[Non-convulsive status epilepticus]

Non-convulsive status epilepticus (NCSE) is an epileptic condition lasting more than 30 minutes in which continuous or recurrent seizure activity on the electroencephalogram (EEG) is responsible for diverse clinical symptoms including alteration of mental state, abnormal behaviour, perception disturbances or consciousness impairment. Most authors recognize two types of NCSE depending on the ictal electroencephalographic changes: generalized (absence status epilepticus) and complex partial status epilepticus (CPSE). In addition, there is also a simple form of partial status which is likely underdiagnosed because of its frequent progression to CPSE, subtle and varied symptomatology and high proportion of normal electroencephalograms (EEG). Absence status epilepticus (ASE) may occur in different clinical situations including idiopathic generalized epilepsy (typical AS), symptomatic generalized epilepsy (atypical AS), and elderly subjects without antecedents of epilepsy on chronic treatment with psychotropic drugs (de novo AS of late onset). Furthermore, CPSE is more frequent than previously mentioned. Although initially was equated with temporal lobe status epilepticus, extratemporal cases of CPSE have been well-documented, and the electroclinical characteristics of two types (I and II) of frontal CPSE have been recently described. NCSE may occur in patients with diverse clinical diagnosis such as hypoxic-anoxic encephalopathy, cancer, drugs, autoimmune disorders, Creutzfeldt-Jakob disease, chromosomal alterations, peritoneal dialysis, infections, cerebral hamartomas or head trauma.

The identification of NCSE may be particularly arduous and, therefore, a high level of suspicion is essential to obtain an early diagnosis. An urgent EEG with administration of intravenous benzodiazepines is considered as the method of choice in the diagnostic evaluation of NCSE.