40-4.12; p = 0.001 and RR 2.81, 95%CI 1.59-4.96; p < 0.0001). The estimated hazard ratio of death was 3.1 (95% CI1.6-6.0; p = 0.001) for patients with HE and 1.1 (95% CI 0.5-2.3; p = 0.745) for patients with brain tumors. RSE duration and nonconvulsive status epilepticus in coma were independently associated with death (for every hour RR 1.001; 95%CI 1.00-1.002; p = 0.011 and RR 3.62; 95%CI 1.34-9.77; p = 0.005). Significance: Brain tumors and HE had high relative risks for death and were independently associated with mortality in our cohort of critically ill RSE patients. Other clinical characteristics, as well as the use of intravenous anesthetic drugs and mechanical ventilation, may not be strongly related to outcome and should therefore be used cautiously for informed decision making regarding treatment. KEY WORDS: Refractory status epilepticus, Mortality, Hypoxic encephalopathy, Brain tumor, Neurocritical care.Refractory status epilepticus (RSE) is one of the most life-threatening neurologic emergencies and is characterized by high morbidity and mortality. This severe condition heralds a worse prognosis than treatment-responsive status epilepticus (SE) (Holtkamp et al., 2005;Rossetti et al., 2005), and serious outcome is considered to be mainly related to its etiology. Most studies propose the definition of RSE as a persistent SE after failure of a first-line (intravenous benzodiazepines) and one second-line antiepileptic drug (AED) (mostly phenytoin, valproate, levetiracetam, or phenobarbital), whereas others suggest a SE duration of >60 min (Hanley and Kross, 1998;Mayer et al., 2002). Despite the clinical and socioeconomic impact of RSE, current knowledge relies almost exclusively on retrospective assessments, its management on small case series, and expert opinions (Mayer et al., 2002;Holtkamp et al., 2005;Leppert et al., 2005;Rossetti et al., 2005;Holtkamp, 2011;Rossetti & Lowenstein, 2011). These reports suggest a frequency of RSE of up to 43% of all SE episodes, with nearly all subjects needing critical care and pharmacologic coma induction. Beyond these series one recent prospective study assessed frequency and clinical predictors of RSE emergence, and reported a 40% mortality in a tertiary clinical setting. However, the small sample size of 29 RSE episodes hinders inferences regarding the individual impact of different comorbidities (Novy et al., 2010). In order to respond to the discrepancy of important clinical and socioeconomic impact on the one hand and lack of larger and quantifying studies on the other hand, the Innsbruck Colloquium on SE held in April 2009, underscored the urgent need for more investigations in this field.

This study is the first independent external validation of the predictive accuracy of the Status Epilepticus Severity Score and its transportability to ICU patients with status epilepticus. Measures of discrimination and calibration indicated that Status Epilepticus Severity Score performed reasonably well on our cohort of ICU patients with status epilepticus. However, the specific optimal cutoff point for survival versus death in our cohort was different than proposed.

Background and Purpose— Intravenous thrombolysis for acute ischemic stroke is usually based on clinical assessment, blood test results, and CT findings. Intravenous thrombolysis of stroke mimics may occur but has not been studied in detail. Methods— We determined frequency, clinical characteristics, and outcome of mimic patients versus patients with stroke treated with intravenous thrombolysis using data of a prospective, single-center thrombolysis data bank. Results— Among 250 patients, 243 (97.2%) had strokes and 7 (2.8%) were mimics. Seizure was the most frequent diagnosis among mimics. There was a trend toward lower National Institutes of Health Stroke Scale scores in mimics (9.9±4.2) compared with strokes (13.7±5.4; P =0.06). Global aphasia without hemiparesis was the presenting symptom in 3 (42.9%) mimics versus 8 (3.3%) strokes ( P =0.002). Orolingual angioedema, symptomatic intracranial hemorrhage, and asymptomatic intracranial hemorrhage occurred in 3 (1.2%), 13 (5.3%), and 30 (12.3%) patients with stroke, but were absent in mimics. After 3 months, 6 (85.7%) mimics and 86 (35.4%) strokes had a modified Rankin Scale score of 0 to 1 ( P =0.01). Conclusions— Only few patients receiving intravenous thrombolysis did eventually have a final diagnosis other than stroke, ie, mostly seizures. Their outcome was favorable. Although clinical features differed between the stroke and the mimic groups, the differences were not distinctive enough to allow assigning individual patients to either of the groups. Multimodal neuroimaging or electroencephalographic recordings may be helpful for this assignment. However, their potential benefit has to be weighed against the potential harm of delayed thrombolysis.

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There is emerging evidence for multifarious neurological manifestations of coronavirus disease 2019 (COVID‐19), but little is known regarding whether they reflect structural damage to the nervous system. Serum neurofilament light chain (sNfL) is a specific biomarker of neuronal injury. We measured sNfL concentrations of 29 critically ill COVID‐19 patients, 10 critically ill non–COVID‐19 patients, and 259 healthy controls. After adjusting for neurological comorbidities and age, sNfL concentrations were higher in patients with COVID‐19 versus both comparator groups. Higher sNfL levels were associated with unfavorable short‐term outcome, indicating that neuronal injury is common and pronounced in critically ill patients. ANN NEUROL 2021;89:610–616