A Study on the Clinical and Electrographic Profile of Nonconvulsive Status Epilepticus (NCSE) in Comatose ICU Patients Using Portable Electroencephalography (EEG)

Background: Coma is one of the frequently encountered clinical conditions in any intensive care unit (ICU), which is responsible for considerable morbidity and mortality. Therefore, this study was designed to look at the clinical and EEG profile of Nonconvulsive Status Epilepticus (NCSE) in comatose ICU patients using portable electroencephalography (EEG).

Methods: In all 102 patients of unresponsive coma (GCS ≤ 8), who remained in poor sensorium despite 48 h of optimum treatment in ICU, were included in the study. All patients underwent 1 h of electroencephalography (EEG) monitoring with a portable EEG machine. All EEGs were screened according to Salzburg Consensus Criteria (SCC) for Nonconvulsive Status Epilepticus (NCSE). Patients with evidence of NCSE were administered parenteral Antiepileptic Drugs (AED). A repeat EEG was done after 24 h of baseline to ascertain the effect of AED. The primary outcome was the recognition of patients with NCSE on the basis of established EEG criteria. The secondary outcome measure was the Glasgow outcome scale (GOS) at the time of discharge.

Results: Out of 102 cases enrolled, 12 (11.8%) cases were detected to have NCSE on portable EEG. The mean age of patients with NCSE was 52.2 years. In terms of gender distribution, 2/12 (17%) were female, and 10/12 (83%) were male (M: F = 5:1). Median GCS was 6 (range 3-8). Looking at CNS infections, 4/12 (33.3%) had evidence of some form of CNS infection in the NCSE group, compared to 16/90 (18%) in the group without NCSE. This difference was statistically significant (P-value < 0.05). The EEG recordings of patients with NCSE showed dynamicity with fluctuating rhythms and ictal-EEG patterns associated with spatiotemporal evolution. All twelve cases showed reversal of EEG changes with AED administration. In 5 out of 12, transient improvement in GCS (>2 points) after administration of AED' was noted with good clinical outcomes (GOS 5). In five of these 12 cases, death was the final outcome (GOS 1).

Conclusions: NSCE should be considered in the differential diagnosis of all unresponsive comatose ICU patients. In resource-limited settings, where continuous EEG monitoring may not be feasible, bedside portable EEG testing can be used to diagnose patients with NCSE. Treating NCSE reverses epileptiform EEG changes and improves clinical outcomes in a subset of comatose ICU patients.