Seizure - grand mal

Alternative names
Seizure - tonic-clonic; Generalized tonic-clonic seizure; Grand mal seizure; Seizure - generalized

A generalized tonic-clonic seizure is a seizure involving the entire body, usually characterized by muscle rigidity, violent rhythmic muscle contractions, and loss of consciousness. The condition is caused by abnormal electrical activity in the nerve cells of the brain.

Causes, incidence, and risk factors

Generalized tonic-clonic seizures (also called grand mal seizures) are the type of seizure that most people associate with the term “seizure,” convulsion, or epilepsy. They may occur in people of any age, as a single episode or as a repeated, chronic condition (epilepsy). The majority of seizures that do occur as just a single episode are generalized tonic-clonic seizures rather than other types.

Generalized seizures are caused by abnormal electrical activity at multiple locations in the brain and/or over a large area of the brain. This results in loss of consciousness and body stiffening, which is followed by shaking of the arms and legs.

Abnormal electrical activity may start in one part of the brain and cause isolated symptoms (see partial seizures). Sometimes this abnormal electrical activity spreads through the brain, resulting in a generalized seizure. Seizures can be caused by a specific area of the brain that is injured or inflamed, or they can be due to stress on the brain from a more widespread systemic process, such as severely low blood sugar.

Some of the more common causes of seizures include:

  • idiopathic (this means the seizure has no identifiable cause)       o usually beginning between ages 5 - 20       o can occur at any age       o no other neurologic abnormalities present       o often a family history of epilepsy or seizures  
  • congenital defects (present from before birth) and perinatal injuries (occur near the time of birth)       o seizures usually beginning in infancy or early childhood  
  • febrile seizure (children)       o usually due to rapidly rising fevers in children  
  • Systemic illness       o acute severe infections of any part of the body       o chronic infections (such as neurosyphilis)       o complications of AIDS or other immune disorders  
  • metabolic abnormalities       o can affect people of any age       o diabetes mellitus complications       o electrolyte imbalances       o kidney failure, uremia (toxic accumulation of wastes)       o nutritional deficiencies       o phenylketonuria (PKU)- rarely causing seizures in infants  
  • brain injury       o seizures are most likely if the brain membranes are damaged       o seizures usually beginning within 2 years after the injury       o early seizures (within 2 weeks of injury) do not necessarily indicate that chronic seizures (epilepsy) will develop  
  • tumors and brain lesions (such as hematomas)       o affecting any age, more common after age 30       o partial (focal) seizures are most common initially       o progressing to generalized tonic-clonic seizures  
  • use of alcohol or other recreational drugs, or withdrawal from alcohol or drugs  
  • low blood sodium or glucose  
  • disorders affecting the blood vessels (stroke, TIA), a common cause of seizures after age 60  
  • degenerative disorders (senile dementia Alzheimer type, or similar organic brain syndromes)  
  • nervous system infections (meningitis, encephalitis) or brain abscess

Risk factors include:

  • any injury to the brain  
  • a family history of seizures  
  • severe medical problems that affect electrolytes  
  • exposure to illicit drugs and certain medications  
  • heavy alcohol use


Many patients have an aura (sensory warning sign) preceding the seizure. This can include a visual, taste, smell, sensory, or other hallucination or dizziness.
The seizure itself involves:

  • loss of consciousness or fainting, usually lasting between 30 seconds and five minutes  
  • general muscle contraction and rigidity (tonic posture), usually lasting 15 to 20 seconds  
  • violent rhythmic muscle contraction and relaxation (clonic movement), usually lasting for one to two minutes  
  • biting the cheek or tongue, clenched teeth or jaw  
  • incontinence (loss of urine or stool control)  
  • breathing difficulty  
  • stopped breathing or difficulty breathing during seizure  
  • blue skin color

Almost all people experience loss of consciousness, and most people experience both tonic and clonic muscle activity.

After the seizure:

  • the person usually begins breathing normally when the seizure is over  
  • arousable but sleepy for one hour or longer  
  • loss of memory (amnesia) regarding events surrounding the seizure episode  
  • headache  
  • drowsiness  
  • confusion, temporary and mild  
  • may be weak for 24-48 hours following seizure (Todd’s paralysis)

Signs and tests

Diagnosis of a grand mal seizure is based on the symptoms and excluding other medical problems that can look like a seizure (such as heart arrythmia). A neuromuscular examination may or may not reveal neurologic deficits (decreases in brain functions) when the person is not actively having seizures.

An EEG may show characteristic changes and in some cases may show the focus (location of the cause of the seizure). An EEG can be normal in between seizures and a normal EEG does not rule out a seizure disorder.

Tests for the cause may include various blood tests (depending on the suspected cause), including:

  • complete blood count  
  • blood chemistry, blood glucose  
  • liver function tests  
  • kidney function tests (BUN, creatinine, etc.)  
  • tests for infectious diseases (depending on the suspected cause)

Tests for the cause may include procedures such as:

Disorders that may cause symptoms resembling seizures include transient ischemic attacks, rage, or panic attacks.


If a generalized seizure occurs, give appropriate emergency first aid.


  • Protect the person from injury. Clear the area of furniture or other objects that may cause injury from falls during the seizure.  
  • Do not attempt to force a hard object (such as a spoon, or a tongue depressor, etc.) between the teeth. You can cause more damage than you can prevent by doing this!  
  • Do not attempt to restrain or hold the person down during the seizure.  
  • Protect the person from inhaling vomit or mucus. Turn the person to the side if vomiting occurs. Keep the person on his or her side while sleeping after the seizure is over.  
  • If the person having a seizure turns blue or stops breathing, try to position the head to prevent the tongue from obstructing the airway. Breathing usually starts on its own once the seizure is over.  
  • CPR or mouth-to-mouth breathing is rarely needed after seizures and cannot be performed during the seizure.  
  • Repeated or prolonged seizures without regaining consciousness or returning to normal behavior between them (status epilepticus) may cause severe lack of oxygen in the body. This an emergency situation requiring immediate professional assistance!


  • Measures to protect the airway may be needed, including use of tubes to keep the airway open. Breathing should be supported as needed.  
  • Thiamine and/or intravenous glucose may be given.  
  • Medications such as diazepam (Valium) or lorazepam, or anticonvulsant medications such as phenytoin or phenobarbital, may control prolonged, repeated generalized seizures. They are usually injected into a vein. Other medical treatment may be needed, including general anesthesia with muscle-paralyzing medications.  
  • After status epilepticus is controlled, anticonvulsants may be begun and tests are performed to determine the cause of the condition, if not known already.


  • Treat any injuries from bumps or falls.  
  • Record details of the seizure to report to the health care provider. Important details include the date and time of the seizure, how long it lasted, which body parts were affected, the type of movements or other symptoms, possible causes, behavior after the seizure, and other factors noted.

Treating the cause, if one has been identified, may stop seizures. This may include medication, surgical repair of tumors or brain lesions, or other treatments. An isolated seizure with an obvious trigger (such as fever and toxic reaction) is treated by eliminating or avoiding the precipitating factor.

An isolated seizure without an obvious trigger (the examination and EEG are normal and there are no abnormalities on other testing) may not require treatment.

Oral anticonvulsants (anti-seizure medications) may prevent or reduce the number of future seizures. The response is individual, and the medication and dosage may have to be adjusted repeatedly. There are numerous medications which may be effective alone or when used in combination. Side effects of these medications and plasma drug-levels will need to be monitored to various degrees, depending on which medications are used.

Women who might get pregnant may need to take additional medications or vitamins to reduce the risk of birth defects associated with some of these medications. Such women may need to be followed in a high-risk pregnancy clinic.

Patients who continue to have seizures despite several medications may benefit from a vagal nerve stimulator (implantable device that stimulates a nerve in the neck) or from brain surgery to remove tissue responsible for causing the seizures.

The use of informational jewelry or cards (such as Medic-Alert or similar products) that indicate a seizure disorder may be advised to help the patient receive prompt medical treatment if a seizure occurs.

Expectations (prognosis)

Seizures can occur as a single isolated occurrence, as closely repeated seizures, or at various intervals. Seizures that recur create a condition known as epilepsy.

Seizures that occur singly or in a closely associated groups are commonly caused by an condition such as brain injury. They may occur as an isolated incident or may develop into a chronic seizure disorder. Seizures within the first two weeks of a brain injury do not necessarily mean that a chronic seizure disorder will develop.

A seizure-free period may indicate that reduction or elimination of medications may be possible. Medications should be changed only under the supervision of the health care provider.

Death or permanent brain damage from seizures is rare. A serious injury can occur if a seizure occurs while driving or operating dangerous equipment; these activities are often restricted for people with poorly controlled seizure disorders.

Infrequent seizures may not severely restrict the patient’s lifestyle. Work, school, and recreation do not necessarily need to be restricted.


  • recurrent seizures (seizure disorder)  
  • prolonged or closely occurring seizures without returning to normal behavior(status epilepticus)  
  • injury from falls, bumps, and biting oneself  
  • injury to oneself or others if seizure occurs during driving or operating machinery  
  • inhaling fluid into the lungs, pneumonia  
  • permanent brain damage (stroke or other damage)  
  • side effects of medications (with or without observable symptoms)  
  • women planning to get pregnant need to alert their physician in advance in order to adjust their medications (many anti-epileptic medications cause birth defects)  
  • learning disorders (either from seizures or medications)

Calling your health care provider

Call your local emergency number (911) if this the first time a person has had a seizure or a seizure is occuring in someone without a medical ID bracelet (instructions explaining what to do). In the case of someone who has had seizures before, call the ambulance for any of these emergency situations:

  • This is a longer seizure than the person normally has, or an unusual number of seizures for the person  
  • Repeated seizures over a few minutes  
  • Repeated seizures where consciousness or normal behavior is not regained between them (status epilepticus)

Call your health care provider if any new symptoms occur, including possible side effects of medications (drowsiness, restlessness, confusion, sedation, or others), nausea/vomiting, rash, loss of hair, tremors or abnormal movements, or problems with coordination.


Generally, there is no known prevention for seizures. However, you can decrease the likelihood of triggering a seizure by taking medicines as directed, getting enough sleep, eating a proper diet, and abstaining from alcohol and drugs.

Reduce the chance of head injuries by wearing head protection and avoiding risky behavior.

Johns Hopkins patient information

Last revised: December 7, 2012
by Sharon M. Smith, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.