Absence status epilepsy.

Absence status (AS), or "Petit Mal status" is a polymorphic condition that can complicate many epileptic syndromes. Diagnosis is difficult on the basi s of clinical semiology alone, and requires emergency EEG. Although heterog eneous, the most typical ictal pattern is constituted by slow generalized r hythmic spike-waves (SW) or polyspike-waves (PSW) complexes. In a number of cases, clinical and EEG normalization is obtained after intravenous (IV) b enzodiazepine (BZ) injection. In some difficult cases, neuropsychological i nvestigations before and after BZ injection is useful: a significant improv ement of the neuropsychological score should occur following BZ injection. On a nosographic point of view, literature data indicate that 4 types of AS may be recognized. Typical AS occurs as par? of an idiopathic generalised epilepsy most often characterized by absences. Isolated impairment of consc iousness, at times with subtle jerks of the eyelids, is the essential sympt omatology. The EEG correlates with repetitive absence seizures and shows sy mmetric and bilateral synchronous SW or PSW complexes faster than 3 Hz. The immediate prognosis is excellent Atypical AS occurs in patients with sympt omatic or cryptogenic generalized epilepsies and is characterized by a fluc tuating confusional state with more prominent tonic and/or myoclonic and/or lateralized ictal manifestations than occur in typical AS. The EEG shows c ontinuous or intermittent diffuse irregular slow SW or PSW complexes. The i mmediate prognosis is guarded, as these episodes tend to recur and to be re sistant to medication. "De novo" absence status of late onset is characteri zed by toxic or metabolic precipitating factors in middle-aged or elderly s ubjects with no previous history of epilepsy. Patients often have a history of psychiatric illness with multiple psychotropic drug intake. The electro clinical characteristics and the immediate prognosis are variable. These ep isodes of AS generally represent acute symptomatic seizures and may not rec ur if the triggering factors can be controlled or corrected. Long-term anti epileptic drugs may thus not be needed. Absence status with focal character istics occur in subjects with a pre-existing or newly developing partial ep ilepsy, most often of extra-temporal origin. The EEG shows bilateral but of ten asymmetric ictal discharges. The immediate prognosis is variable. Some of these cases are difficult to distinguish from complex partial status epi lepticus of frontal lobe origin.