Absence Seizure - Clinical Presentation

Clinical Presentation

The clinical manifestations of absence seizures vary significantly among patients. Impairment of consciousness is the essential ictal element and may be the only clinical symptom, but this is often combined with other manifestations. The hallmark of the absence seizures is abrupt and sudden onset impairment of consciousness, interruption of ongoing activities, a blank stare, possibly a brief upward rotation of the eyes. If the patient is speaking, speech is slowed or interrupted, if walking, he or she stands transfixed; if eating, the food will stop on his way to the mouth. Usually, the patient will be unresponsive when addressed. In some cases, attacks are aborted when the patient is called. The attack lasts from a few seconds to half a minute, and evaporates as rapidly as it commenced.

1. Absence with impairment of consciousness only as per the above description
2. Absence with mild clonic components. Here the onset of the attack is indistinguishable from the above, but clonic components may occur in the eyelids, at the corner of the mouth, or in other muscle groups which may vary in severity from almost imperceptible movements to generalised myoclonic jerks. Objects held in the hand may be dropped.
3. Absence with atonic components. Here there may be a diminution in tone of muscles subserving posture as well as in the limbs leading to drooping of the head, occasionally slumping of the trunk, dropping of the arms, and relaxation of the grip. Rarely tone is sufficiently diminished to cause this person to fall.
4. Absence with tonic components. Here during the attack tonic muscular contraction may occur, leading to increase in muscle tone which may affect the extensor muscles or the flexor muscles symmetrically or asymmetrically. If the patient is standing the head may be drawn backward and the trunk may arch. This may lead to retropulsion. The head may tonically draw to one or another side.
5. Absence with automatisms. Purposeful or quasipurposeful movements occurring in the absence of awareness during an absence attack are frequent and may range from lip licking and swallowing to clothes fumbling or aimless walking. If spoken to the patient may grunt or to the spoken voice and when touched or tickled may rub the site. Automatisms are quite elaborate and may consist of combinations of the above described movements or may be so simple as to be missed by causal observation.
6. Absence with autonomic components. These may be pallor and less frequently flushing, sweating, dilatation of pupils and incontinence of urine.

Mixed forms of absence frequently occur. These seizures can happen a few times a day or in some cases hundreds of times a day, to the point that the person cannot concentrate in school or other situations requiring sustained, concentrated attention.