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Generalized Seizures (Grand Mal Seizures)

Medically reviewed by Last updated on May 15, 2023.

What are Generalized Seizures (Grand Mal Seizures)?

Harvard Health Publishing

Normally, the brain’s nerve cells (neurons) communicate with one another by firing tiny electric signals that pass from cell to cell. The firing pattern of these electric signals reflects how busy the brain is. The location of these signals indicates what the brain is doing, such as thinking, seeing, feeling, hearing, controlling the movement of muscles, etc. A seizure occurs when the firing pattern of the brain’s electric signals suddenly becomes very abnormal and unusually intense, either in an isolated area of the brain or throughout the brain.

If the whole brain is involved, the electrical disturbance is called a generalized seizure. This type of seizure used to be called a grand mal seizure. The most easily recognizable symptom of a generalized seizure is the body stiffness and jerking limbs known as tonic-clonic motor activity.

Generalized Seizures (Grand Mal Seizures)

Epilepsy is the condition of being prone to repeated seizures, but this can be any kind of seizures, not just generalized seizures. A person can have a seizure without having epilepsy. Today, seizure disorder is the term used more commonly than epilepsy.

A seizure can be provoked by any situation that seriously disturbs the physical or chemical environment of the brain. Some common triggers include:

  • A severe chemical imbalance in the blood — Abnormal levels of blood acids, sodium, calcium or blood sugar (especially in diabetics)
  • Drug reactions — Reactions to illegal drugs (crack cocaine, amphetamines and others), anesthetics or prescription medications (penicillin, anti-asthma drugs, anticancer drugs and many others)
  • Drug withdrawal — Withdrawal from alcohol or sedatives
  • Medical illnesses — Extreme high blood pressure (hypertension), eclampsia (a complication of pregnancy), liver failure, kidney failure, sickle-cell disease, systemic lupus erythematosus (lupus or SLE), and many others
  • A local problem involving the brain — Head trauma, developmental brain disorders, stroke, brain tumors, and infections in or near the brain (brain abscess, encephalitis, meningitis)
  • Other causes — High fever, sleep deprivation, starvation, flashing lights (even from video games), intermittent noise and, rarely, menstruation

If doctors can successfully treat the physical or chemical disturbance in the brain, the seizure problem often goes away. If not, seizures may return again and again, whenever the underlying problem flares up.

Sometimes, a person will experience an unprovoked generalized seizure, one that occurs for no apparent reason. In some people, this type of seizure may be related to a genetic (inherited) vulnerability that makes the brain cells unusually sensitive to minor changes in the environment. In other cases, seizures may be related to scarring caused by prior head trauma or by a previous stroke, brain tumor or brain infection.

Many people who have one unprovoked seizure never experience a second one. However, if a second seizure occurs, the risk of having a third or even more is about 80 percent. For this reason, doctors often regard the second seizure as a sign of epilepsy.


A seizure begins suddenly. Without warning, the person loses consciousness and experiences the following symptoms:

  • Becomes rigid (extends the arms and legs, arches the back) and falls down
  • Utters a cry (the "epileptic cry") as the diaphragm contracts and forces air out between the contracted vocal cords
  • Has jerking movements of the arms, legs, and trunk muscles
  • Involuntarily passes urine and sometimes feces

The seizure usually subsides within two minutes or less, leaving the person confused and sleepy. Over the following 24 hours, he or she may complain of sore muscles, headache, fatigue and difficulty concentrating.


If you have had symptoms of a seizure, your doctor will begin by looking for an underlying medical trigger, such as low blood sugar or eclampsia. If your doctor can confirm a definite medical reason for your seizure, your treatment will be geared toward correcting the underlying illness.

If your seizure appears to be unprovoked (not triggered by any underlying medical problem), your doctor will review your medical history, family history and any eyewitness reports of your seizure symptoms. Next, the doctor will do a thorough physical and neurological examination and order routine blood tests. In most cases, the results of your examinations and blood tests will be normal.

Your doctor also may order an electroencephalogram (EEG), a painless test that detects the electrical activity in your brain and translates it into a series of printed patterns. In 40 percent to 50 percent of people with epilepsy, the first EEG will show a specific combination of patterns that confirms the diagnosis. If the first EEG is normal, repeat EEG tests usually will detect the abnormal brain-wave pattern.

Sometimes, even when a series of EEG tests fails to show evidence of seizure activity, the diagnosis can be based on evidence from the reports of people who have seen your seizure episodes.

In some cases, the doctor may also order a magnetic resonance imaging (MRI) or computed tomography (CT) scan of your brain to look for evidence of a local problem, such as a brain tumor or scarring from a previous brain injury. These scans are especially important if:

  • You are an adult with your first generalized seizure.
  • You have an unusual pattern of symptoms.
  • Your neurological exam is abnormal.
  • You have a history of brain damage (birth trauma, head injury, train tumor, encephalitis, meningitis).

Expected Duration

About half of all people who have one unprovoked seizure never have another.

Most people who have epilepsy can avoid seizures if they get enough sleep and take prescribed medications as directed. Most people with epilepsy need to take medication indefinitely. Never stop medication without specific instructions from your physician.

If you have had only a couple of seizures and have a normal EEG, your doctor might reevaluate the need for medication if you have no seizures after two to five years.


Most of the time epilepsy cannot be prevented. But whether or not you have epilepsy, you can help prevent a generalized seizure by observing the following:

  • Avoid using illegal drugs.
  • Drink alcohol in moderation or not at all.
  • Faithfully follow your doctor’s treatment plan if you have diabetes or high blood pressure.
  • Protect yourself from head trauma by wearing seat belts and bicycle helmets. If you play sports, wear appropriate protective headgear.
  • If you are pregnant, see your doctor regularly for prenatal care.


If you have had only one unprovoked seizure, you may not have another. For this reason, your doctor may decide to monitor your condition without prescribing medication. In most cases, you will be considered to have a low risk of a second seizure if you have no history of brain injury (tumor, trauma, infections), no family history of epilepsy and normal results on diagnostic tests, including an EEG.

If you have had at least two seizure episodes and have been diagnosed with epilepsy, your doctor will treat you with an anti-epileptic medication (an anticonvulsant). Common anti-epileptic medications used to treat generalized seizures include valproate (Depakote), levetiracetam (Keppra), carbamazepine (Tegretol), phenytoin (Dilantin), topiramate (Topamax) and lamotrigine (Lamictal). If your seizures cannot be controlled with one drug alone, your doctor will try a combination of two drugs.

When To Call a Professional

Call your doctor immediately if you or anyone in your family experiences a series of symptoms that appear to be a generalized seizure. If you already have been diagnosed with epilepsy, call your doctor if you continue to have seizures even though you are taking anti-epileptic medication.

If you witness someone having a generalized seizure that lasts for more than five minutes, call for emergency medical help immediately. Also call for emergency medical help immediately if you witness someone having a generalized seizure who:

  • Does not awaken soon after the seizure is over
  • Is a pregnant woman
  • Is wearing medical identification jewelry stating that he or she has diabetes
  • Has a seizure after head trauma
  • Has a seizure while swimming


Many factors play a role in determining whether a person with generalized epilepsy eventually becomes seizure-free. Overall, the outlook is best in those who have had very few seizures before beginning treatment, have good seizure control with only one anti-epileptic drug, have a normal EEG between seizures, have no history of brain damage, and have a normal neurological exam at the end of treatment.

In many cases, the outlook is very good. With proper treatment, up to 70 percent of people with epilepsy ultimately become seizure-free for five or more years.

Most children with generalized seizures can lead normal lives, including participating in organized sports, with minimal restrictions.

Additional Info

National Institute of Neurological Disorders and Stroke

American Academy of Neurology (AAN)

Epilepsy Foundation

American Epilepsy Society


Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.