Abstracts

Rationale: There are currently no standard guidelines for the treatment of new-onset refractory status epilepticus (NORSE). However, immune modulatory therapies are often used in this setting given that an autoimmune process is frequently suspected although often not confirmed until late in the course. We assess the association between the use and timing of immune therapy and the underlying etiology, duration of SE and functional outcomes. Methods: We performed a multi-center, retrospective review of patients undergoing continuous EEG (cEEG) between January 2008 and December 2013 to identify patients fulfilling the following criteria: (1) age greater than or equal to 18 years; (2) refractoriness to first and second-line anticonvulsants; (3) no etiology identified within 48 hours of admission; and (4) antineuronal antibody panel ordered. We reviewed medical charts, including EEG reports, lab results, medication administration records, and imaging reports. Specifically, the timing, duration and dose of immune modulatory therapies were documented. Results: We identified 121 patients (80 women) with age ranging from 18 to 83 years. Detailed information was available for review in 116 cases. Seventy patients (60%) received at least one or a combination of the following immune therapies: steroids, intravenous immunoglobulin (IVIg), plasmapharesis, rituximab, or cyclophosphamide (Table 1). The most commonly used therapy was Methylprednisolone 1000 mg IV daily for 5 days. Forty-one patients (35%) received a combination of therapies with the most common being steroids and IVIg. Range of days from admit to immune therapy was 0-145 (median= 11). Etiologies of NORSE were categorized as the following: autoimmune, cryptogenic, infectious, and paraneoplastic. Immune therapy was employed more frequently in autoimmune and paraneoplastic etiologies versus infectious (p= 0.0015, Table 2). For cryptogenic cases, treatment was split almost equally between those receiving immune treatment and those who did not. Patients with prolonged SE lasting greater than or equal to 15 days were more likely to receive immune therapy (p= 0.0003). There was no significant association between the use of immune therapy and good functional outcome determined as modified Rankin Scale 0-3 (p= 0.4915). Conclusions: Immune modulatory therapy is commonly used in the setting of NORSE, particularly in cases with an autoimmune or paraneoplastic etiology. However, it is typically initiated in cases with more prolonged SE and likely not until later in the disease course from symptom onset. There was no significant association between good functional outcome and use of immune therapy in this retrospective case series, yet the use with longer durations of SE and probable delay in initiation from symptom onset is likely influencing this. Prospective studies are needed to evaluate the benefit of immune therapy with a more standardized approach with consideration of earlier use.