Grand Mal Seizure - Generalized Tonic-Clonic Seizure

Seizures are caused by sudden, large discharges of electrical impulses from brain cells. Generalized tonic-clonic seizures were formerly called grand mal seizures. They involve repeated convulsions, or jerking movements, of the limbs and trunk.

What is going on in the body?

Neurons are the nerve cells within the brain. They coordinate movement, thinking, personality, and sensory activities. Neurons communicate with each other through electrical discharges. A seizure occurs when excitable neurons give off abnormal electrical discharges. There are different types of seizures, depending on where the excitable neurons are located. Epilepsy is diagnosed when an individual has a repeating pattern of seizures.

Seizures are divided into two main types: generalized and partial. Generalized seizures affect the entire brain. The person loses consciousness or awareness of the environment. Partial seizures affect only one part of the brain. The individual usually doesn't lose consciousness. Generalized tonic-clonic seizures affect the whole brain.

What are the causes and risks of the condition?

Seizures have many causes. These may include conditions such as:

Diseases also can be a factor in seizures, such as:

Injuries that may cause seizures include the following:

Additional factors that may cause seizures include the following:

What are the signs and symptoms of the condition?

Symptoms of seizures vary according to the type of seizure and the portion of the brain that is affected. Generalized tonic-clonic seizures often have the following characteristics:

How is the condition diagnosed?

Diagnosis of seizures begins with a medical history and physical exam. The healthcare provider will ask about contributing illnesses or injuries. An electroencephalogram, or EEG, will be ordered. An EEG measures electrical activity within the brain. If a seizure occurs during the EEG, the abnormal activity can be detected. A normal EEG does not rule out seizures. Other tests that may be ordered include:

What can be done to prevent the injury?

By reducing excessive alcohol use, a person decreases his or her risk of seizures. However, if a person with alcoholism stops drinking completely, the risk of withdrawal seizures increases. A sudden withdrawal from certain medicines, such as phenobarbital, can also cause seizures. It's important to follow the healthcare provider's prescription for decreasing or stopping a medicine or alcohol.

Keeping blood pressure under control reduces a person's risk of seizures. It also helps prevent stroke, which can lead to seizures. People with epilepsy need to take their medicines as prescribed.

Protection against head injury is critical for all ages. Following sports safety guidelines for children, adolescents, and adults can prevent some injuries.

Many times, there is no way to prevent the onset of epilepsy. Once it is diagnosed, individuals can lower their risk of seizures by:

What are the long-term effects of the condition?

Seizures can lead to physical injury from falling. Epilepsy may interfere with school or work.

What are the risks to others?

Generalized tonic-clonic seizures are not contagious and pose no risk to others.

What are the treatments for the condition?

Medicines used to treat seizures are known as anticonvulsants. Common anticonvulsants include the following:

If a person's seizures are not controlled with medicine, a vagal nerve stimulator may be used. A small pacemaker-like box is inserted under the skin of the chest. It sends regular electrical discharges to the vagus nerve. This discharge can disrupt the abnormal electrical charges. A vagal nerve stimulator does not involve any surgery on the brain.

People with severe, uncontrollable seizures may be candidates for brain surgery. The surgeon opens the skull with a craniotomy. He or she then removes the abnormal brain tissue.

Underlying problems, such as a brain tumor, may require further treatment.

A person with epilepsy may be embarrassed or depressed. Counseling about the condition may help the individual and the family. Support groups exist for those with epilepsy.

What are the side effects of the treatments?

Medicines used to treat seizures may cause drowsiness, dental problems, and allergic reactions. Insertion of a vagal nerve stimulator involves a small risk for bleeding, infection, or allergic reaction to anesthesia. A craniotomy carries a larger risk of bleeding, infection, brain damage, or allergic reaction to anesthesia.

Many anticonvulsants decrease the effectiveness of oral contraceptives.

What happens after treatment for the condition?

Many substances interfere with the action of anticonvulsants. These include over-the-counter medicines, prescription medicines, and herbal remedies. Individuals with seizures should consult their healthcare provider before taking any new products.

Individuals with seizures may be able to drive if they can remain seizure-free. Laws governing driving vary from place to place. People with seizures can participate in most activities of regular life. They may be advised to avoid hazardous activities. Federal law prohibits discrimination in employment. There are also laws precluding people with epilepsy from certain jobs, such as commercial trucking.

A person with seizures should use an identification bracelet or card informing others of the condition.

How is the condition monitored?

Blood is tested regularly to monitor the levels of anticonvulsants. Any new or worsening symptoms should be reported to the healthcare provider.

Author:Gerald C. McIntosh, MD
Date Written:
Editor:Crist, Gayle P., MS, BA
Edit Date:06/30/01
Reviewer:Karen Preston, PHN, MS, CRRN
Date Reviewed:05/31/01