Epilepsy

Seizures are abnormal electrical discharges in the brain that temporarily disrupt the normal transmission of messages to the body. They can produce alterations in consciousness, cause odd rhythmic or repetitive movements, jerking or twitching of limbs, and/or can lead to convulsions that contract muscles throughout the body.

Sometimes epileptic auras precede seizures. Auras are the heightened sensitivity or unusual perception of sight, sound, smell, taste, or touch that warn people of an imminent seizure. They may involve sensations, for example, of a cool breeze or a bright light and may include feelings of numbness or nausea. What happens during a seizure episode depends on which part(s) of the brain are affected. Many people with epilepsy experience similar symptoms with each seizure, but some may have a wide variety of symptoms.

Most seizures last a few seconds to a few minutes. If a person's consciousness is altered or lost, the person will frequently not remember what has happened. Those affected may have no after-effects, may have a brief period of confusion, and/or may experience weakness and fatigue that can last for several days.

Laboratory and non-laboratory tests are used to diagnose and monitor epilepsy, to determine what kind(s) of seizures a person is having, to identify underlying conditions such as toxins, infections, drug or alcohol withdrawal, fever (in a child), or diabetes that may be causing seizures, and to distinguish epilepsy from conditions such as fainting or a stroke that may cause some of the same symptoms.

A medical history, input from the patient, and input from family members who have witnessed the seizures are important parts of the diagnostic process. Someone with epilepsy may remember a strange smell, an aura, and/or sensations that precede a seizure but may not remember what has happened during the seizure itself. Depending upon the signs and frequency of a person's seizures, it may take some time to determine the proper diagnosis.

Non-laboratory Tests

• Electroencephalogram (EEG) – the primary diagnostic tool for epilepsy; it is used to evaluate the brain's electrical activity and identify changes in brain wave patterns.

Imaging scans:

• Computed tomography (CT) – identifies brain structure abnormalities and tumors
• Magnetic resonance imaging (MRI) – also identifies brain abnormalities
• Positron emission tomography (PET) – radioactive material is used to look at active areas of the brain
• Single-photon emission computed tomography (SPECT) – radioactive material is used to identify the region of the brain where seizures originate when it is not clear on other scans

Laboratory Tests
Laboratory tests are primarily used to monitor anti-epileptic medications and to search for conditions that may cause seizures, such as diabetes, infection, meningitis or encephalitis.

Periodic therapeutic drug monitoring is performed when a patient is taking a specific medication to ensure that therapeutic levels are achieved. Epileptic medications that are monitored include:

• Carbamazepine
• Phenytoin
• Valproic acid
• Phenobarbital

There are some newer second-generation antiepileptic drugs, such as levetiracetam, that usually do not require routine monitoring but may be tested in order to evaluate and adjust dosage as necessary.

Other testing is done to identify possible causes for seizures, including:

• Complete blood count (CBC) – to evaluate blood cells to check for a variety of conditions, including infection
• Glucose – to check for the possibility of diabetes
• CSF analysis – to check for infection and help diagnose meningitis and encephalitis
• Blood culture – to check for septicemia, infection in the blood
• Drug abuse testing—to detect drugs and/or alcohol (ethanol)

Many cases of epilepsy can be prevented by taking precautions. These include safety measures to avoid head injury, such as wearing a helmet while riding a bicycle or motorcycle and wearing a seat belt while in a car. Prenatal care can help to avoid infections and other causes of fetal brain damage. Immunizations reduce the probability of contracting infections that could lead to this condition. Treating medical conditions such as hypertension and cardiovascular disease during adulthood can also help to prevent epilepsy.

Effective treatment depends on accurate diagnosis of the type of epilepsy someone has. For 70-80% of those diagnosed with the disorder, seizures can be controlled with available treatments, such as medication and surgery.

In people who have epilepsy, seizures can often be prevented or decreased in frequency by consistently taking the appropriate anti-epileptic medication. Commonly prescribed drugs include:

• Carbamazepine
• Phenytoin
• Phenobarbital
• Valproic acid

There are several newer second-generation antiepileptic drugs, such as levetiracetam, that may be prescribed as an adjunctive (secondary) treatment in combination with other antiepileptic drugs.

The choice of drug depends on the person and on the type of seizure. Patients should work with their healthcare provider to find the right medication(s) and dose. In cases where medication is not effective or produces severe side effects, a special diet that is high in fat and low in carbohydrate may help to control seizures. For some types of epilepsy, surgery is the best option to reduce or eliminate seizures.

The number of seizures can also be decreased by avoiding triggers such as sleep deprivation, excessive stress, visual stimuli such as bright, flashing lights, alcohol consumption, and use of illicit drugs (e.g., cocaine). Treating underlying conditions can also lessen the frequency of seizures. An implanted device called a vagus nerve stimulator is another possibility for those who have seizures that are not well controlled by medication. More devices are being researched, including an implantable, pacemaker-type instrument that is designed to prevent epileptic seizures. For more on treatment options, visit the NINDS page Seizures and Epilepsy: Hope Through Research.