Epilepsy is an ongoing disorder of the nervous system that produces sudden, intense bursts of electrical activity in the brain. This causes seizures, which may briefly affect muscle control, movement, speech, vision or awareness. People with epilepsy have repeated seizures, usually occurring without warning and often for no clear reason. If epilepsy is not treated, seizures may occur throughout a person's life and in some cases become more severe and more frequent over time.
Epilepsy is not a form of mental retardation or mental illness. Although some forms of childhood epilepsy are associated with below-average intelligence and problems with physical and mental development, epilepsy is not the cause of these problems. Seizures may look scary or strange, but they do not make a person violent or dangerous. Epilepsy and the seizures it causes can upset a person's independence, self-esteem and quality of life.
According to the Epilepsy Foundation of America, about 3 million people are afflicted with epilepsy in the United States. One quarter are children. About 200,000 new cases of seizure disorders and epilepsy are diagnosed each year. There is no central registry of cases of epilepsy or seizures in the United States. Epidemiologists base these estimates on peer-reviewed studies of medical records at specific institutions or in defined local communities. Surveys of physicians and patients, self reporting, and studies in matched populations or segments of the population.
Not all seizures are epileptic. Some are caused by injury, illness or other medical conditions. In these cases, seizures end when the condition improves or goes away. That is not epilepsy. Although epilepsy is sometimes the result of another condition, many cases have no known cause. Epilepsy most often begins in childhood or after the age of 60, but it can develop at any age.
There are two types of epileptic seizures. Partial seizures begin in a specific location in the brain. Partial seizures may affect only awareness or only one side or part of the body. Generalized seizures begin over the entire surface of the brain and may affect the entire body. It is impossible to pinpoint the source of these types of seizures in the brain. Partial and generalized seizures are often treated differently. Many types of epilepsy can cause partial or generalized seizures. Classifying those types is difficult because they can have more than one cause, result in more than one type of seizure and affect individuals in different ways. Epilepsy that causes partial seizures, for instance, can take on an endless number of forms, depending on which part of the brain is affected. The most common type of epileptic seizure in adults is temporal lobe epilepsy. Other types include benign focal childhood epilepsy, childhood and juvenile absence epilepsy, infantile spasms (West's syndrome), juvenile myoclonic epilepsy and Lennox-Gastaut syndrome.
Epileptic seizures are caused by abnormal electrical activity in the brain that briefly upsets normal brain function. What causes this change in electrical activity is not always clear.
Several conditions can damage the brain and cause epilepsy, including a serious head injury, stroke, hardening of the arteries in the brain, brain tumor, brain infection (meningitis or encephalitis) and Alzheimer's disease.
Such damage can affect the brain's electrical system, causing the type of electrical activity that triggers seizures. Tumors, scar tissue from injury or disease or abnormal brain development may damage a specific area of the brain and cause partial seizures.
In seven out of 10 cases, there is no known cause of epilepsy. Children are more likely than adults to develop the disorder from an unknown cause. A family history of epilepsy may sometimes be a factor, although experts are not sure how the disease is passed from parent to child.
Making an accurate diagnosis is vital in planning the correct treatment to control seizures. Misdiagnosis followed by the wrong treatment is one reason why people sometimes keep having seizures. Inappropriate treatment also results in unnecessary side effects from medication. Diagnosing epilepsy can be difficult, however. The doctor needs to determine whether:
- The event was actually a seizure or something else (fever or medications). Several conditions can appear to be seizures but are not - e.g., breath-holding spells, migraine headaches, muscle twitches or tics, sleep disorders or psychogenic (psychological) seizures. Taking antiepileptic medications to treat events that are not seizures can put the patient at needless risk.
- The seizure was caused by epilepsy and the type of seizure that occurred. Was the event a seizure, or was it something that looked like a seizure?
- Complete blood count (CBC) to check for infection, abnormal electrolyte levels (such as magnesium, potassium and calcium), signs of kidney or liver malfunction and other common problems
- Lumbar puncture (sometimes called a spinal tap) to rule out infections, such as meningitis and encephalitis
- Toxicology screening for poisons, illegal drugs or other toxins
If the patient has epilepsy, the EEG may show abnormal spikes or waves in electrical activity patterns. Different types of epilepsy cause different patterns. An EEG, however, is not foolproof.
Video and EEG monitoring can be done at the same time to record seizures on videotape and computer so that the doctor can see what happens just before, during and right after a seizure. The video records what the body is doing, while the EEG records the electrical activity occurring in the brain. Such monitoring may be used prior to surgery, or when repeated EEG tests have not provided enough clues as to the type of seizure or to diagnose psychogenic seizures.
Magnetic resonance imaging (MRI) and computed tomography (CT) scans may be used to evaluate the cause and the location of a possible source of epilepsy within the brain. The scans can reveal scar tissue, tumors or structural problems in the brain. These tests also may be used before epilepsy surgery to pinpoint the exact location of a problem in the brain.
For most people with epilepsy, treatment can reduce or prevent seizures and allow many patients to remain seizure-free for the rest of their lives. Uncontrolled seizures can have a big impact on lifestyle, restricting the individual from driving and limiting their work and leisure time activities. Although seizures themselves usually are not physically harmful to people who have epilepsy, they carry a risk of injury and death. The risk is greater for people who have many seizures, depending on the type of seizure they have. Unexpected seizures can cause falls, drowning or other accidents, and a lengthy seizure condition (status epilepticus) can lead to coma or death. By reducing or stopping seizures, treatment may greatly improve the patient's quality of life and safety.
A correct diagnosis is very important to effective treatment. A complete epilepsy program that includes epileptologists, nurse specialists, electroneurodiagnostic technologists, neuropsychologists, social workers is important in the management of seizure disorders. Decisions about how to treat epilepsy are based first on the type of epilepsy and the kinds of seizures that occur. Treatment that controls one kind of seizure may have no effect on other kinds of seizures. Age, health and lifestyle are also important factors in planning treatment. Available treatments include:
- Medication. This is the first and most common approach to treating epilepsy. Antiepileptic medications do not cure epilepsy, but they help prevent seizures in well over half of the people who take them.
- Brain surgery. Some patients with partial epilepsy do not respond to medication but have great success with surgery.
- Vagus nerve stimulator. This device is used with medication or surgery to reduce seizures.
- Ketogenic diet. A high-fat diet has been used with some success to treat people, especially children, who have severe, uncontrolled seizures. However, some doctors may not support its use.
The patient's vital signs will be checked, and the doctor will do a physical exam and order various lab tests to rule out or identify any life-threatening medical conditions (such as meningitis, stroke or failure of the heart, liver or kidneys).
