(1362) New-Onset Refractory Status Epilepticus: Retrospective Analysis and Developing a Practice Guideline

Introduction: New onset refractory status epilepticus (NORSE) is a clinical syndrome that occurs in patients without active epilepsy or other relevant pre-existing neurological disorder and without a clear acute structural, toxic, or metabolic cause. It is estimated that NORSE accounts for 20% of refractory status epilepticus (RSE) cases, making it a common entity encountered in the neurological intensive care. Additionally, this syndrome is complex and associated with significant comorbidities. In a review of 125 cases, the most common identified etiologies were autoimmune (19%) and paraneoplastic (18%) encephalitis while 50% remained cryptogenic. Poor outcome occurred in 77 of 125 cases (62%), and 28 (22%) patients died. As a result, the development of a clinical practice guideline (CPG) to instill a consistent approach when treating this complex patient population is of paramount importance.

Methods: An analysis of 4 retrospective studies on patients suspected to have NORSE. Specific characteristics of each cohort were noted, including cerebrospinal fluid (CSF) profile and additional test results, MRI patterns, duration of status epilepticus, description of electroencephalogram (EEG) pattern, steroid use, immunosuppressant use, among others. This data was used to develop an institutional CPG.

Results: A CPG was authored in a decision tree format. Notable guidance includes specific timing and types of diagnostic tests, explicit CSF and serum tests to be ordered, seizure treatment escalation, MRI protocols and timing, criteria for first and second line treatment, and conditions required for repeat testing of any of the above.

Conclusions: While NORSE, overall, is a rare neurological entity, it is a common cause of RSE. Our literature appraisal aided in the development of a CPG to more consistently evaluate and treat these patients in an attempt to improve neurological outcomes in a treatable condition. Interestingly, based on a survey of providers included in the Neurocritical Care Society emailing list from 2014, nearly 66% of institutions did not employ a protocol to evaluate a patients with NORSE. Additionally, 25% would not perform an autoimmune or paraneoplastic evaluation. We intend on employing a retrospective and prospective evaluation to better assess the impact of our CPG.