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Epilepsy (Seizure Disorders)

  • Definition

    Article updated and reviewed by Peter B. Kang, MD, Assistant in Neurology, Children's Hospital Boston, and Instructor in Neurology, Harvard Medical School, Boston, MA on May 18, 2005.

    A seizure is an event characterized by abnormal electrical activity in the brain, usually resulting in abnormal movements, abnormal sensations, and/or changes in consciousness. An individual is usually diagnosed as having epilepsy (seizure disorder) when he or she has had multiple spontaneous seizures, that is, ones that are not associated with an obvious trigger such as fever, electrolyte imbalance, or head trauma.


    There are many forms of epilepsy, each with its own characteristic symptoms. Whatever the form, the disease is caused by a problem in communication among the brain's nerve cells. Normally, such cells communicate with one another by sending tiny electrical signals back and forth. For someone with epilepsy, the electrical signals are at high risk of occurring with an abnormal rhythm, either in one particular region of the brain, multiple regions, or throughout the brain. A seizure that begins in one part of the brain may spread to other parts, depending on the severity of the epilepsy.

    The underlying cause may be structural, including a brain injury such as a contusion, infection such as encephalitis, lack of oxygen to one part of the brain as occurs in a stroke, or a tumor. In some cases, there may be a brain malformation that developed before birth. In other cases, the cause may be a more generalized dysfunction of the brain that is not primarily structural, such as a genetic or metabolic disorder. In a large number of patients, the ultimate cause is not found at all, despite extensive testing.

    Seizures are divided into two basic categories, generalized and partial. In generalized seizures, the abnormal electrical discharges occur throughout the brain, whereas partial seizures only affect a specific region of the brain. Within each of these major categories are two common seizure types. There are generalized tonic-clonic (“grand mal”) seizures, and absence (“petit mal”) seizures. There are complex partial seizures and simple partial seizures. Other types exist, but these are the major ones.

    A generalized tonic-clonic (“grand mal”) seizure is the most dramatic. It begins with a tonic phase in which the individual falls to the ground unconscious, with stiffening of the entire body. This is followed by the clonic phase, in which the arms and legs jerk rhythmically and uncontrollably. This may last for several minutes and may be accompanied by tongue-biting and incontinence of bladder or bower function. The seizure is usually followed by a period of deep sleep or mental confusion, called a post-ictal period.

    Absence (“petit mal”) epilepsy is typically a disease of childhood that does not usually persist past late adolescence. During such a seizure, the child suddenly stops in the middle of an activity and stares blankly around for a few seconds (sometimes up to half a minute), and is unaware of what is happening. There may be a slight jerking movement of the head or an arm, or sometimes lip smacking, but petit mal seizures do not generally involve falling to the ground and thus may be very subtle. Usually, there is no tongue-biting or incontinence. When the seizure ends, the child often does not realize that the brief blank spell has occurred and resumes the interrupted activity without a post-ictal phase (period of sleeping or drowsiness). A child may have dozens of these spells a day. Such children are often thought by teachers and parents to be "day-dreamers," and may be misdiagnosed with attention deficit hyperactivity disorder because of the difficulty concentrating.

    A complex partial seizure causes a change of consciousness that may range from confusion to complete unresponsiveness. Some complex partial seizures, including temporal lobe seizures, may be preceded by an aura, which can occur just prior to the seizure or as much as several hours beforehand. The aura may consist of nothing but a sense of tension or some other ill-defined feeling, but some epileptics have quite specific auras such as an impression of smelling unpleasant odors or hearing peculiar sounds, distorted vision, or an odd bodily sensation, particularly in the stomach. Many epileptics learn to recognize their special aura, and this may give them time to prepare as much as possible for the seizure by sitting or lying down, or stopping a potentially dangerous activity. Because only part of the brain is affected, the seizure may be much more subtle than a generalized tonic-clonic seizure. There may be twitching of one part of the body on only one side, an unusual sensation in one location, lip smacking, chewing movements, blinking, or a combination of these, accompanied by a change in consciousness. Some complex partial seizures remain localized in the affected part of the brain, and the seizure may be so subtle that it may be confused with absence (“petit mal”) seizures. In other individuals, the seizure may start with focal symptoms but then spread throughout the brain, resulting in a generalized tonic-clonic seizure. This is an example of a mixed type of seizure. Complex partial seizures are typically followed by a post-ictal phase (period of sleeping of drowsiness).

    Simple partial seizures are similar to complex partial seizures but are not accompanied by changes in consciousness. The individual will be able to talk and describe what he/she feels during the seizure. This is the only major type of seizure that the individual usually remembers, but is relatively rare outside of certain childhood seizure syndromes such as Rolandic epilepsy.

    The basic symptom of epilepsy is a brief and abnormal phase of behavior, commonly known as a seizure, fit or convulsion. It is important to realize that a single such episode does not indicate that you have epilepsy. By definition, epileptic seizures recur.


    First aid for epilepsy is designed to protect the safety of the person until the seizure stops naturally by itself. These are the key things to remember:

    • Keep calm and reassure other people who may be nearby.

      Unless the individual and his/her disorder are well-known to you, you should have someone call 911 and ask for an ambulance immediately. Especially if this is a first time seizure, the person should be taken to the nearest hospital emergency department for an evaluation. A first-time seizure may sometimes be the first symptom of a stroke, cerebral hemorrhage, or meningitis/encephalitis, all of which are life-threatening conditions. Also, a seizure may sometimes not stop by itself, and the prompt arrival of an ambulance crew may be lifesaving.

    • Clear the area around the person of anything hard or sharp.
    • If the person is not lying on a flat surface, transfer him/her gently to one, preferably a carpeted floor.

    • Loosen ties or anything round the neck that may make breathing difficult.
    • Turn the person gently onto his/her side. This will help keep the airway clear.
    • Do not try to force the mouth open with any hard implement or with fingers. It is not true that a person having a seizure can swallow his/her tongue, and efforts to hold the tongue down can injure his/her teeth or jaw. A person in the middle of a seizure may bite down with enough force to bite off fingers.
    • Don't hold the person down or try to stop his movements.
    • Don't attempt artificial respiration, except in the unlikely event that a person does not start breathing again after the seizure has stopped.
    • Stay with the person until the seizure ends naturally.
    • If the individual awakens before the ambulance arrives, be friendly and reassuring and explain what happened.

    These guidelines are not a substitute for formal life support training. Defer to another person on the scene who has had basic life support training if you are not certified, and be as helpful as possible. If you expect to be in proximity to someone, either at home or at work, with epilepsy, you may wish to consider enrolling in a basic life support course.


    What type of epilepsy is it?

    Is there a test to diagnose epilepsy?

    How early in life can you be tested?

    Is epilepsy hereditary?

    Can a normal life be led?

    What activities are safe for me to continue? (i.e., driving, swimming, working)

    Is medication necessary? If so, what type of medication do you recommend?

    What are the side effects?

    Does this type of epilepsy require surgery?

    If so, what is the success rate?

    Is epilepsy curable?


    Editorial review provided by VeriMed Healthcare Network.


    In the past, there were few medications available to treat epilepsy and an affected individual was condemned to recurrent, harmful, and socially embarrassing events. Severe cases of epilepsy are still difficult to control, but recent advances in both medical and surgical therapies are helping many more people than before. In some cases, treatments are so successful that people go for years with complete seizure control. Epileptic seizures can often be prevented by one or more of the following measures:

    • regular use of anti-seizure medication
    • removal of brain tissue where seizures take place
    • special diet to produce a change in body chemistry (known as the ketogenic diet, for severe cases of epilepsy only)
    • avoidance of special conditions known to trigger seizures in susceptible people (useful if a trigger such as sleep-deprivation can be identified)

    Of the methods listed above, drug therapy is by far the most often used and is almost always the method tried first. Sixteen medications to prevent epileptic seizures are currently approved for use in the U.S., and of these, the following six are used most frequently: Phenytoin (Dilantin), phenobarbital, ethosuximide (Zarontin), primidone (Mysoline), valproic acid (Depakene, Depakote) and carbamazepine (Tegretol, Carbatrol). Newer medications that have become increasingly accepted include lamotrigine (Lamictal), topiramate (Topamax), zonisamide (Zonegran), and levitiracetam (Keppra). Many of these medications have potentially severe or even life-threatening side effects, and should be discussed in detail with a physician before starting a course of therapy.

    When taken regularly as prescribed, medication can prevent seizures in about half of all cases and produce improvement in about 30 percent of all cases. The remaining patients do not get much relief from existing medications.

    When drugs fail to prevent seizures, surgery may be an option, but surgery is only possible when the seizures begin in one fairly small part of the brain that can be removed without affecting speech, memory or some other important brain function. Although surgery is not used as often as drug therapy, the results are similar – about 70 percent of all patients getting either full or greatly improved control of seizures, and the rest have only a slight improvement or none at all.