Abstracts

Rationale: New onset refractory status epilepticus (NORSE) is an increasingly recognized form of SE characterized by refractoriness and no known immediate cause. Methods: We performed a retrospective review of patients undergoing continuous EEG (CEEG) databases from 12 tertiary medical centers of the period between January 2008 and December 2013 to identify the following patients fulfilling our inclusion criteria: (1) age > 18 years; (2) refractoriness to first and second line anticonvulsants; (3) autoimmune/paraneoplastic panel ordered; and (4) CEEG for at least 24h. We reviewed medical charts, EEG, lab results and imaging reports. Results: We identified 121 patients (80 women) with age ranging from 18 to 83 years, with a bimodal distribution (peaks at 27 and 69 years). An etiology was found in 60 (48%) cases (Table 1). Sixty-two (51%) cases remained cryptogenic despite an extensive work-up. Detailed information was available for review in 116 cases. Twenty-eight (24%) patients responded to conventional anticonvulsants, while 88 (76%) required anesthetic treatment, including 38 (33%) requiring more than one anesthetic. SE was ultimately controlled in 102 (88%). Median SE duration was 4 days (range: 0-169 days) and longer in cryptogenic cases (median of 6 vs. 3 days; p<0.01). Twenty-six patients (22%) died and 46 (40%) achieved a good outcome (modified Rankin Scale (MRS) 0-3) at discharge, including 4 (3%) without any disabilities. Causes of death included uncontrolled SE (14 [12%]), sepsis (8 [7%]) and cardiac arrest (4 [3%]). Care was withdrawn in 10 patients (9%). All survivors had epilepsy at time of last follow-up. In a multivariate logistic regression model including determinants of outcome (age, type of SE, level of consciousness on admission, complications, type and number of anesthetic drugs used, and duration of SE), the use of pentobarbital (OR: 2.6 [95% CI 1.0-6.4]), need for vasopressors (OR: 2.0 [95% CI 1.0-4.1]), acute renal failure (4.7 [95% CI 1.5-14.8]), and pneumonia (2.4 [95% CI 1.3-4.3]) were independent predictors of poor outcome (MRS 4-6). Conclusions: An autoimmune process commonly causes NORSE, although half of the cases remained cryptogenic in our cohort and other etiologies should be considered. Refractoriness varies, with 70% of patients receiving anesthetic treatment. The use of pentobarbital, need for vasopressors, acute renal failure, and pneumonia, but not anesthetic use, were associated with mortality.