Definition

Seizures are episodes during which the electrical system within the brain fires abnormally. The term “epilepsy” refers to any disorder characterized by recurrent unprovoked seizures. During a seizure, you may lose consciousness, stare into space, have convulsions (abnormal jerking of the muscles), or experience abnormalities of sensation or emotion. Because seizures can be an indication of another, underlying medical problem, such as a brain tumor , it is important to seek medical attention if you have even one seizure.

Seizure disorders may be classified by the part of the brain they affect or the kinds of symptoms they cause. The main categories are generalized or partial seizures.

Generalized Seizure Disorder

These are caused by more widespread abnormalities throughout the brain. Generalized seizure disorders include:

• Generalized tonic-clonic seizures—These are classic convulsions, in which you lose consciousness and the muscles throughout your body jerk uncontrollably. Seizures that accompany fevers in young children are often of this type. Children generally outgrow the tendency to have seizures with fevers, which runs in families. However, even with a history of seizures with fevers, medical attention should be sought immediately because of the possibility that the seizure may be related to a more serious medical condition, such as encephalitis or meningitis .
• Absence seizures—These seizures are characterized by staring, eye blinking, or eye rolling.

Partial Seizure Disorder

Partial seizure disorders are caused by more localized abnormalities within certain areas of the brain. These types of seizures include:

• Complex partial or temporal lobe seizures—During this type of seizure, you will briefly lose contact with reality, stop purposeful activity, and begin a series of automatic gestures, such as lip smacking, hand-wringing, picking at clothing, etc. Not everyone develops automatic gestures during these seizures; sometimes it simply appears as a brief moment of confusion or loss of attentiveness. Occasionally this type of seizure is accompanied by the perception of unusual sights, sounds, or smells.
• Simple partial seizures—In this type of seizure, you retain contact with reality and consciousness, but a single area of your body moves uncontrollably, such as a leg or arm shaking. You may experience an odd sensation, such as the perception of an odor, sound, or taste, or an emotion unrelated to the environment.

Seizure disorders are potentially serious conditions that require care from your doctor. If you suspect you have a seizure disorder, contact your doctor immediately.

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Causes

Seizures occur when the electrical signals that pass between nerve cells within the brain become abnormal. This may occur for no known reason, or it may be associated with:

• Abnormalities of the brain structure (congenital brain abnormalities)
• Genetic
• Birth injuries which deprive the brain of oxygen
• Traumatic brain injury (eg, concussion , skull fracture, oxygen deprivation due to near-drowning )
• Brain infection (encephalitis, cerebritis, brain abscess)
• Brain tumor
• Sudden spike in fever in a baby or very young child (febrile seizure)
• Medications, such as:
  • Penicillin
  • Theophylline
  • Lidocaine
  • Meperidine
  • Amitriptyline
  • Imipramine
  • Doxepin
  • Fluoxetine
  • Haloperidol
  • Chlorpromazine
  • Ephedrine
  • Terbutaline
  • Methotrexate
  • Asparaginase
  • Cyclosporine
• Street drugs, such as cocaine and amphetamines
• Withdrawal from certain medications, street drugs, or alcohol
• Drug overdose
• Chemical abnormalities (decreased or excess blood sodium or glucose, low blood calcium)
• Liver or kidney failure
• Severe, untreated high blood pressure
• Stroke
• Chronic diseases such as systemic lupus erythematosus , polyarteritis nodosa , porphyria , sickle cell disease , Whipple’s disease
• Syphilis

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

The following factors increase your chance of having a seizure. If you have any of these risk factors, tell your doctor:

• Previous brain injury
• Previous brain infection
• Brain tumor
• History of stroke
• High fever (especially common in babies or young children)
• Use of certain medications or recreational drugs
• Stopping the use of medications, recreational drugs, or alcohol
• Drug overdose
• Exposure to toxins such as arsenic, lead, or carbon monoxide
• Alzheimer’s disease
• Toxemia during pregnancy

If you already have a seizure disorder, the following factors can increase your chance of having a seizure:

• Sleep deprivation
• Alcohol
• Hormonal changes (such as those that occur at points during the menstrual cycle)
• Stress
• Flashing lights, especially strobe lights
• Use of certain medications
• Missing doses of anti-epileptic medications

Symptoms

There are many kinds of seizure disorders with a variety of symptoms. Possible symptoms include:

• Aura—a sensation at the start of a seizure, which may involve the perception of an odd smell or sound, spots appearing in front of the eyes, or unusual stomach sensations.
• Staring
• Loss of consciousness
• Repeated jerking of a single limb
• Generalized convulsion, with uncontrollable jerking of muscles throughout the body
• Hand rubbing
• Lip smacking
• Picking at clothing
• Perception of an odor, sound, or taste
• Loss of bladder or bowel control
• Postictal state—a state of drowsiness, alteration in responsiveness, and/or confusion that commonly occurs after a generalized tonic-clonic seizure. This state may last minutes to hours.

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. You may need to see a neurologist, a specialist in conditions of the nervous system and brain.

Tests may include the following:

• Blood tests—to look for abnormal levels of different substances in the blood
• Electroencephalogram (EEG)—a test of the electrical activity of the brain. This may be performed for a brief amount of time, or you may be given an ambulatory monitor to use for several days, or be admitted to the hospital for several days of video and EEG monitoring.
• MRI scan (or sometimes CT scan)—to look for abnormalities in the brain, such as tumor, blood, infection, malformed blood vessels, scarring or swelling
• Spinal tap (lumbar puncture)—may be performed to look for infection and/or bleeding

Treatment

Anti-epileptic Medications

There are a wide variety of medications that are used to treat seizures. Some of these include:

• Phenytoin
• Diazepam
• Lorazepam
• Carbamazepine
  • According to the Food and Drug Administration (FDA), patients of Asian ancestry who have a certain gene, called HLA-B*1502, and take carbamazepine are at risk for dangerous or even fatal skin reactions. If you are of Asian descent, the FDA recommends that you get tested for this gene before taking carbamazepine. If you have been taking this medication for a few months with no skin reactions, then you are at low risk of developing these reactions. Talk to your doctor before stopping this medication. *
• Valproic acid
• Divalproex
• Levetiracetam
• Gabapentin
• Phenobarbital
• Ethosuximide
• Clonazepam
• Primidone
• Oxcarbazepine
• Lamotrigine
• Topiramate
• Felbamate
• Tiagabine
• Zonisamide

These drugs may be given alone or in combination.

Surgery

When medication does not control seizures, or when the side effects of the medications are too severe, surgery may be advised. Surgery involves the removal of the seizure focus, an area of the brain that has been identified as “starting” the seizure activity. Surgery is only an option for individuals who have very localized areas of the brain involved in generating seizure activity.

Vagus Nerve Stimulation

A device is implanted in the chest to provide intermittent electrical stimulation to the vagus nerve. Although the mechanism is unclear, this somehow prevents seizures, decreasing the frequency of seizures an individual experiences. Although you may still require anti-epileptic medications, the dosage may be less.

Ketogenic Diet

This treatment involves following a very strict diet that is high in fat and low in carbohydrates and proteins. This diet keeps the body’s chemical balance in something called “ketosis,” which decreases the frequency of seizures for an unknown reason. Following a ketogenic diet is most successful in children, and less successful in adults.

A study comparing the ketogenic diet to no change in treatment showed that the diet may reduce seizures in children.*

Modification of Activity

If you have a very severe seizure disorder, some modification of normal activity may be required. For example, depending on the frequency of seizures, you may not be able to obtain a driver’s license. Do not swim or bathe alone, or work on ladders or ledges. Certain athletic activities may need to be modified or avoided. You should talk to your doctor about these kinds of issues.

Prevention

Although there are no known ways to prevent every type of seizure disorder, you can take steps to prevent brain injuries which could lead to seizures:

• Always wear a helmet when biking, rollerblading, skateboarding, or riding on a scooter.
• Wear protective headgear when playing sports like football or hockey.
• Dive in safe depths of water.
• Always wear a seatbelt in all vehicles.
• Avoid using street drugs.
• Control high fevers in babies and young children.
• Get prenatal care, and make sure to follow all recommendations regarding the treatment of high blood pressure during pregnancy.
• Carefully treat all chronic illnesses.

If you have a seizure disorder, you can take the following steps to try to decrease the possibility that you will have a seizure:

• Get sufficient sleep.
• Avoid hyperventilating.
• Avoid places where flashing or strobe lights are in use.
• Wear a medical alert bracelet so that, if you have a seizure, people around you will understand what is happening and take appropriate steps to be helpful.
• Consider keeping a seizure log, in which you record things that were happening around the time of a seizure to try to identify a seizure trigger.
• Take your seizure medications according to the prescription.

RESOURCES:

Epilepsy Foundation
http://www.efa.org

National Institute of Neurological Disorders and Stroke
http://www.ninds.nih.gov

CANADIAN RESOURCES:

The Center for Epilepsy and Seizure Education
http://epilepsy.cc/

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

References:

Epilepsy. EBSCO Dynamed website. Available at: http://www.ebscohost.com/dynamed/what.php . Accessed January 15, 2008.

Ferri FF, ed. Ferri’s Clinical Advisor: Instant Diagnosis and Treatment. Philadelphia, PA: Mosby Elsevier; 2004.

Goetz CG, ed. Textbook of clinical Neurology . 2nd ed. Philadelphia, PA: WB Saunders Company; 2006.

Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 22nd ed. Philadelphia, PA: WB Saunders Company; 2004.

*12/20/2007 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : 2007 safety alerts for drugs, biologics, medical devices, and dietary supplements: Carbamazepine (marketed as Carbatrol, Equetro, Tegretol and generics). Medwatch. US Food and Drug Administration website. Available at: http://www.fda.gov/medwatch/safety/2007/safety07.htm #carbamazepine .

*5/14/2008 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Neal EG, Chaffe H, Schwartz RH, et al. The ketogenic diet for the treatment of childhood epilepsy: a randomised controlled trial. Lancet Neurol. 2008 May 2. [Epub ahead of print]

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