Generalized tonic-clonic seizure

Alternative names:

grand mal seizure; seizure - generalized; seizure - grand mal; seizure - tonic-clonic

Definition:

A seizure involving the entire body, usually characterized by muscle rigidity, violent rhythmic muscle contractions, and loss of consciousness, caused by abnormal electrical activity in the nerve cells of the brain.

Causes, incidence, and risk factors:

Grand mal seizures (generalized tonic-clonic seizures, total seizures) affect approximately 2 out of 10,000 people. They are the type of seizure that most people associate with the term "seizure" (convulsion). They may occur in people of any age, as a single episode or as a repeated, chronic condition (epilepsy). The majority of seizures that occur as a single episode are grand mal seizures rather than other types.

Transmission of information from nerve cell to nerve cell occurs by an electrochemical process. This process can be detected as electrical activity by an EEG. Abnormal patterns of electrical activity are associated with seizures. Given sufficient circumstances, any person will have a seizure. Generalized tonic-clonic seizures are caused by abnormal electrical activity at multiple locations in the brain, or over the majority of the brain area.

Some of the more common causes of seizures include:

• idiopathic (no identifiable cause)
  • usually beginning between ages 5 - 20
  • occurring at any age
  • no other neurologic abnormalities present
  • often a family history of epilepsy or seizures

• congenital defects and perinatal (near the time of birth) injuries
  • seizures usually beginning in infancy or early childhood

• metabolic abnormalities
  • affecting any age
  • diabetes mellitus complications
  • electrolyte imbalances
  • kidney failure, uremia (toxic accumulation of wastes)
  • nutritional deficiencies
  • phenylketonuria (PKU)-- rarely causing seizures in infants
  • use of or intoxication from alcohol or drugs
  • withdrawal from alcohol
  • withdrawal from drugs

• brain injury
  • affecting any age, highest incidence in young adults
  • most likely if the brain membranes are damaged
  • seizures usually beginning within 2 years after the injury
  • early seizures (within 2 weeks of injury) not necessarily indicating that chronic seizures (epilepsy) will develop

• tumors and brain lesions occupying space (such as hematomas)
  • affecting any age, more common after age 30
  • partial (focal) seizures most common initially
  • progressing to generalized tonic-clonic seizures

• disorders affecting the blood vessels (stroke, TIA, etc.)
  • most common cause of seizures after age 60

• degenerative disorders (senile dementia Alzheimer type, or similar organic brain syndromes)
  • mostly affecting older people

• infections
  • may affect all ages
  • may be a reversible cause of seizures
  • brain infections (meningitis, encephalitis)
  • brain abscess
  • acute severe infections of any part of the body
  • chronic infections (such as neurosyphilis)
  • complications of AIDS or other immune disorders

There may be changes in mental status (alertness, awareness) and/or focal neurologic symptoms (localized symptoms of changes in brain function) associated with the seizures.