electroencephalograph (e-lek-tro-en-SEF-a-lo-graf). Commonly known as an EEG, this machine records electrical currents in the brain and tracks normal and abnormal electrical activity. If the EEG does not show seizure activity or if certain other features in the patient's physical exam or medical history are present, then doctors may order other types of imaging tests, including computed tomography and magnetic resonance scanning/imaging.
Treating epilepsy has three goals: (1) eliminate seizures or at least reduce their frequency; (2) avoid side effects of long-term medical treatments; and (3) assist in maintaining or restoring normal activities of daily living.
If drug therapy does not work, a surgical procedure can remove the damaged cells that cause partial seizures. Patients qualify for surgery if the tissue resides in one small area of the brain and the surgeon can remove this tissue without harming a person's intellectual abilities or personality. Surgery performed on adults is sometimes successful, but it usually has better results when performed on children and infants.
Although it was discontinued as a therapy when medicines became available, a ketogenic diet (a doctor-monitored, high-fat, and highcalorie diet) was reinstated in the treatment arsenal for epilepsy, especially for children who do not respond to medicines. It does not, however, work for all patients. Some people believe the diet can stop seizures by creating ketosis (ke-TO-sis), a condition in which the body burns fat for energy instead of glucose. The ketogenic diet is used primarily with children whose epilepsy is not responding to antiepileptic drugs, and research continues into the effect of dietary restrictions on seizures.
Another potential treatment is biofeedback. When combined with other therapies, biofeedback has been beneficial in some patients. The treatment relies on electronic instruments to monitor a person's brain waves, blood pressure, heart rate, and skin temperature. The patient learns techniques to lower these bodily functions to more relaxed levels.
Many cases of epilepsy have no known cause, which makes prevention a challenge. Those cases of epilepsy that result from injuries to the brain, however, can often be prevented through safety precautions and good health practices. These strategies include the following:
See also AIDS and HIV Infection • Brain Injuries • Brain Tumor • Kidney Disease • Lupus • Metabolic Disease • Seizures • Stroke
Devinsky, Orrin, Erin Conway, and Courtney Schnabel Glick. Epilepsy in Children. New York: Demos Health, 2015.
World Health Organization. “Epilepsy.” http://www.who.int/mediacentre/factsheets/fs999/en/ (accessed October 13, 2015).
Epilepsy Foundation. 8301 Professional Pl., Suite 200, Landover, MD 20785. Toll-free: 800-332-1000. Website: http://www.epilepsy.com (accessed October 13, 2015).
Epilepsy Society. Chesham Lane, Chalfont St Peter, Buckinghamshire, SL9 0RJ, UK. Website: http://www.epilepsysociety.org.uk (accessed October 13, 2015).
International League Against Epilepsy. 342 North Main St., West Hartford, CT 06117-2507. Telephone: 860-586-7547. Website: http://www.ilae.org (accessed October 13, 2015).
National Institute of Neurological Disorders and Stroke. PO Box 5801, Bethesda, MD 20824. Website: http://www.ninds.nih.gov (accessed June 3, 2016).
* withdrawal is a series of symptoms that occur when a drug that causes physical or psychological dependence is used regularly for a long time and then is suddenly discontinued or decreased in dosage.
* menstrual cycle (MEN-stroo-al SY-kul) culminates in menstruation (men-stroo-AY-shun), the discharging through the vagina of blood, secretions, and tissue debris from the uterus. The menstrual cycle recurs at approximately monthly intervals in females of reproductive age.
* cerebral cortex (suh-REE-brul KOR-teks) is the part of the brain that controls functions such as conscious thought, listening, and speaking.
* incontinence (in-KON-ti-nens) is loss of control of urination or bowel movement.
* convulsions (kon-VUL-shuns) are sudden bursts of disorganized electrical activity that interrupt the normal functioning of the brain, often leading to uncontrolled movements in the body and sometimes a temporary change in consciousness. Also called seizures.
* neurologist (new-RHAL-eh-jist) is a physician who specializes in diagnosing and treating diseases of the nervous system.
* anticonvulsants (an-tie-kon-VUL-sents) are medications that affect the electrical activity in the brain and are given to prevent or stop seizures.
* remission is an easing of a disease or its symptoms for a prolonged period.