Epilepsy

Overview

Epilepsy is a central nervous system disorder (neurological disorder) in which the nerve cell activity in your brain is disturbed, causing a seizure during which you experience abnormal behavior, symptoms and sensations, including loss of consciousness.

Seizure symptoms vary. Some people with epilepsy simply stare blankly for a few seconds during a seizure, while others repeatedly twitch their arms or legs.

About 1 in 100 people in the United States may have an unprovoked seizure once in life. However, a solitary seizure doesn't mean you have epilepsy. At least two unprovoked seizures are generally required for an epilepsy diagnosis.

Even mild seizures may require treatment because they can be dangerous during activities such as driving or swimming. Treatment, which generally includes medications or sometimes surgery, may eliminate or reduce the frequency and intensity of seizures. Some children with epilepsy even outgrow the condition with age.

Symptoms

Because epilepsy is caused by abnormal activity in brain cells, seizures can affect any process your brain coordinates. A seizure can produce symptoms such as:

  • Temporary confusion
  • A staring spell
  • Uncontrollable jerking movements of the arms and legs
  • Loss of consciousness or awareness
  • Psychic symptoms

Symptoms vary depending on the type of seizure. In most cases, a person with epilepsy will tend to have the same type of seizure each time, so the symptoms will be similar from episode to episode.

Doctors generally classify seizures as either focal or generalized, based on how the abnormal brain activity begins.

Focal seizures

When seizures appear to result from abnormal activity in just one area of your brain, they're called focal (partial) seizures. These seizures fall into two categories.

  • Simple focal seizures. These seizures don't result in loss of consciousness. They may alter emotions or change the way things look, smell, feel, taste or sound. They may also result in involuntary jerking of a body part, such as an arm or leg, and spontaneous sensory symptoms such as tingling, dizziness and flashing lights.
  • Dyscognitive focal seizures. These seizures alter consciousness or awareness and may cause you to lose awareness for a period of time. Dyscognitive focal seizures often result in staring and purposeless movements — such as hand rubbing, chewing, swallowing or walking in circles.

Generalized seizures

Seizures that appear to involve all areas of the brain are called generalized seizures. Six types of generalized seizures exist.

  • Absence seizures. Absence seizures, also called petit mal seizures, are characterized by staring and subtle body movement. These seizures can cause a brief loss of awareness.
  • Tonic seizures. Tonic seizures cause stiffening of your muscles. These seizures usually affect muscles in your back, arms and legs and may cause you to fall to the ground.
  • Clonic seizures. Clonic seizures are associated with rhythmic, jerking muscle movements. These seizures usually affect the neck, face and arms.
  • Myoclonic seizures. Myoclonic seizures usually appear as sudden brief jerks or twitches of your arms and legs.
  • Atonic seizures. Atonic seizures, also known as drop seizures, cause a loss of muscle control, which may cause you to suddenly collapse or fall down.
  • Tonic-clonic seizures. Tonic-clonic seizures, also called grand mal seizures, are characterized by a loss of consciousness, body stiffening and shaking, and sometimes loss of bladder control or biting your tongue.

Causes

Epilepsy has no identifiable cause in about half of those with the condition. In about half the people with epilepsy, the condition may be traced to various factors.

  • Genetic influence. Some types of epilepsy, which are categorized by the type of seizure you experience, run in families. In these cases, it's likely that there's a genetic influence.

    Researchers have linked some types of epilepsy to specific genes, though it's estimated that up to 500 genes could be tied to the condition. For most people, genes are only part of the cause of epilepsy. Certain genes may make a person more sensitive to environmental conditions that trigger seizures.

  • Head trauma. Head trauma that occurs due to a car accident or other traumatic injury can cause epilepsy.
  • Brain conditions. Brain conditions that result in damage to the brain, such as brain tumors or strokes, also can cause epilepsy. Stroke is a leading cause of epilepsy in adults older than age 35.
  • Infectious diseases. Infectious diseases, such as meningitis, AIDS and viral encephalitis, can cause epilepsy.
  • Prenatal injury. Before birth, babies are sensitive to brain damage that could be caused by several factors, such as an infection in the mother, poor nutrition or oxygen deficiencies. This brain damage can result in epilepsy or cerebral palsy.
  • Developmental disorders. Epilepsy can sometimes be associated with developmental disorders, such as autism and neurofibromatosis.

Diagnosis

To diagnose your condition, your doctor will review your symptoms and medical history. Your doctor may order several tests to diagnose epilepsy and determine the cause of seizures.

  • Neurological examination. Your doctor may test your behavior, motor abilities, mental function and other areas to diagnose your condition and determine the type of epilepsy you may have.
  • Blood tests. Your doctor may take a blood sample to check for signs of infections, genetic conditions or other conditions which may be associated with seizures.

Your doctor may also suggest tests to detect brain abnormalities, such as:

    • Electroencephalogram (EEG). This is the most common test used to diagnose epilepsy. In this test, doctors attach electrodes to your scalp with a paste-like substance. The electrodes record the electrical activity of your brain.

If you have epilepsy, it's common to have changes in your normal pattern of brain waves, even when you're not having a seizure. Your doctor may monitor you on video while conducting an EEG while you're awake or asleep, to record any seizures you may experience. Recording the seizures may help the doctor determine what kind of seizures you're having or rule out other conditions.

Your doctor may give you instructions to do something that will cause seizures, such as getting little sleep prior to the test.

    • Computerized tomography (CT) scan. A CT scan uses X-rays to obtain cross-sectional images of your brain. CT scans can reveal abnormalities in your brain that might be causing your seizures, such as tumors, bleeding and cysts.
    • Magnetic resonance imaging (MRI). An MRI uses powerful magnets and radio waves to create a detailed view of your brain. Your doctor may be able to detect lesions or abnormalities in your brain that could be causing your seizures.
    • Functional MRI (fMRI). A functional MRI measures the changes in blood flow that occur when specific parts of your brain are working. Doctors may use an fMRI before surgery to identify the exact locations of critical functions, such as speech and movement, so that surgeons can avoid injuring those places while operating.
    • Positron emission tomography (PET). PET scans use a small amount of low-dose radioactive material that's injected into a vein to help visualize active areas of the brain and detect abnormalities.

    • Single-photon emission computerized tomography (SPECT). This type of test is used primarily if you've had an MRI and EEG that didn't pinpoint the location in your brain where the seizures are originating.

A SPECT test uses a small amount of low-dose radioactive material that's injected into a vein to create a detailed, 3-D map of the blood flow activity in your brain during seizures.

Doctors also may conduct a form of a SPECT test called subtraction ictal SPECT coregistered to magnetic resonance imaging (SISCOM), which may provide even more detailed results.

  • Neuropsychological tests. In these tests, doctors assess your thinking, memory and speech skills. The test results help doctors determine which areas of your brain are affected.

Treatment

Doctors generally begin by treating epilepsy with medication. If medications don't treat the condition, doctors may propose surgery or another type of treatment.

Medication

Most people with epilepsy can become seizure-free by taking one anti-seizure medication, called anti-epileptic medication. Others may be able to decrease the frequency and intensity of their seizures by taking medications. Your doctor will advise you about the appropriate time to stop taking medications.

More than half the children with epilepsy who aren't experiencing epilepsy symptoms can eventually discontinue medications and live a seizure-free life. Many adults also can discontinue medications after two or more years without seizures.

Finding the right medication and dosage can be complex. Your doctor will consider your condition, frequency of seizures, your age and other factors when choosing which medication to prescribe. Your doctor will also review any other medications you may be taking, to ensure the anti-epileptic medications won't interact with them.

Your doctor likely will first prescribe a single medication at a relatively low dosage and may increase the dosage gradually until your seizures are well controlled.

Anti-seizure medications may have some side effects. Mild side effects include:

  • Fatigue
  • Dizziness
  • Weight gain
  • Loss of bone density
  • Skin rashes
  • Loss of coordination
  • Speech problems
  • Memory and thinking problems

More severe but rare side effects include:

  • Depression
  • Suicidal thoughts and behaviors
  • Severe rash
  • Inflammation of certain organs, such as your liver

To achieve the best seizure control possible with medication:

  • Take medications exactly as prescribed.
  • Always call your doctor before switching to a generic version of your medication or taking other prescription medications, over-the-counter drugs or herbal remedies.
  • Never stop taking your medication without talking to your doctor.
  • Notify your doctor immediately if you notice new or increased feelings of depression, suicidal thoughts, or unusual changes in your mood or behaviors.
  • Tell your doctor if you have migraines. Doctors may prescribe one of the anti-epileptic medications that can prevent your migraines and treat epilepsy.

At least half of all people newly diagnosed with epilepsy will become seizure-free with their first medication. If anti-epileptic medications don't provide satisfactory results, your doctor may suggest surgery or other therapies. You'll have regular follow-up appointments with your doctor to evaluate your condition and medications.

Surgery

Surgery is most commonly done when tests show that your seizures originate in a small, well-defined area of your brain that doesn't interfere with vital functions like speech, language, motor function, vision or hearing. In surgery, your doctor removes the area of your brain that's causing the seizures.

If your seizures originate in an area of the brain that controls movement, speech and other functions, you may be awake during part of the surgery. Doctors will monitor you and ask you questions during the procedure.

If your seizures originate in a part of your brain that can't be removed, your doctor may recommend a different type of surgery in which surgeons make several cuts in your brain (multiple subpial transection). These cuts are designed to prevent seizures from spreading to other parts of your brain.

Although many people continue to need some medication to help prevent seizures after successful surgery, you may be able to take fewer drugs and reduce your dosages.

In a small number of cases, surgery for epilepsy can cause complications such as permanently altering your thinking (cognitive) abilities. Talk to your surgeon about his or her experience, success rates and complication rates with the procedure you're considering.

Therapies

    • Vagus nerve stimulation. In vagus nerve stimulation, doctors implant a device called a vagus nerve stimulator underneath the skin of your chest, similar to a heart pacemaker. Wires from the stimulator are connected to the vagus nerve in your neck.

The battery-powered device sends bursts of electrical energy through the vagus nerve and to your brain. It's not clear how this inhibits seizures, but the device can usually reduce seizures by 20 to 40 percent.

Most people still need to take anti-epileptic medication, although some people may be able to lower their medication dose. You may experience side effects from vagus nerve stimulation, such as throat pain, hoarse voice, shortness of breath or coughing.

  • Ketogenic diet. Some children with epilepsy have been able to reduce their seizures by following a strict diet that's high in fats and low in carbohydrates.

    In this diet, called a ketogenic diet, the body breaks down fats instead of carbohydrates for energy. After a few years, some children may be able to stop the ketogenic diet and remain seizure-free.

    Consult a doctor if you or your child is considering a ketogenic diet. It's important to make sure that your child doesn't become malnourished when taking the diet.

    Side effects of a ketogenic diet may include dehydration, constipation, slowed growth because of nutritional deficiencies, and buildup of uric acid in the blood, which can cause kidney stones. These side effects are uncommon if the diet is properly and medically supervised.

Potential future treatments

Researchers are studying brain stimulation as a potential treatment for epilepsy. In brain stimulation, surgeons implant electrodes into a specific part of your brain. The electrodes are connected to a generator implanted in your chest or the skull that sends electrical pulses to your brain and may reduce your seizures.

Researchers also study stereotactic radiosurgery as a potential treatment for some types of epilepsy. In this procedure, doctors direct radiation at the specific area of your brain that is causing your seizure.