Abstracts

Rationale: Status epilepticus (SE) is seen frequently in the elderly. Refractory status epilepticus (RSE) is defined as persistence of SE after administration of one first-line (IV benzodiazepine) and one second-line medication (IV AED). New-onset refractory status epilepticus (NORSE) is defined as “patient without active epilepsy or other pre-existing relevant neurological disorder, with new onset of refractory status epilepticus without a clear acute or active structural, toxic, or metabolic cause.” We aimed to evaluate the clinical features, prognostic factors and outcomes in elderly patients with NORSE and compare those to RSE in established epilepsy (RSEiE). Methods: We prospectively identified and retrospectively collected data on patients with SE admitted to our tertiary care hospital between 2014 and 2017. Statistical analysis was done using Chi-square test, Fisher’s exact test and t-test to compare NORSE and RSEiE groups. Results: One hundred ninety-six patients were admitted during this period with diagnosis of SE, 90 of whom were elderly (age>60). Forty-three of the 90 had RSE. Among these 43 patients, 14 had NORSE and 27 had RSEiE. Two patients with anoxic brain injury were excluded. Elderly with NORSE had a higher mean age than RSEiE (72.8 versus 68 years, p=0.04, t=1.789). Majority of the elderly with NORSE were females (64.2% versus 37%, p=0.097). They also had a higher incidence of non-convulsive SE (NCSE) (85.7% vs 55.5%, p=0.053), and majority of them presented with NCSE (28.6% vs 7.4%, p=0.07). Duration of SE was also longer in elderly with NORSE which lasted over a day in 78.6% versus 44% in elderly with RSEiE (p=0.037, ?2=4.36). Elderly with NORSE had a higher proportion of patients with Status Epilepticus Severity score (STESS) =3 (92.3% vs 63%, p=0.04), modified STESS score of =4 (92.3% vs 52.3%, p=0.084), lower number of patients with a modified Rankin Scale score of =2 (14.3% vs 22.2%, p=0.54), and an overall higher in-hospital death rate (28.6% vs 11.1%, p=0.019, ?2=4.197). Conclusions: This retrospective study aims to describe and compare elderly with NORSE versus RSEiE. Older age of NORSE group suggests continued increased risk of SE with increasing age. Strong trends pointing towards the higher incidence of NCSE in the NORSE group at any point and NCSE on initial presentation may play a role in the significantly increased duration of SE in NORSE, especially in conjunction with increased in-hospital mortality. These elderly patients with NCSE, in view of increased mortality as shown in other studies, may need a more aggressive approach for treatment of SE and a lower threshold for EEG recording for altered sensorium. STESS scores were more often =3 in NORSE patients, which have been shown to predict a poor outcome and can help in early prognostication. No significant associations between independent variables and outcomes were seen which can be due to the small sample size and the retrospective nature of the study. In summary, elderly with NORSE were more likely to be older, with SE lasting >1 day, STESS scores =3 and greater in-hospital mortality. Funding: None