Long-term Functional Outcomes and Relapse of Anti-NMDA Receptor Encephalitis: A Cohort Study in Western China

Autoimmune encephalitis: recovery, residual symptoms and predictors of long-term sequelae

BACKGROUND

Data regarding long-term recovery from autoimmune encephalitis (AE) remain limited.

METHODS

This retrospective observational study investigated outcomes in 182 patients who met the 2016 criteria for definite AE. Recovery data were available in 172 patients. Follow-up data at ≥24 months post-attack were available for 119. Recovery trajectory, residual symptoms, outcome predictors and causes of post-AE death were assessed.

RESULTS

Of 172 patients, 138 (80%) achieved good recovery (modified Rankin Scale (mRS) ≤2) with a median recovery time of 4 months (95% CI: 2 to 6 months). Recovery varied by associated neural antibody, with the best recovery observed in leucine-rich glioma-inactivated 1 (97% good recovery, median recovery time 0 (0 to 2) months). Paraneoplastic AE (p=0.007), severe attacks (eg, mRS ≥4 at attack, p=0.007) and cerebrospinal fluid pleocytosis (p=0.005) were associated with a lower likelihood of good recovery, while seizure presentation (p=0.026) was associated with better recovery. Despite good recovery, several residual symptoms persisted ≥24 months post-AE, including cognitive deficits (53%), seizures (26%), depression (23%), sleep disorders (25%), brainstem/cerebellar symptoms (13%), other movement disorders (14%) and autonomic symptoms (12%). Predictors of long-term sequelae included disabling cognitive deficit at onset and delayed immunotherapy for post AE-dementia, and medial temporal atrophy as well as escalation to cyclophosphamide therapy for both drug-resistant epilepsy and chronic depression. Of 182 patients, 20 (11%) died; the most common cause of death was progression of AE (6/20 (30%)).

CONCLUSION

While the majority of patients achieved functional independence after AE, several residual symptoms persisted. Several clinical and paraclinical features were associated with long-term sequelae.

Identifying Key Prognostic Indicators for Relapse and Chronic Epilepsy in Autoimmune Encephalitis: Insights from a Multicenter Retrospective Study

Objective

The aims of this study were to investigate clinical factors associated with encephalitis relapse and chronic epilepsy development, and to evaluate the effectiveness of immunotherapy on encephalitis relapse.

Methods

Patients with autoimmune encephalitis diagnosed as positive for neuronal surface antibodies in five general hospitals were included. A minimum 12-month follow-up period was conducted, and binary logistic regression analysis was used to identify predictors of encephalitis relapse and chronic epilepsy development. Additionally, decision curve analysis (DCA) was employed to assess the clinical net benefit of predicting encephalitis relapse and chronic epilepsy.

Results

The study encompassed 65 patients with autoimmune encephalitis. The one-year relapse rate for encephalitis was 13.9%. The CASE score (P=0.045) was associated with encephalitis relapse, with subsequent immunotherapy proving beneficial in enhancing outcomes. Chronic epilepsy prevalence at one year was 26.2%, particularly higher among patients with positive LGI1 antibodies. Although adjustments in antiseizure medications were partially effective, 41.2% of patients developed drug-resistant epilepsy (DRE). DCA confirmed that the predictive models provided significant net clinical benefit in assessing the risk of encephalitis relapse and chronic epilepsy. Notably, the presence of diffuse cortical atrophy, medial temporal lobe atrophy, or cerebellar hemisphere atrophy was linked to relapsing encephalitis and chronic epilepsy.

Conclusion

Most cases of autoimmune encephalitis are effectively managed, however, a minority of patients experience relapse or chronic epilepsy. The CASE score and LGI1 antibodies are independent risk factors for encephalitis relapse and chronic epilepsy development, respectively. Immunotherapy remains beneficial for relapsing patients, yet a portion may progress to DRE. Individuals with relapses and chronic epilepsy are predisposed to the development of cortical, temporal lobe, and cerebellar atrophy.

Late relapse of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis: a case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is a sporadic autoimmune disorder of the brain that presents in a variety of neuropsychiatric manifestations, including seizures, psychosis, and alterations in behavior. N-methyl-D-aspartate receptor is primarily seen in young females. Although this disease can be treated, it can relapse in rare cases. Relapsing typically occurs within the early years following the initial episode and is exceedingly rare after 5 years.

CASE PRESENTATION

In this case study, we report on a 16-year-old Iranian female experiencing a relapse of anti-N-methyl-D-aspartate receptor encephalitis 8 years after her initial diagnosis. She was admitted to the hospital with dysphasia (a speech disorder) and dyslexia (reading and writing impairment). A thorough clinical evaluation revealed the presence of anti-glutamate receptor type N-methyl-D-aspartate receptor antibodies in her serum and cerebrospinal fluid, confirming the diagnosis. Following treatment with immunotherapy and plasmapheresis, she made a complete recovery.

CONCLUSION

This case of relapsing anti-N-methyl-D-aspartate receptor encephalitis, occurring more than 5 years after the initial episode, is exceptionally rare. This late relapse underscores the importance of long-term follow-up for patients with this condition.

MRI findings in autoimmune encephalitis

Autoimmune encephalitis encompasses a spectrum of conditions characterized by distinct clinical features and magnetic resonance imaging (MRI) findings. Here, we review the literature on acute MRI changes in the most common autoimmune encephalitis variants. In N-methyl-D-aspartate (NMDA) receptor encephalitis, most patients have a normal MRI in the acute stage. When lesions are present in the acute stage, they are typically subtle and non-specific white matter lesions that do not correspond with the clinical syndrome. In some NMDA receptor encephalitis cases, these T2-hyperintense lesions may be indicative of an NMDA receptor encephalitis overlap syndrome with simultaneous co-existence of multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD) or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Encephalitis with leucine-rich glioma-inactivated 1 (LGI1)-, contactin-associated protein-like 2 (CASPR2)- or glutamic acid decarboxylase (GAD)- antibodies typically presents as limbic encephalitis (LE) with unilateral or bilateral T2/fluid attenuated inversion recovery (FLAIR) hyperintensities in the medial temporal lobe that can progress to hippocampal atrophy. Gamma aminobutyric acid-B (GABA-B) receptor encephalitis also often shows such medial temporal hyperintensities but may additionally involve cerebellar lesions and atrophy. Gamma aminobutyric acid-A (GABA-A) receptor encephalitis features multifocal, confluent lesions in cortical and subcortical areas, sometimes leading to generalized atrophy. MRI is unremarkable in most patients with immunoglobulin-like cell adhesion molecule 5 (IgLON5)-disease, while individual case reports identified T2/FLAIR hyperintense lesions, diffusion restriction and atrophy in the brainstem, hippocampus and cerebellum. These findings highlight the need for MRI studies in patients with suspected autoimmune encephalitis to capture disease-specific changes and to exclude alternative diagnoses. Ideally, MRI investigations should be performed using dedicated autoimmune encephalitis imaging protocols. Longitudinal MRI studies play an important role to evaluate potential relapses and to manage long-term complications. Advanced MRI techniques and current research into imaging biomarkers will help to enhance the diagnostic accuracy of MRI investigations and individual patient outcome prediction. This will eventually enable better treatment decisions with improved clinical outcomes.

Efficacy and safety of different oral prednisone tapering courses in adult anti-NMDAR encephalitis: A multicenter prospective cohort study

OBJECTIVE

In adult anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, corticosteroids are commonly used as first-line treatment. However, the optimal oral prednisone tapering (OPT) following intravenous methylprednisolone pulse therapy remains unclear. We aim to compare the efficacy and safety of different OPT courses in anti-NMDAR encephalitis.

METHODS

The CHASE study, a multicenter prospective observational cohort study, enrolled patients with autoimmune encephalitis from October 2011 to March 2023. Patients were grouped based on oral prednisone tapering course: ≤3 months (Group ≤3 month), 3-6 months (Group 3-6 months, including 3 months), and >6 months (Group > 6 months). Kaplan-Meier plots were used to analyze time to relapse and time to total recovery within 2 years.

RESULTS

Among 666 screened patients, 171 (median [IQR] age 27 [21.0-36.5] years, 55.0% female) met selection criteria. Responders at 3 months were prevalent in Group ≤3 months (OR 7.251 [95% CI 2.252 to 23.344] and Group 3-6 months (OR, 3.857 [95% CI 1.107 to 13.440] than in Group >6 months. Clinical Assessment Scale for Autoimmune Encephalitis (CASE) scores at 12 months were higher in Group >6 months than in Group ≤3 months and Group 3-6 months (β, -2.329 [95% CI -3.784 to -.875]; β, -2.871 [95% CI -4.490, -1.253]). CASE seizures subscore was higher in Group >6 months than in Group 3-6 months (β, -.452 [95% CI -.788 to -.116]). No significant difference in seizure freedom rates among the groups. Adverse events were higher in Group 3-6 months and Group >6 months than in Group ≤3 months (OR 6.045 [95% CI 2.352 to 15.538]; OR 6.782 [95% CI 1.911 to 24.073]).

SIGNIFICANCE

Longer oral prednisone courses for adult patients with anti-NMDAR encephalitis did not show superior effects compared to shorter courses in improving modified Rankin Scale (mRS) scores and CASE scores, reducing the risk of relapse within 2 years, or achieving seizure freedom. Instead, extended prednisone courses may lead to more side effects- particularly weight gain. This outcome recommends evaluating the possibility of shortening the duration of oral prednisone after a thorough patient assessment.

Development of a short-term prognostic model for anti-N-methyl-D-aspartate receptor encephalitis in Chinese patients

BACKGROUND

Recognizing the predictors of poor short-term prognosis after first-line immunotherapy in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is essential for individualized treatment strategy. The objective of this study was to ascertain the factors that forecast short-term prognosis in patients with anti-NMDAR encephalitis, develop a prognostic prediction model, and authenticate its efficacy in an external validation cohort. Further, all patients were followed-up long-term to assess the factors of long-term outcome and relapses.

METHODS

A prospective enrollment of patients diagnosed with anti-NMDAR encephalitis was conducted across five clinical centers in China from June 2014 to Mar 2022. The enrolled patients were divided into the derivation and validation sets based on enrollment time. The short-term prognostic model was visualized using a nomogram. Further, all patients were followed-up long-term to assess the factors of long-term outcome.

RESULTS

This study found that poor short-term prognosis was a risk factor for poor long-term outcome (6-month prognosis, OR 29.792, 95%CI 6.507-136.398, p < 0.001; 12-month prognosis, OR 15.756, 95%CI 3.384-73.075, p < 0.001; 24-month prognosis, OR 5.500, 95%CI 1.045-28.955, p = 0.044). Abnormal behavior or cognitive dysfunction (OR 8.57, 95%CI 1.48-49.79, p = 0.017), consciousness impairment (OR19.32, 95%CI 3.03-123.09, p = 0.002), autonomic dysfunction or central hypoventilation (OR 5.66, 95%CI 1.25-25.75, p = 0.025), CSF pleocytosis (OR 4.33, 95%CI 1.48-12.65, p = 0.007), abnormal EEG (OR 5.48, 95% CI 1.09-27.54, p = 0.039) were independent predictors for a poor short-term prognosis after first-line immunotherapy. A nomogram that incorporated those factors showed good discrimination and calibration abilities. The area under the curve (AUC) for the prognostic model were 0.866 (95%CI: 0.798-0.934) with a sensitivity of 0.761 and specificity of 0.869.

CONCLUSION

We established and validated a prognostic model that can provide individual prediction of short-term prognosis after first-line immunotherapy for patients with anti-NMDAR encephalitis. This practical prognostic model may help neurologists to predict the short-term prognosis early and potentially assist in adjusting appropriate treatment timely.

Predictors and Clinical Characteristics of Relapses in LGI1-Antibody Encephalitis

BACKGROUND AND OBJECTIVES

Relapses occur in 15%-25% of patients with leucine-rich glioma-inactivated 1 antibody (LGI1-Ab) autoimmune encephalitis and may cause additional disability. In this study, we clinically characterized the relapses and identified factors predicting their occurrence.

METHODS

This is a retrospective chart review of patients with LGI1-Ab encephalitis diagnosed at our center between 2005 and 2022. Relapse was defined as worsening of previous or appearance of new symptoms after at least 3 months of clinical stabilization.

RESULTS

Among 210 patients, 30 (14%) experienced a total of 33 relapses. The median time to first relapse was 23.9 months (range: 4.9-110.1, interquartile range [IQR]: 17.8). The CSF was inflammatory in 11/25 (44%) relapses, while LGI1-Abs were found in the serum in 16/24 (67%) and in the CSF in 12/26 (46%); brain MRI was abnormal in 16/26 (62%) relapses. Compared with the initial episode, relapses manifested less frequently with 3 or more symptoms (4/30 patients, 13% vs 28/30, 93%; p < 0.001) and had lower maximal modified Rankin scale (mRS) score (median 3, range: 2-5, IQR: 1 vs 3, range: 2-5, IQR: 0; p = 0.001). The median mRS at last follow-up after relapse (2, range: 0-4, IQR: 2) was significantly higher than after the initial episode (1, range: 0-4, IQR: 1; p = 0.005). Relapsing patients did not differ in their initial clinical and diagnostic features from 85 patients without relapse. Nevertheless, residual cognitive dysfunction after the initial episode (hazard ratio:13.8, 95% confidence interval [1.5; 129.5]; p = 0.022) and no administration of corticosteroids at the initial episode (hazard ratio: 4.8, 95% confidence interval [1.1; 21.1]; p = 0.036) were significantly associated with an increased risk of relapse.

DISCUSSION

Relapses may occur years after the initial encephalitis episode and are usually milder but cause additional disability. Corticosteroid treatment reduces the risk of future relapses, while patients with residual cognitive dysfunction after the initial episode have an increased relapse risk.

Antibody-positive autoimmune encephalitis and paraneoplastic neurological syndrome: A Swedish case series

OBJECTIVE

This study aimed to explore the clinical characteristics and temporal disease course of patients with autoimmune encephalitis (AE) and paraneoplastic neurological syndrome (PNS) in Sweden.

METHODS

Thirty-seven antibody-positive AE and PNS cases were identified in the Healthcare region Mid Sweden between 2015 and 2019. Clinical data were collected through a retrospective review of electronic health records. Patients were divided into three subgroups based on antibody type: neuronal surface antibodies (NSAbs), onconeural antibodies, and anti-GAD65 antibodies.

RESULTS

Nineteen patients had NSAbs, 11 onconeural antibodies, and seven anti-GAD65 antibodies. Anti-LGI1 and anti-NMDAR were the most frequently detected NSAbs, with anti-NMDAR cases having an older-than-expected age distribution (median age 40, range 17-72). Only 11 of 32 (30%) of patients had findings suggesting encephalitis on initial MRI, but 28 of 31 (90%) had pathological findings on initial cerebrospinal fluid analysis. All patients but one had abnormal EEG findings. Median time to immunotherapy was comparable among the three subgroups, whereas patients with anti-LGI1, anti-CASPR2, and anti-IgLON5 had an eightfold longer time to immunotherapy than anti-NMDAR and anti-GABA-B (p = .0016). There was a seasonal variation in onset for patients with non-tumor-related NSAbs and anti-GAD65 antibodies, with most patients (72%) falling ill in spring or summer.

CONCLUSION

Swedish patients with AE and PNS had similar clinical characteristics as previously described cohorts from other geographical regions except for anti-NMDAR encephalitis, with older onset than expected. The onset of non-tumor-related AE occurred predominantly in the warm seasons, and AE with a more insidious onset was associated with delayed treatment initiation.

Predictive value of persistent antibodies at 6 months for relapse in neuronal surface antibody-associated autoimmune encephalitis

BACKGROUND

For patients with neuronal surface antibody-associated autoimmune encephalitis (NSAE) whose clinical symptoms gradually improve, the recommended course of immunotherapy in China is about 6 months. We aim to explore the relationship between persistent antibody positivity when immunotherapy is discontinued at 6 months and subsequent relapse.

METHODS

Prospective inclusion of NSAE patients with clinical remission after 6-month immunotherapy. Their antibody titers and other clinical data were collected at onset and 6 months later. Based on the antibody test results at 6 months, patients were divided into an antibody-persistent group and an antibody-negative conversion group, and then the rate of relapse between the two groups were compared.

RESULTS

The study included 28 NSAE patients who were antibody-positive at diagnosis. After 6-month immunotherapy, there were 16 (57.1%) cases with persistent antibodies and 12 (42.9%) cases with antibody-negative conversion. In the acute phase of onset, seizures were more common in patients with persistent antibodies (87.5% vs. 50.0%, p = 0.044). During a mean follow-up period of 22 months, patients with persistent antibodies were more likely to experience relapse than those with antibody-negative conversion (37.5% vs. 0.0%, p = 0.024). There were no significant differences in antibody types, CSF findings, results of MRI and EEG, tumor combination, immunotherapy, and long-term outcome between the two groups (p > 0.05).

CONCLUSIONS

For patients with persistent antibodies when immunotherapy is discontinued at 6 months, persistent antibody positivity was associated with a higher relapse rate.

Disease course and psychosocial outcome for children and adolescents with anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVES

Explore psychosocial outcome and impact of persisting deficits on quality of life (QoL) and global functioning after anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) in children and adolescents.

METHODS

Four female patients (age 7-16y) and their caregivers participated in the study. Information was collected from the medical records and the caregivers via a questionnaire. Both the patients and their caregivers were interviewed by means of the structured clinical interview for DSM-5 disorders, junior version (SCID-5 junior). CGAS and mRS scores were defined and the Pediatric Quality of Life Inventory (PedsQL) was used to assess quality of life of patients and caregivers.

RESULTS AND CONCLUSION

After the acute phase of the disease patients go through a post-acute phase in which several persisting physical, cognitive and psychiatric symptoms gradually resolve during the following months to a year. In long-term follow up these symptoms partly resolved, but deficits persisted on several domains. Psychiatric symptoms, fatigue and mild cognitive deficits were present in three out of four patients at current assessment. In three patients their academic trajectory was altered. These deficits can have an impact on the quality of life and the global functioning of the patients and caregivers.

The T1-weighted/T2-weighted ratio as a biomarker of anti-NMDA receptor encephalitis

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis rarely causes visible lesions in conventional MRI, yet advanced imaging detects extensive white matter damage. To improve prognostic capabilities, we evaluate the T1-weighted/T2-weighted (T1w/T2w) ratio, a measure of white matter integrity computable from clinical MRI sequences, in NMDAR encephalitis and examine its associations with cognitive impairment.

METHODS

T1-weighted and T2-weighted MRI were acquired cross-sectionally at 3 Tesla in 53 patients with NMDAR encephalitis (81% women, mean age 29 years) and 53 matched healthy controls. Quantitative and voxel-wise group differences in T1w/T2w ratios and associations with clinical and neuropsychological outcomes were assessed. P-values were false discovery rate (FDR) adjusted where multiple tests were conducted.

RESULTS

Patients with NMDAR encephalitis had significantly lower T1w/T2w ratios across normal appearing white matter (p=0.009, Hedges' g=-0.51), which was associated with worse verbal episodic memory performance (r=0.39, p=0.005, p(FDR)=0.026). White matter integrity loss was observed in the corticospinal tract, superior longitudinal fascicle, optic radiation and callosal body with medium to large effects (Cohen's d=[0.42-1.17]). In addition, patients showed decreased T1w/T2w ratios in the hippocampus (p=0.002, p(FDR)=0.005, Hedges' g=-0.62), amygdala (p=0.002, p(FDR)=0.005, Hedges' g=-0.63) and thalamus (p=0.010, p(FDR)=0.019, Hedges' g=-0.51).

CONCLUSIONS

The T1w/T2w ratio detects microstructural changes in grey and white matter of patients with NMDAR encephalitis that correlate with cognitive performance. Computable from conventional clinical MRI sequences, this measure shows promise in bridging the clinico-radiological dissociation in NMDAR encephalitis and could serve as an imaging outcome measure in clinical trials.

Single-cell RNA sequencing reveals diverse B cell phenotypes in patients with anti-NMDAR encephalitis

BACKGROUNDS

Anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E) is a severe autoimmune disorder characterized by prominent psychiatric symptoms. Although the role of NMDAR antibodies in the disease has been extensively studied, the phenotype of B cell subsets is still not fully understood.

METHODS

We utilized single-cell RNA sequencing, single-cell B cell receptor sequencing (scBCR-seq), bulk BCR sequencing, flow cytometry, and enzyme-linked immunosorbent assay to analyze samples from both NMDAR-E patients and control individuals.

RESULTS

The cerebrospinal fluid (CSF) of NMDAR-E patients showed significantly increased B cell counts, predominantly memory B (Bm) cells. CSF Bm cells in NMDAR-E patients exhibited upregulated expression of differential expression genes (DEGs) associated with immune regulatory function (TNFRSF13B and ITGB1), whereas peripheral B cells upregulated DEGs related to antigen presentation. Additionally, NMDAR-E patients displayed higher levels of IgD- CD27- double negative (DN) cells and DN3 cells in peripheral blood (PB). In vitro, DN1 cell subsets from NMDAR-E patients differentiated into DN2 and DN3 cells, while CD27+ and/or IgD+ B cells (non-DN) differentiated into antibody-secreting cells (ASCs) and DN cells. NR1-IgG antibodies were found in B cell culture supernatants from patients. Differential expression of B cell IGHV genes in CSF and PB of NMDAR-E patients suggests potential antigen class switching.

CONCLUSION

B cell subpopulations in the CSF and PB of NMDAR-E patients exhibit distinct compositions and transcriptomic features. In vitro, non-DN cells from NMDAR-E can differentiate into DN cells and ASCs, potentially producing NR1-IgG antibodies. Further research is necessary to investigate the potential contribution of DN cell subpopulations to NR1-IgG antibody production.

Longitudinal Disability, Cognitive Impairment, and Mood Symptoms in Patients With Anti-NMDA Receptor Encephalitis

BACKGROUND AND OBJECTIVES

Longitudinal outcomes in anti-NMDA receptor encephalitis (anti-NMDARe) are still not fully understood and may not be adequately captured with the modified Rankin Scale (mRS), often the sole reported outcome. We aim to characterize longitudinal outcomes in anti-NMDARe using multiple outcome measures.

METHODS

This single-center, retrospective, observational study examined outcome measures (mRS and Clinical Assessment Scale in Autoimmune Encephalitis [CASE]) in adults with NMDA receptor-IgG in CSF at short- and long-term follow-ups using linear and logistic regression modeling. Patients with evaluations for cognitive impairment (Montreal Cognitive Assessment/Mini-Mental State Examination), depression (Patient Health Questionnaire-9), and anxiety (General Anxiety Disorder-7) >6 months from symptom onset were correlated with final CASE scores.

RESULTS

Thirty-eight patients (76% female, median disease onset age = 28 years, range = 1-75 years) were included. The majority received first-line immunosuppressants (97%) at a median of 3.9 weeks (interquartile range [IQR] = 2.1-9.7) from symptom onset and 68% received second-line therapies. At baseline, median/mean mRS and CASE were 4 (IQR = 3-5) and 12.9 (SD = 7.2), respectively. At short-term follow-up (median = 10 weeks, IQR = 6-17), factors associated with higher CASE and mRS included dysautonomia, coma/lethargy, seizures/status epilepticus, and intensive care unit admission (p < 0.05). At long-term follow-up (median = 70 weeks, IQR = 51-174), median/mean mRS and CASE were 2 (IQR = 1-3) and 4.4 (SD = 4.2), respectively. Only weakness at symptom onset predicted higher mRS scores (odds ratio = 5.6, 95% confidence interval 1.02-30.9, p = 0.047). Despite both mRS and CASE improving from baseline (p < 0.001), only 9 patients (31%) returned to their premorbid function. Among patients with cognitive and mood evaluations >6 months from onset, moderate-severe cognitive impairment (42%), depression (28%), and anxiety (30%) were frequent. Cognitive and depression measures were associated with final CASE subscores (including memory, language, weakness, and psychiatric).

DISCUSSION

Multiple clinical factors influenced short-term outcomes, but only onset weakness influenced long-term mRS, highlighting that mRS is predominantly affected by global motor function. Although mRS and CASE improved over time for most patients, these outcome measures did not capture the full extent of long-term functional impairment in terms of mood, cognition, and the ability to return to premorbid function. This emphasizes the need for increased utilization of more nuanced cognitive and mood outcome measures.

Canadian Consensus Guidelines for the Diagnosis and Treatment of Autoimmune Encephalitis in Adults

Autoimmune encephalitis is increasingly recognized as a neurologic cause of acute mental status changes with similar prevalence to infectious encephalitis. Despite rising awareness, approaches to diagnosis remain inconsistent and evidence for optimal treatment is limited. The following Canadian guidelines represent a consensus and evidence (where available) based approach to both the diagnosis and treatment of adult patients with autoimmune encephalitis. The guidelines were developed using a modified RAND process and included input from specialists in autoimmune neurology, neuropsychiatry and infectious diseases. These guidelines are targeted at front line clinicians and were created to provide a pragmatic and practical approach to managing such patients in the acute setting.

Anti-NMDAR Encephalitis Clinical Practice Guideline: Improving Time to Diagnosis, Treatment, and Hospital Length of Stay

Background and Objectives

A clinical practice guideline (CPG) was created to standardize evaluation and treatment for patients with suspected anti-methyl-d-aspartate receptor (NMDAR) autoimmune encephalitis (AE), the most common AE in children. The objective of this study was to evaluate the CPG effect on time to diagnosis, treatment, and hospital length of stay (LOS).

Methods

Patients with an inpatient consult to pediatric rheumatology for AE during a 4-year period (period 2) after CPG implementation were identified. Data were extracted and compared with data over the preceding 4-year period (period 1).

Results

During period 1, fewer patients underwent diagnostic testing than during period 2 (34 vs 80). Number of patients diagnosed with AE did not differ from period 1 to that from period 2 (NMDAR AE 9 vs 8; seronegative AE 4 vs 5). The average time to diagnostic evaluation with lumbar puncture decreased from 5.4 to 1.5 days (p = 0.0082), and time to treatment decreased from 7.6 to 3.9 days (p = 0.018). LOS showed a trend toward improvement (40.4-29.2 days (p = 0.23)).

Discussion

Creation of a CPG for patients with suspected AE was associated with an improved time to diagnostic evaluation and treatment. With the CPG, more patients underwent AE testing, though total diagnoses remained the same.

Brain magnetic resonance imaging as predictors in pediatric anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

To investigate the associations between brain magnetic resonance imaging (MRI) changes and clinical profiles in children with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.

METHODS

Clinical data and brain MRI results of children diagnosed with anti-NMDAR encephalitis in Guangzhou Women and Children's Medical Center from October 2014 to June 2022 were retrospectively studied.

RESULTS

A total of 143 children (Male: female 54:89) were enrolled, with a mean onset age of 6.8 years (6.8 ± 3.1). 40.6 % (58/143) of patients had abnormal initial brain MRI. Lesions in temporal lobe (34.5 %, 20/58) and frontal lobe (25.9 %, 15/58) were relatively common. Children with abnormal initial brain MRI were prone to have fever (P = 0.023), dystonia (P = 0.037), positive MOG antibodies (P = 0.015), higher cerebrospinal fluid (CSF) white blood cell count (WBC) (P = 0.019) and to receive rituximab treatment (P = 0.037). There were no significant differences in modified Rankin Scale (mRS) scores before immunotherapy, after immunotherapy and at last follow-up between the normal initial brain MRI group and abnormal group. No initial brain MRI changes were found to be associated with relapses. Brain MRI was reviewed in 72 patients at last follow-up with a median follow-up time of 25.5 months and 48.6 % (35/72) of patients had abnormal brain MRI. The mRS score of the group with normal brain MRI at last follow-up was significantly lower than that of the abnormal group.

CONCLUSIONS

About 40.0 % of children with anti-NMDAR encephalitis had abnormal initial brain MRI. Initial brain MRI was associated with certain clinical profiles, but not with relapse and prognosis. Around half of patients had abnormal brain MRI at last follow-up and were prone to have higher mRS score.

Outcome and Sequelae of Autoimmune Encephalitis

Autoimmune etiologies are a common cause for encephalitis. The clinical syndromes consistent with autoimmune encephalitis are both distinct and increasingly recognized, but less is known about persisting sequelae or outcomes. We searched PubMed for reports on outcomes after autoimmune encephalitis. Studies assessing validated, quantitative outcomes were included. We performed a narrative review of the published literature of outcomes after autoimmune encephalitis. We found 146 studies that produced outcomes data. The mortality rates were 6%-19% and the relapse risks were 10%-62%. Most patients achieved a good outcome based on a score on the modified Rankin Scale (mRS) of ≤2. Forty-nine studies evaluated outcomes beyond mRS; these studies investigated cognitive outcome, psychiatric sequelae, neurological deficits, global function, and quality-of-life/patient-reported outcomes using various tools at varying time points after the index hospital discharge. These more-detailed assessments revealed that most patients had persistent impairments, with frequent deficits in cognitive function, especially memory and attention. Depression and anxiety were also common. Many of these sequelae continued to improve over months or even years after the acute illness. While we found that lasting impairments were common among survivors of autoimmune encephalitis, additional research is needed to better understand the nature and impact of these sequelae. Standardized evaluation protocols are needed to improve the ability to compare outcomes across studies, guide rehabilitation strategies, and inform outcomes of interest in treatment trials as the field advances.

Mycophenolate mofetil reduces the risk of relapse in anti-leucine-rich glioma-inactivated protein 1 encephalitis: a prospective observational cohort study

BACKGROUND

Mycophenolate mofetil (MMF) is frequently used in the treatment of neurological autoimmune disorders. However, its effect on the relapse risk in anti-leucine-rich glioma-inactivated protein 1 (anti-LGI1) encephalitis is not well studied.

METHODS

In this prospective observational cohort study, anti-LGI1 encephalitis patients were grouped according to MMF treatment status (MMF and non-MMF groups). The primary outcome was relapse after disease onset.

RESULTS

A total of 83 patients were included, with a median onset age of 60 years. Fifty-four patients were men (65.1%). The MMF group comprised 28 patients and the non-MMF group comprised 55. Median follow-up from symptom onset was 26 months. Relapse occurred in 43 patients (51.8%). Median modified Rankin scale (mRS) score at enrollment was significantly higher in the MMF group than the non-MMF group (3 vs. 2; p = 0.001). Median mRS score at last follow-up was comparable between groups (1 vs. zero; p = 0.184). Both MMF treatment (HR 0.463; 95% CI, 0.231-0.929; p = 0.030) and cognitive impairment at enrollment (HR 3.391; 95% CI, 1.041-11.044; p = 0.043) were independent predictors of relapse. Starting immunotherapy before development of cognitive impairment trended towards reducing relapse risk. Outcome at last follow-up was good (mRS score 0-2) in all patients except for one in the non-MMF group. Adverse events associated with MMF treatment were mild and transient.

CONCLUSION

Although the outcome of anti-LGI1 encephalitis patients is generally favorable, relapse is common, especially in those with cognitive impairment. MMF treatment is well-tolerated and can significantly reduce the risk of relapse.

Analysis of the relation between cerebrospinal fluid antibody titers and clinical characteristics in pediatric patients with anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

This retrospective study aimed to investigate the relationship between cerebrospinal fluid (CSF) antibody titers of N-methyl-d-aspartate receptor (NMDAR), and clinical characteristics in pediatric patients with anti-NMDAR encephalitis.

METHODS

The clinical and laboratory characteristics of hospitalized patients with anti-NMDAR encephalitis, stratified by antibody titers in CSF and disease severity, were retrospectively studied. The demographics, clinical characteristics, main accessory examinations, immunotherapy, and prognosis of patients were recorded, and each observed indicator was statistically analyzed.

RESULTS

A total of 103 pediatric anti-NMDAR encephalitis patients were enrolled in the study, including 41 males (39.8%) and 62 females (60.2%) with a mean age of 8.0 ± 4.0 years. The proportion of patients with cognitive dysfunction and the positive pathogen was higher in the high-titer group than in the low-titer group (p = 0.023, p = 0.042). Consciousness disturbance that occurred as an initial symptom or during the course in the severe group was higher than in the non-severe group (p = 0.002, p < 0.001). More patients in the high-titer group received plasma exchange (PE) than in the low-titer group (p = 0.022). The cure rate of patients was higher with PE (65.2%) than with Corticosteroids and (or) intravenous immunoglobulin (58.1%).

CONCLUSIONS

Patients with symptoms of disturbance of consciousness may be severer. The severity in pediatric anti-NMDAR encephalitis patients was not correlated with anti-NMDAR antibody titers. Patients with high CSF antibody titers had a better prognosis after early PE therapy.

Patient with concurrent anti-NMDAR autoimmune encephalitis and immature teratoma of the ovary

In young women with anti-N-methyl-D-aspartate receptor (anti-NMDAR) autoimmune encephalitis (AE), co-occurrence with ovarian teratoma is common. While the management of mature teratoma with AE is well documented, literature on managing immature teratoma (IT) in tandem with AE is relatively scarce. Here, we report a case of a female patient in her early adolescence who presented with abdominal pain and was diagnosed with grade 3 IT combined with anti-NMDAR AE after an ovarian tumour was discovered and resected. Postsurgery, the patient received immunotherapy, chemotherapy and antiepileptic therapy, and two follow-up evaluations showed no signs of recurrence or sequelae. This case highlights the importance of a high index of suspicion for concurrent AE in the presence of ovarian teratoma, particularly IT, and the crucial role of concurrent administration of immunotherapy and chemotherapy following tumour resection in impacting prognosis.

Long-term efficacy and safety of different corticosteroid courses plus mycophenolate mofetil for autoimmune encephalitis with neuronal surface antibodies without tumor

Objective

To compare the efficacy and safety of different-course corticosteroids plus mycophenolate mofetil (MMF) as maintenance therapy in autoimmune encephalitis (AE) with neuronal surface antibodies (NSAbs) without tumor and explore the optimal course of corticosteroids.

Methods

Fifty-five patients with definite AE without tumor were enrolled consecutively between June 2015 and November 2020 and retrospectively divided three groups according to the course of treatment with corticosteroid, i.e., a group of patients with a course of 3-6 months (Group 3-6mo), 6-12 months (Group 6-12mo), and >12 months (Group >12mo). Demographic data, clinical manifestation and ancillary tests results were recorded. The dosage and courses of corticosteroid treatment, the recovery of neurological function, the occurrence of adverse effects, and relapses were followed up.

Results

A total of 55 patients were included in the final analysis. The numbers of patients in Group 3-6 mo, Group 6-12 mo, and Group >12 mo was 14, 17, and 24, respectively. A significantly higher proportion of patients in Group >12 mo showed a decreased level of consciousness at the onset (12, 50%) than in Group 3-6 mo and Group 6-12 mo (2,14.3%; 3, 17.6%) (p = 0.033). The incidence of MRI abnormalities was significantly higher in Group 6-12 mo and Group >12 mo (10, 58.8%; 16, 66.7%) than in Group 3-6 mo (3, 21.4%) (P=0.023). Ordinal regression analysis indicated that decreased level of consciousness was associated with the course of corticosteroid (OR=3.838, 95% CI: 1.103-13.323, P=0.035). No significant difference was observed between the three groups regarding the cumulative dose of corticosteroids administered during the first three months of long-term treatment (P>0.05). Additionally, no significant difference in the cumulative dosage of corticosteroids was found between patients in Group 6-12 months and Group >12 months during the first 6 months after beginning long-term treatment. The mRS scores of the three groups were not statistically significant before and after first-line treatment or at the last follow-up. Bonferroni multiple comparison test indicated that the mRS scores of patients in Group 6-12 months and Group >12 months were not statistically significant at 3 months and 12 months after the start of long-term treatment. During the follow-up, 50 (90.9%) patients achieved satisfactory neurological function (mRS score ≤2). Five patients (9.1%) experienced a first relapse and 2 of them were overlapped with both anti-NMDA receptor and glial antibodies. The incidence of adverse effects was significantly higher in Group >12 mo (17, 70.8%) than in Group 3-6 mo (3, 21.4%) and Group 6-12 mo (5, 29.4%) (P=0.003).

Conclusions

The beneficial effects of oral corticosteroid treatment may do not persist beyond 12 months and may even contribute to an increased incidence of adverse effects. In order to optimize the effectiveness and safety of treatment, we recommend a corticosteroid course of 3-12 months. Patients with reduced levels of consciousness may be more inclined to choose longer courses of corticosteroids for long-term treatment. Patients with an "overlapping syndrome" may require more intense immunotherapy to prevent relapse.

Effectiveness of intra-thecal methotrexate in refractory Anti-N-methyl-d-aspartate receptor encephalitis

BACKGROUND

Anti-N-methyl-d-aspartate "anti-NMDA" receptor encephalitis is one of the most common autoimmune encephalitis for which first- and second-line therapies have been recommended following international consensus. However, some refractory cases do not respond to the first- and second-line therapy and require further immune-modulatory therapies such as intra-thecal methotrexate. In this study, we reviewed six confirmed cases of refractory anti-NMDA receptor encephalitis from two tertiary centers in Saudi Arabia that required escalation of treatment and received a six-month course of intra-thecal methotrexate. The aim of this study was to evaluate the effectiveness of intra-thecal methotrexate as immunomodulatory therapy for refractory anti-NMDA receptor encephalitis.

METHODS

We retrospectively evaluated six confirmed cases of refractory anti-NMDA receptor encephalitis who did not improve after first- and second-line therapy and received monthly intra-thecal methotrexate treatment course for six consecutive months. We reviewed patient demography, underlying etiologies, and compared their modified Rankin score prior to receiving intra-thecal methotrexate and six months after completing the treatment.

RESULTS

Three of the six patients showed a marked response to intra-thecal methotrexate with a modified Rankin scale of 0-1 at 6-month follow-up. None of the patients experienced any side effects during or after intra-thecal methotrexate treatment, and no flareups were observed.

CONCLUSION

Intra-thecal methotrexate may be a potentially effective and relatively safe escalation option for immunomodulatory therapy of refractory anti-NMDA receptor encephalitis. Future studies on intra-thecal methotrexate -specific treatment regimens may further support its utility, efficacy, and safety in treating refractory anti-NMDA receptor encephalitis.

Anti-N-methyl-D-aspartate receptor encephalitis and positive human herpesvirus-7 deoxyribonucleic acid in cerebrospinal fluid: a case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is a neuroautoimmune syndrome typically presenting with seizures, psychiatric symptoms, and autonomic dysfunction. Human herpesvirus-7 is often found with human herpesvirus-6 and infects leukocytes such as T-cells, monocytes-macrophages, epithelial cells, and central nervous system cells. The pathogenicity of human herpesvirus-7 is unclear. Cases of anti-N-methyl-D-aspartate receptor encephalitis with human herpesvirus-7 present in cerebrospinal fluid have been documented, but the clinical significance of this finding remains unclear.

CASE PRESENTATION

An 11-year-old Caucasian boy was admitted to hospital after a generalized tonic-clonic seizure. Generalized tonic seizures repeated three more times during the day of hospitalization. Blood tests showed minor ongoing inflammation, while brain computed tomography yielded normal results. Brain magnetic resonance imaging showed hyperintense focal alterations in both temporal lobes, hippocampi, and at the base of the right frontal lobe. Positive anti-N-methyl-D-aspartate receptor antibodies were found in both serum and cerebrospinal fluid. Positive novel coronavirus 2 (severe acute respiratory syndrome coronavirus 2) immunoglobulin G antibodies were found in serum. Polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2 was negative. Furthermore, positive human herpesvirus-7 deoxyribonucleic acid was found in cerebrospinal fluid. The patient was treated with acyclovir, human immunoglobulin, and methylprednisolone. The seizures did not repeat, and no psychiatric symptoms were present. The patient made a full recovery.

CONCLUSIONS

We present a pediatric case of anti-N-methyl-D-aspartate receptor encephalitis with atypical clinical presentation. The role of human herpesvirus-7 in neurological disorders remains unclear in immunocompetent patients.

Factors influencing prognosis and relapse in patients with anti-N-methyl-D-aspartate receptor encephalitis

BACKGROUND

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is the most common type of autoimmune encephalitis. Here, we investigated the factors associated with poor prognosis and relapse in patients with anti-NMDAR encephalitis.

METHODS

In this single-center observational cohort study, we retrospectively analyzed 51 patients with anti-NMDAR encephalitis treated in our hospital from January 2014 to October 2022. The demographic data, clinical characteristics, scale scores, results of auxiliary examination, and treatment details were statistically analyzed. Based on modified Rankin Scale (mRS) scores measured before final discharge, patients were divided into groups with good (mRS score 0-2) and poor (mRS score 3-6) prognoses for functional evaluation. The chi-squared test or Fisher's exact test was used to compare categorical data, and the t-test and Mann-Whitney U test were used to compare normally and non-normally distributed continuous data, respectively. Binary logistic regression was used to identify the risk factors for prognosis and relapse.

RESULTS

At admission, the main clinical manifestations observed were psychobehavioral disorders (50 cases, 98.0%), consciousness disorders (28 cases, 54.9%), epilepsy (33 cases, 64.7%), motor disorders (28 cases, 54.9%), speech disorders (24 cases, 47.1%), and dysfunction of the autonomic nervous system (15 cases, 29.4%). All 51 patients (100%) had mRS scores of 3-5 at admission, and 50 were treated with intravenous methylprednisolone and human immunoglobulin. A total of 22 patients (43.1%) had an mRS score of 3-6 at discharge, which was significantly lower than those at admission. One patient died (mRS score 6) after developing septic shock (fatality rate 1.9%). Binary logistic regression analysis showed that movement disorders/involuntary movement (odds ratios [OR] 3.778, p = 0.029), abnormal brain magnetic resonance imaging (OR 4.817, p = 0.013), electroencephalogram slow wave activity of >50% (OR 8.400, p = 0.001), a white blood cell count of >10 × 10⁶/L in the cerebrospinal fluid (OR 3,210, p = 0.048), and male sex (OR 3.282, p = 0.050) were risk factors for poor prognosis. A duration of disease of >12 months (OR 8.800, p = 0.001) and first-line-immunotherapy for less than 3 months after first onset (OR 3.719, p = 0.048) were identified as risk factors for relapse.

CONCLUSION

Motor disorders or involuntary movement, abnormal brain magnetic resonance imaging, electroencephalogram slow wave activity >50%, and elevated white blood cell counts in cerebrospinal fluid were associated with poor prognosis in patients with NMDAR encephalitis. First-line immunotherapy less than 3 months after first onset may be a risk factor for relapse.

Single-nucleus RNA sequencing unveils critical regulators in various hippocampal neurons for anti-N-methyl-D-aspartate receptor encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a neuropsychiatric disease with variable clinical manifestations caused by NMDAR autoantibody. The underlying molecular underpinnings of this disease are rarely characterized on a genomic scale. Anti-NMDAR encephalitis mainly affects the hippocampus, however, its effect on gene expression in hippocampal neurons is unclear at present. Here, we construct the active and passive immunization mouse models of anti-NMDAR encephalitis, and use single-nucleus RNA sequencing to investigate the diverse expression profile of neuronal populations isolated from different hippocampal regions. Dramatic changes in cell proportions and differentially expressed genes were observed in excitatory neurons of the dentate gyrus (DG) subregion. In addition, we found that ATP metabolism and biosynthetic regulators related genes in excitatory neurons of DG subregion were significantly affected. Kcnq1ot1 in inhibitory neurons and Meg3 in interneurons also changed. Notably, the latter two molecules exhibited opposite changes in different models. Therefore, the above genes were used as potential targets for further research on the pathological process of anti-NMDAR encephalitis. These data involve various hippocampal neurons, which delineate a framework for understanding the hippocampal neuronal circuit and the potential molecular mechanisms of anti-NMDAR encephalitis.

Limitations on knowledge of autoimmune encephalitis and barriers to its treatment among neurologists: a survey from western China

BACKGROUND

Autoimmune encephalitis (AE) is a group of severe antibody-mediated brain diseases. The understanding of clinical management of AE has developed rapidly. However, the knowledge level of AE and barriers to effective treatment among neurologists remains unstudied.

METHODS

We conducted a questionnaire survey among neurologist in western China on knowledge of AE, treatment practices, and perspectives on barriers to treatment.

RESULTS

A total of 1113 neurologists were invited and 690 neurologists from 103 hospitals completed the questionnaire with a response rate of 61.9%. Respondents correctly answered 68.3% of medical questions about AE. Some respondents (12.4%) never assayed for diagnostic antibodies if patients had suspected AE. Half (52.3%) never prescribed immunosuppressants for AE patients, while another 7.6% did not know whether they should do so. Neurologists who never prescribed immunosuppressants were more likely to have less education, a less senior job title, and to practice in a smaller setting. Neurologists who did not know whether to prescribe immunosuppressants were associated with less AE knowledge. The most frequent barrier to treatment, according to respondents, was financial cost. Other barriers to treatment included patient refusal, insufficient AE knowledge, lack of access to AE guidelines, drugs or diagnostic test, etc. CONCLUSION: Neurologists in western China lack AE knowledge. Medical education around AE is urgent needed and should be more targeted to individuals with less educated level or working in non-academic hospitals. Policies should be developed to increase the availability of AE related antibody testing or drugs and reduce the economic burden of disease.

Autoimmune Encephalitis Associated with Anti-N-methyl-D-aspartate Receptor and Anti-Hu Antibodies Successfully Treated with Carboplatin and Etoposide for Small-cell Lung Cancer

The coexistence of multiple autoantibodies associated with autoimmune encephalitis (AE) is rare. A 63-year-old woman developed psychosis and consciousness disorder. Her cerebrospinal fluid was positive for anti-N-methyl-D-aspartate receptor antibodies, and her serum was positive for anti-Hu antibodies. Enhanced computed tomography revealed a mass in the right pulmonary hilum. AE complicated with small-cell lung cancer was diagnosed. Immunotherapy (steroid therapy and intravenous immunoglobulin) and four courses of carboplatin-etoposide chemotherapy were required to improve her neurological symptoms. When the coexistence of multiple antibodies is detected, despite its rarity, aggressive detection and treatment of any underlying malignancy may be recommended.

Anti-NMDA Receptor Autoimmune Encephalitis: Diagnosis and Management Strategies

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most recognized form of autoimmune encephalitis. It is characterized by a constellation of neurologic and psychiatric features along with positive NMDAR antibody, which is more sensitive and specific in CSF than serum. All patients should be screened at least once for neoplasm, with ovarian teratoma being found in most tumor-related cases. In the acute phase, first-line immunotherapy, often a combination of high-dose steroids, immunoglobulins, and/or plasma exchange, is strongly recommended. When first-line therapy fails, escalation to second-line immunotherapy, particularly rituximab, can further improve outcomes and prevent relapses. In refractory cases, additional complementary immunotherapies, such as cyclophosphamide, bortezomib and/or tocilizumab may be considered. Relapses occur in 10-30% of cases, mostly within the first two years from onset. Individuals should be followed up to determine if chronic maintenance therapy is required.

Autoimmune encephalitis with mGluR5 antibodies: A case series from China and review of the literature

Background

Only 15 patients of autoimmune encephalitis with metabotropic glutamate receptor 5 (mGluR5) antibodies have been reported worldwide since 2011, mostly from western countries. Patients with different genetic backgrounds are necessary to further clarify the clinical phenotype and prognosis of this rare disease.

Objective

We initially describe a case series from China to confirm the previous findings, expand the clinical phenotype, and identify the prognostic factors of autoimmune encephalitis with mGluR5 antibodies.

Methods

Observational data with follow-up were prospectively collected from autoimmune encephalitis patients with mGluR5 antibodies. Clinical information and outcomes on current and previously reported cases were combined and analyzed.

Results

We identified five patients (median age 35 years); two were female. The main clinical manifestations were behavioral/personality changes (five of five, 100%) and cognitive disorders (four of five, 80%), accompanied with other neurologic symptoms. Hypoventilation occurred in two (40%) patients, which was life-threatening. One patient had meningoencephalitis, suggesting a new phenotype in anti-mGluR5 encephalitis. All patients received immunotherapy. At the last follow-up (median 18 months), two (40%) patients showed complete recovery, two (40%) patients showed partial recovery, and one (20%) patient died. One (20%) patient had multiple relapses. Together with the 15 previously reported cases, associated tumors occurred in seven of 12 (58%) Western patients vs. one of eight (13%) Chinese patients. Modified Rankin Scale (mRS) scores at the last follow-up (median 31 months) were available in 16 patients. Patients with bad outcomes (mRS > 2, n = 4) were more likely to have hypoventilation at onset and higher mRS scores at peak of the disease.

Conclusions

In patients with different genetic background, as Chinese, the clinical phenotype of anti-mGluR5 encephalitis is similar. Fewer paraneoplastic cases were observed in Chinese patients. Most patients showed good responses to immunotherapy and cancer treatment. The clinical outcomes were favorable in most patients.

Brain magnetic resonance imaging predictors in anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

Brain magnetic resonance imaging (MRI) findings in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis are nonspecific and rarely have obvious associations with clinical characteristics and outcomes. This study aimed to comprehensively describe the MRI features of patients with NMDAR encephalitis, examine their associations with clinical characteristics, and evaluate their predictive power for disease recurrence and prognosis.

METHODS

We retrospectively extracted the clinical data and brain MRI findings of 144 patients with NMDAR encephalitis. Patients underwent a 2-year follow-up to assess disease outcomes. We evaluated the associations of brain MRI findings at the onset with clinical characteristics, recurrence, and prognosis.

RESULTS

Initial MRI showed typical abnormalities in 65 patients (45.1%); of these, 34 (29.3%) developed recurrence and 10 (9.4%) had poor prognosis (mRS ≥3). Binary logistic regression analyses revealed that insula abnormalities were associated with acute seizure (odds ratio [OR] = 3.048, 95% confidence interval [CI]: 1.026-9.060) and white matter lesions were associated with cognitive impairment (OR = 2.730, 95% CI: 1.096-6.799). Risk factors for a poor 2-year prognosis included a higher number of brain MRI abnormalities (OR = 1.573, 95% CI: 1.129-2.192) and intensive care unit (ICU) admissions (OR = 15.312, 95% CI: 1.684-139.198). The risk factors for 2-year recurrence included abnormalities of the thalamus (HR = 3.780, 95% CI: 1.642-8.699).

INTERPRETATIONS

Brain MRI features of patients with NMDAR encephalitis were associated with clinical manifestations, prognosis, and recurrence. Higher numbers of MRI abnormalities and ICU admissions were predictive of poor prognosis. Abnormalities of the thalamus constituted a recurrence-related risk factor.

First-line immunotherapy of neuronal surface antibody-mediated autoimmune encephalitis: Assessment of therapeutic effectiveness and cost-efficiency

OBJECTIVE

To evaluate the therapeutic effectiveness and cost-efficiency of first-line immunotherapies on neuronal surface antibody-mediated autoimmune encephalitis (AE) based on a real-world observational study in China.

METHODS

Our study retrospectively collected the clinical and paraclinical data of patients with definite neuronal surface antibody-mediated AE between July 2014 and July 2020. Regular follow-up was performed after administering standard regimens of first-line immunotherapies, including intravenous methylprednisolone (IVMP) and / or intravenous immunoglobulin (IVIG). Therapeutic effectiveness was reflected by modified Rankin Scale scores. The health resource utilization and direct medical costs were extracted to analyze the cost-efficiency.

RESULTS

Among the 78 eligible patients, 48 (61.5%) were males with a median age of 40 years. More than half (56, 71.8%) were treated with combination therapy, with the rest receiving IVMP and IVIG monotherapy (both of 11, 14.1%). Related objective variables, i.e., sex, onset age, disease course, onset symptoms, antibody types, abnormal paraclinical results, disease severity, and the health insurance, showed insignificant differences on the selection of therapy. Each therapy showed similar short-term (4-week) and long-term (1-year) therapeutic effects. Yet the single or combination of IVIG had a slightly better effectiveness but higher cost than the monotherapy of IVMP.

CONCLUSION

The combination of IVMP and IVIG was used more frequently than either alone, which may be associated with neurologist's personal experience and patient's wishes. Though with similar therapeutic effectiveness, the use of IVMP alone might be a better choice with a better cost-efficiency.

Relapses of Anti-NMDAR, Anti-GABABR and Anti-LGI1 Encephalitis: A Retrospective Cohort Study

Objective

To investigate the relapse rate and study the factors that may predict the subsequent relapse in anti-NMDAR, anti-GABABR and anti-LGI1 encephalitis in Northeast China.

Methods

In the retrospective cohort study, we consecutively enrolled patients with anti-N1MDAR, anti-GABABR and anti-LGI1 encephalitis between March 2015 and November 2021. The patients were followed up for at least 6 months. The outcome variable was a binary variable of relapse or not. Predictors of relapse were identified.

Results

A total of 100 patients were enrolled. Relapse occurred in 26 (26%) patients after a median follow-up of 18 months since the first event. The relapse rates of anti - NMDAR, anti - GABABR and anti - LGI1 encephalitis were 25%, 33.3%, and 28.6%, respectively. The multivariable analysis results suggested that immunotherapy delay at the acute phase was independently associated with an increased risk of relapse in total patients (HR = 2.447, 95% CI = 1.027 - 5.832; P = 0.043). Subgroup analysis results showed that antibody titer was associated with the likelihood of relapse in anti-LGI1 encephalitis. The higher the concentration, the more likely it was for patients to have relapse (p=0.019).

Conclusion

The general relapse rate of anti-NMDAR, anti-GABABR and anti-LGI1 encephalitis was 26%. The risk of subsequent relapse was elevated in those with delayed immunotherapy in the first episode. In subgroup of anti-LGI1 encephalitis, higher antibody titer was the risk factors of relapse. Thus, timely and aggressive immunotherapy may be beneficial for patients to prevent subsequent relapse.

Clinical Variables, Deep Learning and Radiomics Features Help Predict the Prognosis of Adult Anti-N-methyl-D-aspartate Receptor Encephalitis Early: A Two-Center Study in Southwest China

Objective

To develop a fusion model combining clinical variables, deep learning (DL), and radiomics features to predict the functional outcomes early in patients with adult anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in Southwest China.

Methods

From January 2012, a two-center study of anti-NMDAR encephalitis was initiated to collect clinical and MRI data from acute patients in Southwest China. Two experienced neurologists independently assessed the patients’ prognosis at 24 moths based on the modified Rankin Scale (mRS) (good outcome defined as mRS 0–2; bad outcome defined as mRS 3-6). Risk factors influencing the prognosis of patients with acute anti-NMDAR encephalitis were investigated using clinical data. Five DL and radiomics models trained with four single or combined four MRI sequences (T1-weighted imaging, T2-weighted imaging, fluid-attenuated inversion recovery imaging and diffusion weighted imaging) and a clinical model were developed to predict the prognosis of anti-NMDAR encephalitis. A fusion model combing a clinical model and two machine learning-based models was built. The performances of the fusion model, clinical model, DL-based models and radiomics-based models were compared using the area under the receiver operating characteristic curve (AUC) and accuracy and then assessed by paired t-tests (P < 0.05 was considered significant).

Results

The fusion model achieved the significantly greatest predictive performance in the internal test dataset with an AUC of 0.963 [95% CI: (0.874-0.999)], and also significantly exhibited an equally good performance in the external validation dataset, with an AUC of 0.927 [95% CI: (0.688-0.975)]. The radiomics_combined model (AUC: 0.889; accuracy: 0.857) provided significantly superior predictive performance than the DL_combined (AUC: 0.845; accuracy: 0.857) and clinical models (AUC: 0.840; accuracy: 0.905), whereas the clinical model showed significantly higher accuracy. Compared with all single-sequence models, the DL_combined model and the radiomics_combined model had significantly greater AUCs and accuracies.

Conclusions

The fusion model combining clinical variables and machine learning-based models may have early predictive value for poor outcomes associated with anti-NMDAR encephalitis.

Long-Term Prognosis of Patients With Anti-N-Methyl-D-Aspartate Receptor Encephalitis Who Underwent Teratoma Removal: An Observational Study

Objective

This study aimed to evaluate the clinical characteristics and long-term surgical outcomes of patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis with teratoma.

Methods

Patients who were admitted to West China Hospital from June 2012 to June 2019 and diagnosed with anti-NMDAR encephalitis were enrolled in the study. Medical records were reviewed prospectively to gather clinical characteristic data. Patients were followed up at long-term every 3 months.

Results

This study included 192 patients, among whom 21 (10.9%) were detected with having a teratoma. Patients included 20 women, with a mean age of 24.62 ± 7.61 years. Seizure and psychiatric symptoms were the most dominant symptoms in both groups, followed by memory deficits. Central hypoventilation (52.4 vs. 17%, p < 0.001) and decreased consciousness (71.4 vs. 31.3%, p = 0.002) were significantly more frequent in patients with teratoma than in those without. Moreover, the anti-NMDAR antibody titer was higher (p = 0.021) and the baseline modified Rankin scale score was lower (p = 0.004) in patients with teratoma than in those without. First-line immunotherapy was performed in 21 (100%) patients with teratoma and 167 (97.7%) patients without teratoma. All patients with teratoma had the tumor removed. During follow-up, two (9.5%) patients with teratoma and 11 (6.4%) patients without teratoma died, whereas 1 (4.8%) patient with teratoma and 37 (21.6%) patients without teratoma had relapses. Overall, 19 (90.5%) patients with teratoma and 151 (88.3%) patients without teratoma achieved favorable clinical outcomes at the final follow-up.

Conclusions

With early detection and removal of teratoma, most patients with anti-NMDAR encephalitis and teratoma achieved a favorable long-term prognosis.

Relapse factors of patients of anti-N-methyl-D-aspartate receptor encephalitis

BACKGROUND

The factors associated with anti-N-methyl-D-aspartate (NMDA) receptor encephalitis relapse are yet to be elucidated.

AIMS OF THE STUDY

To investigate the factors associated with relapse and prognosis of anti-NMDA receptor encephalitis.

METHODS

This retrospective study included patients diagnosed with anti-NMDA receptor encephalitis admitted to the First Affiliated Hospital of Zhengzhou University from January 2013 to October 2019. The clinical features, auxiliary examinations, treatment regimens, and follow-up were recorded. The outcomes were relapse and 2-year disease prognosis.

RESULTS

A total of 160 patients were included. Consequently, 6 (5%) deaths, 34 (25.4%) relapses, and 19 (15.2%) patients had a poor prognosis (modified Rankin score (mRS) ≥3) were recorded. The multivariable analyses showed that age (p = .011), abnormal magnetic resonance imaging (MRI) (p = .019), glucocorticoid pulse (p = .009), and intracranial pressure (p = .023) were independently associated with the relapse, while age (p = .030) and central hypoventilation (p = .020) were independently associated with a poor prognosis at 2 years.

CONCLUSION

Glucocorticoid pulse therapy reduces the relapse of anti-NMDA receptor encephalitis. Age, abnormal MRI, and intracranial pressure are risk factors for relapse, while age and central hypoventilation are independently associated with poor prognosis.

Long-term seizure outcomes in patients with autoimmune encephalitis: A prospective observational registry study update

OBJECTIVE

To update and evaluate long-term seizure outcomes in patients with autoimmune encephalitis (AE) based on a large cohort study with long follow-up.

METHODS

In this prospective observational registry study, we analyzed data from patients with AE mediated by common types of neuronal surface antibodies (anti-NMDAR, anti-LGI1/Caspr2, anti-GABA_B R). All patients were recruited from the Department of Neurology at the West China Hospital between October 2011 and June 2019, and data were collected prospectively on their demographic and clinical characteristics, treatment strategy, and seizure outcomes with a median follow-up of 42 months (range 6-93 months). Potential risk factors associated with seizure recurrence were also assessed.

RESULTS

Of 320 AE patients, 75.9% had acute seizures, among whom more than 90% of patients had their last seizure within 12 months of disease onset. During our follow-up, 21 (9.3%) patients experienced seizure recurrence. Patients with anti-GABA_B R encephalitis had a higher cumulative incidence of seizure recurrence than those with anti-NMDAR (log-rank P = 0.03) or anti-LGI1/Caspr2 encephalitis (log-rank P = 0.04). Among patients with anti-NMDAR encephalitis, women had a significantly higher cumulative incidence of seizure recurrence than men (log-rank P = 0.01). Interictal epileptiform discharges (IEDs) or seizures captured on continuous EEG in the acute phase were identified as potential risk factors for seizure recurrence (P=0.04; P=0.007). Among 163 patients with ≥ 24 months of follow-up, five (3.1%) showed persistent seizures and required ongoing anti-seizure medications (ASMs) despite aggressive immunotherapy.

SIGNIFICANCE

Seizure recurrence occurred in a small number of patients and chronic epilepsy occurred in 3.1% of patients during prolonged follow-up. Across all types of AE, risk factors for seizure recurrence were IEDs or seizures captured on EEG in the acute phase; for anti-NMDAR encephalitis, female sex was also a risk factor.

Recurrence of Anti-N-Methyl-D-Aspartate Receptor Encephalitis: A Cohort Study in Central China

Objective

To investigate factors that could impact or predict the probability of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis recurrence in central China.

Methods

From November 2014 to October 2020, observational data of anti-NMDAR encephalitis inpatients in our institution were collected and analyzed prospectively. The demographics, clinical characteristics, tumor status, lesion locations on MRI and immunotherapies, etc. had entered into a Cox regression model for the identification of the factors associated with relapse-free survival.

Results

We enrolled 113 patients in a row (median age: 28 years, range: 1-61 years). The gender distribution was not statistically significant (p = 0.158), with 49 people (43.4%) being female. The median follow-up time was 16 (4-77) months. Among them, 16.8% of patients relapsed. The average interval between recurrences was 8 months (range 3-54 mo). The severity of the initial relapse was less severe than it had been at the start. The first relapse had considerably fewer symptoms (median 2, range 1-6) than the first episode (median 4, range 1-8, p = 0.005). The mRS at first relapse (median 3, mean 2.84, range 1-5) had been significantly lower than that at onset (median 4, mean 3.89, range 3-5, p = 0.004). The length of hospitalization at first relapse (median 17 days, range 5-46) was significantly shorter than the first episode (median 35 days, range 14-102, p = 0.002). In the survival analysis, the risk of recurrence was significantly higher for patients with a brainstem lesion (HR: 4.112, 95% CI: 1.205-14.030; p = 0.024) or ≥3 abnormal sites (HR: 2.926, 95% CI: 1.085-7.896; p = 0.034) on brain MRI at the first episode. There was no significant difference in neurological outcomes between the recurrent and monophasic groups at the most recent follow-up (mRS 0-2 in 17/19 vs. 86/94; p = 0.674).

Conclusions

Anti-NMDAR encephalitis can recur in around one out of every six cases, and symptoms are generally milder than when it first appears. Recurrence is not related to the severity in the acute phase or the prognosis at follow-up. Patients with ≥3 abnormal sites on MRI or lesions located in the brainstem at onset must be alert to the possibility of recurrence.

Risk Factors for Mortality in Anti-NMDAR, Anti-LGI1, and Anti-GABABR Encephalitis

Objective

We aimed to investigate the mortality rate and identify the predictors of death in patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis.

Methods

Patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis were recruited from the Neurology Department of the First Hospital of Jilin University from March 2015 to November 2021. The primary outcome variable was a binary variable of death vs. survival. The potential risk factors for mortality were evaluated. The mortality rates were determined, and the independent predictors of death were identified using multivariable logistic regression analysis.

Results

A total of 100 hospitalized patients with anti-NMDAR, anti-LGI1, or anti-GABABR encephalitis were included in the final analysis. Fifteen patients (15%) died during a median follow-up period of 18 months. The mortality rates were 10% for anti-NMDAR encephalitis, 2.8% for anti-LGI1 encephalitis, and 41.7% for anti-GABABR encephalitis. The multivariable analysis results showed that older age at onset [adjusted odds ratio (OR) = 1.017, 95% confidence interval (CI) = 1.009–1.136; p = 0.023] was independently associated with an increased risk of death. Antibody type was also associated with mortality. Patients with anti-GABABR encephalitis had 13.458-fold greater odds of dying than patients with anti-LGI1 encephalitis (adjusted OR = 13.458, 95% CI = 1.270–142.631; p = 0.031).

Conclusion

The general mortality rate of anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis was 15%. Age at onset and type of autoimmune encephalitis antibody were independent predictors of death in these patients.

Validation of the Clinical Assessment Scale in Autoimmune Encephalitis in Chinese Patients

Background and Objectives

The Clinical Assessment Scale in Autoimmune Encephalitis (CASE) is a scale for assessing severity in autoimmune encephalitis. We aimed to validate the CASE score in a Chinese population and evaluate its clinical significance.

Methods

Patients diagnosed with autoimmune encephalitis were recruited between June 2014 and May 2019 from two hospitals. CASE and modified Rankin Scale (mRS) scores were obtained. Data regarding clinical features, treatment, and available information were gathered from the hospital information system.

Results

Of the 176 patients with autoimmune encephalitis, 11 died and 14 had tumors. Ten patients received second-line treatment. The CASE scores of patients receiving second-line treatment were significantly higher (median CASE: 15) than in those receiving first-line treatment (median CASE: 8) (p<0.001). Twenty-two patients had poor functional status (mRS>2). Areas under the curve of CASE on whether functional status was poor at 1 year were 0.89 (p<0.001). Sixty patients were admitted to the intensive care unit (ICU), and the CASE scores were positively correlated with days in the ICU (r=0.58, p<0.001). There was no statistically significant association between the CASE scores and relapse (p=0.39>0.05). Additionally, the CASE scores were positively associated with the mRS scores (r=0.85 p<0.001).

Conclusions

The CASE score is suitable for the comprehensive assessment of Chinese patients with autoimmune encephalitis, which may help clinicians to select the appropriate intervention and estimate the disease severity and prognosis.

Contemporary advances in anti-NMDAR antibody (Ab)-mediated encephalitis

The study of antibody (Ab)-mediated encephalitis has advanced dramatically since the discovery of antibodies directed against the N-methyl-D-aspartate receptor (NMDAR) in association with a unique neuro-psychiatric syndrome, over a decade-and-a-half ago. Anti-NMDAR Ab-mediated encephalitis now represents the most well characterised form of autoimmune encephalitis. The disease most commonly manifests in young women, but all ages and both sexes can be affected. Autoantibodies may arise in the context of two well-recognised disease triggers in a proportion of patients, and ultimately facilitate NMDAR displacement from synapses. Various CSF cytokines, chemokines, and other molecules have been explored as candidate biomarkers but are limited in sensitivity and specificity. The clinical spectrum is diverse, with evolution and a combination of neuro-psychiatric abnormalities at disease nadir common. Anti-NMDAR Ab-mediated encephalitis is immunotherapy responsive, and a near-majority ultimately acquire a broadly favourable clinical outcome. The diagnosis, and more particularly, the management of the disease can still hold considerable challenges. Moreover, well-defined biomarkers remain elusive. The present review will therefore delineate pathogenic and clinical advances to date in anti-NMDAR antibody-mediated encephalitis.

Clinical characteristics, long-term functional outcomes and relapse of anti-LGI1/Caspr2 encephalitis: a prospective cohort study in Western China

Objective:

To study the clinical characteristics of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis and anti-contactin-associated protein-like 2 (Caspr2) encephalitis and to investigate factors associated with poor long-term neurological functional outcomes and relapse among patients in western China.

Methods:

In this single-center prospective cohort study, we consecutively enrolled patients with anti-LGI1 encephalitis and anti-Caspr2 encephalitis from April 2014 to February 2021. Patient outcomes were assessed using the modified Rankin scale. Predictors of long-term functional outcomes and relapse were analyzed.

Results:

Forty-four anti-LGI1 encephalitis patients [median age: 44 years, range: 18–82 years; females: 25 (56.8%)], 35 anti-Caspr2 encephalitis patients [median age: 43 years, range: 14–80 years; females: 19 (54.3%)], and 5 dual-positive patients [median age: 44 years, range: 36–58 years; females: 5 (100%)] were enrolled. Overall, 86.4% anti-LGI1 encephalitis patients and 80% anti-Caspr2 encephalitis had a favorable neurological functional outcome (mRS 0-2). Tumor occurrence and weight loss were associated with poor long-term functional outcomes in anti-LGI1 encephalitis, whereas in anti-Caspr2 encephalitis, predictors included behavioral disorder at acute phase, abnormalities in brain magnetic resonance imaging, higher modified Rankin scale scores at onset, poor response to the initial immunotherapy at 4 weeks, age at onset<30 years, and relapse ( p<0.05). Overall, 13.6% of anti-LGI1 encephalitis patients and 20% of anti-Caspr2 encephalitis patients had at least one relapse. Sleep disorder at the acute phase was the risk factor of relapse in anti-LGI1 encephalitis, while female, age at onset <30 years, and behavioral disorder at acute phase were the risk factors of relapse in anti-Caspr2 encephalitis (log rank p<0.05).

Conclusion:

The clinical characteristics such as age, gender, and tumor occurrence rates of anti-LGI1 encephalitis and anti-Caspr2 encephalitis in western China are different from those in the Western countries. Most patients in our study had favorable long-term functional outcomes. The relapse rates are still high in both types of encephalitis, which warrants caution.

Antibody-Mediated Autoimmune Diseases of the CNS: Challenges and Approaches to Diagnosis and Management

Antibody-mediated disorders of the central nervous system (CNS) are increasingly recognized as neurologic disorders that can be severe and even life-threatening but with the potential for reversibility with appropriate treatment. The expanding spectrum of newly identified autoantibodies targeting glial or neuronal (neural) antigens and associated clinical syndromes (ranging from autoimmune encephalitis to CNS demyelination) has increased diagnostic precision, and allowed critical reinterpretation of non-specific neurological syndromes historically associated with systemic disorders (e.g., Hashimoto encephalopathy). The intracellular vs. cell-surface or synaptic location of the different neural autoantibody targets often helps to predict the clinical characteristics, potential cancer association, and treatment response of the associated syndromes. In particular, autoantibodies targeting intracellular antigens (traditionally termed onconeural autoantibodies) are often associated with cancers, rarely respond well to immunosuppression and have a poor outcome, although exceptions exist. Detection of neural autoantibodies with accurate laboratory assays in patients with compatible clinical-MRI phenotypes allows a definite diagnosis of antibody-mediated CNS disorders, with important therapeutic and prognostic implications. Antibody-mediated CNS disorders are rare, and reliable autoantibody identification is highly dependent on the technique used for detection and pre-test probability. As a consequence, indiscriminate neural autoantibody testing among patients with more common neurologic disorders (e.g., epilepsy, dementia) will necessarily increase the risk of false positivity, so that recognition of high-risk clinical-MRI phenotypes is crucial. A number of emerging clinical settings have recently been recognized to favor development of CNS autoimmunity. These include antibody-mediated CNS disorders following herpes simplex virus encephalitis or occurring in a post-transplant setting, and neurological autoimmunity triggered by TNFα inhibitors or immune checkpoint inhibitors for cancer treatment. Awareness of the range of clinical and radiological manifestations associated with different neural autoantibodies, and the specific settings where autoimmune CNS disorders may occur is crucial to allow rapid diagnosis and early initiation of treatment.