An absence seizure, formerly known as a petit mal, is defined as a sudden, involuntary, transient alteration in cerebral function due to abnormal discharge of neurons in the central nervous system. Absence seizures fall in the category of generalized seizures, of which there are two types: primary and secondary. Primary generalized seizures are characterized by synchronous bilateral epileptic discharges. The first sign of seizure appears simultaneously in both hemispheres. A secondary generalized seizure is one that begins in one hemisphere and then spreads throughout the brain. In some cases, generalized tonic-clonic seizures develop; in fact, approximately 50% of children with absence seizures have at least one generalized tonic-clonic seizure during their lifetimes.
In epilepsy, a kind of seizure that involves brief periods of blankly staring unconsciousness.
Brain dysfunction involving a brief loss of consciousness without motor involvement; also called petit-mal seizure.
Also known as petit mal, a type of seizure characterized by brief episodes of loss of awareness. Persons having an absence seizure are described as staring or daydreaming. These seizures commonly occur during childhood and often disappear during adolescence. However, people with absence seizures are at greater risk for developing major motor or grand mal seizures during adolescence or young adulthood. Absence seizures are diagnosed by a characteristic electroencephalogram (EEC) pattern. Some children experience frequent brief seizures throughout the day that impair the ability to concentrate and learn. Treatment with appropriate medications usually allows a return to full participation in school and social activities.
Seizure in which there is a sudden, brief lapse of consciousness, usually for about 2 to 10 sec. The patient (typically a child) shows a blank facial expression that may be accompanied by movements such as repeated eye-blinking or rolling or lip-smacking and minor myoclonus of the upper extremities or neck. There is no convulsion or fall. The patient resumes activity as if the seizure had not occurred. The seizure may be induced by voluntary hyperventilation for 2 to 3 min. This type of attack is characteristic of petit mal epilepsy and may recur repeatedly if it is not recognized and treated. It also may progress to a generalized tonic-clonic seizure.