Medical definition of epilepsy

Medical definition of epilepsy DEFAULT

A Revised Definition of Epilepsy

Seizures and epilepsy are not the same. An epileptic seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy is a disease characterized by an enduring predisposition to generate epileptic seizures and by the neurobiological, cognitive, psychological, and social consequences of this condition. Translation: a seizure is an event and epilepsy is the disease involving recurrent unprovoked seizures.

The above definitions were created in a document generated by a task force of the International League Against Epilepsy (ILAE) in The definitions were conceptual, (theoretical) and not sufficiently detailed to indicate in individual cases whether a person did or did not have epilepsy. Therefore, the ILAE commissioned a second task force to develop a practical (operational) definition of epilepsy, designed for use by doctors and patients. The results of several years of deliberations on this issue have now been published (Fisher RS et al. A practical clinical definition of epilepsy, Epilepsia ; ) and adopted as a position of the ILAE.

A commonly used definition of epilepsy heretofore has been two unprovoked seizures more than 24 hours apart. This definition has many positive features, but also a few limitations. This definition does not allow the possibility of "outgrowing" epilepsy. Inclusion of the word "provoked" seems to imply that people who have photosensitive seizures provoked by flashing lights or patterns do not have epilepsy; whereas, most people think that they do. Some individuals who have had only one unprovoked seizure have other risk factors that make it very likely that they will have another seizure. Many clinicians consider and treat such individuals as though they have epilepsy after one seizure. Finally, some people can have what is called an epilepsy syndrome and these individuals should meet the definition for having epilepsy even after just one seizure. You should not have an epilepsy syndrome but not epilepsy. The new definition of epilepsy addresses each of these points.

A person is considered to have epilepsy if they meet any of the following conditions.

  1. At least two unprovoked (or reflex) seizures occurring greater than 24 hours apart.
  2. One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years.
  3. Diagnosis of an epilepsy syndrome
    • Epilepsy is considered to be resolved for individuals who had an age-dependent epilepsy syndrome but are now past the applicable age or those who have remained seizure-free for the last 10 years, with no seizure medicines for the last 5 years.

In the definition, epilepsy is now called a disease, rather than a disorder. This was a decision of the Executive Committees of the ILAE and the International Bureau for Epilepsy. Even though epilepsy is a heterogeneous condition, so is cancer or heart disease, and those are called diseases. The word "disease" better connotes the seriousness of epilepsy to the public.

Item 1 of the revised definition is the same as the old definition of epilepsy. Item 2 allows a condition to be considered epilepsy after one seizure if there is a high risk of having another seizure. Often, the risk will not precisely be known and so the old definition will be employed, i.e., waiting for a second seizure before diagnosing epilepsy. Item 3 refers to epilepsy syndromes such as benign epilepsy with central-temporal spikes, previously known as benign rolandic epilepsy, which is usually outgrown by age 16 and always by age If a person is past the age of the syndrome, then epilepsy is resolved. If a person has been seizure-free for at least 10 years with the most recent 5 years off all anti-seizure medications, then their epilepsy also may be considered resolved. Being resolved does not guarantee that epilepsy will not return, but it means the chances are small and the person has a right to consider that she or he is free from epilepsy. This is a big potential benefit of the new definition.

What will change as the result of this new definition? Although revision of the definition has generated some controversy, it is likely that real-world changes will be fairly minor. Some people will be able to say their epilepsy is resolved. Others may encounter the problems and stigma of being told that they have epilepsy after one seizure in some circumstances, rather than after two seizures. The definition might stimulate research on how likely another seizure is after a first seizure in various clinical circumstances. Governments and regulatory agencies, people who do therapeutic trials for epilepsy, insurance companies and other third-party payers might have to adjust some of their definitions. One reason changes will be small is that individuals with one seizure and a high risk for another are currently practically thought of as having epilepsy by many treating physicians. This process simply formalizes that thinking.

Making a diagnosis of epilepsy is not the same as deciding to treat. Some seizures are minor; some patients choose to avoid the side effects of medications. Treatment decisions will be individualized between a person with epilepsy and a physician. Sometimes, information is incomplete; for example, a possible seizure may not have been observed. In these conditions it can be impossible to confidently diagnose epilepsy using any definition. Clinicians will apply best judgment when faced with such incomplete information and often will wait for future developments.

This practical definition is designed for clinical use. Researchers, statistically-minded epidemiologists and other specialized groups may choose to use the older definition or a definition of their own devising. Doing so is perfectly allowable, so long as it is clear what definition is being used. In the process of developing the revised definition of epilepsy, consensus was reached by forging opinions of 19 co-authors of the publication, while accounting for criticisms by five anonymous journal reviewers and over public commenters on the ILAE website. The revised definition is not perfect. It will become more useful over time as we gain better information on seizure recurrence risks. But for now, the new definition better reflects the way clinicians think about epilepsy.

**If you think that you do not or might not have epilepsy, please do not change any of your treatments and do not stop any medications without first consulting with your doctor.




paroxysmal transient disturbances of nervous system function resulting from abnormal electrical activity of the brain. Epilepsy is not one specific disease, but rather a group of symptoms that are manifestations of any of a number of conditions involving overstimulation of nerve cells of the brain. The estimated incidence is per cent of the population, making this a relatively common disease. Over 70 per cent of patients have their first attack (or seizure) either during childhood or after age The type of seizure varies with age of onset.

Types. There are several methods for classifying types of epilepsy. On the basis of origin, it may be either idiopathic (cryptogenic, essential, genetic) or symptomatic (acquired, organic). Symptomatic epilepsy has a physical cause, such as a brain tumor, injury to the brain at birth, a wound or blow to the head, or an endocrine disorder.&#;

One classification of epileptic seizures, called the Clinical and Electroencephalographical Classification of Epileptics of the International League Against Epilepsy, identifies four main types: (1) partial seizures, including those that begin locally, which are subdivided into (A) partial seizures with elementary symptomatology, (B) partial seizures with complex symptomatology (those with impairment of consciousness only, psychomotor symptomatology, and psychosensory symptomatology), and (C) partial seizures that are secondarily generalized; (2) generalized seizures that are bilaterally symmetrical and without local onset; (3) unilateral seizures (those involving only one hemisphere); and (4) other unclassified epileptic seizures.

Types According to Symptoms. The manifestations of epilepsy depend on the area of the brain where the abnormal discharge occurs. Simple partial seizures, called also focal seizures, result from a localized cortical discharge. The symptoms may be either motor, sensory, autonomic, or any combination of the three. Complex partial seizures, as in psychomotor (temporal lobe) epilepsy, usually, but not always, originate in the temporal lobe of the brain, often with a preceding aura. As the name implies, there are many different cognitive, affective, and psychomotor symptoms. There is either loss or alteration of consciousness when the seizure begins, and afterwards the patient may feel drowsy or confused.&#;

An attack of petit mal (absence) epilepsy lasts only a few seconds and has sudden onset with no aura or warning and no postictal symptoms. Seizures of this type usually affect children between the ages of 5 and 12 years and may disappear during puberty, but they can continue throughout life. There typically is a twitching about the eyes or mouth, the patient remains sitting or standing, and appears to have had no more than a lapse of attention or a moment of absent-mindedness.

An attack of grand mal (tonic-clonic) epilepsy usually begins with bilateral jerks of the extremities or focal seizure activity. There is loss of consciousness and both tonic and clonic type convulsions. The patient may be incontinent during the attack and there is danger of tongue biting. In the postictal phase the patient is confused and drowsy.

Atonic or akinetic seizures are characterized by loss of body tone that can produce nodding of the head, weakness of the knees, or total collapse and falling. The patient usually remains conscious during the attack.

Diagnosis. A complete assessment of the patient's status is necessary, including a medical history, physical and neurological examination, and laboratory studies of the blood and spinal fluid. The latter are especially useful in determining whether an infection is the cause of the seizures. A CT scan may demonstrate a causative lesion. The diagnosis is confirmed by an electroencephalogram, which is helpful in locating the site and possibly the cause of the seizures.

Treatment. Medical management with anticonvulsant drugs is the preferred therapy for about 95 per cent of patients with epilepsy. Surgical intervention for the remaining 5 per cent involves removal of the portion of brain tissue believed to be responsible for the seizures. Because of the dangers inherent in the surgery, this mode of therapy is reserved for those patients who do not respond to medical management and in whom the focus of seizure activity is accessible.

The major antiepileptic drugs are phenytoin (Dilantin), which is usually the drug of choice, phenobarbital, primidone (Mysoline), carbamazepine (Tegretol) for complex partial tonic-clonic seizures, and ethosuximide (Zarontin) and clonazepam (Klonopin) for absence seizures. Valproic acid (Depakene) is also used in the treatment of absence seizures. The choice of drug and calculation of optimal dosage is very difficult and highly individualized.

All of the anticonvulsant drugs can produce unpleasant side effects. They include gingival hyperplasia, rash, and, in the case of Dilantin, fever and leukopenia. Physical dependence can become a problem in patients taking phenobarbital or primidone, which is largely converted to phenobarbital in the blood stream. Toxic side effects are also common and include drowsiness, ataxia, nausea, sedation, and dizziness. The untoward effects of anticonvulsant drug therapy require close monitoring of the patient's response to therapy and regulation of dosage as indicated.

Patient Care. Emergency care of the patient having a seizure includes clearing the immediate area to protect the patient and others, administering per cent oxygen by face mask, and intravenous administration of antiepileptic medication. No one should force an object into the patient's mouth to hold it open (such as a comb, bite block, or wallet), as such objects might obstruct the airway. Do not attempt to restrain the patient, as that may cause harm to both the rescuer and the patient.&#;

Until a diagnosis of epilepsy is confirmed, observations made before, during, and after each of the seizures can provide important information to the diagnostician. Such data also can help prepare an effective plan of care for managing the seizures once a definitive diagnosis is made.

Just before a seizure (the preictal stage) the patient may experience an abnormal somatic, visceral, or psychic sensation called an aura. The presence or absence of the aura and its nature (if it is present) should be noted and recorded. If a patient does experience a particular kind of aura just before each seizure, this information can be useful when planning care for prevention of injury. It also is helpful to note what the patient was doing just before the seizure began. If a particular emotional event or environmental or physiologic condition is found to trigger the seizures, the patient might be able to use this information to avoid or minimize the recurrence of seizures.

During the interictal stage (while the seizure is occurring) significant data include the time the seizure begins and its duration; where in the body the seizure begins and what parts of the body are involved; whether the head or eyes turn to one side and, if so, to which side; whether there is incontinence of urine or stool, bleeding, or foaming or frothing at the mouth; effects of the seizure on the vital signs; and changes in skin color or profuse perspiration.

During the postictal period the patient is assessed for lethargy, confusion, impaired speech, and reports of headache or muscle soreness.

The successful long-term management of epilepsy requires coordinated effort on the part of the patient, family, and health care professionals. Patient and family education and support are essential components of any plan of care. Epileptic patients must take their prescribed medications on their own and actively participate in the management of their illness. They and those upon whom they are dependent (as in the case of children) must know the nature of the illness, the purpose and expected effects of treatment, the side effects of the drug they are taking and its potential for interaction with other drugs that could inhibit or enhance its anticonvulsant action, and the signs and symptoms of drug intolerance that should be reported to the physician or nurse.

Education should also include information about possible seizure triggers and ways in which they might be avoided. Alcohol is especially dangerous for epileptic persons because most antiepileptic drugs are sedatives and cardiopulmonary depressants. The combination of drug and alcohol could cause loss of consciousness or even death. Moreover, alcohol acts as a seizure trigger in some persons.

It is important that patients with epilepsy wear some form of medical identification. In spite of efforts to educate the general public about the nature of epilepsy and its effects on those who have it, there remains some social stigma attached to epilepsy. Therefore, many patients do not want their friends, classmates, or employers to know they have the disease. Efforts must be made to improve the self-esteem of these people. Local chapters of the Epilepsy Association of America offer programs and opportunities for social interaction and group support to help persons with epilepsy and their families deal with the psychosocial effects of the disease. Information and guidance to a local chapter can be obtained by contacting the Epilepsy Association of America, W. 55th St., New York, NY

The Epilepsy Foundation of America, Garden City Dr., Suite , Landover, MD , supplies information on all aspects of epilepsy and can refer patients and their families to specialists and clinics in their locality.

One of the major challenges to persons working in the health field and concerned with the care of patients with epilepsy is the dispelling of myths and superstitions about the disease and the propagation of accurate information. Most persons with epilepsy can lead normal lives with few restrictions, but many are subjected to unfair employment practices and social stigma because of prejudices resulting from the general public's ignorance of the effects of epilepsy.

absence epilepsypetit mal epilepsy.

audiogenic epilepsyreflex epilepsy brought on by sound.

grand mal epilepsy a form attended by loss of consciousness and convulsive movements, as distinguished from petit mal epilepsy. See epilepsy.

jacksonian epilepsy a form of epilepsy characterized by unilateral clonic movements that start in one group of muscles and spread systematically to adjacent groups, reflecting the march of the epileptic activity through the motor cortex.

myoclonus epilepsy any form of epilepsy accompanied by myoclonus; one type is Lafora's disease.

petit mal epilepsy a relatively mild type of epilepsy in which the person loses consciousness only momentarily, in contrast to grand mal epilepsy; called also absence epilepsy. See epilepsy.

photogenic epilepsyreflex epilepsy brought on by flickering light.

psychomotor epilepsytemporal lobe epilepsy.

reflex epilepsy epileptic seizures occurring in response to sensory stimuli (tactile, visual, auditory, or musical).

temporal lobe epilepsy a type manifested by impaired consciousness of variable degree, with the patient carrying out bizarre but coordinated movements; called also psychomotor epilepsy. See epilepsy.

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © by Saunders, an imprint of Elsevier, Inc. All rights reserved.



A chronic disorder characterized by paroxysmal brain dysfunction due to excessive neuronal discharge, and usually associated with some alteration of consciousness. The clinical manifestations of the attack may vary from complex abnormalities of behavior including generalized or focal convulsions to momentary spells of impaired consciousness. These clinical states have been subjected to a variety of classifications, none has been universally accepted to date and, accordingly, the terminologies used to describe the different types of attacks remain purely descriptive and nonstandardized; they are variously based on: the clinical manifestations of the seizure (motor, sensory, reflex, psychic or vegetative); the pathologic substrate (hereditary, inflammatory, degenerative, neoplastic, traumatic, or cryptogenic); the location of the epileptogenic lesion (rolandic, temporal, diencephalic regions); and the time of day at which the attacks occur (nocturnal, diurnal, menstrual).

Synonym(s): convulsive state, epilepsia, falling sickness

[G. epil&#x;psia, seizure]

Farlex Partner Medical Dictionary © Farlex



Any of various neurological disorders marked by sudden recurring attacks of motor, sensory, or cognitive dysfunction, with or without convulsive seizures or loss of consciousness. Also called seizure disorder.

The American Heritage® Medical Dictionary Copyright © , by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Neurology Any syndrome characterized by paroxysmal, usually transient, defects in cerebral function which are manifest as episodic impairment of neurologic activity, loss of consciousness, abnormal motor activity, sensory defects and alterations in the autonomic nervous system Imaging MRI, PET, SPECT. See Absence, Automatic epilepsy, Focal epilepsy, Gelastic epilepsy, Juvenile myoclonic epilepsy, Progressive myoclonus epilepsy, Seizure disorder.

McGraw-Hill Concise Dictionary of Modern Medicine. © by The McGraw-Hill Companies, Inc.



A chronic disorder characterized by paroxysmal brain dysfunction due to excessive neuronal discharge, and usually associated with some alteration of consciousness. The clinical manifestations of the attack may vary from complex abnormalities of behavior including generalized or focal convulsions to momentary spells of impaired consciousness. These clinical states have been subjected to a variety of classifications, none universally accepted to date and, accordingly, the terminologies used to describe the different types of attacks remain purely descriptive and nonstandardized; they are variously based on the clinical manifestations of the seizure (motor, sensory, reflex, psychic, or vegetative); the pathologic substrate (hereditary, inflammatory, degenerative, neoplastic, traumatic, or cryptogenic); the location of the epileptogenic lesion (rolandic, temporal, diencephalic regions); and the time period during which the attacks occur (nocturnal, diurnal, menstrual).
Synonym(s): seizure disorder.

[G. epil&#x;psia, seizure]

Medical Dictionary for the Health Professions and Nursing © Farlex


A physical indication of an abnormal electrical discharge in the brain. Epilepsy takes various forms. These include generalized epilepsy, or ‘grand mal’ which is a major fit affecting all the muscles of the body with a massive contraction (tonic stage) followed by a succession of jerky contractions (clonic stage); partial seizures, which may affect only a few muscles (simple partial seizures) or may also involve almost any of the functions of the brain and cause elaborate hallucinations (complex partial seizures); and absence attack, or ‘petit mal’ in which the affected person, usually a child, is momentarily inaccessible but does not fall or appear to lose consciousness.

Collins Dictionary of Medicine © Robert M. Youngson ,


a nervous condition due to abnormalities in the brain cortex that results in seizures ranging from a sense of numbness in certain body areas (petit mal) to extreme muscular convulsions and fits (grand mal). Epileptics exhibit large, abnormal brain waves, which can be detected on an EEG.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham


A neurological disorder characterized by recurrent seizures with or without a loss of consciousness.

Mentioned in: Antianxiety Drugs, Anticonvulsant Drugs, Benzodiazepines, Biofeedback, Electroencephalography

Gale Encyclopedia of Medicine. Copyright The Gale Group, Inc. All rights reserved.



A chronic disorder characterized by paroxysmal brain dysfunction due to excessive neuronal discharge, and usually associated with some alteration of consciousness. The clinical manifestations of the attack may vary from complex abnormalities of behavior including generalized or focal convulsions to momentary spells of impaired consciousness.

[G. epil&#x;psia, seizure]

Medical Dictionary for the Dental Professions © Farlex

Patient discussion about epilepsy

Q. what are the chances for a one time epileptic seizure? I had an epileptic seizure a few years ago and after all the tests it appeared to be a one time seizure. I know having one indicates my tendency for this kind of seizures so should I be afraid now to do things that might bring it up again- like alcohol, drugs, being exposed to flashing lights or having lack of sleep? what are the chances of it to come back after 5 years? any help will be very appreciatedthanks!

A. After 5 years with no recurrence of seizures after a one time episode, tha chances of having another one are low, almost exact to the general population. I would not advise you to start heavily drinking alcohol and doing drugs, because these things can certainly have an effect, however you need not be afraid.

Q. if some one gets a one time epileptic seizure- he have to take medication all his life? how do they decide if it's a one timer or it's going to continue from this day forth?

A. I had a one time epileptic seizure 5 years ago (due to lack of sleep- probably) and didn't have to take any medication though I did have some tests made like EEG and CT every half a year for some time. Like everything else in life- you can't decide it's not a one time till you get the second- which I hope you wont of course

Q. will my son get over his epilepsy he has had seizers since he was 6 months old he is know 3 and a half

More discussions about epilepsy

This content is provided by iMedix and is subject to iMedix Terms. The Questions and Answers are not endorsed or recommended and are made available by patients, not doctors.

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What to know about epilepsy

People with epilepsy usually experience recurrent seizures. These seizures occur due to a disruption of electrical activity in the brain, which temporarily disturbs the messaging systems between brain cells.

This article explains the many types of epilepsy, including their symptoms, treatment options, and prognoses.


The Centers for Disease Control and Prevention (CDC) as “a common brain condition that causes repeated seizures.”


The main symptom of epilepsy is recurrent seizures. However, if a person experiences one or more of the following symptoms, they should seek medical attention, as it may indicate epilepsy:

  • a convulsion with no fever
  • short blackouts or confused memory
  • intermittent fainting spells, during which they lose bowel or bladder control, frequently followed by extreme tiredness
  • temporary unresponsiveness to instructions or questions
  • sudden stiffness for no apparent reason
  • sudden falling for no apparent reason
  • sudden bouts of blinking without apparent stimuli
  • sudden bouts of chewing without any clear reason
  • temporarily seeming dazed and unable to communicate
  • repetitive movements that seem involuntary
  • fearfulness for no apparent reason
  • panic or anger
  • peculiar changes in senses, such as smell, touch, and sound
  • jerking arms, legs, or body, which will appear as a cluster of rapid jerking movements in babies

It is vital to seek consultation with a doctor if any of these symptoms occur repeatedly.

The following conditions may cause similar symptoms to those above, so some people can mistake them for those of epilepsy:

  • high fever with epilepsy-like symptoms
  • fainting
  • narcolepsy, or recurring episodes of sleep during the day
  • cataplexy, or periods of extreme muscle weakness
  • sleep disorders
  • nightmares
  • panic attacks
  • fugue state, a rare psychiatric condition in which a person forgets details about their identity
  • psychogenic seizures, or seizures with a psychological or psychiatric cause


There is currently no cure for most types of epilepsy.

A doctor may prescribe antiepileptic drugs (AEDs) to help prevent seizures. If these drugs do not work, some other potential options include surgery, vagus nerve stimulation, or a special diet.

Doctors’ objective is to prevent further seizures. They also aim to prevent side effects so that the person can lead an active and productive life.


AEDs appear to help control seizures in around 60–70% of cases, according to the American Epilepsy Society. The type of seizure a person has will decide which specific drug the doctor will prescribe.

People take the majority of AEDs by mouth. for treating epilepsy include:

  • valproic acid
  • carbamazepine
  • lamotrigine
  • levetiracetam

It is important to note that some drugs may prevent seizures in one person but not in another. Also, even when a person finds the right drug, it may take some time to find the ideal dosage.


If at least two medications have been ineffective in controlling seizures, a doctor may consider recommending epilepsy surgery. A study from Sweden found that 62% of adults and 50% of children with epilepsy had no seizures for around 7 years after epilepsy surgery.

According to the National Institute of Neurological Disorders and Stroke, some include:

  • Lobectomy: During this procedure, a surgeon will remove the section of the brain in which seizures start. This is the oldest type of epilepsy surgery.
  • Multiple subpial transection: During this procedure, a surgeon will make several cuts to limit seizures to one part of the brain.
  • Corpus callosotomy: A surgeon will cut the neural connections between the two halves of the brain. This prevents seizures from spreading from one side of the brain to the other.
  • Hemispherectomy: In extreme cases, a surgeon may need to cut out a hemisphere, which is one half of the cerebral cortex of the brain.

For some people, undergoing surgery may reduce the frequency and severity of their seizures. However, it is often important to continue taking antiseizure medication for several years following the procedure.

Another surgical option is the implantation of a device in the chest to stimulate the vagus nerve in the lower neck. The device sends preprogrammed electrical stimulation to the brain to help reduce seizures.


Diet may play a role in reducing seizures. A review of research that appeared in the journal Neurology suggested that high fat, low carbohydrate diets could benefit children and adults with epilepsy.

Five of the studies in the review used the ketogenic diet, while another five used a modified Atkins diet. Typical foods in these diets include eggs, bacon, avocados, cheese, nuts, fish, and certain fruits and vegetables.

The review found that 32% of study participants adhering to the ketogenic diet and 29% of those following the modified Atkins diet experienced at least a 50% drop in the regularity of seizures. However, many participants had difficulty maintaining these diets.

Specific diets may be beneficial in some cases, but more research is needed to confirm this.

Learn more about the study and the effect of diet on epilepsy here.


Messaging systems in the brain control every function in the human body. Epilepsy develops due to a disruption in this system, which may result from brain dysfunction.

In many cases, healthcare professionals will not know the exact cause. Some people inherit genetic factors that make epilepsy more likely to occur. Other factors that may increase the risk include:

  • head trauma, such as from a vehicle accident
  • brain conditions, including stroke and tumors
  • infectious diseases, such as viral encephalitis
  • cysticercosis
  • AIDS
  • prenatal injury or brain damage that occurs before birth
  • developmental conditions, including autism and neurofibromatosis

According to the CDC, epilepsy is to develop in children under 2 years and adults over 65 years.

Is epilepsy common?

In , the CDC stated that epilepsy affected around of the United States population. That amounts to approximately million people, including 3 million adults and , children.

The World Health Organization (WHO) estimate that epilepsy affects approximately worldwide.


Doctors can sometimes identify the cause of a person’s seizures. There are two main types of seizure based on whether or not they can determine the cause:

  • Idiopathic, or cryptogenic: There is no apparent cause, or the doctor cannot pinpoint one.
  • Symptomatic: The doctor knows what the cause is.

There are also three seizure descriptors — partial, generalized, and secondary generalized — depending on which area of the brain the seizure originates in.

A person’s experience during a seizure will depend on the affected brain area and how widely and quickly the electrical activity in the brain spreads from that initial area.

The sections below discuss partial, generalized, and secondary generalized seizures in more detail.

Partial seizure

A partial seizure occurs when the epileptic activity takes place in one part of a person’s brain. There are two subtypes of partial seizure:

  • Simple partial seizure: During this type of seizure, the person is conscious. In most cases, they are also aware of their surroundings, even when the seizure is in progress.
  • Complex partial seizure: During this type, the seizure impairs a person’s consciousness. They will generally not remember the seizure. If they do, their memory of it will be vague.

Generalized seizure

A generalized seizure occurs when the epileptic activity affects both halves of the brain. The person will usually lose consciousness while the seizure is in progress.

There are several subtypes of generalized seizure, including:

Tonic-clonic seizures: Perhaps the best-known type of generalized seizure, tonic-clonic seizures cause loss of consciousness, body stiffness, and shaking. Doctors previously called these grand mal seizures.

  • Absence seizures: Previously known as petit mal seizures, these involve short lapses of consciousness wherein the individual appears to be staring off into space. Absence seizures often respond well to treatment.
  • Tonic seizures: In tonic seizures, the muscles become stiff, and the person may fall.
  • Atonic seizures: A loss of muscle tone causes the individual to drop suddenly.
  • Clonic seizures: This subtype causes rhythmic, jerking movements, often in the face or one arm or leg.
  • Myoclonic seizures: This subtype causes the upper body or legs to suddenly jerk or twitch.

Secondary generalized seizure

A secondary generalized seizure occurs when the epileptic activity starts as a partial seizure but spreads to both halves of the brain. As this seizure progresses, the person will lose consciousness.


A doctor will review an individual’s medical history and the symptoms they have experienced, including a description and timeline of past seizures, to diagnose epilepsy.

They may also request tests to determine the type of epilepsy and the type of seizures the person has. Based on these results, the doctor will be able to recommend treatment options, such as antiseizure medications.

Testing for epilepsy

Several types of imaging test can help a doctor diagnose epilepsy. These tests include:

  • an EEG, to look for abnormal brain waves
  • CT and MRI scans, to detect tumors or other structural irregularities
  • functional MRI scans, which can identify normal and abnormal brain function in specific areas
  • single-photon emission CT scans, which may be able to find the original site of a seizure in the brain
  • a magnetoencephalogram, which can identify irregularities in brain function using magnetic signals

The doctor may also use blood tests to identify any underlying conditions that could be causing the epilepsy. Neurological tests may also help a doctor determine the type of epilepsy the person has.

Is epilepsy genetic?

According to one , around 70–80% of epilepsy cases occur as a result of genetics.

A review of research linked over genes to epilepsy. This number continues to grow as more studies take place.

Genes may link to epilepsy directly, to brain anomalies that can lead to epilepsy, or to other genetic conditions that can cause seizures.

Some people inherit genetic factors. However, certain genetic mutations may also cause epilepsy in people without a family history of the condition.

A doctor may sometimes request genetic testing to determine the cause of epilepsy.


A variety of factors can lead to seizures. One study identified stress, sleep deprivation, and fatigue as the most frequent triggers among participants. Flickering lights and high levels of alcohol consumption can also cause seizures.

Stress is a common cause of seizures, but the reason is unclear. in the journal Science Signaling focused on this trigger. The team found that the brain’s stress response worked differently in rats with epilepsy than in those without.

The study also found that the molecule that typically suppresses brain activity in response to stress enhanced activity instead. This may contribute to seizures.

Read our coverage of this study here.

Epilepsy vs. seizures

Seizures are the main symptom of epilepsy. In fact, Johns Hopkins Medicine define epilepsy as having “two or more unprovoked seizures.”

Some people may have a single seizure, or they may experience seizures that are not due to epilepsy.

It is even possible for doctors to misdiagnose nonepileptic seizures as epilepsy. However, nonepileptic seizures do not stem from abnormal electrical activity in the brain. The causes of these can be physical, emotional, or psychological.

There are also different types of seizure, which may vary among people with epilepsy. In two people with epilepsy, for example, the condition may look different.

For this reason, the CDC describe epilepsy as .

Is it a disability?

The Americans with Disabilities Act (ADA) prohibits discrimination against people with disabilities, including epilepsy. This applies whether or not the person is able to manage their seizures with medication or surgery.

People with epilepsy have certain employment-related protections under the ADA, including the following:

  • Employers may not ask about job applicants’ medical conditions, including epilepsy.
  • Job applicants do not need to inform an employer that they have epilepsy unless they need reasonable accommodation during the application period.
  • Employers may not cancel a job offer if the person can complete the primary functions of the job.

According to the Social Security Administration, people with epilepsy may be eligible for disability benefits. This requires that people document their seizure type and frequency while taking all the prescribed medications.

Warning devices

Some devices can monitor seizures and alert caregivers, potentially benefiting treatment and helping prevent sudden unexpected death in epilepsy (SUDEP).

A small study involving 28 participants, the results of which appeared in the journal Neurology, compared one such multimodality device, the Nightwatch, to an Emfit bed sensor. The Nightwatch detected 85% of all severe seizures, compared with 21% for the bed sensor. It also only missed one serious attack every 25 nights.

Nearly of SUDEP cases occur during sleep, according to one study. This indicates that there may be potential benefits of using accurate nighttime warning systems.

Read our coverage of this study here.

Is it contagious?

Anyone can develop epilepsy, but it is not contagious. A of research highlighted some misconceptions and stigma about epilepsy, including the false belief that epilepsy can transmit between people.

The study authors note that people with lower education levels and socioeconomic status had a high rate of misconceptions, as did those who did not know any people with epilepsy.

As a result, interventions and other educational efforts may be useful to reduce stigma around epilepsy and increase understanding of the condition.


Epilepsy can impair a person’s life in multiple ways, and the outlook will depend on various factors.

Seizures can sometimes be fatal, depending on the circumstances. However, many people with epilepsy can manage their seizures using antiseizure medications.

More research is necessary to confirm the alleged relationship between seizures and brain damage.

Is epilepsy fatal?

Seizures can lead to drowning, falling, vehicle accidents, or other injuries that could be fatal. Although it is rare, SUDEP can also occur.

Cases of SUDEP typically occur during a seizure or immediately after it. For example, the seizure may cause the person to go too long without breathing, or it could result in heart failure.

The exact cause of SUDEP is unclear, but suggested that acid reflux could explain it.

After blocking acid from reaching the esophagus, SUDEP did not occur in the rats the researchers tested. It is not clear whether this has any relevance to humans, however.

Read more about the study and its implications here.

According to the CDC, people are at more risk of SUDEP if they have had epilepsy for many years, or if they have regular seizures. Following can help reduce the risk of SUDEP:

  • taking all doses of antiseizure medication
  • limiting alcohol intake
  • getting sufficient sleep

Regularly taking prescribed medication may also help prevent status epilepticus, a condition wherein seizures last for longer than 5 minutes.

A study found that treating status epilepticus within 30 minutes reduced the risk of death.

Will seizures continue?

A of research in the journal Brain indicated that 65–85% of people may experience long-term remission of seizures.

Seizures with an identifiable cause, however, are more likely to continue.

Other factors affecting the chances of remission include:

  • access to treatment
  • response to treatment
  • other health conditions a person may have

With the correct use of antiseizure medications, the majority of people with epilepsy may be able to control their seizures.

Can epilepsy lead to brain damage?

Research into whether or not seizures can cause brain damage has shown mixed outcomes.

A examined postsurgical brain tissue from people with recurrent seizures. The researchers found no brain damage markers in people with certain types of epilepsy.

However, several other studies have suggested that severe, long lasting seizures could lead to brain injury. For example, one study found that seizures could result in brain abnormalities, with status epilepticus causing irreversible brain lesions.

Other studies have looked at cognitive changes in children as they get older, either with or without epilepsy. Results that epilepsy is associated with worse cognitive outcomes.

However, it is unclear whether:

  • epilepsy causes the impairment
  • a similar structural change causes both epilepsy and the impairment
  • antiepileptic drugs have an effect

This is an area that needs further research.

Other effects

Epilepsy can affect various aspects of a person’s life, including their:

  • emotions and behavior
  • social development and interaction
  • ability to study and work

The scale of impact on these areas of life will depend largely on the frequency and severity of their seizures.

Life expectancy of people with epilepsy

In , researchers from the University of Oxford and University College London, both in the United Kingdom, reported that people with epilepsy are more likely to experience premature death than people without it..

The risk appears to be greater if the person also has a mental health condition. Suicide, accidents, and assaults accounted for % of early deaths. Most people affected by these had also received a diagnosis of a mental health condition.

Lead researcher Seena Fazel says, “Our results have significant public health implications, as around 70 million people worldwide have epilepsy, and they emphasize that carefully assessing and treating psychiatric disorders as part of standard checks in [people] with epilepsy could help reduce the risk of premature death in these patients.”

“Our study,” he adds, “also highlights the importance of suicide and nonvehicle accidents as major preventable causes of death in people with epilepsy.”

Risk factors

Several factors may have links to an increased risk of epilepsy. According to a research review in the journal NeuroToxicology, these factors include:

  • age, with new cases occurring more frequently in young children and older adults
  • brain injuries and tumors
  • genetics and family history
  • alcohol consumption
  • perinatal factors, such as stroke and preterm birth
  • central nervous system infections, such as bacterial meningitis, viral encephalitis, and neurocysticercosis

Some risk factors, such as alcohol consumption, are modifiable when trying to prevent the development of epilepsy.

Is it curable?

There is currently no cure for epilepsy, but people with the condition can usually manage their symptoms.

According to the WHO, up to of people with epilepsy can experience a reduction in their seizure frequency and severity with antiseizure medications. Around half of all people with epilepsy may be able to stop taking medications after 2 years without a seizure.

In some cases, surgery can also reduce or eliminate seizures when drugs are ineffective.

This can have long-term benefits. In one , 47% of the participants reported no debilitating seizures 5 years after surgery, and 38% reported the same after 10 years.


The WHO explain that of epilepsy cases are preventable. People can reduce the risk of developing epilepsy by following these steps:

  • wearing a helmet when riding a bicycle or motorcycle, to help prevent head injuries
  • seeking perinatal care, to prevent epilepsy from birth injuries
  • managing risk factors for stroke and heart disease, which could cause brain damage that results in epilepsy
  • practicing good hygiene and preventative methods to avoid cysticercosis, an infection that is of epilepsy around the world, according to the CDC.

A review of research in the journal Seizure also suggested that regular physical activity may help prevent the development of epilepsy and reduce how often seizures occur.

It is not possible to prevent all cases of epilepsy. However, taking the above steps may help reduce the risk.


Depending on the situation, seizures may lead to negative outcomes such as drowning or vehicle accidents. Long lasting seizures, or status epilepticus, may also cause brain damage or death.

People with epilepsy are eight times more likely than people without it to experience certain other chronic conditions, including dementia, migraine, heart disease, and depression. Some of these conditions could also make seizures worse.

Other complications may occur due to the side effects of antiseizure medications. For example, one study found that % of people taking the antiseizure drug lamotrigine (Lamictal) developed a skin rash.

Rash can also occur with other AEDs, including phenytoin (Dilantin) and phenobarbital. The rash usually disappears once the person stops taking the medication. However, %–% of adults developed a serious rash that could be fatal.

What is Epilepsy - Towards a definition


Epilepsy is a brain disorder in which a person has repeated seizures over time. Seizures are episodes of uncontrolled and abnormal firing of brain cells that may cause changes in attention or behavior.

Epilepsy occurs when changes in the brain cause it to be too excitable or irritable. As a result, the brain sends out abnormal signals. This leads to repeated, unpredictable seizures. (A single seizure that does not happen again is not epilepsy.)

Brain structures

Epilepsy may be due to a medical condition or injury that affects the brain. Or, the cause may be unknown (idiopathic).

Common causes of epilepsy include:

  • Stroke or transient ischemic attack (TIA)
  • Dementia, such as Alzheimer disease
  • Traumatic brain injury
  • Infections, including brain abscess, meningitis, encephalitis, and HIV/AIDS
  • Brain problems that are present at birth (congenital brain defect)
  • Brain injury that occurs during or near birth
  • Metabolism disorders present at birth (such as phenylketonuria)
  • Brain tumor
  • Abnormal blood vessels in the brain
  • Other illness that damages or destroys brain tissue
  • Seizure disorders that run in families (hereditary epilepsy)

Epileptic seizures usually begin between ages 5 and There is also a higher chance of seizures in adults older than But epileptic seizures can happen at any age. There may be a family history of seizures or epilepsy.

Symptoms vary from person to person. Some people may have simple staring spells. Others have violent shaking and loss of alertness. The type of seizure depends on the part of the brain that is affected.

Most of the time, the seizure is similar to the one before it. Some people with epilepsy have a strange sensation before each seizure. Sensations may be tingling, smelling an odor that is not actually there, or emotional changes. This is called an aura.

Your doctor can tell you more about the specific type of seizure you may have:

The doctor will perform a physical exam. This will include a detailed look at the brain and nervous system.

An EEG (electroencephalogram) will be done to check the electrical activity in the brain. People with epilepsy often have abnormal electrical activity seen on this test. In some cases, the test shows the area in the brain where the seizures start. The brain may appear normal after a seizure or between seizures.

To diagnose epilepsy or plan for epilepsy surgery, you may need to:

  • Wear an EEG recorder for days or weeks as you go about your everyday life.
  • Stay in a special hospital where brain activity can be recorded while video cameras capture what happens to you during the seizure. This is called video EEG.

Tests that may be done include:

Head CT or MRI scan is often done to find the cause and location of the problem in the brain.

Treatment for epilepsy includes taking medicines, lifestyle changes, and sometimes surgery.

If epilepsy is due to a tumor, abnormal blood vessels, or bleeding in the brain, surgery to treat these disorders may make the seizures stop.

Medicines to prevent seizures, called anticonvulsants (or antiepileptic drugs), may reduce the number of future seizures:

  • These drugs are taken by mouth. Which type you are prescribed depends on the type of seizures you have.
  • Your dosage may need to be changed from time to time. You may need regular blood tests to check for side effects.
  • Always take your medicine on time and as directed. Missing a dose can cause you to have a seizure. DO NOT stop taking or change medicines on your own. Talk to your doctor first.
  • Many epilepsy medicines cause birth defects. Women who plan to become pregnant should tell their doctor in advance in order to adjust medicines.

Many epilepsy drugs may affect the health of your bones. Talk to your doctor about whether you need vitamins and other supplements.

Epilepsy that does not get better after 2 or 3 anti-seizure drugs have been tried is called "medically refractory epilepsy." In this case, the doctor may recommend surgery to:

  • Remove the abnormal brain cells causing the seizures.
  • Place a vagal nerve stimulator (VNS). This device is similar to a heart pacemaker. It can help reduce the number of seizures.
Role of the vagus nerve in epilepsy

Some children are placed on a special diet to help prevent seizures. The most popular one is the ketogenic diet. A diet low in carbohydrates, such as the Atkins diet, may also be helpful in some adults. Be sure to discuss these options with your doctor before trying them.

Lifestyle or medical changes can increase the risk for a seizure in adults and children with epilepsy. Talk with your doctor about:

  • New prescribed drugs, vitamins, or supplements
  • Emotional stress
  • Illness, especially infection
  • Lack of sleep
  • Pregnancy
  • Skipping doses of epilepsy medicines
  • Use of alcohol or other recreational drugs
  • Exposure to flickering lights or stimuli
  • Hyperventilation 

Other considerations:

  • People with epilepsy should wear medical alert jewelry so that prompt treatment can be obtained if a seizure occurs.
  • People with poorly controlled epilepsy should not drive. Check your state's law about which people with a history of seizures are allowed to drive.
  • DO NOT use machinery or do activities that can cause loss of awareness, such as climbing to high places, biking, and swimming alone.

The stress of having epilepsy or being a caretaker of someone with epilepsy can often be helped by joining a support group. In these groups, members share common experiences and problems.

Some people with epilepsy may be able to reduce or even stop their anti-seizure medicines after having no seizures for several years. Certain types of childhood epilepsy go away or improve with age, usually in the late teens or 20s.

For many people, epilepsy is a lifelong condition. In these cases, anti-seizure drugs need to be continued. There is a very low risk for sudden death with epilepsy.

Complications may include:

  • Difficulty learning
  • Breathing in food or saliva into the lungs during a seizure, which can cause aspiration pneumonia
  • Injury from falls, bumps, self-inflicted bites, driving or operating machinery during a seizure
  • Permanent brain damage (stroke or other damage)
  • Side effects of medicines

Call your local emergency number (such as ) if:

  • This is the first time a person has a seizure
  • A seizure occurs in someone who is not wearing a medical ID bracelet (which has instructions explaining what to do)

In the case of someone who has had seizures before, call for any of these emergency situations:

  • This is a longer seizure than the person normally has, or an unusual number of seizures for the person
  • Repeated seizures over a few minutes
  • Repeated seizures in which consciousness or normal behavior is not regained between them (status epilepticus)

Call your doctor if any new symptoms occur:

  • Loss of hair
  • Nausea or vomiting
  • Rash
  • Side effects of medicines, such as drowsiness, restlessness, confusion, sedation
  • Tremors or abnormal movements, or problems with coordination

There is no known way to prevent epilepsy. Proper diet and sleep, and staying away from alcohol and illegal drugs may decrease the likelihood of triggering seizures in people with epilepsy.

Reduce the risk for head injury by wearing a helmet during risky activities. This can lessen the likelihood of a brain injury that leads to seizures and epilepsy.

Seizure disorder; Epileptic - epilepsy

Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; chap

González HFJ, Yengo-Kahn A, Englot DJ. Vagus nerve stimulation for the treatment of epilepsy. Neurosurg Clin N Am. ;30(2) PMID:

Thijs RD, Surges R, O'Brien TJ, Sander JW. Epilepsy in adults. Lancet. ;() PMID:

Wiebe S. The epilepsies. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; chap

Updated by: Amit M. Shelat, DO, FACP, FAAN, Attending Neurologist and Assistant Professor of Clinical Neurology, Stony Brook University School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.


Of medical epilepsy definition

What is Epilepsy?

The human brain is the source of human epilepsy.

Epilepsy is a chronic disorder, the hallmark of which is recurrent, unprovoked seizures. A person is diagnosed with epilepsy if they have two unprovoked seizures (or one unprovoked seizure with the likelihood of more) that were not caused by some known and reversible medical condition like alcohol withdrawal or extremely low blood sugar.

The seizures in epilepsy may be related to a brain injury or a family tendency, but often the cause is completely unknown. The word "epilepsy" does not indicate anything about the cause of the person's seizures or their severity.

Many people with epilepsy have more than one type of seizure and may have other symptoms of neurological problems as well. Sometimes EEG (electroencephalogram) testing, clinical history, family history, and outlook are similar among a group of people with epilepsy. In these situations, their condition can be defined as a specific epilepsy syndrome.

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Essentially, anything the brain can do, it can do in the form of a seizure.

Although the symptoms of a seizure may affect any part of the body, the electrical events that produce the symptoms occur in the brain. The location of that event, how it spreads, how much of the brain is affected, and how long it lasts all have profound effects. These factors determine the character of a seizure and its impact on the individual.

Having seizures and epilepsy can affect one's safety, relationships, work, driving, and so much more. Public perception and treatment of people with epilepsy are often bigger problems than actual seizures.

Are you new to epilepsy and seizures?

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