Is rat hippocampus section immunostaining an indicator for immunotherapy in cryptogenic adult new-onset refractory status epilepticus (NORSE)?

Risk factors for super-refractory and mortality in generalized convulsive status epilepticus: a 10-year retrospective cohort study

Background

Generalized convulsive status epilepticus (GCSE) is one of the most challenging life-threatening neurological emergencies. If GCSE becomes super-refractory, it is associated with significant mortality. Although aggressive management of prolonged status epilepticus was conducted, the mortality has not decreased since the late 1990s.

Objectives

The present study aimed to explore the risk factors for progression to super-refractory in patients with generalized convulsive status epilepticus (GCSE). Moreover, we illustrated the risk factors for mortality in GCSE patients.

Design

An observational retrospective cohort study.

Methods

We conducted a retrospective study of patients with GCSE admitted to our neurocritical unit, in Guangzhou, China, from October 2010 to February 2021. The data of sociodemographic information, etiology, laboratory results, treatment, and prognosis were collected and analyzed.

Results

A total of 106 patients were enrolled; 51 (48%) of them developed super-refractory status epilepticus (SRSE). Multivariate logistic regression analysis demonstrated that patients with autoimmune encephalitis (p = 0.015) and intracranial infection (p = 0.019) are likely to progress to SRSE. The in-hospital mortality was 11.8% and 9.1% for patients in the SRSE and non-SRSE groups, respectively (p = 0.652). Multivariate logistic regression analysis showed that neutrophil-to-lymphocyte ratios (NLR) at admission were independently associated with in-hospital mortality. Up to 31.4% of SRSE patients and 29.1% of non-SRSE patients died within 6 months after discharge (p = 0.798). Multivariate logistic regression analysis showed that plasma exchange (PE) was a protective factor for 6-month mortality. A high NLR at discharge was a risk factor for 6-month mortality.

Conclusion

In the current study, about 48% of GCSE patients progressed to SRSE. Regarding etiology, autoimmune encephalitis or intracranial infection was prone to SRSE. No significant differences were observed in the in-hospital and 6-month mortality between SRSE and non-SRSE groups. Multivariate logistic regression analysis showed that NLR at admission and discharge was an independent predictor of in-hospital and 6-month mortality, respectively. Moreover, PE significantly reduced the 6-month mortality.

Review and standard operating procedures for collection of biospecimens and analysis of biomarkers in new onset refractory status epilepticus

New onset refractory status epilepticus (NORSE), including its subtype with a preceding febrile illness known as febrile infection-related epilepsy syndrome (FIRES), is one of the most severe forms of status epilepticus. The exact causes of NORSE are currently unknown, and there is so far no disease-specific therapy. Identifying the underlying pathophysiology and discovering specific biomarkers, whether immunologic, infectious, genetic, or other, may help physicians in the management of patients with NORSE. A broad spectrum of biomarkers has been proposed for status epilepticus patients, some of which were evaluated for patients with NORSE. Nonetheless, none has been validated, due to significant variabilities in study cohorts, collected biospecimens, applied analytical methods, and defined outcome endpoints, and to small sample sizes. The NORSE Institute established an open NORSE/FIRES biorepository for health-related data and biological samples allowing the collection of biospecimens worldwide, promoting multicenter research and sharing of data and specimens. Here, we suggest standard operating procedures for biospecimen collection and biobanking in this rare condition. We also propose criteria for the appropriate use of previously collected biospecimens. We predict that the widespread use of standardized procedures will reduce heterogeneity, facilitate the future identification of validated biomarkers for NORSE, and provide a better understanding of the pathophysiology and best clinical management for these patients.

The etiology and mortality of new-onset refractory status epilepticus (NORSE) in adults: A systematic review and meta-analysis

New-onset refractory status epilepticus (NORSE) is a devastating neurological presentation. There is a paucity of large studies on NORSE as it is a relatively new clinical syndrome. The aim of this review was to summarize the etiologies and establish a mortality rate for NORSE. Two independent authors systematically searched the following electronic databases from January 1, 2005 April 20, 2021: PubMed, Embase, OVID, Scopus, Web of Science, "Clinicaltrials.gov," and the International Standard Randomised Controlled Trial Number (ISRCTN) registry. We included all primary research studies of NORSE in adults and excluded commentaries, reviews, pre-clinical studies, and pediatric populations. Etiology was extracted from all studies meeting eligibility criteria, whereas data relating to treatments, hospital stay, functional outcomes, and mortality were extracted from studies with sample size ≥5. We conducted a random-effects meta-analysis of mortality rate with meta-regression testing for significant covariates. Of 1482 studies, 109 case reports and case series met our criteria, comprising 395 cases of NORSE. The most common etiology was cryptogenic in 197 cases (49.9%), followed by autoimmune in 143 cases (36.2%). The pooled mortality rate was 22% (95% confidence interval 17%-27%; N studies  = 15), with low heterogeneity ( I 2  = 0%). Meta-regression revealed that year of study, treatment with ketogenic diet or immunotherapy, percentage of cryptogenic cases, and length of intensive care unit stay were not significant covariates for mortality. Common treatments included antiseizure medications (median 5), general anesthesia, and immunotherapy such as corticosteroids, intravenous immunoglobulin, and plasma exchange. Mean length of intensive care admission was 33.4 days, with 52% of cases diagnosed with epilepsy on discharge. Neurocognitive impairment was a common sequela of NORSE. NORSE is associated with a high mortality. Half of cases remain cryptogenic, which presents a diagnostic challenge. Future focus should be on elucidating the underlying neurobiology and determining the most effective therapeutic interventions.

Multi-proteomic Analysis Revealed Distinct Protein Profiles in Cerebrospinal Fluid of Patients Between Anti-NMDAR Encephalitis NORSE and Cryptogenic NORSE

New-onset refractory status epilepticus (NORSE) is rare but intractable. Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis and cryptogenic etiologies are the two major causes of NORSE with distinct clinical features. To elucidate the underlying mechanisms, 6 patients with anti-NMDAR encephalitis NORSE and 5 with cryptogenic NORSE (C-NORSE) were enrolled. Five patients of cerebrovascular disorders were used as controls. Quantitative proteomic analysis of the cerebrospinal fluid (CSF) samples of the patients revealed 101 and 56 proteins were changed, respectively. The average fold-change of the upregulated proteins, namely up-proteomic score in this study, was positively correlated with the severity and prognosis of the diseases, including ICU stay (r = 0.9308, P = 0.0035 in NMDAR group; r = 0.8977, P = 0.0193 in C-NORSE group), mRS score at discharge (r = 0.9710, P = 0.0111 in NMDAR group; r = 0.7071, P = 0.2000 in C-NORSE group), and time taken for patients awaking from a coma (r = 0.8823, P = 0.0100 in NMDAR group; r = 0.7906, P = 0.2000 in C-NORSE group). Pathways involved in humoral immune response, wound healing, and epigenetic regulation of transcription were upregulated in anti-NMDAR encephalitis NORSE. Pathways of innate and lymphocyte mediated immune response, synaptic functions, ubiquitination, and cell apoptosis were up-regulated in C-NORSE, which was consistent with a mouse model of status epilepticus. Fc receptor and B cell mediated immunity signaling pathways were downregulated in C-NORSE. Immunome microarray analysis demonstrated high autoantibody targeting 48 proteins in CSF samples of anti-NMDAR encephalitis NORSE. While the reaction was kept at a very low level in C-NORSE. There is no significant difference in inflammatory cytokine level between each group. The level of IL-4 (r = 0.7435, P = 0.0451), IL-13 (r = 0.7643, P = 0.0384), IFN-γ (r = 0.7973, P = 0.0287) and TNF-α (r = 0.8598, P = 0.0141) in NMDAR group, and IL-6 (r = 0.8479, P = 0.0348), IL-8 (r = 0.9076, P = 0.0166) in C-NORSE group were positively correlated with the up-proteomic score. The present study suggests that the up-proteomic score of CSF could be a promising indicator for assessment of the severity of anti-NMDAR encephalitis NORSE and C-NORSE. The distinct CSF proteomes imply different pathogenic mechanisms of the two diseases, and immunotherapy strategies as well.