by Karen Schroeder, MS, RD
Seizures result when clusters of nerve cells in the brain, called neurons, communicate with each other abnormally or send excessive numbers of signals (called discharges) to other neurons. During a seizure, the neurons' normal pattern of activity is disturbed. This can cause strange sensations, emotions, and behavior; or convulsions, and loss of consciousness. When a seizure occurs more than once without a known cause, the condition is called epilepsy.
Epilepsy is caused by abnormal brain wiring or caused by excessive electrical discharges in the brain wiring. This may be due to structural damage to the brain or to a chemical abnormality. It may be related to an imbalance, which is often related to an imbalance of nerve signaling chemicals called neurotransmitters.
Most of the time, we don't know what causes a person's seizures. Seizures may be caused by:
Brain abnormalities existing since birth
Brain damage from other disorders:
Celiac disease (intolerance to wheat gluten)
Conditions that alter normal brain function: brain tumors, alcoholism, Alzheimer's disease
Conditions that deprive the brain of oxygen: stroke, heart failure, near drowning
Head injury leading to brain swelling or bleeding
Hydrocephalus (excess fluid in the brain)
Infectious diseases: meningitis, AIDS, viral encephalitis
Exposure to certain illegal drugs, such as cocaine
Exposure to lead, carbon monoxide, pesticides, or other environmental toxins
Overdose of antidepressants, aspirin, and other medications
A risk factor is something that increases your chance of getting a disease or condition. Some factors, called seizure triggers, can cause first seizures, or breakthrough seizures in people whose seizures are controlled with medication. These triggers include:
Hormonal changes of the menstrual cycle
Lack of sleep
Light flashing at a certain speed or the flicker of a computer monitor (photosensitive epilepsy)
Symptoms vary widely because there are many types of seizures. Symptoms may include:
Episodes of unusual or automatic behavior
Generalized convulsions (generalized shaking with loss of consciousness)
Localized convulsions (shaking of one or more arms or legs but without loss of consciousness)
Odd sensations or emotions
The doctor will perform a detailed examination to determine if you have epilepsy. The exam may include the following:
Brain imaging – detects brain tumors, blood clots, malformations, tissue scarring, swelling or hydrocephalus:
Computed tomography (CT) scan
In babies, echoencephalogram – use of high-frequency sound waves to produce pictures of the brain
Magnetic resonance imaging (MRI)
Positron emission tomography (PET) scan
Single photon emission computed tomography (SPECT)
Developmental, neurological, and behavioral tests
Electroencephalogram (EEG) – measures electrical activity of the brain to detect abnormal activity
Lumbar puncture (also called a spinal tap) – removal of a small amount of spinal fluid to determine if your seizure was caused by infection, bleeding, or some other abnormalities in the brain.
Physical exam, especially of the nervous system
Questions about your family history and medical history, including medications and current or previous health problems
Medications to prevent seizures are typically the first line of treatment. These medications are called anticonvulsants or antiepileptic drugs. They do not cure epilepsy, but for many people, they prevent seizures. Others may continue to have seizures, but less frequently.
Most people with epilepsy are treated with medications. Although only a small percentage of people with seizures are treated with surgery, this course of treatment may be considered in the following situations:
To treat the underlying cause of epilepsy, such as a brain tumor or excess fluid
When seizures begin as partial seizures before spreading to the rest of the brain
When seizures occur in just one part of the brain (partial seizures)
Surgeries to treat epilepsy include:
Lobectomy or Lesionectomy – removal of the area of the brain that is producing the seizures, called the seizure focus. The most common surgery of this type is a temporal lobectomy.
Multiple Subpial Transection – a series of cuts along the nerve path through which seizure impulses spread; designed to prevent seizures from spreading into other parts of the brain
Corpus Callosotomy –cutting the nerve connections between the right and left halves of the brain to prevent seizures from spreading from one side to the other
Hemispherectomy – removal of half of the brain's outer layer
Vagus Nerve Stimulation
A medical device powered by a battery that prevents seizures by sending regular small pulses of electrical energy to the brain through the vagus nerve (a large nerve in the neck).
A diet very high in fat and low in protein and carbohydrate. It produces a change in body chemistry that controls or decreases the frequency of seizures in some children. It is sometimes used for children whose seizures cannot be controlled with medication, or who experience negative side effects from medication. Adults may also benefit from this diet, but it is very difficult to follow. The long-term effects of such a high fat diet are unknown.
To reduce your chance of getting seizures:
Avoid illicit drugs and excessive alcohol.
Control high fevers in young children.
Get prenatal care, including treatment of high blood pressure and infections during pregnancy, to help prevent brain damage in a developing baby.
Prevent and treat heart disease, high blood pressure, infections, and other disorders that can affect the brain.
Prevent head injury by wearing seat belts and bicycle helmets, and putting children in car seats.
Take medication after first or second seizures.
Last reviewed: July 2004 by Judy Logan, MD, MS.