Prognosis in nonconvulsive status epilepticus

Abstract

Determining the prognosis in nonconvulsive status epilepticus (NCSE) is complicated by several factors: under-recognition of NCSE with its spontaneous resolution (thus decreasing the "denominator" of total cases that will have a poor outcome); incorrect diagnosis of NCSE based on misinterpretation of EEG "epileptiform" activity; mis-classification of certain EEG patterns as NCSE (e.g. PLEDs; triphasic waves); and grouping of different populations that have markedly different co-morbidities (ambulatory patients with NCSE together with comatose patients with electrographic seizure activity on EEG). There are almost no prospective studies with premorbid neuropsychometric studies, and retrospective studies typically include isolated cases, or case series that include conditions in which the cause of NCSE itself causes cognitive morbidity. To summarize available data, absence status (ambulatory generalized non-convulsive status epilepticus) would appear to carry no lasting morbidity. Complex partial status epilepticus in ambulatory patients rarely results in measurable permanent neurologic deficit, although rarely, short or long-standing deficits may clearly occur. Because intensive treatment with intravenous anticonvulsants (e.g. benzodiazepines or phenytoin) can confer morbidity, the equation has not yet been made as to whether the morbidity of such intensive treatment for all cases of NCSE exceeds the morbidity of the disease itself. Larger, prospective studies will be needed to truly determine the prognosis in the different types of NCSE, stratified according to associated degrees of impairment (minimally impaired, moderately obtunded, comatose).