Clinical Characteristics and Short-Term Prognosis of Autoimmune Encephalitis: A Single-Center Cohort Study in Changsha, China

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.

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.

Clinical features, cerebrospinal fluid changes, and prognosis in Chinese patients with autoimmune encephalitis

INTRODUCTION

Autoimmune encephalitis (AE) is a rare, treatable disease of the central nervous system (CNS) caused by an antibody-related immune response. This study is to investigate the correlation of clinical features, cerebrospinal fluid (CSF) characteristics, and prognosis in patients with AE.

METHODS

A total of 71 patients diagnosed with antibody-positive AE were retrospectively analyzed. The patients were divided into three groups: anti-NMDAR group, anti-LGI1 group, and other types. Clinical data were collected to analyze clinical features and CSF results, and prognosis was determined by modified Rankin Scale (mRS).

RESULTS

There was statistical difference in the incidences of decreased consciousness level (P < 0.001), memory loss (P = 0.017), speech disorders (P = 0.035), and dyskinesia (P = 0.001) in different antibodies groups. Younger age (P = 0.018), elevated CSF chloride content (P = 0.006), and white blood cells > 50/mm3 (P = 0.026) were highly correlated with ICU admission. Anti-LGI1 encephalitis had a relatively small risk for ICU admission (P = 0.034), and a lower risk of poor functional recovery (P = 0.048) and recurrence (P = 0.041). Patients with first-line treatment failure (P = 0.021) had an increased risk of poor functional recovery. Delayed treatment (P = 0.011) would increase the risk of recurrence.

CONCLUSION

There are differences in age, gender, clinical characteristics, and CSF results in different subtypes of AE. First-line therapy failure would have poor functional recovery, and delayed therapy would increase the risk of relapse. Chloride ion content and white blood cell count in cerebrospinal fluid are positively correlated with the patient's exacerbation and admission to ICU. These indicators have certain clinical value for the prognosis of AE patients.

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.

Comparing clinical features, severity and prognosis of autoimmune encephalitis and with and without oligoclonal bands

Objective

This study aimed to examine the clinical distinctions among patients diagnosed with autoimmune encephalitis (AE) based on the presence or absence of cerebrospinal fluid (CSF) oligoclonal bands (OCBs). Additionally, it sought to explore the relationship between OCBs and the severity and prognosis of autoimmune encephalitis.

Methods

A retrospective analysis was conducted on 94 patients diagnosed with AE at the People's Hospital of Zhengzhou University between October 2016 and June 2022. The patients were divided into OCB-positive and OCB-negative groups based on CSF-OCBs. Patient severity at admission was assessed utilizing the Clinical Assessment Scale for Autoimmune Encephalitis (CASE) and the modified Rankin scale (mRS). Additionally, some oligoclonal-positive patients underwent dynamic longitudinal analysis of cerebrospinal fluid test indices. The mRS score was ultimately employed to evaluate patients' short-term prognosis (6 months) and long-term prognosis (at least 12 months) following immunotherapy.

Results

Of the 94 patients, 34 (36.2%) belonged to the OCB-positive group, while 60 (63.8%) belonged to the OCB-negative group. The group with anti-n-methyl-d-aspartate receptor (anti-NMDAR) encephalitis exhibited the highest rate of oligoclonal positivity at 27 (49.1%), followed by anti-aminobutyric acid B receptor (GABABR) encephalitis with 4 cases (30.8%), anti-contactin-associated protein-like 2 (CASPR2) encephalitis with 2 cases (20%), and anti-leucine-rich glioma inactivating protein 1 (LGI1) encephalitis with 1 case (6.25%). No statistically significant differences were found between the two groups regarding gender, age, prodromal symptoms, psychiatric disorders, seizures, language disorders, motor dysfunction, cognitive dysfunction, tumor incidence, and magnetic resonance imaging (MRI) abnormalities (p > 0.05). The OCB-positive group exhibited higher rates of autonomic dysfunction, intensive care unit (ICU) admission, CSF leukocytes, and IgG index compared to the OCB-negative group (p < 0.05). Additionally, the OCB-positive group had significantly higher median CASE and mRS scores prior to immunotherapy than the OCB-negative group (p < 0.001 and p < 0.001). Furthermore, in both short-term follow-up and long-term follow-up, the OCB-positive group had a significantly lower proportion of patients with a favorable prognosis compared to the OCB-negative group (50% vs. 71.7, 61.8% vs. 83.3%; p = 0.036, p = 0.002).

Conclusion

Autonomic dysfunction, ICU admission, leukocytes in the cerebrospinal fluid, and elevated IgG index are more commonly observed in OCB-positive patients. OCB-positivity has also been linked to the severity and prognosis of AE, making it a potential biomarker. Initial OCB testing aids clinicians in identifying potentially critically ill patients early and monitoring disease progression, thereby optimizing clinical treatment decisions.

Abnormalities in modular connectivity of functional brain networks and cognitive changes in patients with anti -N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

To explore potential mechanisms of cognitive changes in patients with anti-NMDAR encephalitis (ANMDARE) from intramodule and intermodule effects of brain functional networks.

METHODS

Resting-state functional MRI(rs-fMRI) imaging data was collected from 30 ANMDARE and 30 healthy controls (HCs). A brain functional matrix was constructed, and sparsity was established by module similarity. For both groups, changes in functional connectivity (FC) within and between modules was calculated, and whole-brain functional topology was analyzed. Finally, the association of brain functional with cognitive function in ANMDARE was further analyzed.

RESULTS

Compared to HCs, ANMDARE had enhanced connectivity within the modules that included the occipito-parietal-temporal and parahippocampal gyri. ANMDARE had significantly higher participation coefficients (PC) in the right inferior frontal gyrus than HCs and significantly lower PC in the left superior parietal lobule, left caudate nucleus, and right putamen. No statistically significant differences in global topological properties were found between the two groups. No correlations were found between functional and structural brain indicators and the Cognitive Assessment Scale and the Emotional Deficit Scale.

CONCLUSIONS

Patients with ANMDARE are manifested by enhanced intramodular FC and intermodular connectivity changes in the brain. This may help to understand the pathophysiological mechanisms of the disease from a global perspective.

Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study

Background

The frequency of antibodies in autoimmune encephalitis (AIE) may vary in different populations, however, data from developing countries are lacking. To describe the clinical profile of AIE in Brazil, and to evaluate seasonality and predictors of AIE in adult and pediatric patients.

Methods

We evaluated patients with possible AIE from 17 centers of the Brazilian Autoimmune Encephalitis Network (BrAIN) between 2018 and 2022. CSF and serum were tested with TBAs and CBAs. Data on clinical presentation, complementary investigation, and treatment were compiled. Seasonality and predictors of AIE in adult and pediatric populations were analyzed.

Results

Of the 564 patients, 145 (25.7%) were confirmed as seropositive, 69 (12.23%) were seronegative according to Graus, and 58% received immunotherapy. The median delay to diagnosis confirmation was 5.97 ± 10.3 months. No seasonality variation was observed after 55 months of enrolment. The following antibodies were found: anti-NMDAR (n=79, 54%), anti-MOG (n=14, 9%), anti-LGI1(n=12, 8%), anti-GAD (n=11, 7%), anti-GlyR (n=7, 4%), anti-Caspr2 (n=6, 4%), anti-AMPAR (n=4, 2%), anti-GABA-BR (n=4, 2%), anti-GABA-AR (n=2, 1%), anti-IgLON5 (n=1, 1%), and others (n=5, 3%). Predictors of seropositive AIE in the pediatric population (n=42) were decreased level of consciousness (p=0.04), and chorea (p=0.002). Among adults (n=103), predictors of seropositive AIE were movement disorders (p=0.0001), seizures (p=0.0001), autonomic instability (p=0.026), and memory impairment (p=0.001).

Conclusion

Most common antibodies in Brazilian patients are anti-NMDAR, followed by anti-MOG and anti-LGI1. Only 26% of the possible AIE patients harbor antibodies, and 12% were seronegative AIE. Patients had a 6-month delay in diagnosis and no seasonality was found. Findings highlight the barriers to treating AIE in developing countries and indicate an opportunity for cost-effect analysis. In this scenario, some clinical manifestations help predict seropositive AIE such as decreased level of consciousness, chorea, and dystonia among children, and movement disorders and memory impairment among adults.

Autoimmune encephalitis and paraneoplastic encephalitis: difficulties in diagnosis and management in the ICU

Autoimmune encephalitis (AIE) represents a category of relatively newly described neurological disorders associated with an increasing prevalence, a significant impact on the healthcare system, and a high rate of intensive care unit (ICU) admission. This category of diseases often requires prompt treatment, even before a definitive diagnosis is established. In the ICU, patients present with nonspecific signs and symptoms for AIE, which pose challenges in both management and diagnosis. Patients frequently exhibit dysautonomia, severe physical and psychic agitation, as well as tremors and dyskinesia, all of which complicate the diagnosis. They are prone to developing infections, including ventilator-associated pneumonia, and issues related to difficult venous access and pressure ulcers. Early initiation of immunosuppressive treatment is necessary to improve patients' outcome. Through this article, we aimed to summarize current knowledge in terms of the difficulties in diagnosing and management of this pathology in the ICU, as well as the implications for the healthcare system in terms of human and financial resources.

Efficacy of immunotherapy and prognosis in anti-LGI1 encephalitis patients: A meta-analysis

OBJECTIVE

To assess the efficacy and safety of immunotherapy for LGI1 antibody encephalitis, and consider the predictors of poor outcomes following immunotherapy.

METHODS

We searched PubMed and Embase for articles reporting the immunotherapy data of anti-LGI1 encephalitis patients. The proportions of patients with poor outcomes (modified Rankin Scale [mRS] score > 2) at 3 months, 12 months, and the last follow-up, as well as the odds ratio [OR] of predictors were pooled.

RESULTS

The review included 162 articles with 1066 patients. The proportion of patients with poor functional outcomes was 21% at 3 months, 14% at 12 months, and 14% at the last follow-up after receiving immunotherapy. The proportion of patients with reported relapse was 16.6%. The mean duration from onset to the first relapse was 15.6 months. Predictors significantly associated with poor outcomes were age (increase of 1 year), the presence of cognitive impairment, and CSF LGI1 antibody positive. We did not find a statistically significant association between the worst mRS score in the acute phase, the presence of faciobrachial dystonic seizures (FBDS), days from symptom onset to immunotherapy, second-line treatment, maintenance immunotherapy, or follow-up time and outcomes.

INTERPRETATION

Although most patients respond to immunotherapy, a minority of patients still have poor outcomes. Advanced age, cognitive impairment, and CSF LGI1 antibody positive are associated with an increased risk of poor outcomes. However, due to the insufficiency of the data, these conclusions need to be interpreted with caution.

Retrospective Comparison of Patients Evaluated for Pediatric Autoimmune Encephalitis with Typical and Atypical Premorbid Neuropsychiatric Development

PURPOSE

Patients with neurodevelopmental disorders (NDD) (i.e. autism, developmental delay, early-onset psychiatric or seizure disorders) increasingly seek evaluation of new or exacerbated symptoms concerning for autoimmune encephalitis (AE). Clinical AE evaluation can be challenging in NDD patients with symptom overlap between anti-neuronal autoimmunity and baseline atypical neurodevelopment. This study sought to explore differences in AE features by neurodevelopmental status.

METHODS

This retrospective chart review included 67 children with typical development (TD) or NDD evaluated for AE at the authors' institution. AE diagnosis included seronegative AE or seropositive AE with anti-NMDAR or anti-GAD antibodies. Reported AE clinical domains, symptom onset acuity, and treatment response were compared between three groups: (1) TD children with AE (TD-AE, N = 24); (2) NDD children with AE (NDD-AE, N = 21); and (3) NDD children with a non-AE diagnosis following appropriate workup (NDD-nonAE, N = 22).

RESULTS

Children with AE had a greater number of reported clinical domains than non-AE children with NDD (p < 0.0001) regardless of baseline developmental status. There were no observed differences in reported domains between TD-AE and NDD-AE groups. Onset acuity differed across the three groups (p = 0.04). No treatment response differences were observed between groups.

CONCLUSION

NDD children with AE had a comparable number of reported clinical domains relative to TD children and a similar treatment response. NDD patients with AE had a greater number of reported clinical domains than their NDD peers without an AE diagnosis. These findings suggest that AE is a multi-domain process in both TD and NDD children.

The Diagnostic Challenge and Prognosis of Autoimmune Encephalitis in Children: A Single-Center Retrospective Study

BACKGROUND

Autoimmune encephalitis (AE) is an immune-mediated encephalitis; nevertheless, its diagnosis in children remains challenging. This study aimed to reveal the clinical characteristics, diagnostic processes, and therapeutic outcomes of AE in children.

METHODS

A total of 18 children with AE were enrolled. Antibody assay was performed in the cerebrospinal fluid (CSF) and serum samples by indirect immunofluorescence. Electroencephalography (EEG) and magnetic resonance imaging (MRI) were monitored to reflect abnormal neural signals. In addition, demographics data, neurological symptoms, therapeutic strategies, and outcomes were recorded and analyzed.

RESULTS

Convulsion (50.00%) and emotional disturbance (44.44%) were common clinical symptoms of AE. The biochemical parameters in the CSF had a relatively low diagnostic value. Antibodies in the CSF were dominant in the diagnosis of AE but those in the serum were limited in the diagnosis of anti-MOG or anti-LGI1 AE. In addition, all children showed abnormalities in EEG (72.22%) or MRI (66.67%). Methylprednisolone combined with sequential oral prednisone (83.33%) and gamma globulin (88.89%) were the dominant drugs, achieving an overall recovery rate of 72.22%. However, there were still two patients who had poor outcomes, including Patient 3 with a young age (two years old) and progressive symptom and Patient 12 with a long disease course before treatment (>120 days).

CONCLUSIONS

The clinical manifestations of AE are varied in children. Antibody in the CSF was dominant, and EEG and MRI were instructive in the diagnosis of AE. Young age, progressive symptom, and prolonged disease course before treatment may contribute to poor outcomes.

Spatial and Ecological Factors Modulate the Incidence of Anti-NMDAR Encephalitis-A Systematic Review

Anti-NMDAR encephalitis has been associated with multiple antigenic triggers (i.e., ovarian teratomas, prodromal viral infections) but whether geographic, climatic, and environmental factors might influence disease risk has not been explored yet. We performed a systematic review and a meta-analysis of all published papers reporting the incidence of anti-NMDAR encephalitis in a definite country or region. We performed several multivariate spatial autocorrelation analyses to analyze the spatial variations in the incidence of anti-NMDA encephalitis depending on its geographical localization and temperature. Finally, we performed seasonal analyses in two original datasets from France and Greece and assessed the impact of temperature using an exposure-lag-response model in the French dataset. The reported incidence of anti-NMDAR encephalitis varied considerably among studies and countries, being higher in Oceania and South America (0.2 and 0.16 per 100,000 persons-year, respectively) compared to Europe and North America (0.06 per 100,000 persons-year) (p < 0.01). Different regression models confirmed a strong negative correlation with latitude (Pearson's R = -0.88, p < 0.00001), with higher incidence in southern hemisphere countries far from the equator. Seasonal analyses showed a peak of cases during warm months. Exposure-lag-response models confirmed a positive correlation between extreme hot temperatures and the incidence of anti-NMDAR encephalitis in France (p = 0.03). Temperature analyses showed a significant association with higher mean temperatures and positive correlation with higher ultraviolet exposure worldwide. This study provides the first evidence that geographic and climatic factors including latitude, mean annual temperature, and ultraviolet exposure, might modify disease risk.

[Clinical characteristics and short-term outcomes of autoimmune encephalitis in adults]

OBJECTIVE

To characterize clinical, paraclinical features and short-term outcomes in different types of autoimmune encephalitis (AE) in a one-center cohort of Russian patients, as well as to evaluate the frequency and significance of the joint expression of antineuronal and anti-glial antibodies (Abs) in AE.

MATERIAL AND METHODS

Forty-one patients were diagnosed with AE at the Research Center of Neurology from November 2020 to December 2022. Demographic, clinical characteristics, results of laboratory tests, MRI of brain, treatment and outcomes of disease were analyzed. The analysis of Abs to glial antigens (myelin-oligodendrocyte glycoprotein - MOG, glial fibrillar acidic protein - GFAP, aquaporin 4 - AQP-4) was performed by indirect immunofluorescence assay (Euroimmun, Germany).

RESULTS

In 24 (58.5%) patients was established definite AE, confirmed by specific Abs detection; in 2 (4.9%) - definite limbic encephalitis, in 15 (36.6%) - seronegative probable AE (including 3 cases of Hashimoto's encephalitis). GFAP-Abs in cerebrospinal fluid (CSF) were detected only in two patients - with clinical and MRI-picture of autoimmune GFAP-astrocytopathy (A-GFAP-A). GFAP- and MOG-Abs in the blood were detected in 25.7% and 6%, respectively, AQP-4-Abs were not detected. There were no correlations between co-expression with glial Abs and clinical characteristics. Systemic and antithyroid Abs were present in 15% and 31%, respectively. Paraneoplastic AE accounted for 22%. For the first time in the Russian population, 2 cases of A-GFAP-A, 6 cases of AE associated with COVID-19 were described. The most common first syndrome were epileptic seizure (34%), psychiatric (29%) and cognitive (14%) disorders. Relapses of AE was observed in 22%. Inflammatory changes in CSF were detected in 41%, focal changes on MRI in 68%. First-line immune therapy was performed in all patients, 85% of cases received pulse therapy with methylprednisolone. Second-line immune therapy (rituximab or cyclophosphamide intravenously) was performed in 19.5%, 78% of patients achieved significant improvement during treatment (scores ≤2 on the modified Rankin scale).

CONCLUSIONS

The results allow us to consider COVID-19 as a trigger of AE. The absence of detection of GFAP-Abs in CSF in patients with other types of AE contributes to the confirmation of the specificity of GFAP-seropositivity of CSF for the diagnosis of A-GFAP-A. The expression of GFAP- and MOG-Abs in AE can serve as confirmation of the immuno-mediated etiology of the disease, which is especially important for the AE diagnosis in the absence of antineuronal Abs.

Cerebral gray matter volume changes in patients with anti-N-methyl-D-aspartate receptor encephalitis: A voxel-based morphometry study

Background:

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disease with typical clinical features. Whether and how cerebral gray matter structural damage inherent to the disorder affects cognitive function in patients is still unclear. Therefore, this study aimed to explore the changes in cerebral gray matter volume and whether these alterations contribute to cognitive impairment and mood disorders.

Methods

Forty patients with anti-NMDAR encephalitis and forty healthy controls (HCs) matched for gender, age, and education were recruited. All participants underwent attention network tests (ANT), neuropsychological tests and magnetic resonance imaging (MRI). Voxel-based morphological analysis (VBM) and correlation analysis was performed on all participants. Finally, according to the course of disease, patients were divided into two groups: NMDARE_SD (short duration; course ≤ 2 years since diagnosis) and NMDARE_LD (long duration; course >2 years since diagnosis), to evaluate gray matter volume changes that differ as a function of disease course.

Results

Compared to HCs, patients with anti-NMDAR encephalitis showed decreased executive control ability and lower MoCA score, while increased anxiety and depression as reflected by HAMA and HAMD24 scores (all P < 0.05). In VBM analysis, patients showed decreased gray matter volume in bilateral thalamus, left medial prefrontal cortex (mPFC_L), left superior temporal gyrus (STG_L), and left rectus gyrus. In the analysis stratified by disease course, the NMDARE_LD group exhibited decreased gray matter volume in the left precuneus and right posterior cerebellar lobe compared to the NMDARE_SD group.

Conclusions

Patients with anti-NMDAR encephalitis have cognitive, executive, and emotional dysfunction, and the sites of gray matter atrophy are concentrated in the thalamus, frontal lobe, and temporal lobe. These abnormalities may be involved in the process of cognitive and affective dysfunction.Patients with different courses of anti-NMDAR encephalitis have different brain atrophy sites. These results may help to clarify the contradiction between clinical and imaging manifestations of anti NMDAR encephalitis, which is worthy of further longitudinal studies.

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.

The Neutrophil-to-Lymphocyte and Monocyte-to-Lymphocyte Ratios Are Independently Associated With the Severity of Autoimmune Encephalitis

Background

The neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) are biomarkers that may reflect inflammatory status in some immune-related diseases. This study aims to investigate the association of NLR and MLR with the severity and prognosis of autoimmune encephalitis (AE).

Methods

A total of 199 patients diagnosed with AE in the First Affiliated Hospital of Zhengzhou University from October 2015 to October 2021 were retrospectively analyzed. The Clinical Assessment Scale for Autoimmune Encephalitis (CASE) and the modified Rankin Scale (mRS) were used to evaluate the severity of the patients at admission, and the patients were divided into mild group (CASE ≤ 4) and severe group (CASE ≥ 5) according to the CASE score. Poor prognosis was described as an mRS of 3 or more at 12 months. Binary logistic regression analysis was performed to assess risk factors for the severity and prognosis of AE.

Results

NLR and MLR of severe group were significantly higher than that of mild group. NLR and MLR were positively correlated with the CASE score (r = 0.659, P < 0.001; r = 0.533, P < 0.001) and the mRS score (r = 0.609, P < 0.001;r = 0.478, P < 0.001) in AE patients. Multivariate logistic analysis showed that NLR (OR = 1.475, 95%CI: 1.211-1.796, P < 0.001) and MLR (OR = 15.228, 95%CI: 1.654-140.232, P = 0.016) were independent risk factors for the severity of AE. In addition, the CASE score and the mRS score were positively correlated (r = 0.849, P < 0.001). Multivariate logistic analysis showed that the CASE at admission (OR = 1.133, 95%CI: 1.043-1.229, P = 0.003) and age (OR = 1.105, 95%CI: 1.062-1.150, P < 0.001) were independent risk factors for the poor prognosis of AE patients. The NLR and MLR at admission and whether they decreased after immunotherapy were not associated with the prognosis of AE patients (P > 0.05).

Conclusions

NLR and MLR, readily available and widespread inflammatory markers, were helpful for clinicians to monitor disease progression and identify potentially severe patients of AE early to optimize clinical treatment decisions.

Aberrant resting-state interhemispheric functional connectivity in patients with anti-N-methyl-D-aspartate receptor encephalitis

PURPOSE

Previous studies have discovered different neuroimaging features in anti-NMDAR encephalitis associated with cognitive dysfunction. However, it is unknown whether there is a correlation between abnormal homotopic connectivity and cognitive impairment in anti-NMDAR encephalitis. We aim to explore the homotopic connectivity patterns of patients with anti-NMDAR encephalitis and their associations with clinical characteristics.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) was performed on 29 patients with anti-NMDAR encephalitis and 26 healthy controls (HCs). Voxel-mirrored homotopic connectivity (VMHC) and multivariate pattern analysis (MVPA) were applied to analyze the imaging data. A correlation was also performed between aberrant brain regions and clinical parameters.

RESULTS

Compared to HCs, the performance of alertness in the patient group was typically worse (p < 0.05). A significant decrease in VMHC was observed in many regions of the patients in comparison to HCs, including the cerebellar 6, para-hippocampal gyrus, insula, precuneus, and middle frontal gyrus (p < 0.001). The insula and middle frontal gyrus were found to show positive correlations with alertness. The MVPA method achieved a classification accuracy of 74.55% with a sensitivity of 82.76% and a specificity of 65.38% in discriminating patients from HCs.

CONCLUSION

Our findings indicate that interhemispheric functional imbalance may play a significant role in the pathophysiology of cognitive dysfunction in anti-NMDAR encephalitis. The MVPA results suggest that abnormal VMHC may play a crucial role in the identification of patients with anti-NMDAR encephalitis from HCs.

Influential Factors, Treatment and Prognosis of Autoimmune Encephalitis Patients With Poor Response to Short-Term First-Line Treatment

Objective

This study was performed to assess the potential factors for poor short-term first-line treatment response, the appropriate further treatment options, and the prognosis in patients with autoimmune encephalitis (AE).

Methods

This retrospective study consisted of 135 patients with AE. According to their short-term first-line treatment response, patients were divided into the response group and the non-response group. The demographics, clinical characteristics, main accessory examinations, immunotherapy, and outcomes of patients were compared between the two groups. Univariate and multivariate logistic regression models were used to analyze whether non-responders have poor long-term outcomes. Further treatment and prognosis of non-responders were also analyzed.

Results

Of the 128 patients who were treated with first-line immunotherapy, 59 (46.1%) were non-responders. Patients in the non-response group had more symptoms and exhibited a higher proportion of mental behavior disorder, central hypoventilation, and autonomic nervous dysfunction. The modified Rankin scale (mRS) scores and neutrophil-to-lymphocyte ratio (NLR) levels were significantly higher and albumin, high-density lipoprotein cholesterol (HDL-C), apolipoprotein A (apoA) levels were significantly lower in the non-response group (p < 0.05, all). Multivariate logistic regression analysis showed that the number of clinical symptoms, mental behavior disorder, central hypoventilation, maximum mRS score, and albumin level was independently associated with non-response to short-term first-line treatment. Non-responders had poor long-term outcomes compared with the responders at all times of followed-up (p < 0.05, all). In multivariable analysis, initial first-line treatment response was independently associated with the long-term prognosis, both at 12-month [odds ratio (OR), 4.74, 95% CI, 1.44–15.59, and p=0.010] and 24-month follow-ups (OR, 8.81, 95% CI, 1.65–47.16; and p = 0.011). Among the non-responders, a higher improvement of mRS scores was observed in those who received second-line treatment than those who had no further treatment or repetition of first-line immunotherapy in the follow-up. However, the rate of a good outcome and median mRS scores were not significantly different among the three groups.

Conclusion

Disease severity, clinical features, anti-N-methyl-D-aspartate receptor subtypes, antibody titers, NLR, albumin, HDL-C, and apoA levels were all associated with non-response to short-term first-line treatment. The short-term first-line treatment response is a valuable predictor of long-term outcomes in patients with AE. Second-line immunotherapy may be a more aggressive treatment option for patients who failed short-term first-line immunotherapy.

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.

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.

Clinical Characteristics and Short-Term Prognosis of Children With Antibody-Mediated Autoimmune Encephalitis: A Single-Center Cohort Study

BACKGROUND

The incidence and prevalence of autoimmune encephalitis (AE) is gradually increasing in pediatric patients (between the ages of 3 months and 16 years). The aim of this retrospective observational study was to investigate the clinical characteristics and short-term prognosis of children with antibody-mediated AE at Hunan Children's Hospital.

METHODS

Antibody analysis of blood and/or cerebrospinal fluid was performed in suspected AE patients admitted to the Department of Neurology, Hunan Children's Hospital from June 2014 to June 2021. Ultimately, 103 patients were diagnosed with antibody-mediated AE and were enrolled in this study. Clinical data and corresponding demographic, clinical characteristics, laboratory and imaging data, treatment, and prognosis data were collected and analyzed.

RESULTS

In our study, 103 AE patients with antibody-positive were identified. The main subtype of AE in our cohort was anti-NMDAR encephalitis. Few patients have anti-CASPR2 encephalitis, anti-GABABR encephalitis, or anti-LGI1 encephalitis. In our AE patients, the most common clinical manifestations were behavioral symptoms, seizures, and involuntary movements, with seizures being the most common initial symptom. All patients underwent brain magnetic resonance imaging (MRI) and electroencephalography (EEG). Forty-five (43.7%) patients had abnormal MRI findings. And 96 (93.2%) patients had abnormal EEG results. All 103 patients were given first-line immunotherapy, 21 of which were also treated with the combination of the second-line immunotherapy. All surviving patients were followed up for at least 6 months. Seventy-seven patients recovered completely, 23 had sequelae of different degrees, and 3 died. Eight patients had one or more relapses during the follow-up period.

CONCLUSIONS

AE is a treatable disease that can occur in children of all ages. The mortality rate is low, as most patients have a good response to immune therapy. Compared with the older children, infants and young children (≤ 3 years old) with anti-NMDAR encephalitis have a higher incidence of fever and status epilepticus, more severe condition, higher PICU admission rate and worse prognosis. AE patients with high maximum mRS scores and PICU admissions may require second-line immunotherapy.

Antinuclear antibodies in neurology and their clinical application

Antinuclear antibodies (ANA) are a diverse group of autoantibodies found in various systemic autoimmune disorders. They represent a key diagnostic marker in the diagnosis of connective tissue disorders (CTD). Although many techniques exist, ANA by Indirect Immunofluorescence (IIF) remains the gold standard for diagnosing CTDs. Neurologists should be aware of the type of assay used for detection and the advantages and disadvantages of using each method. Through this article, we aimed to review the methodological aspects of the detection of ANA and its subtypes and their clinical relevance in various neurologic disorders.

Correlation analysis between regional homogeneity and executive dysfunction in anti-N-methyl-D-aspartate receptor encephalitis patients

BACKGROUND AND PURPOSE

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is characterized by a range of cognitive impairments, especially in executive function. Our study aims to identify the abnormal regional homogeneity (ReHo) in anti-NMDAR encephalitis patients and its relationship with the executive function.

METHODS

Forty patients and 42 healthy volunteers undertook an Attention Network Test and a resting-state functional magnetic resonance imaging scan. ReHo analysis was performed to investigate the neuronal activity synchronization in all subjects. Based on ReHo analysis, a multivariate pattern analysis (MVPA) was carried out to identify the brain regions that differed the most between the two groups.

RESULTS

Compared to controls, the patients had higher executive control scores (p < 0.05). The patients presented reduced ReHo values in the bilateral posterior cerebellar lobe, anterior cerebellar lobe, midbrain, bilateral caudate nucleus, right superior frontal gyrus, right middle temporal gyrus, bilateral inferior parietal lobule and the left middle frontal gyrus. The ReHo values of the bilateral inferior parietal lobule in patients were found to be negatively associated with executive control scores. The classification of patients and controls using MVPA had an accuracy of 76.83%, a sensitivity of 82.50%, a specificity of 71.43% and the area under the curve was 0.83.

CONCLUSIONS

Our study provides evidence of abnormal cerebral function in anti-NMDAR encephalitis patients, which may contribute to unveiling the neuropathological mechanisms of anti-NMDAR encephalitis and their influences on executive dysfunction. The MVPA classifier, based on ReHo, is helpful in identifying anti-NMDAR encephalitis patients from healthy controls.

Analysing Triggers for Anti-NMDA-Receptor Encephalitis Including Herpes Simplex Virus Encephalitis and Ovarian Teratoma: Results from the Queensland Autoimmune Encephalitis Cohort

INTRODUCTION

Anti-N-methyl-D-Aspartate-Receptor (anti-NMDA-R) encephalitis is a complex autoimmune neuropsychiatric syndrome. Although initially associated with ovarian teratoma, subsequent studies have demonstrated that anti-NMDA-R encephalitis may occur without an identifiable cause or be triggered by viral infection of the central nervous system such as herpes simplex virus encephalitis (HSVE). This study will present details from a Queensland cohort analysing triggering events in patients with anti-NMDA-R encephalitis in an Australian context.

METHODOLOGY

The authors identified patients with anti-NMDA-R encephalitis diagnosed and managed through public hospitals in Queensland, Australia between 2010 and the end of 2019. Data collected included demographics, clinical presentation, investigation results, management and outcome measurements.

RESULTS

Thirty-one cases of anti-NMDA-R encephalitis were included in the study. Three cases of anti-NMDA-R encephalitis were triggered by prior HSVE, five cases were associated with ovarian teratoma and twenty-three cases had no identifiable trigger. There were an additional three cases in which anti-NMDA receptor antibodies were present in the context of other disease states but where the patient didn't develop anti-NMDA-R encephalitis. Cases triggered by HSVE or associated with ovarian teratoma experienced a more severe disease course compared to cases with no identifiable trigger. All groups responded to immunosuppressive or immunomodulatory therapy. Analysis of clinical characteristics revealed a complex heterogeneous syndrome with some variability between groups.

CONCLUSION

In this cohort, the number of cases of anti-NMDA-R encephalitis triggered by HSVE is comparable to those triggered by ovarian teratoma. However, the majority of cases of anti-NMDA-R encephalitis had no identifiable trigger or associated disease process. This article is protected by copyright. All rights reserved.

Association between autoimmune encephalitis and epilepsy: Systematic review and meta-analysis

BACKGROUND

Diverse neuronal antibodies are related to autoimmune encephalitis (AE) and AE-related epilepsy. However, the epidemiological characteristics of AE, AE-associated antibodies, and AE-related seizures are still unclear.

AIMS

This research evaluated the relationship between AE, AE-related seizures, and neuronal antibodies, as well as the morbidity of AE with early incidence.

METHODS

The PubMed, Embase, Cochrane, and Web of Science databases were searched. Pooled estimates and 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS

Of the 4,869 citations identified, 100 articles were reviewed in full, and 42 subgroups were analyzed. The overall incidence of AE patients with seizures was 42% (95% CI: 0.40-0.44), and among them, the incidence of epilepsy in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients was 73% (95% CI: 0.70-0.77). Subsequently, we found that the prevalence of AE as the cause of epilepsy within the pooled period was 1% (95% CI: 0.01-0.02), while the overall positive rate of neuronal antibodies in epilepsy patients was 4% (95% CI: 0.03-0.05). Additionally, the detection rates of different antibodies among epilepsy patients were as follows: anti-NMDAR, 1%; anti-leucine-rich glioma inactivated 1 (LGI1), 1%; anti-contactin-associated protein-like 2 (CASPR2), 2%.

CONCLUSION

Based on our findings, neuronal antibodies may serve as a bridge to study AE and immune-related epilepsy. To further understand the differences in outcomes following different treatment measures, and to provide more information for public health policy and prevention, more research is needed to improve the accuracy of estimations.

Clinical Characteristics and Long-Term Prognosis of Anti-LGI1 Encephalitis: A Single-Center Cohort Study in Beijing, China

Background: This study aimed to analyze the clinical characteristics of anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis patients and investigate prognostic factors by using a large-sample and long-term follow-up cohort.

Methods: The clinical data of 45 patients (29 males; mean age, 57.0 years) from May 2014 to August 2019 were collected. All patients were followed up by face-to-face interviews in the third month after discharge and then by telephone and/or face-to-face interviews every 6 months until November 2020. We evaluated each patient's response to the initial treatments at the first interview and divided them into “responders” and “nonresponders.” Relapses were recorded. At the end of follow-up, each patient was evaluated and reclassified into “complete recovery” or “unhealed” groups. Intergroup differences were assessed.

Results: All patients presented with seizures at the initial consultation. Other common manifestations included cognitive dysfunction (82.2%), psychiatric disturbance (66.7%), sleep disorder (54.5%), and hyponatremia (66.7%). During the follow-up period (32.8 ± 13.5 months), six patients experienced relapse within 6–37 months. We observed that the patients who did not respond to the initial treatments and those who relapsed all had a poor long-term prognosis. The patients in the “unhealed” group were older (p = 0.009), had a lower incidence of generalized tonic–clonic seizures (p = 0.041), and had a higher probability of cerebrospinal fluid (CSF) abnormalities (p = 0.024) than those in the “complete recovery” group.

Conclusion: Anti-LGI1 encephalitis was characterized by seizures, cognitive impairment, psychiatric disturbance, and sleep disorders and was often accompanied by hyponatremia. Patients who responded poorly to the initial treatments and those patients who relapsed had dismal long-term prognoses. Advanced age and CSF abnormalities may be risk factors for poor prognosis, but these still need to be verified.

Characteristics and Prognosis of Autoimmune Encephalitis in the East of China: A Multi-Center Study

Objective: This study aimed to investigate epidemiological characteristics, clinical manifestations, and long-term outcomes of patients with autoimmune encephalitis (AE) in the east of China.

Methods: From January 2015 to December 2019, 226 potential AE patients were recruited from five clinical centers, and a total of 185 patients who met the diagnostic criteria were included in the study. We retrospectively reviewed clinical features, auxiliary examinations, details of treatments, and outcomes of AE, and identified risk factors of poor prognosis. Modified Rankin Scale scores were used to evaluate neurological function, and scores of 3–6 indicated a poor-prognosis.

Results: Patients with five main subtypes of AE were enrolled in the study, as follows: anti-NMDAR (79), anti-LGI1 (55), anti-CASPR2 (30), anti-GABABR (16), and anti-AMPAR (5). Among 185 patients, 58.38% (108/185) were male and 41.62% (77/185) were female. The median age at disease onset was 41 years (interquartile range, 17–62). The most common clinical manifestations of AE were seizures (146, 78.92%) and memory deficit (123, 66.49%). A total of 95 (51.35%) patients had abnormal brain magnetic resonance imaging results. Electroencephalographic findings were abnormal in 131 (70.81%) patients, and 168 (90.81%) and 26 (14.05%) patients were treated with first- and second-line immunotherapies, respectively. All surviving patients were followed-up for at least 1 year (range 12–36 months). Good clinical outcomes were achieved in 117 (63.24%), while 68 (36.76%) patients had a poor prognosis. Further, 33 (17.84%) patients relapsed and 10 (5.41%) died within 1 year post-discharge. Older patients tended to have a poorer prognosis, and the occurrence of mental behavioral disorders, movement disorders, disturbance of consciousness, central hypoventilation, and tumors were overrepresented in the poor-prognosis group.

Conclusions: AE is a treatable disease, and most patients have a good prognosis. There are differences in the clinical manifestations of patients with different AE subtypes. Some with AE will relapse, and long-term follow-up is of great significance for further research.

The Insula Is a Hub for Functional Brain Network in Patients With Anti-N-Methyl-D-Aspartate Receptor Encephalitis

BACKGROUND

In recent years, imaging technologies have been rapidly evolving, with an emphasis on the characterization of brain structure changes and functional imaging in patients with autoimmune encephalitis. However, the neural basis of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis and its linked cognitive decline is unclear. Our research aimed to assess changes in the functional brain network in patients with anti-NMDAR encephalitis and whether these changes lead to cognitive impairment.

METHODS

Twenty-one anti-NMDAR encephalitis patients and 22 age-, gender-, and education status-matched healthy controls were assessed using resting functional magnetic resonance imaging (fMRI) scanning and neuropsychological tests, including the Hamilton Depression Scale (HAMD24), the Montreal Cognitive Assessment (MoCA), and the Hamilton Anxiety Scale (HAMA). A functional brain network was constructed using fMRI, and the topology of the network parameters was analyzed using graph theory. Next, we extracted the aberrant topological parameters of the functional network as seeds and compared causal connectivity with the whole brain. Lastly, we explored the correlation of aberrant topological structures with deficits in cognitive performance.

RESULTS

Relative to healthy controls, anti-NMDAR encephalitis patients exhibited decreased MoCA scores and increased HAMA and HAMD24 scores (p < 0.05). The nodal clustering coefficient and nodal local efficiency of the left insula (Insula_L) were significantly decreased in anti-NMDAR encephalitis patients (p < 0.05 following Bonferroni correction). Moreover, anti-NMDAR encephalitis patients showed a weakened causal connectivity from the left insula to the left inferior parietal lobe (Parietal_Inf_L) compared to healthy controls. Conversely, the left superior parietal lobe (Parietal_sup_L) exhibited an enhanced causal connectivity to the left insula in anti-NMDAR encephalitis patients compared to controls. Unexpectedly, these alterations were not correlated with any neuropsychological test scores.

CONCLUSION

This research describes topological abnormalities in the functional brain network in anti-NMDAR encephalitis. These results will be conducive to understand the structure and function of the brain network of patients with anti-NMDAR encephalitis and further explore the neuropathophysiological mechanisms.

Clinical Characteristics and Outcome of Neuronal Surface Antibody-Mediated Autoimmune Encephalitis Patients in a National Cohort

Background: In our previous single-center study of autoimmune encephalitis (AE) related autoantibody test results we found positivity in 60 patients out of 1,034 with suspected AE from 2012 through 2018 as part of a Hungarian nationwide program. In our current multicenter retrospective study, we analyzed the clinical characteristics and outcome of AE patients with positive neuronal cell surface autoantibody test results.

Methods: A standard online questionnaire was used to collect demographic and clinical characteristics, laboratory and imaging data, therapy and prognosis of 30 definitive AE patients in four major clinical centers of the region.

Results: In our study, 19 patients were positive for anti-NMDAR (63%), 6 patients (20%) for anti-LGI1, 3 patients for anti-GABABR (10%) and 3 patients for anti-Caspr2 (10%) autoantibodies. Most common prodromal symptoms were fever or flu-like symptoms (10/30, 33%). Main clinical features included psychiatric symptoms (83%), epileptic seizures (73%) and memory loss (50%). 19 patients (63%) presented with signs of central nervous system (CNS) inflammation, which occurred more frequently in elder individuals (p = 0.024), although no significant differences were observed in sex, tumor association, time to diagnosis, prognosis and immunotherapy compared to AE patients without CNS inflammatory markers. Anti-NMDAR encephalitis patients were in more severe condition at the disease onset (p = 0.028), although no significant correlation between mRS score, age, sex and immunotherapy was found. 27% of patients (n = 8) with associated tumors had worse outcome (p = 0.045) than patients without tumor. In most cases, immunotherapy led to clinical improvement of AE patients (80%) who achieved a good outcome (mRS ≤ 2; median follow-up 33 months).

Conclusion: Our study confirms previous publications describing characteristics of AE patients, however, differences were observed in anti-NMDAR encephalitis that showed no association with ovarian teratoma and occurred more frequently among young males. One-third of AE patients lacked signs of inflammation in both CSF and brain MRI, which emphasizes the importance of clinical symptoms and autoantibody testing in diagnostic workflow for early introduction of immunotherapy, which can lead to favorable outcome in AE patients.

Leucine-rich glioma-inactivated protein 1 antibody-mediated autoimmune encephalitis in a 4-year-old girl: a case report

Background

Leucine-rich glioma-inactivated protein 1 (LGI1) antibody-mediated encephalitis is a rare subtype of autoimmune encephalopathy, which is associated with autoimmunity against the neuronal plasma membrane proteins. The characteristic symptoms of this disease are memory dysfunction, seizures, faciobrachial dystonic seizures, cognitive deficits, neuropsychiatric disturbances, and intractable hyponatremia. The diagnosis of this disease mainly depends on the presence of anti-LGI1 antibody in serum or cerebrospinal fluid of patients. LGI1 antibody encephalitis has been reported mostly in adults, with rare occurrences in children.

Case presentation

In this report, we described a 4-year-old girl with typical seizures. Seizure types included focal seizures and generalized tonic-clonic seizures. The electroencephalogram findings showed focal discharges. Brain magnetic resonance imaging (MRI) showed normal. The cerebrospinal fluid (CSF) levels of cells, glucose, and chloride were within the normal range, and the culture did not reveal growth of any pathogen. Test of serum LGI1-Ab was positive, while the tests for autoimmune encephalitis antibody series in CSF were negative. The seizures of the patient were completely controlled after the therapy of immunoglobulin, methylprednisolone and antiepileptic drugs (AEDs), and the mental state almost returned to normal.

Conclusion

To our knowledge, the patient described here may be the youngest case of LGI1 antibody encephalitis reported to date. Children with the LGI1 antibody-associated encephalitis may present only with single symptoms such as epileptic seizures and have good response to the therapy of immunoglobulin, methylprednisolone and antiepileptic drugs. Our case report will provide hints for pediatricians in the diagnosis and treatment of LGI1-antibody encephalitis.

An Australian State-Based Cohort Study of Autoimmune Encephalitis Cases Detailing Clinical Presentation, Investigation Results, and Response to Therapy

Introduction: Autoimmune encephalitis is a disorder associated with antibodies directed against central nervous system proteins with variable clinical features. This study aims to add to knowledge of the disease by reporting the details of a cohort of patients with autoimmune encephalitis in Queensland, Australia.

Methodology: We surveyed patients with autoimmune encephalitis diagnosed and managed through public hospitals in Queensland, Australia between 2010 and the end of 2019. Cases were identified via case detection through a centralized diagnostic neuroimmunology laboratory (Division of Immunology, HSQ Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia) and a survey of neurologists. Data including demographic details, clinical presentation, investigation results, treatments including immune therapy and outcomes was collected.

Results: Sixty cases of antibody positive autoimmune encephalitis were identified. Twenty-eight were of anti-NMDA-receptor encephalitis with other cases associated with antibodies against LGi1, Caspr2, glycine receptor, DPPX, GABA_B receptor, IgLON5, GFAP, and SOX1. The number of diagnosed cases, especially of anti-NMDA-receptor encephalitis has markedly increased over the period 2017 to 2019. Clinical presentations were marked by heterogeneous symptom complexes and prolonged hospital admissions. Imaging studies were largely normal or non-specific. There was a response to immune therapy and a low mortality rate. Most cases affected by this disorder were left with ongoing symptoms associated with mild disability.

Conclusion: Autoimmune encephalitis in Queensland, Australia is an increasingly common but complex clinical entity marked by heterogeneous presentations, response to immune therapy and outcome results marked by low mortality and incomplete recovery.

Neuronal Surface Antibody-Medicated Autoimmune Encephalitis (Limbic Encephalitis) in China: A Multiple-Center, Retrospective Study

Objective: The epidemiological characteristics of patients with antibody-medicated autoimmune encephalitis in China remain unclear, and a large-scale epidemiological survey is necessary.

Methods: A multiple-center retrospective study was performed. We collected 1,047 patients with suspected autoimmune encephalitis and ultimately enrolled 778 defined patients across centers in China. All patients were positive for serum [or cerebrospinal fluid (CSF)] antibodies. Demographic information and clinical data from January 2014 to January 2019 from 22 centers in China were reviewed.

Results: A total of 778 patients with autoimmune encephalitis were enrolled in the study. In general, the ratio of males to females was ~1.2:1. The main subtypes of autoimmune encephalitis were NMDAR-AE (61.35%), LGI-1-AE (20.61%), and GABAbR-AE (12.40%). According to the characteristics of age of onset, the incidence of autoimmune encephalitis showed a “double peak” distribution entailing a 20-year-old age group and a 60-year-old age group. We next analyzed the proportion of patients with tumors in this cohort. More specifically, there were 34 patients with tumors and 85 with tumor marker positivity. Relapse occurred in 81 patients within at least 1 year's follow up study: 52 with NMDAR-AE (18.2%); 19 with LGI-1-AE (16.8%); 5 with GABAbR-AE (9%); and 3 with CASPR2-AE.

Interpretation: Due to the vast differences in demographic features, the incidence of cancer and the genetic characteristics between the populations in China and Western countries, the demographics, sex distribution, concomitant tumor rate, clinical features, and relapse characteristics associated with autoimmune encephalitis in China shows a similar profile with Western countries with some minor differences.

Electrophysiological Evaluation in Identifying Unique Sleep Features Among Anti-LGI1 Encephalitis Patients During Active and Recovery Phase

OBJECTIVE

The purpose of this study was to illustrate the electrophysiological features of sleep disturbances in patients with anti-leucine-rich glioma-inactivated protein 1 (anti-LGI1) encephalitis in both active and recovery stages.

METHODS

Retrospectively filed video electroencephalogram (VEEG) and polysomnography (PSG) data in 24 patients with anti-LGI1 encephalitis were analyzed in comparison with that in 20 individuals without sleep disorders as control group.

RESULTS

Sleep efficiency (SE) and total sleep time involving REM and NREM sleep were significantly decreased in patients with anti-LGI1 encephalitis during the active stage compared to that during the recovery stage and in the control group. Imbalanced sleep structure was found, demonstrated by elevated N1, decreased N3 and REM components, as well as abnormal N2 structure characterized with significantly lower spindle duration and density during the active stage. These findings were independent of the presence of nocturnal episodic events or sleep hyperkinetic movements (HMs). HMs were present in 11/23 patients throughout NREM and REM sleep (nonspecific in sleep stages) during the active stage. During the recovery stage, SE and sleep structures were dramatically improved, including the percentage of N3 and REM sleep, spindle duration and density. Ten of 11 patients with HMs were followed up. HMs were totally remitted in 3 patients and still persistent in 1, while evolved into REM sleep behavior disorder (RBD) in 4 with comorbid periodic limb movement syndrome (PLMS) in 3/4, and only PLMS in 2.

CONCLUSION

Sleep disturbances were remarkable and intrinsic features in active anti-LGI1 encephalitis, marked by overall disruptions of both NREM and REM sleep, as well as the presence of HMs, which tend to evolve into RBD or PLMS during the recovery stage. Long-term follow-up with PSG is needed, especially for those patients with severe sleep disturbances during the active phase.