Pediatric Autoimmune Encephalitis: Case Series From Two Chinese Tertiary Pediatric Neurology Centers

Efficacy of rituximab as second-line therapy for autoimmune encephalitis: A systematic review and meta-analysis

Background

Approximately 20%-50 % of individuals with autoimmune encephalitis (AE) demonstrate suboptimal responses to first-line therapies, leading to persistent neurological deficits and the need for second-line interventions. Although rituximab has shown potential as an alternative treatment in AE, the existing evidence remains insufficient. This study systematically evaluated and meta-analyzed the efficacy of rituximab in AE patients who either failed or exhibited inadequate responses to first-line treatments, aiming to refine and optimize therapeutic strategies for AE.

Methods

A comprehensive search of PubMed, Embase, and the Cochrane Library databases was conducted, covering studies published up to June 10, 2024. In addition, manual cross-referencing of relevant studies was performed using both subject-specific and free-text terms such as "Rituximab," "Rituxan," "Mabthera," "RTX," "Mab," "Ma," "AE," "encephalitis," "Anti-NMDAR encephalitis," and "autoimmune encephalitis." Data on rituximab's efficacy as a second-line therapy in AE were independently screened and extracted by two researchers. Statistical analyses were conducted using R4.2.1 software to assess the pooled outcomes of the included studies.

Results

Analysis of 14 studies involving 277 AE cases revealed an 80 % favorable prognosis rate (0.72-0.89) for rituximab, with superior efficacy in patients under 18 years compared to those over 18 (I2 = 65.9 %, 38.7%-81.0 %; p < 0.01). The prognosis rate for patients under 18 was 0.85 (0.76-0.93), while for those over 18, it was 0.72 (0.56-0.88). Furthermore, a disease duration of ≤180 days correlated with a better prognosis than durations exceeding 180 days, with rates of 0.82 (0.69-0.94) and 0.74 (0.61-0.87), respectively.

Conclusion

Rituximab demonstrates an 80 % favorable prognosis rate in AE cases unresponsive to first-line treatments, particularly in patients under 18 or those with disease duration ≤180 days.

The therapeutic effect of ofatumumab in pediatric anti-NMDAR encephalitis: A case series

Ofatumumab (OFA) is an anti-CD20 antibody. We assessed the therapeutic potential of OFA in five pediatric anti-NMDAR encephalitis patients who showed poor responses to the first-line immunotherapy. OFA treatment showed clinical improvement including alleviation of clinical symptoms and mRS decrease accompanied by anti-NMDAR antibody turning negative in 3 patients and decline in 2 patients. And all patients achieved B cell depletion after OFA treatment. During follow-up, all patients' symptoms were stable. OFA treatment is safe and effective, easy to administer, and favorable for pediatric anti-NMDAE encephalitis patients who are refractory to the first-line immunotherapy.

Frequency of anti-MOG antibodies in serum and CSF of patients with possible autoimmune encephalitis: Results from a Brazilian multicentric study

INTRODUCTION

MOGAD encephalitis and ADEM share several clinical features with autoimmune encephalitis (AE) associated with antineuronal antibodies (ANeA); nonetheless, treatment and prognosis differ. Anti-MOG antibodies (abs) are not routinely tested in possible AE, and epidemiological studies on MOGAD encephalitis are scarce.

OBJECTIVES

To determine the frequency of anti-MOG abs in the serum and CSF in a cohort of possible AE and to compare the clinical characteristics of MOGAD patients and those with seropositive AE.

METHODS

481 patients with possible AE from the Brazilian Autoimmune Encephalitis Network underwent tissue-based assay and cell-based assay (CBA) for ANeA. Anti-MOG abs were assessed in serum and CSF with in-house CBA. Clinical and laboratory characteristics of MOGAD and seropositive AE patients were compared.

RESULTS

Of the 481 patients, 87 (18 %) had ANeA, and 17 (3.5 %) had anti-MOG abs. Three AE patients with anti-MOG abs and ANeA were excluded from further analysis. Anti-MOG abs were detected in 4 (1.2 %) of the 328 adults and 10 (6.5 %) of the 153 children. Of the 14 patients with MOGAD, nine had ADEM (mostly children), and five had encephalitis (including three adults). Only one patient with ADEM had anti-MOG abs exclusively in CSF. All patients with MOGAD encephalitis were seropositive for anti-MOG abs, and three had normal brain MRI. Patients with MOGAD had fewer behavioral changes (MOGAD 21 % x AE 96 %, p ≤ 0.0001) and movement disorders (MOGAD 42 % x AE 81 %, p = 0.0017) and more demyelinating symptoms, such as myelitis and optic neuritis (MOGAD 14 % x AE 0 %, p = 0.013).

CONCLUSION

Approximately 3.5 % of patients with possible AE harbor anti-MOG abs, and 0.9 % of the adults had MOGAD encephalitis. Anti-MOG abs were more frequent than other ANeAs regularly tested in AE. We provide evidence that MOGAD is a differential diagnosis in possible AE, even in adult patients with normal brain MRI, and that serum anti-MOG should be considered as an add-on diagnostic tool in AE among adults and pediatric patients.

Pediatric Autoimmune Encephalitis: A Nationwide Study in Latvia

BACKGROUND

Autoimmune encephalitis (AE) is the third most common encephalitis in children. Diagnosis can be challenging due to overlapping and diverse clinical presentations as well as various investigation results. This study aims to characterize the clinical, diagnostic features, as well as treatment and outcomes of AE in children and determine the incidence of pediatric AE in Latvia.

METHODS

The study was conducted at the Children's Clinical University Hospital in Riga. The study participants were patients under the age of 18 years diagnosed with AE from 2014 to 2022. Data regarding clinical characteristics, investigation findings, treatment strategy, and outcomes were retrospectively collected from the medical history data system.

RESULTS

We included 18 pediatric patients diagnosed with AE. The mean incidence of pediatric AE in Latvia was 0.56 per 100,000 children. Most patients (66.6%) had seronegative AE. In the seropositive group, the most common was anti-methyl-D-aspartate receptor AE, with two patients having other antibodies. The most prevalent clinical features were personality change, cognitive impairment, autonomic dysfunction, and movement disorders. The majority of patients (58.8%) received first-line treatment only. More than half (55.6%) of our AE patient group had long-term sequelae.

CONCLUSIONS

Our study shows that the pediatric AE incidence in Latvia is similar to what has been previously reported in other studies. A relatively high proportion of seronegative AE was present in our cohort, indicating that awareness of possible misdiagnosis should be raised. Further research is needed to better understand the underlying mechanisms, characterize clinical features, and determine the treatment of choice in different situations to improve long-term outcomes.

Radiological features in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease-diagnostic criteria and lesion dynamics

The spectrum of acquired pediatric demyelinating syndromes has been expanding over the past few years, to include myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), as a distinct neuroimmune entity, in addition to pediatric-onset multiple sclerosis (POMS) and aquaporin 4-IgG-seropositive neuromyelitis optica spectrum disorder (AQP4+NMOSD). The 2023 MOGAD diagnostic criteria require supporting clinical or magnetic resonance imaging (MRI) features in patients with low positive myelin oligodendrocyte glycoprotein IgG titers or when the titers are not available, highlighting the diagnostic role of imaging in MOGAD. In this review, we summarize the key diagnostic features in MOGAD, in comparison to POMS and AQP4+NMOSD. We describe the lesion dynamics both during attack and over time. Finally, we propose a guideline on timing of imaging in clinical practice.

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.

Less common phenotypes of myelin oligodendrocyte glycoprotein antibody-related diseases in children deserve more attention

BACKGROUND

To facilitate the identification of less common clinical phenotypes of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) in children.

METHODS

We retrospectively reviewed medical records of 236 patients with MOGAD. The following phenotypes were considered to be typical for MOGAD: ADEM, ON, TM, and NMOSD. Less common onset clinical phenotypes were screened out; their clinical and magnetic resonance imaging (MRI), diagnosis, treatment, and prognosis were summarized and analyzed.

RESULTS

16 cases (6.8%) presented as cortical encephalitis, with convulsions, headache, and fever as the main symptoms. 15 cases were misdiagnosed in the early period. 13 cases (5.5%) showed the overlapping syndrome of MOGAD and anti-N-methyl-D aspartate receptor encephalitis (MNOS), with seizures (92.3%) being the most common clinical symptom. 11 cases (84.6%) showed relapses. The cerebral leukodystrophy-like phenotype was present in seven cases (3.0%), with a recurrence rate of 50%. Isolated seizures without any findings on MRI phenotype was present in three cases (1.3%), with the only clinical symptom being seizures of focal origin. Three cases (1.3%) of aseptic meningitis phenotype presented with prolonged fever.

CONCLUSION

40/236 (16.9%) of children with MOGAD had less common phenotypes. Less common clinical phenotypes of pediatric MOGAD are susceptible to misdiagnosis and deserve more attention.

IMPACT

This is the first comprehensive analysis and summary of all less commonl clinical phenotypes of MOGAD in children, while previous studies have only focused on a specific phenotype or case reports. We analyzed the characteristics of MOGAD in children and further revealed the reasons why these less common clinical phenotypes are prone to misdiagnosis and deserve more attention. Our research on treatment has shown that early detection of MOG antibodies and early treatment are of great significance for improving the prognosis of these patients.

A systematic review of the epidemiology of pediatric autoimmune encephalitis: disease burden and clinical decision-making

Background

Autoimmune encephalitis (AIE) comprises a group of rare, immune system-mediated conditions. Clinical manifestations among children are not well-characterized, and there are challenges in testing and diagnosis. This can result in treatment delays, which has been found to correlate with poorer long-term outcomes. This challenge is exacerbated by the scarcity of epidemiological reporting of AIE. The objective of this systematic literature review (SLR) was to identify studies reporting epidemiological data on AIE in children.

Methods

MEDLINE, Embase, the Cochrane Library, and the University of York Centre for Reviews and Dissemination (CRD) were searched in May 2023 for studies reporting on the epidemiology of AIE in children. These were supplemented with additional searches of conference proceedings, gray literature, and the reference lists of identified SLRs. Quality of studies was assessed using a modified version of the Joanna Briggs Institute (JBI) Checklist for Prevalence Studies.

Results

Forty-three publications reporting on 41 unique studies were included. Nine studies reported incidence estimates of different subtypes of AIE, with only one reporting the incidence of overall AIE in children ≤ 18 years, estimated at 1.54 per million children per year in the Netherlands. Three studies reported the incidence of pediatric N-methyl-D-aspartate receptor (NMDAR)-AIE [in United Kingdom (UK), Hong Kong, and Denmark]. The other studies reported incidence data for selected populations.

Conclusion

This SLR highlights a paucity of epidemiology data for AIE in children, which is likely reflective of difficulties in testing and diagnosis. There is a clear need for further research and awareness of these challenges in clinical practice to avoid treatment delays and improve patient outcomes. A deeper understanding of the epidemiology of AIE will help determine the worldwide burden of disease and inform research, health policies and clinical decision-making.

Anti-NMDAR encephalitis in a child with long impaired consciousness and persistent antibodies: a case report and mini review

We described a challenging case of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in a young girl. Despite enduring months of reduced consciousness with ongoing antibody presence, she ultimately exhibited remarkable improvement within a 5-year follow-up period. Additionally, we conducted a concise review of relevant literature on anti-NMDAR encephalitis, with a specific focus on anti-NMDAR antibodies. Our findings enhance the clinical comprehension of anti-NMDAR encephalitis and offer valuable insights to clinicians for its management.

Autoimmune encephalitis in Israeli children - A retrospective nationwide study

Immune-mediated or autoimmune encephalitis (AE) is a relatively new, rare and elusive form of encephalitis in children. We retrospectively collected seropositive children (0-18 years old) with well characterized antibodies through 3 reference laboratories in Israel. Clinical symptoms, MRI and EEG findings and treatment courses were described. A total of 16 patients were included in the study, with 10 females. Anti NMDA encephalitis was most common followed by anti HU and anti mGLuR1. Psychiatric symptoms, abnormal movements, seizures and behavioral changes were the most common presentation. Pathological MRI and EEG findings were described in 37% and 56% of children, respectively. Treatment with corticosteroids, Intravenous immunoglobulins (IVIG) was first line in most children. Following inadequate response children were treated with plasmapheresis and/or rituximab. Two patients relapsed following both first and second line protocols. In terms of long term prognosis, 9 children (56%) had one or more residual behavioral, psychiatric or neurologic findings. Three children required hospitalization for rehabilitation. AE remains a rare diagnosis with variable presenting symptoms, requiring a high index of suspicion. Consensus recommended treatment is generally effective in the pediatric population. Female gender was associated with a higher chance of severe disease. Larger cohorts would be needed to identify prognostic factors in the pediatric population.

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.

Clinical characteristics of Chinese pediatric patients positive for anti-NMDAR and MOG antibodies: a case series

Introduction

The cases of MOG-AD (MOG antibody-associated disorder) and anti-NMDAR encephalitis overlapping syndrome (MNOS) are rare, especially among pediatric patients, and their clinical understanding is limited. This study aimed to investigate the clinical manifestations, imaging findings, treatments, and prognosis of Chinese pediatric patients who tested positive for anti-NMDAR and MOG antibodies.

Methods

This retrospective study enrolled 10 MNOS pediatric patients, 50 MOG-AD (anti-NMDAR antibody-negative), and 81 anti-NMDAR encephalitis (MOG antibody-negative) pediatric patients who were admitted from July 2016 to June 2022 and used their clinical data for comparison.

Results

The MNOS patients had a significantly lower incidence of psycho-behavioral abnormalities and involuntary movements than anti-NMDAR antibody (+)/MOG antibody (-) patients and had a significantly higher incidence of sleep disorders, seizures, and psycho-behavioral abnormalities than MOG antibody (+)/anti-NMDAR antibody (-) patients. The MNOS patients had a significantly higher incidence of MRI abnormalities than the anti-NMDAR antibody (+)/MOG antibody (-) patients, while there was no significant difference in the incidence between the MNOS patients and the MOG antibody (+)/anti-NMDAR antibody (-) patients. No significant difference was seen in the initial mRS score between the three groups of patients. The anti-NMDAR antibody (+)/MOG antibody (-) patients had a higher rate of admission to the ICU, a longer length of in-hospital stay, and a higher rate of introduction to second-line treatment than the other two groups of patients. No significant difference was seen in the mRS score at the last follow-up and in the disease recurrence rate between the three groups. All these patients respond well to immunosuppressive therapy.

Discussion

In the presence of psycho-behavioral abnormalities, sleep disorders, and frequent seizures in MOG-AD patients or demyelinating symptoms of the central nervous system or demyelinating lesions on head MRI in anti-NMDAR encephalitis patients, the coexistence of MOG and anti-NMDAR antibodies should be considered and would suggest a diagnosis of MNOS for these patients. Immunotherapy is effective among these patients and should be given possibly earlier.

Clinical characteristics of Leucine-rich glioma-inactivated protein 1 antibody-mediated autoimmune encephalitis in a 6-year-old girl: case report and literature reviews

BACKGROUND

Autoimmune encephalitis related to the leucine-rich glioma-inactivated protein 1(LGI1) antibody is the most prevalent in older adults, manifesting as seizures, faciobrachial dystonic seizures (FBDS), cognitive impairment, memory disturbance, hyponatremia and neuropsychiatric disorders. However the data pertaining to children affected by the disease is still limited.

CASE PRESENTATION AND LITERATURE REVIEWS

This study presents a detailed report of a 6-year-old Chinese girl who experienced nose aches and faciobrachial dystonic seizures (FBDS). Electrolyte testing revealed that she had hyponatremia and brain MRI showed an abnormality in the left temporal pole. Additionally, anti-LGI1 antibodies were detected in both her serum (1:100) and CSF (1:30). The patient was treated with immunotherapy and symptom management, which proved effective. Furthermore, we provide a summary of 25 pediatric cases of anti-LGI1 encephalitis. Pediatric patients rarely exhibited FBDS and hyponatremia, and some cases presented with isolated syndromes. But the therapeutic outcomes of pediatric patients were generally good.

CONCLUSIONS

In this report, we describe a patient who developed a rare symptom of nose aches possibly as one of symptoms of anti-LGI1 encephalitis, which highlights the possibility of atypical symptoms in children that may be misdiagnosed. Reviewing the literature, the clinical features differed between pediatric and adult cases. Therefore, it is crucial to collect and analyze data from more cases to promote accurate diagnosis and timely treatment.

Anti-LGI1 encephalitis with initiating symptom of seizures in children

Background

Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is infrequently reported but more and more recognizable in children. Here we give detailed description of the clinical features and long-term outcome of three cases of childhood onset anti-LGI1 encephalitis.

Methods

Three anti-LGI1 encephalitis patients were hospitalized in the Department of Pediatrics at Qilu Hospital of Shandong University. Data about the clinical manifestations, treatments and long-term follow-up outcomes were described in detail.

Results

Case 1 showed an adolescent girl with initiating symptom of acute-onset frequent focal seizures. Her serum LGI1-antibody test was positive, and she had a good response to antiseizure medication (ASM) and IVIG. Case 2 showed a preschool-age boy with long-period refractory focal seizures and recent behavioral change. Both serum and cerebrospinal fluid (CSF) tests of LGI1-antibody were positive, and the MRI showed progressive atrophy in the left hemisphere. The symptoms got improved after receiving second-line immunotherapy initially but there are still the sequelae of drug-resistant epilepsy and mild to moderate intellectual disability. Case 3 showed an adolescent boy with initiating symptom of acute-onset frequent focal seizures. Both serum and CSF tests of LGI1-antibody were positive, and he had a good response to immunotherapy. By analyzing all literature-reported 19 pediatric cases, we found pediatric anti-LGI1 encephalitis is more common in female and adolescent. Seizures and behavioral changes were the most common symptoms. CSF pleocytosis and LGI1-antibodies results were mostly negative. Most patients showed good response to immunotherapy.

Conclusion

Childhood onset anti-LGI1 encephalitis is a heterogeneous clinical syndrome, ranging from typical limbic encephalitis to isolating focal seizures. It is important to test autoimmune antibodies when encountering similar cases and repeat antibody testing if necessary. Timely recognition leads to earlier diagnosis and more rapid initiation of effective immunotherapy and potentially better outcomes.

Determination of Clinical, Electrophysiological, and Radiological Characteristics of Pediatric Autoimmune Encephalopathy

Autoimmune encephalopathy (AE) is a group of diseases with subacute onset, that represents a wide clinical spectrum, manifested by complex neuropsychiatric symptoms and signs. In this study, the data of 27 patients diagnosed and followed up in our clinic with the diagnosis of AE between 2011 and 2021 were evaluated retrospectively. Out of 27 patients, 6 were definite seropositive AE, 2 of them met the diagnostic criteria for limbic encephalitis, and the remaining 19 were probable AE. Nowadays, we see AEs with increasing frequency. While there is a generally established approach in the diagnosis and treatment of seropositive patients, there are still hesitations and diagnostic difficulties in seronegative AEs. In this study, clinical, radiological, and prognostic features of definite and probable AE patients diagnosed in a tertiary pediatric neurology clinic were documented. It is thought that pediatric neurologists have an important responsibility to increase awareness about AE in pediatricians. In the future, it is predicted that AE will be diagnosed more frequently with new antibodies and one has to differentiate it from viral encephalitis and neuropsychiatric syndromes and diseases.

Clinical analysis of 173 pediatric patients with antibody-mediated autoimmune diseases of the central nervous system: a single-center cohort study

Background

Antibody-mediated disorders of the central nervous system (CNS) have seen a gradual rise in their incidence and prevalence. This retrospective observational study aimed to investigate the clinical characteristics and short-term prognosis of children with antibody-mediated CNS autoimmune diseases at Hunan Children's Hospital.

Methods

We collected the clinical data of 173 pediatric patients diagnosed with antibody-mediated CNS autoimmune diseases between June 2014 and June 2021 and analyzed their demographics, clinical features, imaging and laboratory data, treatment, and prognosis.

Results

A total of 187 patients tested positive for anti-neural antibodies and 173 patients were finally diagnosed with antibody-mediated CNS autoimmune diseases after excluding the 14 false-positive cases through clinical phenotypic evaluation and follow-up of treatment outcomes. Of the 173 confirmed patients, 97 (56.06%) were positive for anti-NMDA-receptor antibody, 48 (27.75%) for anti-MOG antibody, 30 (17.34%) for anti-GFAP antibody, 5 (2.89%) for anti-CASPR2 antibody, 3 (1.73%) for anti-AQP4 antibody, 2 (1.16%) for anti-GABABR antibody, and 1 (0.58%) for anti-LGI1antibody. Anti-NMDAR encephalitis was the most commonly seen among the patients, followed by MOG antibody-associated disorders and autoimmune GFAP astrocytopathy. Psycho-behavioral abnormalities, seizures, involuntary movements, and speech disorder were the most common clinical presentations of anti-NMDAR encephalitis, while fever, headache, and disturbance of consciousness or vision were the most seen among patients with MOG antibody-associated disorders or autoimmune GFAP astrocytopathy. The coexistence of multiple anti-neural antibodies was detected in 13 patients, among which 6 cases had coexistent anti-NMDAR and anti-MOG antibodies (including 1 case with anti-GFAP antibody also), 3 cases had coexistent anti-NMDAR and anti-GFAP antibodies, 3 cases had coexistent anti-MOG and anti-GFAP antibodies, 1 case had coexistent anti-NMDAR and anti-CASPR2 antibodies, and 1 case had coexistent anti-GABABR and anti-CASPR2 antibodies. All the survivors were followed up for at least 12 months; 137 recovered completely, 33 had varying sequelae, and 3 died; 22 had one or more relapses.

Conclusion

Antibody-mediated CNS autoimmune diseases occur in children of all ages. Most such pediatric patients have a good response to immunotherapy. Despite the low mortality rate, some survivors have a non-negligible risk of developing relapses.

Autoimmune encephalitis after herpes simplex encephalitis: A still undefined condition

Herpes simplex encephalitis (HSE) is one of the most common sporadic viral encephalitis. Generally, HSE is characterized by a monophasic short course, although in some patients neurological relapses or worsening of deficits can develop some weeks later, when viral therapy has been discontinued and signs and symptoms of the central nervous system (CNS) damage seem to have stabilized. The second HSE stage is generally identified as autoimmune encephalitis after HSE (AEaHSE). Aim of this paper is to discuss which are the present knowledge in this regard. Literature analysis showed that AEaHSE exists, it is more common in younger children and it has different clinical manifestations according to age. All the patients with AEaHSE are positive for one or more neuronal cell-surface and synaptic antibodies, mainly anti-NMDAR antibodies, and the earlier the appearance of the antibodies the greater the risk of AEaHSE development. This means that a careful monitoring of antibody production starting from anti-NMDAR antibodies in all HSE cases could lead to the early identification of AEaHSE and the prompt administration of a potentially effective therapy. Further studies are needed to clarify which are the main pathogenetic mechanisms, whether there are differences in risk of development and clinical course of AEaHSE according to the type of antibody production, why response to immunosuppressive therapy significantly varies and whether administration of steroids to patients with HSE during the first phase of disease can play a role for reducing the risk of AEaHSE development.

Evaluation of multiple consensus criteria for autoimmune encephalitis and temporal analysis of symptoms in a pediatric encephalitis cohort

Objective

To evaluate the sensitivity and specificity of current criteria for the diagnosis of autoimmune encephalitis (AE) and the temporal onset of neuropsychiatric symptoms (NP) in a pediatric encephalitis cohort.

Background

Multiple criteria for AE have been developed, including the Graus and pediatric-focused Cellucci consensus criteria, and the Determining Etiology in Encephalitis (DEE) score for patients with encephalitis. Early identification and treatment of AE is crucial to improve outcomes, but this can be difficult given the frequent overlap of clinical presentation between AE and infectious encephalitis (IE).

Design/methods

A retrospective review was conducted of patients seen at our institution from 2000 to 2021 with a final diagnosis of AE or IE. These were narrowed through multiple exclusions to etiology-confirmed IE or antibody-positive/negative AE. Time of onset or results of all symptoms and diagnostics were recorded. Sensitivity and specificity of each criterion under various clinical scenarios were calculated over the first month after initial NP symptom onset.

Results

A total of 23 antibody-positive AE, 9 antibody-negative AE and 23 IE patients were included in final analysis. Under an idealized scenario with rapid initial diagnostic evaluations, the sensitivity for pediatric AE by day 28 after onset of NP symptoms approached 90% for both Cellucci and Graus criteria. Specificity within these 28 days was low without infectious testing results, increasing the greatest with rapid PCR testing and second with infectious antibody testing-reaching ~90% with both. A DEE score of 3 provided a specificity of 100% in identifying IE, but low sensitivity (29%). Symptoms were noted to cluster within several days of onset in IE, but in AE were spread out. Personality/behavioral change, speech change, affective disorder, and sleep disturbance were noted more often in AE, while fever, elevated C-reactive protein or CSF protein, and abnormal MRI-Brain occurred more often in IE.

Conclusion

In this study, we provide the first evaluation of the Cellucci criteria and the first validation of the DEE score in the differentiation of pediatric AE and IE. Further refinement of AE criteria is needed to improve early detection and treatment of pediatric AE.

Clinical Characteristics and Prognosis of Antibody-Negative Autoimmune Encephalitis in Children: A Single-Center Retrospective Study

BACKGROUND

Autoimmune encephalitis (AE) is a group of immune-mediated brain diseases. However, new diagnostic criteria for AE in children indicate that partial pediatric patients with AE may be diagnosed without evidence of positive autoantibodies. Therefore, the clinical characteristics and prognosis of children with antibody-negative but probable AE require further investigation.

METHODS

Forty-one children with AE admitted to our hospital from April 2014 to January 2021 were retrospectively enrolled in this study. Children were divided into two groups according to positive or negative antibody tests. Clinical characteristics, cerebrospinal fluid, video electroencephalography, brain magnetic resonance imaging, and prognosis were analyzed, and the correlation between modified Rankin scale (mRS) and neutrophil-to-lymphocyte ratio (NLR) was examined.

RESULTS

Of 41 children, 16 cases tested positive for autoantibodies. The main features were psychiatric symptoms, cognitive disturbances, speech disturbances, movement disorders, and seizures. All the children were given a combination of intravenous methylprednisolone pulses with intravenous immunoglobulin therapy; 26 cases (63%) had a good outcome, and 15 cases (37%) had a poor outcome. Antibody-positive and antibody-negative but probable AE were analyzed by univariate analysis and showed lower lymphocyte counts and higher NLR and mRS scores in the antibody-negative group (P < 0.05). The Spearman rank correlation analysis showed a positive correlation between NLR level and mRS scores (P < 0.05).

CONCLUSIONS

Antibody-negative but possible AE is frequent in children who may have a more severe neurological impairment and higher NLR than antibody-positive AE. Aggressive immunotherapy in antibody-negative AE is essential to achieve a good prognosis.

Severity of Hospitalized Children with Anti-NMDAR Autoimmune Encephalitis

Background: Information on the clinical characteristics and severity of autoimmune encephalitis with antibodies against the N-methyl-d-aspartate receptor (NMDAR) in children is attracting more and more attention in the field of pediatric research. Methods: In this retrospective cohort study, all cases (n = 67) were enrolled from a tertiary children's hospital, from 2017 to 2020. We compared severe cases that received intensive care unit (ICU) care with nonsevere cases that did not receive ICU care and used machine learning algorithm to predict the severity of children, as well as using immunologic and viral nucleic acid tests to identify possible pathogenic triggers. Results: Mean age of children was 8.29 (standard deviation 4.09) years, and 41 (61.19%) were girls. Eleven (16.42%) were admitted to the ICU, and 56 (83.58%) were admitted to neurology ward. Ten individual parameters were statistically significant differences between severe cases and nonsevere cases (P < .05), including headache, abnormal mental behavior or cognitive impairment, seizures, concomitant tumors, sputum/blood pathogens, blood globulin, blood urea nitrogen, blood immunoglobulin G, blood immunoglobulin M, and number of polynucleated cells in cerebrospinal fluid. Random forest regression model presented that the overall prediction power of severity reached 0.806, among which the number of polynucleated cells in cerebrospinal fluid contributed the most. Potential pathogenic causes exhibited that the proportion of mycoplasma was the highest, followed by Epstein-Barr virus. Conclusion: Our findings provided evidence for early identification of autoimmune encephalitis in children, especially in severe cases.

External Assessment of the Anti-N-Methyl-D-Aspartate Receptor Encephalitis One-Year Functional Status Score in Chinese Pediatric Patients

Objective

to assess the performance of the Anti-N-Methyl-D-Aspartate Receptor encephalitis (NMDAR) One-Year Functional Status (NEOS) score in predicting one-year functional outcome in Chinese children with anti-NMDAR encephalitis.

Methods

children with anti-NMDAR encephalitis at the Children’s Hospital of Chongqing Medical University were retrospectively enrolled from January 2014 to December 2020. Patients were categorized into two groups based on the modified Rankin Scale (mRS) at one-year follow-up. Discrimination of the NEOS score was assessed by the area under curve (AUC) of the receiver operating characteristic curve. Calibration of the NEOS score was assessed by comparing predicted probabilities with observed probabilities using a calibration curve and the Hosmer-Lemeshow test. The clinical practicability of the NEOS score was evaluated by performing a decision curve analysis.

Results

one hundred seventy-five children (101 females and 74 males) with anti-NMDAR encephalitis and a median age of 7.7 years were enrolled. Of those, 149 (85.1%) had a good outcome at 1 year (mRS ≤ 2), and the remaining 26 (14.9%) had a poor outcome (mRS > 2). Patients with a higher NEOS score had a significantly higher mRS at one-year follow-up [Spearman r = 0.3878, 95% confidence interval (CI): 0.2500-0.5103, P < 0.001]. The AUC of the NEOS score was 0.870 (95% CI: 0.801-0.938, P < 0.001). The observed probability and predicted probability showed moderate consistency in the calibration curve and the Hosmer-Lemeshow test (P = 0.912). The decision curve analysis showed that using the NEOS score to predict one-year outcomes could provide additional net benefit during clinical practice.

Conclusions

the NEOS score is a potentially reliable model to predict the one-year functional outcome in Chinese children with anti-NMDAR encephalitis.

Diagnosis and Management of Suspected Pediatric Autoimmune Encephalitis: A Comprehensive, Multidisciplinary Approach and Review of Literature

Autoimmune encephalitis is an increasingly recognized entity in children. When treated promptly, favorable outcomes are seen in a majority of pediatric patients. However, recognition of autoimmune encephalitis in young patients is challenging. Once autoimmune encephalitis is suspected, additional difficulties exist regarding timing of treatment initiation and duration of treatment, as evidence to guide management of these patients is emerging. Here, we review available literature regarding pediatric autoimmune encephalitis and present our institution's comprehensive approach to the evaluation and management of the disease. These guidelines were developed through an iterative process involving both pediatric neurologists and rheumatologists.

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.

Anti-contactin-associated protein-like 2 antibody-associated encephalitis in children: A case report and literature review

BACKGROUND

Anti-Contactin-associated protein-like 2 (CASPR2) antibody-associated encephalitis is a rare group of autoimmune diseases that causes extensive damage to the central and/or peripheral nervous system.

CASE PRESENTATION

Here, we reported a case of anti-CASPR2 antibody-associated encephalitis in a 12-year-old male patient with symptoms of headache, consciousness disturbance, mental abnormalities, urinary incontinence, fasciculations in the extremity muscles, and involuntary movements. The testing for autoimmune encephalitis-associated antibodies showed that CASPR2-associated antibodies were positive, and electroencephalography showed diffuse slow waves. No tumor was found after screening for malignancies. The child's status significantly improved after receiving immunotherapy with intravenous methylprednisolone and immunoglobulin.

CONCLUSIONS

Anti-CASPR2 antibody-associated encephalitis has been rarely reported in children. It has a complex clinical presentation and a low incidence of tumor. Most pediatric patients have a favorable prognosis and relapse is uncommon.

The clinical features, treatment and outcomes of 33 children from Northwestern China with Anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVES

We analyzed the clinical features and outcomes of children with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis in Northwestern China.

METHODS

We retrospectively recruited 33 pediatric patients with anti-NMDAR encephalitis in Northwestern China from December 2013 to April 2020. The demographics, clinical features, treatments, and outcomes were reviewed.

RESULTS

33 patients with anti-NMDAR encephalitis were enrolled in this study (a median age of 6.8 years, 20 females and 13 males). The initial symptoms included seizures (42.4%), psychiatric symptoms (39.4%), speech dysfunction (12.1%), and paralysis (6.1%). During the course of the disease, 31 patients (93.9%) presented with psychiatric symptoms, 29 patients (87.9%) presented with speech dysfunction, 25 patients (75.8%) presented with movement disorders and 24 patients (72.7%) presented with sleep disorders followed by seizures, consciousness disturbance, autonomic nervous dysfunction, paralysis, and hypoventilation. 12 patients (36.4%) had abnormal cerebrospinal fluid (CSF) findings, 10 patients (30.3%) exhibited abnormal brain magnetic resonance imaging (MRI) results, and 29 patients (87.9%) showed abnormal Electroencephalography (EEG) findings. None of the patients had tumors. All patients received first-line immunotherapy and 8 patients both received first and second-line immunotherapy. 30 of the 33 patients achieved good outcomes (score on the modified Rankin Scale [mRS] of 0-2), whilst the other 3 patients had poor outcomes (mRS score of 3-6).

CONCLUSIONS

Patients with higher CSF anti-NMDAR body titer were more likely to develop sleep disorders, consciousness disturbances and more severe disease states.

Clinical Features of Coexisting Anti-NMDAR and MOG Antibody-Associated Encephalitis: A Systematic Review and Meta-Analysis

Coexisting anti-NMDAR and MOG antibody (anti-NMDAR-IgG⁺/MOG-IgG⁺)-associated encephalitis have garnered great attention. This study aimed to perform a secondary analysis to determine the clinical features of this disease. We searched several databases for related publications published prior to April 2021. A pooled analysis was conducted with the fixed-effects model using the Mante-Haenszel method (I ² ≤ 50%), or the random-effects model computed by the DerSimonian-Laird method (I ² > 50%). Stata software (version 15.0 SE) was used for the analyses. Nine observational studies and 16 case reports (58 cases with anti-NMDAR-IgG⁺/MOG-IgG⁺, 21.0 [8.5, 29.0] years, male 58.6%) were included. The incidences (95%CI) of anti-NMDAR-IgG⁺/MOG-IgG⁺ in the patients with serum MOG-IgG⁺ and CSF anti-NMDAR-IgG⁺ were 0.09 (0.02-0.19) and 0.07 (0.01-0.19), respectively. The median [IQR] of CSF anti-NMDAR antibody titer was 32 [10, 100], and the serum anti-MOG antibody titer was 100 [32, 320]. The prominent clinical symptoms were encephalitic manifestations, including seizures (56.9%) and abnormal behavior (51.7%), rather than demyelinating manifestations, such as speech disorder (34.5%) and optic neuritis (27.6%). Relapse occurred in 63.4% of anti-NMDAR-IgG⁺/MOG-IgG⁺ patients, in whom 50.0% of cases relapsed with encephalitic manifestations, and 53.8% relapsed with demyelinating manifestations. The common MRI changes were in the cortex or subcortex (70.7%) and brainstem (31.0%). 31.3% of patients presented with unilateral cerebral cortical encephalitis with epilepsy and 12.5% displayed bilateral frontal cerebral cortex encephalitis. Anti-NMDAR-IgG⁺/MOG-IgG⁺ patients showed more frequent mental behavior (OR, 95%CI, 68.38, 1.36-3,434.37), involuntary movement (57.86, 2.53-1,325.11), sleep disorders (195.00, 7.07-5,380.15), and leptomeninge lesions (7.32, 1.81-29.58), and less frequent optic neuritis (0.27, 0.09-0.83) compared to anti-NMDAR-IgG^-/MOG-IgG⁺ patients and presented more common relapse (5.63, 1.75-18.09), preceding infection (2.69, 1.03-7.02), subcortical lesions (116.60, 4.89-2,782.09), basal ganglia lesions (68.14, 2.99-1,554.27), brainstem lesions (24.09, 1.01-574.81), and spinal cord lesions (24.09, 1.01-574.81) compared to anti-NMDAR-IgG⁺/MOG-IgG^-. In conclusion, anti-NMDAR-IgG⁺/MOG-IgG⁺ was rarely observed, but the incidence rate of relapse was very high. The overall symptoms seemed to be similar to those of NMDAR encephalitis.

Age-dependent characteristics and prognostic factors of pediatric anti-N-methyl-d-aspartate receptor encephalitis in a Chinese single-center study

OBJECTIVE

To describe the clinical features and prognosis of pediatric anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis from a single center in northern China.

METHODS

The clinical and laboratory characteristics of hospitalized patients with anti-NMDAR encephalitis, stratified by age, were retrospectively studied. Risk factors including relapse and long-term (follow-up ≥1 year) outcomes were analyzed.

RESULTS

A total of 273 patients were included between November 2011 and December 2019, and the average age of onset was 7.5 ± 4.0 years (0.5-15.8 years). Of them, 159（58.2%） were female, and the proportion of females increased with age. Seizures were the most common initial symptom. Movement disorders（86.1%） and psychiatric（82.4%） symptoms were most frequent in the acute phase. In the acute stage, the incidence of movement disorders decreased with age (χ² = 10.676, p = 0.011), while the proportion of psychiatric symptoms increased with age (χ² = 21.85, p < 0.001) The recurrence rate was 9.6% (24/250). Demyelination was an independent risk factor for relapse (p = 0.006, OR = 5.877, 95% CI: 1.658-20.835). Among the 210 patients who were followed up for more than one year, 28 patients had a poor prognosis (mRS ≥3). Onset age (p = 0.038，OR = 0.844, 95% CI: 0.720-0.991), precursor of viral encephalitis (p = 0.007，OR = 9.876, 95% CI: 1.878-51.940), and ICU admission (p = 0.023，OR = 5.924, 95% CI: 1.280-27.064) significantly affected the prognosis. The mortality rate was 2.9%.

CONCLUSIONS

The characteristics of anti-NMDAR encephalitis in children are age-dependent. Early-onset, the precursor of viral encephalitis, and ICU admission may indicate poor prognosis. Demyelination may be a risk factor for recurrence.

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.

Clinical Features and Outcomes of Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Infants and Toddlers

OBJECTIVE

We describe the clinical features and outcomes of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis in infants and toddlers.

METHODS

This was a single-center retrospective study. Infants and toddlers who met the diagnostic criteria for anti-NMDAR encephalitis were recruited for the study. Data on clinical features, treatment, and long-term outcomes were collected retrospectively.

RESULTS

A total of 41 patients (age range: six to 34 months; median age: 23 months; female: 19) were enrolled in this study. Nineteen (46%) patients exhibited classical anti-NMDAR encephalitis, whereas 22 (54%) patients exhibited anti-NMDAR encephalitis after viral encephalitis. There was a high presentation of movement disorders (100%), developmental regression (90%), abnormal behaviors (90%). All patients were administered first-line therapy, with only 17% of them being administered second-line immunotherapy. Two patients succumbed to the disease, whereas none of them relapsed. At the long-term follow-up (more than one year), 20 of 35 (57%) exhibited satisfactory outcomes (modified Rankin Scale ≤2). Compared with patients with classical anti-NMDAR encephalitis (n = 18), patients after viral encephalitis (n = 17) were more likely to have worse clinical outcomes. They exhibited a higher modified Rankin Scale/Pediatric Cerebral Performance Category score and more frequent seizures. A predictor of poor outcome was presentation after viral encephalitis (odds ratio 35.7, 95% confidence interval 4.64 to 275.03, P = 0.001).

CONCLUSION

Anti-NMDAR encephalitis in infants and toddlers clinically presents with movement disorders, developmental regression, and abnormal behaviors. Interestingly, this group had a higher proportion of patients after viral encephalitis, which is regarded as the only risk factor for poor outcomes.

Overlapping syndrome of anti-N-methyl-D-aspartate receptor encephalitis and anti-myelin oligodendrocyte glycoprotein inflammatory demyelinating diseases: A distinct clinical entity?

BACKGROUND

The co-existence of anti-N-methyl-D-aspartate receptor encephalitis (NMDARe) and anti-myelin oligodendrocyte glycoprotein (MOG) antibody disease has sparsely been reported, which needs to be investigated.

METHOD

Among the patients with NMDARe in Xuanwu Hospital, MOG antibody disease and NMDARe overlapping syndrome (MNOS) were retrospectively identified. We combined our data with those from previously reported cases to characterize this new entity.

RESULT

There were 45 patients with MNOS with a median onset age of 20. A total of 97.8% of the patients had symptoms of encephalitis; 68.9% of the patients had symptoms of demyelination, including optic neuritis (ON) (37.9%), longitudinally extensive transverse myelitis (LETM) (31.0%) and acute disseminated encephalomyelitis (ADEM) (27.6%). Abnormal signals on magnetic resonance imaging (MRI) usually involved cortical (46.7%), subcortical (31.1%) and basal ganglia (26.7%) lesions, as well as infratentorial (48.9%) and spinal cord (28.9%) lesions. No tumours were found. A total of 62.2% of the patients relapsed, with recurrence rates of 66.7% and 50.0% for those treated with first-line therapy alone and in combination with second-line immunotherapy, respectively. The pathological changes from the biopsy indicated immune-mediated inflammatory demyelination. Although some patients may have residual deficits, 93.3% of the patients became functionally independent.

CONCLUSION

The possibility of MNOS should be considered when patients diagnosed with anti-NMDARe simultaneously or sequentially develop ON, LETM or ADEM. MNOS occurred without tumour association, and inflammatory demyelination may be the pathological change. Steroids combined with second-line immunotherapy can help to reduce high recurrence rates, and most patients will have substantial 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.

Pediatric anti-N-methyl-d-aspartate receptor encephalitis in southern China: Analysis of 111 cases

OBJECTIVE

To study the clinical features of children diagnosed with anti-NMDAR encephalitis in southern China.

METHODS

Clinical data of children diagnosed with anti-NMDAR encephalitis from October 2014 to June 2020 from one national regional medical center were analyzed. Neurological disability was assessed by modified Rankin Scale (mRS) throughout the course of disease.

RESULTS

111 children (M/F = 49/62; mean onset age = 6.8 y) with anti-NMDAR encephalitis were involved. Prodromal events occurred in 34.2% of patients with infectious events being the most common. Seizure was the most common initial symptom, though movement disorder served as the most common event throughout the course of disease. 9.9% of patients had overlapped with other neuronal autoantibodies. Electroencephalogram showed abnormalities with slow wave (100.0%), epileptic discharge (31.5%) and delta brush (8.1%) respectively. 41.4% of patients had abnormal brain MRI, with focal lesions being the most common. None patients had tumor. 80.9% of patients had good response to first line therapy (steroid plus immunoglobulin), while 14 patients accepted second-line therapy (Rituximab) and all had a good response. Boys were significantly more likely to need more course of steroid. 13.8% of patients relapsed. 2 male patients died. mRS score was significantly improved after treatment. 51.4% of patients had a full recovery and 81.7% had mRS score ≤ 2. The median mRS score of boys after treatment was higher than that of girls. Non-infectious prodromal event, past medical history, perivascular lesions in brain MRI, hospital stay, initial mRS score higher than 3, and RTX treatment were independent risk factors associated with poor prognosis, defined as mRS score > 2.

CONCLUSION

Of pediatric anti-NMDAR encephalitis in southern China: median onset age around 7 years; girls more common; boys might have poor outcome than girls; seizure or movement disorder respectively being most common onset or course symptom; a few overlapped with other neuronal autoantibodies; rare combined with tumor; most had a good response to immunotherapy and a good prognosis; relapse rate relatively high; fatality rate relatively low; some risk factors associated with poor prognosis.

Clinical features and management of coexisting anti-N-methyl-D-aspartate receptor encephalitis and myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis: a case report and review of the literature

BACKGROUND

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoimmune encephalitis caused by antibodies targeting the GluN1 subunit of NMDA receptors. Myelin oligodendrocyte glycoprotein (MOG) antibody disorders are now widely accepted as peculiar neuroimmunological diseases with specific clinical and pathological features. Some rare cases of overlapping anti-NMDA receptor encephalitis and MOG antibody-associated diseases have been reported, presenting complex clinical symptoms that make the disease more difficult to recognize.

METHOD

In accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, the terms "NMDAR" and "MOG," "NMDAR" and "demyelination," and "MOG" and "encephalitis" were searched in PubMed. Clinical cases with dual-positive anti-NMDA cerebrospinal fluid receptors and MOG serum antibodies during the disease course were included in this study.

RESULTS

A total of 25 patients were analyzed in this study. The age at onset ranged from 3 to 54 years. The median number of relapses was 2.8. Administration of intravenous methylprednisolone and immunoglobulin was the most widely used treatment strategy (19/25 patients). Second-line treatments such as administration of mycophenolate mofetil, rituximab, interferon-β, azathioprine, cyclophosphamide, and temozolomide were also reported, followed by good outcomes.

CONCLUSIONS

The rates of coexisting anti-NMDA receptor encephalitis and MOG antibody-associated encephalomyelitis may be underestimated. Clinical symptoms such as seizures and cognitive decline accompanied by atypical central nervous system demyelination serve as warning signs of possible coexisting anti-NMDA receptor encephalitis and MOG antibody-associated encephalomyelitis. These patients could achieve good outcomes under proper immunotherapies.

Diagnosis of pediatric anti-NMDAR encephalitis at the onset: A clinical challenge

BACKGROUNDS

To investigate the clinical and instrumental features at the onset addressing to the diagnosis of anti-NMDAR encephalitis.

METHODS

Twenty children (age: 15 months-17 years; 7 males, 13 females) with initial suspected diagnosis of autoimmune encephalitis, observed between January 2008 and March 2018, were included. The final diagnosis was anti-NMDAR encephalitis in 7 children, other/probable autoimmune encephalitis in 7 children, and primary psychosis in the remaining 6 children.

RESULTS

At the clinical onset, anxiety disorder was the main symptom that helped in distinguishing the group of psychotic children from children with non-infectious encephalitis (P = 0.05 OR = 0.001), while epileptic seizures strongly predicted anti-NMDAR encephalitis (P = 0.04 OR = 28.6). At the onset, anti-NMDAR encephalitis could be distinguished from other/probable autoimmune encephalitis for the presence of sleep/wake rhythm alteration (P = 0.05 OR = 15). Among the symptoms occurring during the hospitalization, movement disorders (P = 0.031 OR = 12) were predictive of non-infectious encephalitis rather than primary psychosis. More specifically, the occurrence of language impairment (P = 0.03 OR = 33), epileptic seizures (P = 0.04 OR = 28.6) and catatonia (P = 0.03, OR = 33), were predictive of anti-NMDAR encephalitis. Also at this stage, anxiety disorder (P = 0.03 OR = 0.033) was predictive of primary psychosis.

CONCLUSION

Our findings suggest that at the clinical onset epileptic seizures and sleep/wake rhythm alteration represent the main features addressing to the diagnosis of anti-NMDAR encephalitis rather than primary psychosis and other/probable autoimmune encephalitis, while anxiety disorder could be a solid predictor of primary psychosis.

Diagnostic Value of Structural and Functional Neuroimaging in Autoimmune Epilepsy

Epilepsy is a common nervous system disease, which affects about 70 million people all over the world. In 2017, the International League Against Epilepsy (ILAE) considered immune factors as its independent cause, and the concept of autoimmune epilepsy (AE) was widely accepted. Early diagnosis and timely treatment can effectively improve the prognosis of the disease. However, due to the diversity of clinical manifestations, the expensive cost of autoantibody detection, and the increased prevalence in Western China, the difficulty for clinicians in early diagnosis and treatment has increased. Fortunately, convenient and fast imaging examinations are expected to help even more. The imaging manifestations of AE patients were characteristic, especially the combined application of structural and functional neuroimaging, which improved the diagnostic value of imaging. In this paper, several common autoantibodies associated with AE and their structure and function changes in neuroimaging were reviewed to provide help for neurologists to achieve the goal of precision medicine.

Efficacy and Safety of Rituximab in Chinese Children With Refractory Anti-NMDAR Encephalitis

Purpose: To assess the efficacy and safety of rituximab treatment as second-line immunotherapy in pediatric cases of anti-NMDA receptor (NMDAR) encephalitis. Methods: We retrospectively recruited 8 patients with anti-NMDAR encephalitis who were treated with rituximab as second-line immunotherapy. We evaluated the clinical features, laboratory examination results and treatment protocols of the Chinese children and defined good outcomes based on the modified Rankin scale (mRS) score (0-2) at the last follow-up. Results: A total of eight pediatric patients (median age 6.7 years; four female) with refractory anti-NMDAR encephalitis were recruited to the study. Rituximab was given after a median duration of disease of 57 days (range 50.5-113.75 days). The use of rituximab led to a significant reduction in the mRS and CD19+ B-cells compared to before rituximab infusion (P < 0.05). Five patients (62.5%) had a good outcome (mRS ≤ 2) including four patients (50%) who showed complete recovery (mRS = 0) at the last follow-up. Transient infusion adverse events were recorded in 2 patients (25%). Two patients (25%) had severe infectious adverse events (AEs) and two patients with grade 5 (death). None of the patients developed progressive multifocal leukoencephalopathy (PML). Conclusion: Our study provides evidence that rituximab can efficiently improve the clinical symptoms of anti-NMDAR encephalitis in children. However, due to the risk of adverse infections, rituximab should be restricted in pediatric patients with high rates of mortality and disability.

E.U. paediatric MOG consortium consensus: Part 1 - Classification of clinical phenotypes of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders

Over the past few years, increasing interest in the role of autoantibodies against myelin oligodendrocyte glycoprotein (MOG-abs) as a new candidate biomarker in demyelinating central nervous system diseases has arisen. MOG-abs have now consistently been identified in a variety of demyelinating syndromes, with a predominance in paediatric patients. The clinical spectrum of these MOG-ab-associated disorders (MOGAD) is still expanding and differs between paediatric and adult patients. This first part of the Paediatric European Collaborative Consensus emphasises the diversity in clinical phenotypes associated with MOG-abs in paediatric patients and discusses these associated clinical phenotypes in detail. Typical MOGAD presentations consist of demyelinating syndromes, including acute disseminated encephalomyelitis (ADEM) in younger, and optic neuritis (ON) and/or transverse myelitis (TM) in older children. A proportion of patients experience a relapsing disease course, presenting as ADEM followed by one or multiple episode(s) of ON (ADEM-ON), multiphasic disseminated encephalomyelitis (MDEM), relapsing ON (RON) or relapsing neuromyelitis optica spectrum disorders (NMOSD)-like syndromes. More recently, the disease spectrum has been expanded with clinical and radiological phenotypes including encephalitis-like, leukodystrophy-like, and other non-classifiable presentations. This review concludes with recommendations following expert consensus on serologic testing for MOG-abs in paediatric patients, the presence of which has consequences for long-term monitoring, relapse risk, treatments, and for counselling of patient and families. Furthermore, we propose a clinical classification of paediatric MOGAD with clinical definitions and key features. These are operational and need to be tested, however essential for future paediatric MOGAD studies.

Electroencephalographic findings in antileucine-rich glioma-inactivated 1 (LGI1) autoimmune encephalitis: A systematic review

BACKGROUND

Antileucine-rich glioma-inactivated 1 (LGI1) autoimmune encephalitis is a distinct syndrome of early onset faciobrachial dystonic seizures (FBDS) and other focal seizures followed by neuropsychiatric symptoms. The electroclinical syndrome of this condition is yet to be fully understood. The main objective of this study was to determine the frequencies of electroencephalogram (EEG) findings in patients diagnosed with anti-LGI1 autoimmune encephalitis through a systematic review of published relevant articles.

METHODS

Major electronic healthcare databases were searched for relevant published articles until July 2020.

RESULTS

From 327 articles, 23 case reports and 14 case series were included in the review after satisfying the eligibility criteria. Data from a total of 151 cases of definite anti-LGI1 encephalitis were analyzed in this systematic review. Epileptiform discharges were the most frequent finding at 57.3%. Focal electroencephalographic abnormalities including slow wave (59.3%) and epileptiform activities (53.5%) most commonly arise from the temporal region. Faciobrachial dystonic seizures often have no ictal electroencephalographic correlate but would show electrodecremental events when seizure duration is prolonged.

CONCLUSION

Electroencephalogram abnormalities are seen in anti-LGI1 autoimmune encephalitis with epileptiform discharges as the most common finding followed by focal slowing. These findings were most frequently seen arising in the temporal region. Further studies using a standardized protocol focusing on electroencephalographic findings in anti-LGI1 encephalitis with clinical correlation to disease stage and treatment outcomes in terms of seizure control and memory and cognitive function are needed. Particular attention on ictal electrodecremental activity during FBDS should be done in studies with a larger sample size.

Clinical and imaging features of children with autoimmune encephalitis and MOG antibodies

Objective

To describe the presentations, radiologic features, and outcomes of children with autoimmune encephalitis associated with myelin oligodendrocyte glycoprotein antibodies (MOG abs).

Methods

Identification of children fulfilling the diagnostic criteria for possible autoimmune encephalitis (AE) and testing positive for serum MOG abs. Chart review and comprehensive analysis of serum MOG abs using live cell assays and rat brain immunohistochemistry.

Results

Ten children (4 girls, 6 boys) with AE and serum MOG abs were identified. The median age at onset was 8.0 years (range: 4–16 years). Children presented with a combination of encephalopathy (10/10), headache (7/10), focal neurologic signs (7/10), or seizures (6/10). CSF pleocytosis was common (9/10, median 80 white cell count/μL, range: 21–256). Imaging showed cortical and deep gray matter involvement in all in addition to juxtacortical signal alterations in 6/10 children. No involvement of other white matter structures or contrast enhancement was noted. MOG abs were detected in all children (median titer 1:640; range: 1:320–1:10,540). Nine children had a favorable outcome at discharge (modified Rankin scale of < 2). Five of 10 children had up to 3 additional demyelinating relapses associated with persisting MOG abs. One child had NMDA receptor (NMDAR) abs at initial presentation. A second child had a third demyelinating episode with MOG abs with overlapping NMDAR encephalitis.

Discussion

AE associated with serum MOG abs represents a distinct form of autoantibody-mediated encephalitis in children. We therefore recommend including MOG abs testing in the workup of children with suspected AE.

Autoimmune encephalitis in children and adolescents

Background

Autoimmune encephalitides with neural and glial antibodies have become an attractive field in neurology because the antibodies are syndrome-specific, explain the pathogenesis, indicate the likelihood of an underlying tumor, and often predict a good response to immunotherapy. The relevance and the management of antibody-associated encephalitides in the pediatric age group are to be discussed.

Main body

Subacutely evolving, complex neuropsychiatric conditions that are otherwise unexplained should raise the suspicion of autoimmune encephalitis. Determination of autoantibodies is the key diagnostic step. It is recommended to study cerebrospinal fluid and serum in parallel to yield highest diagnostic sensitivity and specificity. The most frequently found antibodies are those against the N-methyl-D-asparate receptor, an antigen on the neural cell surface. The second most frequent antibody is directed against glutamic acid decarboxylase 65 kDa, an intracellular protein, often found in chronic conditions with questionable inflammatory activity. Immunotherapy is the mainstay of treatment in autoimmune encephalitides. Steroids, apheresis and intravenous immunoglobulin are first-line interventions. Rituximab or cyclophosphamide are given as second-line treatments. Patients with surface antibodies usually respond well to immunotherapy whereas cases with antibodies against intracellular antigens most often do not.

Conclusion

With few exceptions, the experience in adult patients with autoimmune encephalitides can be applied to patients in the pediatric age range.