Prevalence of nonconvulsive status epilepticus in comatose patients

TLDR

Nonconvulsive status epilepticus is an often unrecognized cause of coma. The study aimed to determine how frequently NCSE occurs in comatose patients lacking overt seizure signs. EEG monitoring of 236 comatose patients, validated to detect >95 % of SE, revealed NCSE in those without clinical signs across ages 1 month to 87 years. Eight percent of the cohort met NCSE criteria, confirming it as an under‑recognized coma etiology and supporting routine EEG evaluation even when seizures are not clinically evident.

Abstract

Background: Nonconvulsive status epilepticus (NCSE) is a form of status epilepticus (SE) that is an often unrecognized cause of coma. Objective: To evaluate the presence of NCSE in comatose patients with no clinical signs of seizure activity. Methods: A total of 236 patients with coma and no overt clinical seizure activity were monitored with EEG as part of their coma evaluation. This study was conducted during our prospective evaluation of SE, where it has been validated that we identify over 95% of all SE cases at the Medical College of Virginia Hospitals. Only cases that were found to have no clinical signs of SE were included in this study. Results: EEG demonstrated that 8% of these patients met the criteria for the diagnosis of NCSE. The study included an age range from 1 month to 87 years. Conclusions: This large-scale EEG evaluation of comatose patients without clinical signs of seizure activity found that NCSE is an under-recognized cause of coma, occurring in 8% of all comatose patients without signs of seizure activity. EEG should be included in the routine evaluation of comatose patients even if clinical seizure activity is not apparent.