Absence seizure

Alternative Names

Seizure - petit mal; Seizure - absence; Petit mal seizure; Epilepsy - absence seizure

Definition

An absence seizure is the term given to a staring spell. This type of seizure is a brief (usually less than 15 seconds) disturbance of brain function due to abnormal electrical activity in the brain.

Causes

Absence seizure occur most often in people under age 20, usually in children ages 6 to 12.

They may occur with other types of seizures, such as generalized tonic-clonic seizures (grand mal seizures), twitches or jerks (myoclonus), or sudden loss of muscle strength (atonic seizures).

Symptoms

Most absence seizures last only a few seconds. They often involve staring episodes. The episodes may:

• Occur many times a day
• Occur for weeks to months before being noticed
• Interfere with school and learning
• Be mistaken for lack of attention or other misbehavior

Unexplained difficulties in school and learning difficulties may be the first sign of absence seizures.

During the seizure, the person may:

• Stop walking and start again a few seconds later
• Stop talking in mid-sentence and start again a few seconds later

The person usually does not fall during the seizure.

Immediately after the seizure, the person is usually:

• Wide awake
• Thinking clearly
• Unaware of the seizure

Specific symptoms of typical absence seizures may include:

• Changes in muscle activity, such as no movement, hand fumbling, fluttering eyelids, lip smacking, chewing
• Changes in alertness (consciousness), such as staring episodes, lack of awareness of surroundings, sudden halt in movement, talking, and other awake activities
• May be triggered by hyperventilation or flashing lights, in some cases

Some absence seizures begin slower and last longer. These are called atypical absence seizures. Symptoms are similar to regular absence seizures, but muscle activity changes may be more noticeable.

Treatment

For information on diagnosis and treatment, see:

• Epilepsy
• Seizures

References

Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 67.

Buchhalter J. Treatment of childhood absence epilepsy -- an evidence-based answer at last! Epilepsy Curr. 2011;11(1):12–15.

Wiebe S. The epilepsies. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 410.