Assessing the outcomes in patients with nonconvulsive status epilepticus: nonconvulsive status epilepticus is underdiagnosed, potentially overtreated, and confounded by comorbidity

Abstract

Nonconvulsive status epilepticus (NCSE) is characterized by behavioral or cognitive change from baseline for at least 30 minutes with EEG evidence of seizures. Categorized into complex partial status epilepticus (with lateralized seizures), and generalized nonconvulsive status epilepticus (bilateral diffuse synchronous seizures), there is debate regarding the diagnosis and morbidity of NCSE. Because EEG is needed for diagnosis, only a high index of suspicion leads to a request for the study, whereas EEG is often unavailable after hours or on weekends. Furthermore, the cognitive changes during NCSE are often incorrectly ascribed to a postictal state, intoxication, psychogenic or psychotic states, and mental retardation. Regarding categorization, present classifications address EEG features but fail to distinguish among depths of coma. Deeply comatose patients (with coma etiologies that themselves carry poor prognoses) are mixed with lightly obtunded patients with no morbidity, confusing the prognosis. Thus, a classification that subsumes depth of coma, and possibly etiology, is sorely warranted. Regarding treatment, comatose NCSE patients treated with benzodiazepines may worsen, whereas generalized nonconvulsive status epilepticus patients may suffer iatrogenically from aggressive treatment (hypotension and respiratory depression) necessitating balancing the potential neurologic morbidity of NCSE against the possible morbidity of IV antiepileptic drugs. A high index of suspicion is needed to initiate EEG studies. Better stratification of level of consciousness will be needed to distinguish among morbidity due to underlying conditions, treatment, and the effects of status epilepticus, proper.