Rationale: New-Onset Refractory Status Epilepticus (NORSE) is a rare life-threatening condition in previously healthy patients who develop new-onset medically-refractory status epilepticus of unclear etiology.1NORSE commonly leads to super-refractory status epilepticus (SRSE), a severe form of status epilepticus for which seizures persist despite 24 hours of adequate anti-seizure and anesthetic treatment. The goal of this study is to examine the clinical characteristics and epidemiology of super-refractory NORSE, a subset of SRSE, to determine risk and prognostic factors associated with this rare condition, and mortality rates.
Methods: We performed a retrospective cohort study of all cases of SRSE admitted to Oregon Health & Science University, an academic tertiary care center between 2007 and 2016.
Results: Among 358 patients monitored on continuous EEG for at least 4 days in a single admission, 67 (19%) were identified as having SRSE. In-hospital mortality for SRSE (all causes) was 30% (20), but for the specific NORSE group 15% (2), for pre-existing epilepsy 40% (4) and for symptomatic 32% (14).
Conclusions: The results of this study are consistent with prior reports of NORSE epidemiology: the condition is rare, patients tend to be younger, female-predominate, and there have been no antibodies clearly-associated with the condition. A novel finding in this study was that 50% of NORSE cases had positive antibody testing– the majority of which were thyroid-associated antibodies (41.7%). Based on a population-based study at baseline of 5783 participants, 12.8% were positive for TPO antibodies with a higher prevalence in women compared to men.2 While thyroid-associated antibodies are thought to be non-specific markers of inflammation and/or autoimmunity, this supports the hypothesis that NORSE (or a subset of NORSE cases) may be autoimmune-mediated and establishes a potential autoimmune link
