États de mal épileptiques à symptomatologie confusionnelle

Abstract

Non-convulsive confusional status epilepticus (NCSE) is classically separated into two forms on the basis of the ictal EEG, i.e., absence status (AS) and complex partial status epilepticus (CPSE). The diagnosis is difficult on the basis of clinical semiology alone, and requires emergency EEG investigation. Absence status, or ‘ petit mal’ status, is a polymorphic condition that can complicate many epileptic syndromes, and is the most frequently encountered form of NCSE. It is characterized by confusion of varying intensity, associated in 50% of cases with bilateral periocular myoclonias. The EEG shows ictal generalized paroximal activity; normalization is obtained after benzodiazepine injection. In AS, there is a significant nosographic heterogeneity. Four groups can be distinguished: i) typical AS occurs in the context of a generalized idiopathic epilepsy; ii) atypical AS occurs in patients with symptomatic or cryptogenic generalized epilepsies; iii) ‘de novo’ AS (of late onset) is characterized by toxic or metabolic precipitating factors in middle-aged subjects with no previous history of epilepsy; iv) AS with focal characteristics occurs in subjects with a pre-existing or newly diagnosed partial epilepsy, mostly of extra-temporal origin. The majority of cases are in fact transitional forms between these four groups. CPSE is characterized by continuous or rapidly recurring complex partial seizures which may involve temporal and/or extratemporal regions. Cyclic disturbance of consciousness is characteristic of CPSE of temporal lobe origin, which requires vigorous treatment to prevent recurrence or cognitive sequelae. CPSE of frontal lobe origin is a diagnostic challenge: it is rare, the symptoms are unusual, and the patients should be documented extensively. A focal frontal lesion is revealed in one-third of cases.