Clinically based score predicting cryptogenic NORSE at the early stage of status epilepticus

Autoimmune-associated seizure disorders

With the discovery of an expanding number of neural autoantibodies, autoimmune etiologies of seizures have been increasingly recognized. Clinical phenotypes have been identified in association with specific underlying antibodies, allowing an earlier diagnosis. These phenotypes include faciobrachial dystonic seizures with LGI1 encephalitis, neuropsychiatric presentations associated with movement disorders and seizures in NMDA-receptor encephalitis, and chronic temporal lobe epilepsy in GAD65 neurologic autoimmunity. Prompt recognition of these disorders is important, as some of them are highly responsive to immunotherapy. The response to immunotherapy is highest in patients with encephalitis secondary to antibodies targeting cell surface synaptic antigens. However, the response is less effective in conditions involving antibodies binding intracellular antigens or in Rasmussen syndrome, which are predominantly mediated by cytotoxic T-cell processes that are associated with irreversible cellular destruction. Autoimmune encephalitides also may have a paraneoplastic etiology, further emphasizing the importance of recognizing these disorders. Finally, autoimmune processes and responses to novel immunotherapies have been reported in new-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES), warranting their inclusion in any current review of autoimmune-associated seizure disorders.

Febrile infection-related epilepsy syndrome with claustrum lesion: an underdiagnosed inflammatory encephalopathy

OBJECTIVE

To summarize the clinical characteristics and prognosis of febrile infection-related epilepsy syndrome with claustrum lesions (FIRES-C).

METHOD

Clinical data of FIRES-C patients were collected retrospectively. The study reviewed and analyzed their clinical manifestations, treatment strategies, and prognosis.

RESULT

Twenty patients were enrolled, including 13 females and 7 males, with a median onset age of 20.5 years. All patients developed seizures after fever, with a median interval of 5 days. Brain MRI showed symmetric lesions in the claustrum in all patients. The median interval from seizure onset to abnormal MRI signals detection was 12.5 days. All patients had negative results for comprehensive tests of neurotropic viruses and antineuronal autoantibodies. Seventy percent of cases had been previously empirically diagnosed with autoimmune encephalitis or viral encephalitis before. All patients received anti-seizure medicine. Eleven patients (55%) received antiviral therapy. All patients received immunotherapy, including glucocorticoids (100%), intravenous immunoglobulin (IVIg) (65%), plasma exchange (PLEX) (10%), tocilizumab (10%), rituximab (5%), and cyclophosphamide (5%). Sixty percent of patients received long-term immunotherapy (≥ 3 months). The median follow-up was 11.5 months;60% of patients were diagnosed with refractory epilepsy.

CONCLUSION

Bilateral claustrum lesion on MRI is a distinctive neuroimage feature for FIRES, which may serve as an indication for the initial clinical assessments. FIRES-C should be classified as a type of inflammatory encephalopathy characterized by a monophasic nature. Some FIRES-C patients respond to immunotherapy and antiseizure treatments but most experience refractory epilepsy as a long-term outcome.

[Clinical characteristics of seizure-predominant autoimmune encephalitis and utility of anti-neuronal antibody scores for early treatment]

We analyzed 20 patients diagnosed with autoimmune neurological diseases with seizure predominance. In these patients, we examined the usefulness of Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and Antibodies Contributing to Focal Epilepsy Signs and Symptoms (ACES) score in autoimmune encephalitis (AE) for facilitating early treatment. APE2 score was positive in 19 of 20 patients. ACES score was positive in 15 of 20 patients, and 4 of 5 of the patients with negative ACES score did not have AE. Comprehensive assessment including the use of the above scores is desirable in the early stage of AE.

Time to FIRE NORSE: A single acronym for a heterogeneous presentation. Further information from a case series and discussion of the literature

PURPOSE

New-Onset Refractory Status Epilepticus (NORSE) is a rare and severe form of refractory status epilepticus without an apparent underlying cause at presentation or prior history of epilepsy. We aimed to describe the clinical features, etiology, treatment, and outcomes of NORSE in adults in a quaternary-level hospital in Saudi Arabia.

METHODOLOGY

In this retrospective cohort study, inclusion criteria involved patients over 14 years old who met the 2018 consensus definition for NORSE. Patients were identified using a combination of medical record admission labels 'status epilepticus' and 'encephalitis', and continuous EEG reports documenting status epilepticus. Demographic, clinical, and radiological data were collected and then analyzed for factors correlated with specific etiologies, better functional outcomes, and future diagnosis of epilepsy.

RESULTS

We found 24 patients presenting with NORSE between 2010 and 2021. Fever/infectious symptoms were the most common prodrome. Elevated inflammatory serum and cerebrospinal fluid markers in most patients. Brain MRI revealed T2/FLAIR hyperintensity patterns, predominantly affecting limbic and perisylvian structures. The etiology of NORSE varied, with immune-related causes being the most common. Long-term outcomes were poor, with a high mortality rate and most survivors developing drug-resistant epilepsy.

CONCLUSION

This study provides valuable insights into NORSE's clinical characteristics, highlighting the heterogeneity of this condition. The poor outcome is likely related to the progressive nature of the underlying disease, where refractory seizures are a clinical symptom. Thus, we propose to focus future research on the etiology rather than the NORSE acronym.

Neuromodulation in new-onset refractory status epilepticus

Background

New-onset refractory status epilepticus (NORSE) and its subset of febrile infection-related epilepsy syndrome (FIRES) are devastating clinical presentations with high rates of mortality and morbidity. The recently published consensus on the treatment of these conditions includes anesthetics, antiseizure drugs, antivirals, antibiotics, and immune therapies. Despite the internationally accepted treatment, the outcome remains poor for a significant percentage of patients.

Methods

We conducted a systematic review of the use of neuromodulation techniques in the treatment of the acute phase of NORSE/FIRES using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results

Our search strategy brought up 74 articles of which 15 met our inclusion criteria. A total of 20 patients were treated with neuromodulation. Thirteen cases represented FIRES and in 17 cases the NORSE remained cryptogenic. Ten had electroconvulsive therapy (ECT), seven had vagal nerve stimulation (VNS), and four had deep brain stimulation (DBS); one patient had initially VNS and later DBS. Eight patients were female and nine were children. In 17 out of 20 patients, the status epilepticus was resolved after neuromodulation, while three patients died.

Conclusion

NORSE can have a catastrophic course and the first treatment goal should be the fastest possible termination of status epilepticus. The data presented are limited by the small number of published cases and the variability of neuromodulation protocols used. However, they show some potential clinical benefits of early neuromodulation therapy, suggesting that these techniques could be considered within the course of FIRES/NORSE.

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.

New-onset refractory status epilepticus and febrile infection-related epilepsy syndrome

PURPOSE OF REVIEW

The concept and understanding of new-onset refractory status epilepticus (NORSE), and its subtype with prior fever known as febrile infection-related epilepsy syndrome (FIRES) have evolved in the recent past. This review aims to summarize the recent developments in the pathophysiology, diagnosis and management of these challenging conditions.

RECENT FINDINGS

NORSE and FIRES can have many different causes. Although the list of possible causes is still growing, they mostly fall in the categories of autoimmune encephalitis and genetic disorders. However, despite extensive investigations, most cases of NORSE and FIRES remain cryptogenic. Recent studies have pointed towards the key role of autoinflammation as a unifying pathophysiological mechanism in these cases. These findings also support the use of immunomodulatory treatment in this setting. Consensus recommendations on the management of NORSE and FIRES have recently been published.

SUMMARY

NORSE and FIRES remain challenging conditions to diagnose and treat. Recent findings from clinical and basic research and new recommendations, reviewed in this article, contribute to an emerging framework for management and future research.

Reversible Brain Atrophy in Cryptogenic New-onset Refractory Status Epilepticus: A Case Report

Cryptogenic new-onset refractory status epilepticus (C-NORSE) is a neurologic emergency condition characterized by refractory status epilepticus (RSE) of unknown cause. Brain atrophy in a setting of C-NORSE is usually irreversible. A 33-year-old woman who was highly suspected of C-NORSE once showed mild frontotemporal atrophy on brain magnetic resonance imaging (MRI), but follow-up MRI revealed recovery of the brain atrophy. Her cognitive function also gradually improved, with a reduction in seizure frequency. Early initiation of intensive immunotherapy with anti-seizure medications may have minimized irreversible brain damage associated with RSE, resulting in a relatively good outcome.

International consensus recommendations for management of New Onset Refractory Status Epilepticus (NORSE) incl. Febrile Infection-Related Epilepsy Syndrome (FIRES): Statements and Supporting Evidence

OBJECTIVE

To develop consensus-based recommendations for the management of adult and paediatric patients with NORSE/FIRES based on best evidence and experience.

METHODS

The Delphi methodology was followed. A facilitator group of 9 experts was established, who defined the scope, users and suggestions for recommendations. Following a review of the current literature, recommendation statements concerning diagnosis, treatment and research directions were generated which were then voted on a scale of 1 (strongly disagree) to 9 (strongly agree) by a panel of 48 experts in the field. Consensus that a statement was appropriate was reached if the median score was greater or equal to 7, and inappropriate if the median score was less than or equal to 3. The analysis of evidence was mapped to the results of each statement included in the Delphi survey.

RESULTS

Overall, 85 recommendation statements achieved consensus. The recommendations are divided into five sections: 1) disease characteristics, 2) diagnostic testing and sampling, 3) acute treatment, 4) treatment in the post-acute phase, and 5) research, registries and future directions in NORSE/FIRES. The detailed results and discussion of all 85 statements are outlined herein. A corresponding summary of findings and practical flowsheets are presented in a companion article.

SIGNIFICANCE

This detailed analysis offers insight into the supporting evidence and the current gaps in the literature that are associated with expert consensus statements related to NORSE/FIRES. The recommendations generated by this consensus can be used as a guide for the diagnosis, evaluation, and management of patients with NORSE/FIRES, and for planning of future research.

Autoantibody Encephalitis: Presentation, Diagnosis, and Management

Autoantibody encephalitis causes distinct clinical syndromes involving alterations in mentation, abnormal movements, seizures, psychiatric symptoms, sleep disruption, spasms, and neuromyotonia. The diagnoses can be confirmed by specific antibody tests, although some antibodies may be better detected in spinal fluid and others in serum. Each disorder conveys a risk of certain tumors which may inform diagnosis and be important for treatment. Autoantibodies to receptors and other neuronal membrane proteins are generally thought to be pathogenic and result in loss of function of the targets, so understanding the pharmacology of the receptors may inform our understanding of the syndromes. Patients may be profoundly ill but the syndromes usually respond to immune therapy, although there are differences in the types of immune therapy that are thought to be most effective for the various disorders.

Management of Status Epilepticus, Refractory Status Epilepticus, and Super-refractory Status Epilepticus

PURPOSE OF REVIEW

Status epilepticus is a serious condition caused by disorders and diseases that affect the central nervous system. In status epilepticus, hypersynchronous epileptic activity lasts longer than the usual duration of isolated self-limited seizures (time t1), which causes neuronal damage or alteration of neuronal networks at a certain time point (time t2), depending on the type of and duration of status epilepticus. The successful management of status epilepticus includes both the early termination of seizure activity and the earliest possible identification of a causative etiology, which may require independent acute treatment. In nonconvulsive status epilepticus, patients present only with subtle clinical signs or even without any visible clinical manifestations. In these cases, EEG allows for the assessment of cerebral function and identification of patterns in need of urgent treatment.

RECENT FINDINGS

In 2015, the International League Against Epilepsy proposed a new definition and classification of status epilepticus, encompassing four axes: symptomatology, etiology, EEG, and age. Various validation studies determined the practical usefulness of EEG criteria to identify nonconvulsive status epilepticus. The American Clinical Neurophysiology Society has incorporated these criteria into their most recent critical care EEG terminology in 2021. Etiology, age, symptomatology, and the metabolic demand associated with an increasing duration of status epilepticus are the most important determinants of prognosis. The consequences of status epilepticus can be visualized in vivo by MRI studies.

SUMMARY

The current knowledge about status epilepticus allows for a more reliable diagnosis, earlier treatment, and improved cerebral imaging of its consequences. Outcome prediction is a soft tool for estimating the need for intensive care resources.

Unraveling the enigma of new-onset refractory status epilepticus: a systematic review of aetiologies

BACKGROUND AND PURPOSE

New-onset refractory status epilepticus (NORSE) is a clinical presentation, neither a specific diagnosis nor a clinical entity. It refers to a patient without active epilepsy or other pre-existing relevant neurological disorder, with a NORSE without a clear acute or active structural, toxic or metabolic cause. This study reviews the currently available evidence about the aetiology of patients presenting with NORSE and NORSE-related conditions.

METHODS

A systematic search was carried out for clinical trials, observational studies, case series and case reports including patients who presented with NORSE, febrile-infection-related epilepsy syndrome or the infantile hemiconvulsion-hemiplegia and epilepsy syndrome.

RESULTS

Four hundred and fifty records were initially identified, of which 197 were included in the review. The selected studies were retrospective case-control (n = 11), case series (n = 83) and case reports (n = 103) and overall described 1334 patients both of paediatric and adult age. Aetiology remains unexplained in about half of the cases, representing the so-called 'cryptogenic NORSE'. Amongst adult patients without cryptogenic NORSE, the most often identified cause is autoimmune encephalitis, either non-paraneoplastic or paraneoplastic. Infections are the prevalent aetiology of paediatric non-cryptogenic NORSE. Genetic and congenital disorders can have a causative role in NORSE, and toxic, vascular and degenerative conditions have also been described.

CONCLUSIONS

Far from being a unitary condition, NORSE is a heterogeneous and clinically challenging presentation. The development and dissemination of protocols and guidelines to standardize diagnostic work-up and guide therapeutic approaches should be implemented. Global cooperation and multicentre research represent priorities to improve the understanding of NORSE.

Status epilepticus suspected autoimmune: Neuronal surface antibodies and main clinical features

OBJECTIVES

Status epilepticus (SE) can be associated with neuronal surface antibodies (NS-Abs) but NS-Ab detection rate remains unknown in patients with SE of unclear etiology at symptom presentation but suspected of having an autoimmune etiology (SE suspected autoimmune). We aimed to determine the NS-Ab detection rate and the clinical features that predict the presence of NS-Abs in patients with SE suspected autoimmune.

METHODS

We retrospectively reviewed the clinical information of 137 patients with SE suspected autoimmune who underwent testing for NS-Abs between January 2007 and September 2020. NS-Abs were examined in both serum and cerebrospinal fluid (CSF) obtained at symptom onset with established assays. We classified brain magnetic resonance imaging (MRI) findings into unremarkable, autoimmune limbic encephalitis (ALE) (bilateral abnormalities highly restricted to the medial temporal lobes), ALE-Plus (ALE pattern and additional extramedial temporal lobe abnormalities), multifocal cortico-subcortical (MCS), or other pattern. We compared the clinical features between patients with and without NS-Abs.

RESULTS

Forty-four patients (32.1%) had NS-Abs, including 35 N-methyl-d-aspartate receptor (NMDAR) (one with concurrent γ-aminobutyric acid B receptor [GABAbR] and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor [AMPAR]), 5 γ-aminobutyric acid A receptor (GABAaR), 2 leucine-rich glioma-inactivated 1(LGI1), 1 GABAbR, and 1 unknown antigens. Compared with NS-Ab-negative patients, NS-Ab-positive patients were more likely to have a preceding headache (56.8% vs 26.7%), preceding psychobehavioral or memory alterations (65.9% vs 20.4%), involuntary movements (79.5% vs 16.1%), CSF pleocytosis (81.8% vs 62.0%), elevated immunoglobulin G (IgG) index (45.2% vs 15.6%), oligoclonal bands (51.5% vs 9.5%), tumor (47.7% vs 8.6%), and higher APE2 score (median of 9 vs 7), and they were less likely to have an ALE-Plus pattern (2.3% vs 23.7%). However, preceding fever and ALE or MCS pattern were not different between the two groups of patients.

SIGNIFICANCE

When an autoimmune etiology was suspected, there was a relatively high likelihood (one of three patients) of identifying NS-Abs. Some clinical features (preceding symptoms, inflammatory CSF) predict a higher likelihood of finding NS-Ab positivity, but the ALE-Plus MRI pattern is more likely suggestive of NS-Ab negativity.

Brain dysfunction in COVID-19 and CAR-T therapy: cytokine storm-associated encephalopathy

OBJECTIVE

Many neurological manifestations are associated with COVID-19, including a distinct form of encephalopathy related to cytokine storm, the acute systemic inflammatory syndrome present in a subgroup of COVID-19 patients. Cytokine storm is also associated with immune effector cell-associated neurotoxicity syndrome (ICANS), a complication of chimeric antigen receptor T-cell (CAR-T) therapy, a highly effective treatment for refractory hematological malignancies. We investigated whether COVID-19-related encephalopathy, ICANS, and other encephalopathies associated with cytokine storm, share clinical and investigative findings.

METHODS

Narrative literature review.

RESULTS

Comparisons between COVID-19-related encephalopathy and ICANS revealed several overlapping features. Clinically, these included dysexecutive syndrome, language disturbances, akinetic mutism and delirium. EEG showed a prevalence of frontal abnormalities. Brain MRI was often unrevealing. CSF elevated cytokine levels have been reported. A direct correlation between cytokine storm intensity and severity of neurological manifestations has been shown for both conditions. Clinical recovery occurred spontaneously or following immunotherapies in most of the patients. Similar clinical and investigative features were also reported in other encephalopathies associated with cytokine storm, such as hemophagocytic lymphohistiocytosis, sepsis, and febrile infection-associated encephalopathies.

INTERPRETATION

COVID-19-related encephalopathy and ICANS are characterized by a predominant electro-clinical frontal lobe dysfunction and share several features with other encephalopathies associated with cytokine storm, which may represent the common denominator of a clinical spectrum of neurological disorders. Therefore, we propose a unifying definition of cytokine storm-associated encephalopathy (CySE), and its diagnostic criteria.

Diagnostic yield of cerebrospinal fluid analysis in status epilepticus: an 8-year cohort study

Background

We investigate the frequency and diagnostic yield of cerebrospinal fluid (CSF) analysis in adult patients with status epilepticus (SE) and its impact on the outcome.

Methods

From 2011 to 2018, adult patients treated at the University Hospital Basel were included. Primary outcomes were defined as the frequency of lumbar puncture and results from chemical, cellular, and microbiologic CSF analyses. Secondary outcomes were differences between patients receiving and not receiving lumbar puncture in the context of SE.

Results

In 18% of 408 patients, a lumbar puncture was performed. Of those, infectious pathogens were identified in 21% with 15% detected ± 24 h around SE diagnosis. 74% of CSF analyses revealed abnormal chemical or cellular components without infectious pathogens. Screening for autoimmune diseases was only performed in 22%. In 8%, no or late (i.e., > 24 after SE diagnosis) lumbar puncture was performed despite persistent unknown SE etiology in all, transformation into refractory SE in 78%, and no recovery to premorbid neurologic function in 66%. Withholding lumbar puncture was associated with no return to premorbid neurologic function during hospital stay independent of potential confounders. Not receiving a lumbar puncture was associated with presumed known etiology and signs of systemic infectious complications.

Conclusions

Withholding lumbar puncture in SE patients is associated with increased odds for no return to premorbid neurologic function, and CSF analyses in SE detect infectious pathogens frequently. These results and pathologic chemical and cellular CSF findings in the absence of infections call for rigorous screening to confirm or exclude infectious or autoimmune encephalitis in this context which should not be withheld.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10447-3.