Seizure disorder

Definition

A seizure is a sudden disruption of the brain's normal electrical activity accompanied by an alteration in consciousness or other neurological and behavioral manifestations. Epilepsy is a condition characterized by recurrent seizures that may include repetitive muscle jerking called convulsions.

Description

There are more than 20 different seizure disorders. One in 10 Americans will have a seizure at some time, and at least 200,000 have at least one seizure each month.

Epilepsy affects 1–2% of the United States population. Although epilepsy is as common in adults over 60 as in children under 10, 25% of all cases develop before the age of five. One in every two cases develops before the age of 25. About 125,000 new cases of epilepsy are diagnosed each year, and a significant number of children and adults that have not been diagnosed or treated have epilepsy.

Most seizures are benign, but a seizure that lasts a long time can lead to status epilepticus, a life-threatening condition characterized by continuous seizures, sustained loss of consciousness, and respiratory distress. Non-convulsive epilepsy can impair physical coordination, vision, and other senses. Undiagnosed seizures can lead to conditions that are more serious and more difficult to manage.

Types of seizures

Generalized epileptic seizures occur when electrical abnormalities exist throughout the brain. A partial seizure does not involve the entire brain. A partial seizure begins in an area called an epileptic focus, but may spread to other parts of the brain and cause a generalized seizure. Some people who have epilepsy experience more than one type of seizure.

Motor attacks cause parts of the body to jerk repeatedly. A motor attack usually lasts less than an hour and may last only a few minutes. Sensory seizures begin with numbness or tingling in one area. The sensation may move along one side of the body or the back before subsiding.

Visual seizures, which affect the area of the brain that controls sight, cause people to see things that are not there. Auditory seizures affect the part of the brain that controls hearing and cause a person to imagine voices, music, and other sounds. Other types of seizures can cause confusion, upset stomach, or emotional distress. When such phenomena occur prior to the onset of a seizure, they are called auras.

generalized seizures A generalized tonic-clonic (grand mal) seizure begins with a loud cry before the person having the seizure loses consciousness and falls to the ground. The muscles become rigid for about 30 seconds during the tonic phase of the seizure and alternately contract and relax during the clonic phase, which lasts 30 to 60 seconds. The skin sometimes acquires a bluish tint, and the person may bite the tongue, lose bowel or bladder control, or have trouble breathing.

A grand mal seizure lasts between two and five minutes, and the person may be confused or have trouble talking when consciousness is regained (postictal state). There may be complaints of head or muscle aches or weakness in the arms or legs before falling into a deep sleep.

primary generalized seizures A primary generalized seizure occurs when electrical discharges begin in both halves (hemispheres) of the brain at the same time. Primary generalized seizures are more likely to be major motor attacks than to be absence seizures.

absence seizures Absence (petit mal) seizures generally begin at about the age of four and stop by the time the child becomes an adolescent. Absence seizures usually begin with a brief loss of consciousness and last between one and ten seconds. A person having a petit mal seizure becomes very quiet and may blink, stare blankly, roll eyes, or move lips. A petit mal seizure lasts 15 to 20 seconds. When it ends, the person who had the seizure resumes whatever task was being completed before the seizure began. There will be no memory of the seizure, and the person may not realize that anything unusual has happened. Untreated petit mal seizures can recur as many as 100 times a day and may progress to grand mal seizures.

myoclonic seizures Myoclonic seizures are characterized by brief, involuntary spasms of the tongue or muscles of the face, arms, or legs. Myoclonic seizures are most apt to occur when waking after a night's sleep.

A Jacksonian seizure is a partial seizure characterized by tingling, stiffening, or jerking of an arm or leg. Loss of consciousness is rare. The seizure may progress in characteristic fashion along the limb.

Limp posture and a brief period of unconsciousness are features of akinetic seizures, which occur in young children. Akinetic seizures, which cause the child to fall, are also called drop attacks.

partial seizures Simple partial seizures do not spread from the focal area where they arise. Symptoms are determined by what part of the brain is affected. The person usually remains conscious during the seizure and can later describe it in detail.

complex partial seizures A distinctive smell, taste, or other unusual sensation (aura) may signal the start of a complex partial seizure. These seizures start as simple partial seizures but move beyond the focal area and cause loss of consciousness. Complex partial seizures can become major motor seizures. Although a person having a complex partial seizure may appear to be conscious, the person has no knowledge of what is happening and may behave inappropriately. There will be no memory of the seizure and there may be a brief period of confusion after it ends.

Causes and symptoms

The origin of 50–70% of all cases of epilepsy is unknown. Epilepsy is sometimes the result of trauma at the time of birth. Such causes include insufficient oxygen to the brain; head injury ; heavy bleeding or incompatibility between a woman's blood and the blood of her newborn baby; and infection immediately before, after, or at the time of birth.

Other causes of epilepsy include:

• head trauma resulting from a car accident, gunshot wound, or other injury
• alcoholism
• brain abscess or inflammation of membranes covering the brain or spinal cord
• phenylketonuria (PKU) (A disease that is present at birth, PKU is often characterized by seizures, and can result in mental retardation and other inherited disorders.)
• infectious diseases such as measles, mumps, and diphtheria
• degenerative disease
• lead poisoning, mercury poisoning, carbon monoxide poisoning, or ingestion of some other poisonous substance
• genetic factors

Status epilepticus, a condition in which a person suffers from continuous seizures and may have trouble breathing, can be caused by:

• suddenly discontinuing anti-seizure medication
• hypoxic or metabolic encephalopathy (brain disease resulting from lack of oxygen or malfunctioning of other physical or chemical processes)
• acute head injury
• blood infection caused by inflammation of the brain or the membranes that cover it

Diagnosis

Personal and family medical history, description of seizure activity, and physical and neurological examinations help primary care physicians, neurologists, and epileptologists diagnose this disorder. Doctors rule out conditions that cause symptoms that resemble epilepsy, including small strokes (transient ischemic attacks or TIAs), fainting (syncope), pseudoseizures, and sleep attacks (narcolepsy).

Neuropsychological testing uncovers learning or memory problems. Neuro-imaging provides views of brain areas involved in seizure activity.

An electroencephalogram (EEG) is the main test used to diagnose epilepsy. EEGs use electrodes placed on or within the skull to record the brain's electrical activity and pinpoint the exact location of abnormal discharges. A person may be asked to remain motionless during a short-term EEG or to go about normal activities during extended monitoring. Some people are deprived of sleep or exposed to seizure triggers, such as rapid, deep breathing (hyperventilation) or flashing lights (photic stimulation). In some cases, people may be hospitalized for EEG monitoring that can last as long as two weeks. Video EEGs also document what an individual was doing when the seizure occurred and how the seizure altered behavior.

Other techniques used to diagnose epilepsy include:

• Magnetic resonance imaging (MRI) provides clear, detailed images of the brain. Functional MRI (fMRI), performed while a person does various tasks, can measure shifts in electrical intensity and blood flow and indicate the brain region each activity affects.
• Positron emission tomography (PET) and single photon emission tomography (SPECT) monitor blood flow and chemical activity in the brain area being tested. PET and SPECT are very effective in locating the brain region where metabolic changes take place between seizures.

Treatment

The goal of epilepsy treatment is to eliminate seizures or make the symptoms less frequent and less severe. Long-term anticonvulsant drug therapy is the most common form of epilepsy treatment.

Medication

A combination of drugs may be needed to control some symptoms, but most persons who have epilepsy take one of the following medications:

• phenytoin (Dilantin)
• carbamazepine (Tegretol)
• phenobarbital (Barbita)
• primidone (Mysoline)
• valproic acid or sodium valproate (Depakene)
• clonazepam (Klonopin)
• ethosuximide (Zarontin)

Phenytoin, carbamazepine, phenobarbital, and primidone are used to manage or control generalized tonic-clonic and complex partial seizures. Valproic acid (sodium valproate), clonazepam, and ethosuximide are prescribed for persons who have absence seizures. Gabapentin (Neurontonin) and lamotrigine (Lamictal) are medications recently approved in the United States to treat adults who have partial seizures or partial and grand mal seizures.

Even a person whose seizures are well controlled should have regular blood tests to measure levels of anti-seizure medication in the blood stream and to check to see if the medication is causing any changes in the blood or liver. A doctor should be notified if any signs of drug toxicity appear, including uncontrolled eye movements; sluggishness, dizziness , or hyperactivity; inability to see clearly or speak distinctly; nausea or vomiting; or sleep problems.

Status epilepticus requires emergency treatment, usually with Ativan (Valium), phenytoin, or phenobarbital. An intravenous dextrose (sugar) solution is given to persons whose condition is due to low blood sugar, and a vitamin B₁ preparation is administered intravenously when status epilepticus results from chronic alcohol withdrawal. Because dextrose and thiamine are essentially harmless and because delay in treatment can be disastrous, these medications are given routinely, as it is usually difficult to obtain an adequate history from a person suffering from status epilepticus.

Intractable seizures are seizures that cannot be controlled with medication or without sedation or other unacceptable side effects. Surgery may be used to eliminate or control intractable seizures.

Surgery

Surgery can be used to treat people whose intractable seizures stem from small focal lesions that can be removed without endangering them, changing their personality, dulling their senses, or reducing their ability to function.

Each year, as many as 5,000 new people may become suitable candidates for surgery, which is most often performed at a comprehensive epilepsy center. Potential surgical candidates include people with:

• partial seizures and secondarily generalized seizures (attacks that begin in one area and spread to both sides of the brain)
• seizures and childhood paralysis on one side of the body (hemiplegia)
• complex partial seizures originating in the temporal lobe (the part of the brain associated with speech, hearing, and smell) or other focal seizures (However, the risk of surgery involving the speech centers is that a person will lose speech function.)
• generalized myoclonic seizures or generalized seizures featuring temporary paralysis (akinetic) or loss of muscle tone (atonal)

A physical examination is conducted to verify that a person's seizures are caused by epilepsy, and surgery is not used to treat people with severe psychiatric disturbances or medical problems that raise risk factors to unacceptable levels.

Surgery is never indicated unless:

• The best available anti-seizure medications have failed to control the person's symptoms satisfactorily.
• The origin of a person's seizures has been precisely located.
• There is good reason to believe that surgery will significantly improve the person's health and quality of life.

Every person considering epilepsy surgery is carefully evaluated by one or more neurologists, neurosurgeons, neuropsychologists, and/or social workers. A psychiatrist, chaplain, or other spiritual advisor may help an affected individual and family members family cope with the stresses that occur during and after the selection process.

types of surgery Surgical techniques used to treat intractable epilepsy include:

• Lesionectomy. Removing the lesion (diseased brain tissue) and some surrounding brain tissue is very effective in controlling seizures. Lesionectomy is generally more successful than surgery performed on persons whose seizures are not caused by clearly defined lesions, but removing only part of the lesion lessens the effectiveness of the procedure.
• Temporal resections. Removing part of the temporal lobe and the part of the brain associated with feelings, memory, and emotions (the hippocampus) provides good or excellent seizure control in 75–80% of properly selected individuals with appropriate types of temporal lobe epilepsy. Some people experience post-operative speech and memory problems.
• Extra-temporal resection. This procedure involves removing some or all of the frontal lobe, the part of the brain directly behind the forehead. The frontal lobe helps regulate movement, planning, judgment, and personality, and special care must be taken to prevent post-operative problems with movement and speech. Extra-temporal resection is most successful in people whose seizures are not widespread.
• Hemispherectomy. This method of removing brain tissue is restricted to persons with severe epilepsy and abnormal discharges that often extend from one side of the brain to the other. Hemispherectomies are most often performed on infants or young children who have had an extensive brain disease or disorder since birth or from a very young age.
• Corpus callosotomy. This procedure, an alternative to hemispherectomy in persons with congenital hemiplegia, removes some or all of the white matter that connects the two halves of the brain. Corpus callosotomy is performed almost exclusively on children who are frequently injured during falls caused by seizures. If removing two-thirds of the corpus callosum doesn't produce lasting improvement in a person's condition, the remaining one-third will be removed during another operation.
• Multiple subpial transection. This procedure is used to control the spread of seizures that originate in or affect the “eloquent” cortex, the area of the brain responsible for complex thought and reasoning.

Other forms of treatment

ketogenic diet A special high-fat, low-protein, low-carbohydrate diet is sometimes used to treat persons whose severe seizures have not responded to other treatment. Calculated according to age, height, and weight, the ketogenic diet induces mild starvation and dehydration . This forces the body to create an excessive supply of ketones, natural chemicals with seizure-suppressing properties.

The goal of this controversial approach is to maintain or improve seizure control while reducing medication. The ketogenic diet works best with children between the ages of one and 10. It is introduced over a period of several days, and most children are hospitalized during the early stages of treatment.

If a child following this diet remains seizure-free for at least six months, increased amounts of carbohydrates and protein are gradually added. If the child shows no improvement after three months, the diet is gradually discontinued.

Introduced in the 1920s, the ketogenic diet has had limited, short-term success in controlling seizure activity. Its use exposes people to such potentially harmful side effects as:

• staphylococcal infections
• stunted or delayed growth
• low blood sugar (hypoglycemia)
• excess fat in the blood (hyperlipidemia)
• disease resulting from calcium deposits in the urinary tract (urolithiasis)
• disease of the optic nerve (optic neuropathy)

vagus nerve stimulation The United States Food and Drug Administration (FDA) has approved the use of vagus nerve stimulation (VNS) in persons over the age of 16 who have intractable partial seizures. This non-surgical procedure uses a pacemaker-like device implanted under the skin in the upper left chest, to provide intermittent stimulation to the vagus nerve. Stretching from the side of the neck into the brain, the vagus nerve affects swallowing, speech, breathing, and many other functions, and VNS may prevent or shorten some seizures.

First aid for seizures

A person having a seizure should not be restrained, but sharp or dangerous objects should be moved out of reach. Anyone having a complex partial seizure can be warned away from danger by someone calling out his or her name in a clear, calm voice.

A person having a grand mal seizure should be helped to lie down. Tight clothing should be loosened. A soft, flat object like a towel or the palm of a hand should be placed under the person's head. Forcing a hard object into the mouth of someone having a grand mal seizure could cause injuries or breathing problems . If the person's mouth is open, placing a folded cloth or other soft object between the teeth will protect the tongue. Turning the head to the side will help breathing. After a grand mal seizure has ended, the person who had the seizure should be told what has happened and reminded of the present location.

Alternative treatment

Stress increases seizure activity in 30% of people who have epilepsy. Relaxation techniques can provide some sense of control over the disorder, but they should never be used instead of anti-seizure medication or used without the approval of a person's doctor. Yoga , meditation, and favorite pastimes help some people relax and more successfully manage stress. Biofeedback can teach adults and older adolescents how to recognize an aura and what to do to stop its spread. Children under 14 are not usually able to understand and apply principles of biofeedback. Acupuncture treatments (acupuncture needles inserted for a few minutes or left in place for as long as half an hour) make some people feel pleasantly relaxed. Acupressure can have the same effect on children or on adults who dislike needles.

Aromatherapy involves mixing aromatic plant oils into water or other oils and massaging them into the skin or using a special burner to waft their fragrance throughout the room. Aromatherapy oils affect the body and the brain, and undiluted oils should never be applied directly to the skin. Ylang ylang, chamomile, or lavender can create a soothing mood. People who have epilepsy should not use rosemary, hyssop, sage, or sweet fennel, which seem to make the brain more alert.

Dietary changes that emphasize whole foods and eliminate processed foods may be helpful. Homeopathic therapy also can work for people with seizures, especially constitutional homeopathic treatment that acts at the deepest levels to address the needs of an individual.

Prognosis

People who have epilepsy have a higher-than-average rate of suicide ; sudden, unexplained death ; and drowning and other accidental fatalities.

Benign focal epilepsy of childhood and some absence seizures may disappear in time, but remission is unlikely if seizures occur several times a day, several times in a 48-hour period, or more frequently than in the past.

Seizures that occur repeatedly over time and always involve the same symptoms are called stereotypic seizures. The probability that stereotypic seizures will abate is poor.

About 85% of all seizure disorders can be partially or completely controlled if a person takes antiseizure medication according to directions; avoids seizure-inducing sights, sounds, and other triggers; gets enough sleep; and eats regular, balanced meals.

Caregiver concerns

First aid may be provided by trained individuals. Physicians make the initial diagnosis of seizure disorders. Endocrinologists and radiologists may assist in refining a diagnosis. Neurologists, neurosurgeons, neuropsychologists, and social workers may assess persons prior to receiving surgery for a seizure disorder. Neurosurgeons may perform surgery to remove structures in the brain that are known to cause seizures. Psychiatrists, chaplains, or other spiritual advisors may help an affected individual and relations cope with the stresses that occur during and after surgery. Nurses also teach family and friends about emergency care of patient when having a seizure, as well as home care following a seizure and hospitalization.

Prevention

Eating properly, getting sufficient sleep, and controlling stress and fevers can help prevent seizures. A person who has epilepsy should be careful not to hyperventilate. A person who experiences an aura should find a safe place to lie down and stay there until the seizure passes. Anticonvulsant medications should not be stopped suddenly; and, if other medications are prescribed or discontinued, the doctor treating the seizures should be notified. In some conditions, such as severe head injury, brain surgery, or subarachnoid hemorrhage, anticonvulsant medications may be given to a person to prevent seizures. Seizures that are caused by ingesting substances such as alcohol or drugs can be prevented by discontinuing use of the offending substance.

KEY TERMS

Akinetic seizure —Seizure characterized by limp posture and a brief period of unconsciousness; also called a drop attack.

Aura —A distinctive smell, taste, or other unusual sensation that preceeds the onset of a seizure.

Clonic —Referring to clonus, a series of muscle contractions and partial relaxations that alternate in some nervous diseases in the form of convulsive spasms.

Epileptologist —A physician who specializes in the treatment of epilepsy.

Lesionectomy —Removal of a lesion and surrounding tissue. The term is applied to brain tissue when trying to control seizures.

Myoclonic seizures —Brief, involuntary spasms of the tongue or muscles of the face, arms, or legs.

Petit-mal seizure —Absence seizure.

Post-ictal state —A period of disorientation usually followed by sleep that occurs after a seizure.

Tonic —Characterized by tonus, a state of partial contraction that is maintained at least in part by a continuous bombardment of motor impulses.

Resources

books

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adam's & Victor's Principles of Neurology. 6th ed. New York: McGraw Hill, 1997.

Chesney, Russell W. “Conditions that Mimic Seizurres.” In Nelson Textbook of Pediatrics. 16th ed. Ed. by Richard E. Behrman, et al. Philadelphia: Saunders, 2000, pp.1829–1832.

Gates, John R., and A.J. Rowan. Non-Epileptic Seizures. 2nd ed. Woburn, MA: Butterworth-Heinemann, 2000.

Haslem, Robert H.A. “Febrile Seizures.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1818–1819.

Haslem, Robert H.A. “Generalized Seizures.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1815–1818.

Haslem, Robert H.A. “Neonatal Seizures.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1825–1827.

Haslem, Robert H.A. “Partial Seizures.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia, Saunders, 2000, pp.1814–1815.

Haslem, Robert H.A. “Seizures in Childhood.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1813–1814.

Haslem, Robert H.A. “Status Epilepticus.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1827–1829.

Haslem, Robert H.A. “Treatment of Epilepsy.” In Nelson Textbook of Pediatrics. 16th ed. Ed. Richard E. Behrman et al. Philadelphia: Saunders, 2000, pp.1819–1825.

Lowenstein, Daniel H. “Seizures and Epilepsy.” In Harrison's Principles of Internal Medicine. 14th ed. Ed. Anthony S. Fauci et al. New York: McGraw-Hill, 1998, pp.2311–2325.

Mizrahi, Eli M., and Peter Kellaway. Diagnosis and Management of Neonatal Seizures. New York: Raven Press, 1998.

Pedley, Timothy A. “The Epilepsies.” In Cecil Textbook of Medicine. 21st ed. Ed. Lee Goldman and J. Claude Bennett. Philadelphia: W.B. Saunders, 2000, pp.2151–2164.

periodicals

Anagnostou, E. “On Absence Seizures and Oculomotor Phenomena. Clinical Neurophysiology 112, no. 3 (2001): 563–564.

Beran, R.G. “The Classification of Epileptic Seizures and Syndromes.” Medicine and Law 19, no. 4 (2000):753–756.

Browne, T.R., and G.L. Holmes. “Epilepsy.” New England Journal of Medicine 344, no. 15 (2001): 1145–1151.

Bui, T.T., et al. “Infant Seizures Not So Infantile: Presentations to the Hospital of Children Less Than 6 Months of Age with a First-Time Seizure.” Academy of Emergency Medicine 8, no. 5 (2001): 438–441.

Dale, M.C. “Distinguishing Between Partial Seizures and Panic Attacks. Psychotic and Behavioural Symptoms Are also Common in Elderly Patients.” British Medical Journal 322, no. 7290 (2001): 864–865.

Mack, C.J. “Treating the Person.” Lancet 357, no. 9257 (2001): 724–725.

organizations

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, MN 55116. (651) 695-1940. http://www.aan.com/.

British Epilepsy Association. http://www.epilepsy.org.uk/ (August 14, 2001).

Epilepsy Foundation. 4351 Garden City Drive, Landover, MD 20785-7223. (800) 332-1000. (301) 459-3700. http://www.efa.org.

other

Epilepsy Ontario. http://epilepsyontario.org/.

Greenstein, Doreen B. “Caring for Children with Special Needs: Seizure Disorders.” National Network for Child Care. http://www.nncc.org/Diversity/spec.seiz.html (August 14, 2001).

L. Fleming Fallon Jr., MD, DrPH