Generalized tonic-clonic seizure

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Central nervous system

A generalized tonic-clonic seizure is a seizure involving the entire body, which usually involves muscle rigidity, violent muscle contractions, and loss of consciousness.

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

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 seizures have no identifiable cause. They usually begin between ages 5 and 20, but can occur at any age. There are no other neurological problems, but the patient often has a family history of epilepsy or seizures.
• Congenital defects (present from before birth) and injuries that occur near the time of birth can cause seizures to begin in infancy or early childhood.
• Febrile seizure (in children) are usually caused by rapidly rising fevers in children.
• Acute severe infections of any part of the body, chronic infections (such as neurosyphilis ), and complications of AIDS or other immune disorders can cause seizures.
• Seizures related to metabolic problems can occur at any age, and may be due to:
  • Diabetes mellitus complications
  • Electrolyte imbalances
  • Kidney failure, uremia (toxic accumulation of wastes)
  • Nutritional deficiencies
  • Phenylketonuria (PKU)-- rarely causing seizures in infants
  • Low blood sodium or glucose
• Brain injury usually causes seizures 2 years after the injury. Early seizures (within 2 weeks of injury) do not necessarily indicate that chronic seizures (epilepsy) will develop
• Tumors and brain lesions (such as hematomas) are more common after age 30. They most commonly cause partial (focal) seizures at first, then progress to generalized tonic-clonic seizures.
• Other causes include:
  • Use of alcohol or other recreational drugs, or withdrawal from alcohol or drugs
  • Disorders affecting the blood vessels (stroke, TIA), a common cause of seizures after age 60.
  • Degenerative disorders (senile dementia Alzheimer type)

Risk factors include:

• Any injury to the brain
• Family history of seizures
• Severe medical problems that affect electrolytes
• Using recreational drugs and certain medications
• Heavy alcohol use

Review Date: 11/21/2006
Reviewed By: Daniel Kantor, M.D., Director of the Comprehensive MS Center, Neuroscience Institute, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.