Autoimmune encephalitis in children: clinical phenomenology, therapeutics, and emerging challenges

Higher incidence of acute symptomatic seizures in probable antibody-negative pediatric autoimmune encephalitis than in major antibody-positive autoimmune encephalitis

Purpose

To delineate the characteristics of probable antibody-negative pediatric autoimmune encephalitis (probable Ab-negative AE), we compared the clinical features of probable Ab-negative AE to those of major antibody-positive AE.

Methods

We retrospectively reviewed the clinical features of 18 patients with probable Ab-negative AE, 13 with anti-N-methyl-D-aspartate receptor encephalitis (NMDARE), and 13 with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Clinical characteristics, neuroimaging findings, treatments, and outcomes were analyzed.

Results

The age of onset and length of hospital stay were significantly higher in the NMDARE group than in the other groups (p = 0.02 and p < 0.01). Regarding initial neurological symptoms, acute symptomatic seizures in the probable Ab-negative AE group (67%) were significantly more frequent than in the NMDARE (15%) and MOGAD (23%) groups (p < 0.01). Paraclinical evidence of neuroinflammation within 1 month of disease onset revealed that single-photon emission computed tomography (SPECT) detected abnormal alterations in 14/14 (100%), cerebrospinal fluid (CSF) analysis in 15/18 (83%), and magnetic resonance imaging (MRI) in 11/18 (61%) in patients with probable Ab-negative AE. In the probable Ab-negative AE group, seven patients (39%) developed autoimmune-associated epilepsy, whereas one patient (8%) had both NMDARE and MOGAD (not statistically significant, p = 0.07).

Conclusion

Patients with probable Ab-negative AE exhibited acute symptomatic seizures as initial neurological symptoms significantly more frequently. They developed autoimmune-associated epilepsy more frequently than those with NMDARE and MOGAD, which was not statistically significant. SPECT within 1 month of disease onset might be a valuable surrogate marker of ongoing neuroinflammation and neuronal dysfunction, even in patients with negative MRI findings.

The clinical and predictive value of 18F-FDG PET/CT metabolic patterns in a clinical Chinese cohort with autoimmune encephalitis

AIMS

To investigate the diagnostic and predictive role of 18F-FDG PET/CT in patients with autoimmune encephalitis (AE) as a whole group.

METHODS

Thrty-five patients (20 females and 15 males) with AE were recruited. A voxel-to-voxel semi-quantitative analysis based on SPM12 was used to analyze 18F-FDG PET/CT imaging data compared to healthy controls. Further comparison was made in different prognostic groups categorized by modified Rankin Scale (mRS).

RESULTS

In total, 24 patients (68.6%) were tested positive neuronal antibodies in serum and/or CSF. Psychiatric symptoms and seizure attacks were major clinical symptoms. In the acute stage, 13 patients (37.1%) demonstrated abnormal brain MRI results, while 33 (94.3%) presented abnormal metabolism patterns. 18F-FDG PET/CT was more sensitive than MRI (p < 0.05). Patients with AE mainly presented mixed metabolism patterns compared to the matched controls, demonstrating hypermetabolism mainly in the cerebellum, BG, MTL, brainstem, insula, middle frontal gyrus, and relatively hypometabolism in the frontal cortex, occipital cortex, temporal gyrus, right parietal gyrus, left cingulate gyrus (p < 0.05, FWE corrected). After a median follow-up of 26 months, the multivariable analysis identified a decreased level of consciousness as an independent risk factor associated with poor outcome of AE (HR = 3.591, p = 0.016). Meanwhile, decreased metabolism of right superior frontal gyrus along with increased metabolism of the middle and upper brainstem was more evident in patients with poor outcome (p < 0.001, uncorrected).

CONCLUSION

18F-FDG PET/CT was more sensitive than MRI to detect neuroimaging abnormalities of AE. A mixed metabolic pattern, characterized by large areas of cortical hypometabolism with focal hypermetabolism was a general metabolic pattern. Decreased metabolism of right superior frontal gyrus with increased metabolism of the middle and upper brainstem may predict poor long-term prognosis of AE.

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.

Clinical features and outcomes in children with seronegative autoimmune encephalitis

AIM

To characterize the presenting features and outcomes in children with seronegative autoimmune encephalitis, and to evaluate whether scores at nadir for the Modified Rankin Scale (mRS) and Clinical Assessment Scale for Autoimmune Encephalitis (CASE) or its paediatric-specific modification (ped-CASE) are predictive of outcomes.

METHOD

This observational study included children younger than 18 years of age with seronegative autoimmune encephalitis. Demographics and clinical data were collected. The mRS and CASE/ped-CASE scores were used to evaluate disease severity. Descriptive statistics and logistic regression were used for data analysis and to evaluate associations between scale scores and outcomes.

RESULTS

Sixty-three children were included (39 [62%] females, median age 7 years, interquartile range [IQR] 4 years 1 months-11 years 6 months), with follow-up available for 56 out of 63 patients (median follow-up 12.2 months, IQR 13.4-17.8). The most frequent presenting neurological manifestation was encephalopathy (81%). Median CASE/ped-CASE and mRS scores at nadir were 12.0 (IQR 7.0-17.0) and 1.0 (IQR 0-2.0) respectively. Thirty-three patients (59%) had persistent neurological deficits at follow-up. Both scoring systems suggested good functional recovery (mRS score ≤2, 95%; CASE/ped-CASE score <5, 91%). CASE/ped-CASE score was more likely than mRS to distinguish children with worse outcomes.

INTERPRETATION

Children with seronegative autoimmune encephalitis are likely to have neurological deficits at follow-up. CASE/ped-CASE is more likely to distinguish children with worse outcomes than MRS.

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.

Disease Course and Response to Immunotherapy in Children With Childhood Disintegrative Disorder: A Retrospective Case Series

Childhood disintegrative disorder is a poorly understood neurobehavioral disorder of early childhood characterized by acute to subacute profound regression in previously developed language, social behavior, and adaptive functions. The etiology of childhood disintegrative disorder remains unknown and treatment is focused on symptomatic management. Interest in neuroinflammatory mechanisms has grown with the increased recognition of autoimmune brain diseases and similarities between the presenting symptoms of childhood disintegrative disorder and pediatric autoimmune encephalitis. Importantly, a diagnosis of pediatric autoimmune encephalitis requires evidence of inflammation on paraclinical testing, which is absent in childhood disintegrative disorder. Here we report 5 children with childhood disintegrative disorder who were initially diagnosed with possible autoimmune encephalitis and treated with immunotherapy. Two children had provocative improvements, whereas 3 did not change significantly on immunotherapy. Additionally, a sixth patient with childhood disintegrative disorder evaluated in our Autoimmune Brain Disease Clinic showed spontaneous improvement and is included to highlight the variable natural history of childhood disintegrative disorder that may mimic treatment responsiveness.

Evaluation, Treatment, and Outcomes of Viral and Autoimmune Encephalitis in Children

Viral encephalitis and autoimmune encephalitis are currently the most common causes of encephalitis. Determining the causative agent is helpful in initiating medical treatment that may help reduce long-term sequelae. Cerebrospinal fluid, neuroimaging, serologic, and electroencephalogram in combination with clinical manifestations play a role in determining the cause of the encephalitis. Although motor dysfunction tends to improve, there is a significant risk of long-term neurologic and cognitive sequelae. These persistent deficits that occur in childhood indicate the importance for ongoing rehabilitative services to maximize functional skills, improve cognitive deficits, and assist with community integration.

Pediatric Acute-Onset Neuropsychiatric Syndrome: Current Perspectives

Pediatric acute-onset neuropsychiatric syndrome (PANS) features a heterogeneous constellation of acute obsessive-compulsive disorder (OCD), eating restriction, cognitive, behavioral and/or affective symptoms, often followed by a chronic course with cognitive deterioration. An immune-mediated etiology is advocated in which the CNS is hit by different pathogen-driven (auto)immune responses. This narrative review focused on recent clinical (ie, diagnostic criteria, pre-existing neurodevelopmental disorders, neuroimaging) and pathophysiological (ie, CSF, serum, genetic and autoimmune findings) aspects of PANS. We also summarized recent points to facilitate practitioners with the disease management. Relevant literature was obtained from PubMed database which included only English-written, full-text clinical studies, case reports, and reviews. Among a total of 1005 articles, 205 were pertinent to study inclusion. Expert opinions are converging on PANS as the effect of post-infectious events or stressors leading to "brain inflammation", as it is well-established for anti-neuronal psychosis. Interestingly, differentiating PANS from either autoimmune encephalitides and Sydenham's chorea or from alleged "pure" psychiatric disorders (OCD, tics, Tourette's syndrome), reveals several overlaps and more analogies than differences. Our review highlights the need for a comprehensive algorithm to help both patients during their acute distressing phase and physicians during their treatment decision. A full agreement on the hierarchy of each therapeutical intervention is missing owing to the limited number of randomized controlled trials. The current approach to PANS treatment emphasizes immunomodulation/anti-inflammatory treatments in association with both psychotropic and cognitive-behavioral therapies, while antibiotics are suggested when an active bacterial infection is established. A dimensional view, taking into account the multifactorial origin of psychiatric disorders, should suggest neuro-inflammation as a possible shared substrate of different psychiatric phenotypes. Hence, PANS and PANS-related disorders should be considered as a conceptual framework describing the etiological and phenotypical complexity of many psychiatric disorders.

The presence of human respiratory syncytial virus in the cerebrospinal fluid of a child with Anti-N-methyl-D-aspartate receptor encephalitis of unknown trigger

BACKGROUND

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an important type of brain inflammation caused by autoantibody. As one of the primary agents responsible for respiratory tract infection, the human respiratory syncytial virus (hRSV) has also been reported to be capable of causing extrapulmonary diseases. Here, we first describe a case of anti-NMDAR encephalitis when hRSV was shown to be present in the cerebrospinal fluid.

CASE PRESENTATION

The child was noted to have ataxia and positive anti-NMDA receptors in the cerebrospinal fluid, diagnosed as anti-NMDA receptor encephalitis in combination with cranial MRI images. After high-dose hormone pulse therapy and medication, the disease improved, and he was discharged. However, a relapse occurred almost a year later, and the cranial MRI imaging showed progressive cerebellar atrophy. An hRSV strain from group B was detected in his cerebrospinal fluid, and the whole genome sequence was recovered using transcriptome sequencing.

CONCLUSIONS

To our knowledge, this is the first report of hRSV being found in the cerebrospinal fluid of a patient with anti-NMDAR encephalitis. Even though more clinical records and experimental evidence are needed for validation, this work expands the types of diseases linked to hRSV and the likely cause of anti-NMDAR encephalitis.

Mitochondrial diseases mimicking autoimmune diseases of the CNS and good response to steroids initially

INTRODUCTION

Neuroimmunological diseases such as autoimmune encephalitis (AE) or acquired demyelinating syndromes (ADS), can present with neurological symptoms and imaging features that are indistinguishable from mitochondrial diseases (MD) in particular at initial presentation.

METHODS

Retrospective analysis of the clinical, laboratory and neuroimaging features of five patients who presented with signs of a neuroimmunological disease but all had pathological pathogenic variants in genes related to mitochondrial energy metabolism.

RESULTS

Four patients presented with an acute neurological episode reminiscent of a possible AE and one patient with a suspected ADS at initial presentation. MRI findings were compatible with neuroimmunological diseases in all patients. In two children cerebrospinal fluid (CSF) studies revealed a mildly elevated cell count, two had elevated CSF lactate, none had oligoclonal bands (OCBs). All patients improved rapidly with intravenous steroids or immunoglobulins. Four patients had one or more relapses. Three patients showed worsening of their neurological symptoms with subsequent episodes and one patient died. Relapses in conjunction with new and progressive neurological symptoms, led to additional work-up which finally resulted in different genetic diagnosis of MD in all patients (MT-TL1, MT-ND5, APOA1-BP, HPDL, POLG).

DISCUSSION

We would like to draw attention to a subset of patients with MD initially presenting with signs and symptoms mimicking neuroimmunological. Absence of CSF pleocytosis, elevated CSF lactate and progressive, relapsing course should trigger further (genetic) investigations in search of a MD even in patients with good response initially to immunomodulating therapies.

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.

Diagnosis and Management of Opsoclonus-Myoclonus-Ataxia Syndrome in Children: An International Perspective

BACKGROUND AND OBJECTIVES

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system that classically presents with a combination of characteristic eye movement disorder and myoclonus, in addition to ataxia, irritability, and sleep disturbance. There is good evidence that OMAS is an immune-mediated condition that may be paraneoplastic in the context of neuroblastoma. This syndrome may be associated with long-term cognitive impairment, yet it remains unclear how this is influenced by disease course and treatment. Treatment is largely predicated on immune suppression, but there is limited evidence to indicate an optimal regimen.

METHODS

Following an international multiprofessional workshop in 2004, a body of clinicians and scientists comprising the International OMS Study group continued to meet biennially in a joint professionals and family workshop focusing on pediatric OMAS. Seventeen years after publication of the first report, a writing group was convened to provide a clinical update on the definitions and clinical presentation of OMAS, biomarkers and the role of investigations in a child presenting with OMAS, treatment and management strategies including identification and support of long-term sequelae.

RESULTS

The clinical criteria for diagnosis were reviewed, with a proposed approach to laboratory and radiologic investigation of a child presenting with possible OMAS. The evidence for an upfront vs escalating treatment regimen was reviewed, and a treatment algorithm proposed to recognize both these approaches. Importantly, recommendations on monitoring of immunotherapy response and longer-term follow-up based on an expert consensus are provided.

DISCUSSION

OMAS is a rare neurologic condition that can be associated with poor cognitive outcomes. This report proposes an approach to investigation and treatment of children presenting with OMAS, based on expert international opinion recognizing the limited data available.

Workshop on RanBP2/Nup358 and acute necrotizing encephalopathy

Dominant missense mutations in RanBP2/Nup358 cause Acute Necrotizing Encephalopathy (ANE), a pediatric disease where seemingly healthy individuals develop a cytokine storm that is restricted to the central nervous system in response to viral infection. Untreated, this condition leads to seizures, coma, long-term neurological damage and a high rate of mortality. The exact mechanism by which RanBP2 mutations contribute to the development of ANE remains elusive. In November 2021, a number of clinicians and basic scientists presented their work on this disease and on the interactions between RanBP2/Nup358, viral infections, the innate immune response and other cellular processes.

Antibody Therapies in Autoimmune Encephalitis

Autoimmune encephalitis (AE) comprises a heterogeneous group of disorders in which the host immune system targets self-antigens expressed in the central nervous system. The most conspicuous example is an anti-N-methyl-D-aspartate receptor encephalitis linked to a complex neuropsychiatric syndrome. Current treatment of AE is based on immunotherapy and has been established according to clinical experience and along the concept of a B cell-mediated pathology induced by highly specific antibodies to neuronal surface antigens. In general, immunotherapy for AE follows an escalating approach. When first-line therapy with steroids, immunoglobulins, and/or plasma exchange fails, one converts to second-line immunotherapy. Alkylating agents could be the first choice in this stage. However, due to their side effect profile, most clinicians give preference to monoclonal antibodies (mAbs) directed at B cells such as rituximab. Newer mAbs might be added as a third-line therapy in the future, or be given even earlier if shown effective. In this chapter, we will discuss mAbs targeting B cells (rituximab, ocrelizumab, inebulizumab, daratumumab), IL-6 (tocilizumab, satralizumab), the neonatal Fc receptor (FCRn) (efgartigimod, rozanolixizumab), and the complement cascade (eculizumab).

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.

Characterizing the features and course of psychiatric symptoms in children and adolescents with autoimmune encephalitis

Autoimmune encephalitis (AE) can present like a psychiatric disorder. We aimed to illustrate the psychiatric manifestations, course and management of AE in a paediatric cohort. Neuropsychiatric symptoms, investigations and treatment were retrospectively retrieved in 16 patients (mean age 11.31, SD 2.98) with an AE diagnosis at the liaison psychiatry services in two UK tertiary paediatric centres. Psychiatric presentation was characterised by an acute polysymptomatic (predominantly agitation, anger outbursts/aggressiveness, hallucinations, and emotional lability) onset. Antipsychotics produced side effects and significant worsening of symptoms in four cases, and benzodiazepines were commonly used. This psychiatric phenotype should make clinicians suspect the diagnosis of AE and carefully consider use of treatments.

Autoimmune Encephalitis and Other Neurological Syndromes With Rare Neuronal Surface Antibodies in Children: A Systematic Literature Review

Neuronal surface antibody syndromes (NSAS) are an expanding group of autoimmune neurological diseases, whose most frequent clinical manifestation is autoimmune encephalitis (AE). Anti-NMDAR, anti-LGI1, and anti-CASPR2 autoimmunity represent the most described forms, while other NSAS are rarer and less well-characterized, especially in children. We carried out a systematic literature review of children with rare NSAS (with antibodies targeting D2R, GABAAR, GlyR, GABABR, AMPAR, amphiphysin, mGluR5, mGluR1, DPPX, IgLON5, and neurexin-3alpha) and available individual data, to contribute to improve their clinical characterization and identification of age-specific features. Ninety-four children were included in the review (47/94 female, age range 0.2-18 years). The most frequent NSAS were anti-D2R (28/94, 30%), anti-GABAAR (23/94, 24%), and anti-GlyR (22/94, 23%) autoimmunity. The most frequent clinical syndromes were AE, including limbic and basal ganglia encephalitis (57/94, 61%; GABAAR, D2R, GABABR, AMPAR, amphiphysin, and mGluR5), and isolated epileptic syndromes (15/94, 16%; GlyR, GABAAR). With the limitations imposed by the low number of cases, the main distinctive features of our pediatric literature cohort compared to the respective NSAS in adults included: absent/lower tumor association (exception made for anti-mGluR5 autoimmunity, and most evident in anti-amphiphysin autoimmunity); loss of female preponderance (AMPAR); relatively frequent association with preceding viral encephalitis (GABAAR, D2R). Moreover, while SPS and PERM are the most frequent syndromes in adult anti-GlyR and anti-amphiphysin autoimmunity, in children isolated epileptic syndromes and limbic encephalitis appear predominant, respectively. To our knowledge, this is the first systematic review on rare pediatric NSAS. An improved characterization may aid their recognition in children.

Usefulness of brain FDG PET/CT imaging in pediatric patients with suspected autoimmune encephalitis from a prospective study

Purpose

Early diagnosis and treatment are of paramount importance for pediatric patients with autoimmune encephalitis (AE). The aim is to evaluate the usefulness of FDG PET/CT in pediatric patients with suspected AE from a prospective study.

Methods

The prospective study was conducted over a period of 23.5 months from May 14, 2019, to April 30, 2021. All patients (< 18-year-old) were hospitalized at the department of pediatric neurology and met the criteria of clinical suspected AE. The children underwent the tests of blood samplings, CSF, EEG, MRI, and ¹⁸F-FDG PET/CT. The criteria for FDG PET/CT diagnosis of AE were large lobar hypometabolism with or without focal hypermetabolism found on PET/CT. The clinical final diagnosis of AE includes seropositive and seronegative AE based on the diagnostic criteria.

Results

One hundred four pediatric inpatients (57 boys, 47 girls) were included, of which 58 children were diagnosed with AE (seropositive, 16; seronegative, 42), 45 children were diagnosed with non-AE, and one boy remained indeterminate diagnosis. Large lobar hypometabolism was found in 61 children, of which 54 (88.5%) children were finally diagnosed with AE. The sensitivity, specificity, and accuracy of FDG PET/CT for diagnosis of AE were 93.1%, 84.4%, and 89.3%, respectively, with a positive predictive value of 88.5% and a negative predictive value of 90.5%. The most common involved with hypometabolism was the parietal lobe, followed by occipital and frontal lobes, finally the temporal lobe on PET/CT in children with AE.

Conclusion

Brain FDG PET/CT imaging has high specificity, sensitivity, and accuracy for diagnosis of AE in clinical suspected AE children.

Trial registration.

Clinical Trials.gov. NCT02969213. Registered 17 October 2016.

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.

Use and Safety of Immunotherapeutic Management of N-Methyl-d-Aspartate Receptor Antibody Encephalitis: A Meta-analysis

Question

What are the most effective treatments for N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis?

Findings

In this meta-analysis of individual patient data including 1550 cases, treatment factors at first event that were significantly associated with good functional outcome 12 months from disease onset included first-line treatment with therapeutic apheresis alone, corticosteroids in combination with intravenous immunoglobulin (IVIG), or corticosteroids in combination with IVIG and therapeutic apheresis, while lack of immunotherapy within 30 days of disease onset was significantly associated with poor outcome. Rituximab and long-term IVIG use were significantly associated with nonrelapsing disease course.

Meaning

Separate treatment factors are associated with functional outcomes and relapsing disease biology in those with NMDAR antibody encephalitis.

Importance

Overall, immunotherapy has been shown to improve outcomes and reduce relapses in individuals with N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis (NMDARE); however, the superiority of specific treatments and combinations remains unclear.

Objective

To map the use and safety of immunotherapies in individuals with NMDARE, identify early predictors of poor functional outcome and relapse, evaluate changes in immunotherapy use and disease outcome over the 14 years since first reports of NMDARE, and assess the Anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score.

Data Sources

Systematic search in PubMed from inception to January 1, 2019.

Study Selection

Published articles including patients with NMDARE with positive NMDAR antibodies and available individual immunotherapy data.

Data Extraction and Synthesis

Individual patient data on immunotherapies, clinical characteristics at presentation, disease course, and final functional outcome (modified Rankin Scale [mRS] score) were entered into multivariable logistic regression models.

Main Outcomes and Measures

The planned study outcomes were functional outcome at 12 months from disease onset (good, mRS score of 0 to 2; poor, mRS score greater than 2) and monophasic course (absence of relapse at 24 months or later from onset).

Results

Data from 1550 patients from 652 articles were evaluated. Of these, 1105 of 1508 (73.3%) were female and 707 of 1526 (46.3%) were 18 years or younger at disease onset. Factors at first event that were significantly associated with good functional outcome included adolescent age and first-line treatment with therapeutic apheresis, corticosteroids plus intravenous immunoglobulin (IVIG), or corticosteroids plus IVIG plus therapeutic apheresis. Factors significantly associated with poor functional outcome were age younger than 2 years or age of 65 years or older at onset, intensive care unit admission, extreme delta brush pattern on electroencephalography, lack of immunotherapy within the first 30 days of onset, and maintenance IVIG use for 6 months or more. Factors significantly associated with nonrelapsing disease were rituximab use or maintenance IVIG use for 6 months or more. Adolescent age at onset was significantly associated with relapsing disease. Rituximab use increased from 13.5% (52 of 384; 2007 to 2013) to 28.3% (311 of 1100; 2013 to 2019) (P < .001), concurrent with a falling relapse rate over the same period (22% [12 of 55] in 2008 and earlier; 10.9% [35 of 322] in 2017 and later; P = .006). Modified NEOS score (including 4 of 5 original NEOS items) was associated with probability of poor functional status at 1 year (20.1% [40 of 199] for a score of 0 to 1 points; 43.8% [77 of 176] for a score of 3 to 4 points; P = .05).

Conclusions and Relevance

Factors influencing functional outcomes and relapse are different and need to be considered independently in development of evidence-based optimal management guidelines of patients with NMDARE.

International Consensus Recommendations for the Treatment of Pediatric NMDAR Antibody Encephalitis

Objective

To create an international consensus treatment recommendation for pediatric NMDA receptor antibody encephalitis (NMDARE).

Methods

After selection of a panel of 27 experts with representation from all continents, a 2-step Delphi method was adopted to develop consensus on relevant treatment regimens and statements, along with key definitions in pediatric NMDARE (disease severity, failure to improve, and relapse). Finally, an online face-to-face meeting was held to reach consensus (defined as ≥75% agreement).

Results

Corticosteroids are recommended in all children with NMDARE (pulsed IV preferred), with additional IV immunoglobulin or plasma exchange in severe patients. Prolonged first-line immunotherapy can be offered for up to 3–12 months (oral corticosteroids or monthly IV corticosteroids/immunoglobulin), dependent on disease severity. Second-line treatments are recommended for cases refractory to first-line therapies (rituximab preferred over cyclophosphamide) and should be considered about 2 weeks after first-line initiation. Further immunotherapies for refractory disease 1-3 months after second-line initiation include another second-line treatment (such as cyclophosphamide) and escalation to tocilizumab. Maintenance immune suppression beyond 6 months (such as rituximab redosing or mycophenolate mofetil) is generally not required, except for patients with a more severe course or prolonged impairments and hospitalization. For patients with relapsing disease, second-line and prolonged maintenance therapy should be considered. The treatment of NMDARE following herpes simplex encephalitis should be similar to idiopathic NMDARE. Broad guidance is provided for the total treatment duration (first line, second line, and maintenance), which is dictated by the severity and clinical course (i.e., median 3, 9 and 18 months in the best, average, and worst responders, respectively). Recommendations on the timing of oncologic searches are provided.

Conclusion

These international consensus recommendations for the management of pediatric NMDARE aim to standardize the treatment and provide practical guidance for clinicians, rather than absolute rules. A similar recommendation could be applicable to adult patients.

Anti-IgLON5 disease in a pediatric patient with Langerhans cell histiocytosis

INTRODUCTION

Anti-IgLON5 disease is a rare autoimmune disease of the central nervous system. Different from the previous autoimmune encephalitis, the disease is a chronic progressive disease characterized by abnormal sleep, sleep apnea and motor disorders, which is prone to misdiagnosis and missed diagnosis.

METHODS

We report a unique case of anti-IgLON5 disease in a pediatric patient with Langerhans cell histiocytosis (LCH). He gradually developed increased muscle tone and nystagmus during chemotherapy and showed signs of meningeal enhancement on cranial imaging. Due to insufficient evidence of LCH invasion of the central nervous system, the presence of autoimmune encephalitis-related antibodies was investigated by using cell-based assay (CBA) experiment in indirect immuno-fluorescence assay (IFA).

RESULTS

Clinical manifestations of sleep disorders and motor disorders, plus the presence of IgLON5 IgG antibodies (1:30) in the serum leading to a confirmed diagnosis of anti-IgLON5 disease.

CONCLUSION

Anti-IgLON5 disease is rare and almost no cases of children have been reported. In view of the difficult to recognize symptoms in pediatric patients, especially those with other comorbidities. Clinicians should raise their awareness of this disease and pay attention to the detection of autoimmune antibodies.

Autoimmune encephalitis in a tertiary hospital in the Philippines

BACKGROUND

Autoimmune encephalitis (AE) is an emerging disorder in adults and children. Due to its potentially reversible nature, prompt recognition and intervention are of utmost importance.

OBJECTIVE

To describe the clinical and paraclinical features, as well as treatment outcomes of patients with AE admitted in a Philippine tertiary hospital.

METHODS

Retrospective case series of patients with definite AE.

RESULTS

Eighteen (18) patients were included (12 adults, 6 children), majority of whom had anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. The median age of onset was 32 (IQR: 10.8) years old and 13 (IQR: 4.8) years old in the adult and pediatric population, respectively. In both age groups, most presented with psychiatric symptoms and normal imaging findings. Cerebrospinal fluid (CSF) pleocytosis was detected in 8/12 (66.7%) adults and 2/6 (33.3%) children, while CSF protein elevation was only seen in 6/12 (50%) adults. Most patients presented with seizures, and the most frequent electroencephalography (EEG) abnormality detected was slow activity (70.5%). A high proportion of patients received high dose steroids, alone (35.3%) or in combination with intravenous immunoglobulin (IVIG, 52.9%). Overall, 66.7% had improved outcomes, mostly seen in the pediatric population.

CONCLUSION

This study highlighted the broad clinical phenotype, as well as the similarities and differences of AE manifestations in adults and children. It demonstrated the limited but supportive role of laboratory investigations in the diagnosis of AE. It also underscored the importance of early intervention in AE and highlighted factors influencing treatment practices and discharge outcomes in the local setting.

Psychiatric Phenotypes of Pediatric Patients With Seropositive Autoimmune Encephalitis

OBJECTIVES

Patients with autoimmune encephalitis (AE) often present with symptoms that are broadly characterized as psychiatric or behavioral, yet little attention is given to the precise symptomatology observed. We sought to more fully define the psychiatric symptoms observed in patients with anti-N-methyl-D-aspartate receptor (NMDAR), anti-glutamic-acid-decarboxylase 65 (GAD65), and anti-voltage-gated-potassium-channel complex (VGKC) antibody-mediated AE using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition nomenclature.

METHODS

We present a case series (n = 25) using a retrospective chart review of 225 patients evaluated for AE in a tertiary care academic medical center between 2014 and 2018. The included patients were ≤18 years old with anti-NMDAR AE (n = 13), anti-GAD65 AE (n = 7), or anti-VGKC AE (n = 5). The frequency of neuropsychiatric symptoms present at the onset of illness and time to diagnosis were compared across groups.

RESULTS

Psychiatric symptoms were seen in 92% of patients in our cohort. Depressive features (72%), personality change (64%), psychosis (48%), and catatonia (32%) were the most common psychiatric symptoms exhibited. On average, patients experienced impairment in ≥4 of 7 symptom domains. No patients had isolated psychiatric symptoms. The average times to diagnosis were 1.7, 15.5, and 12.4 months for anti-NMDAR AE, anti-GAD65 AE, and anti-VGKC AE, respectively (P < .001).

CONCLUSIONS

The psychiatric phenotype of AE in children is highly heterogenous. Involving psychiatry consultation services can be helpful in differentiating features of psychosis and catatonia, which may otherwise be misidentified. Patients presenting with psychiatric symptoms along with impairments in other domains should prompt a workup for AE, including testing for all known antineuronal antibodies.

Autoimmune Encephalitis in Tunisia: Report of a Pediatric Cohort

Background

Autoimmune encephalitis (AE) is a rapidly progressive encephalopathy caused by antibodies targeting neurons in the central nervous system generating specific immune responses. It is increasingly recognized in children.

Objective

To describe clinical, neuroimaging, and laboratory features, treatment, and outcome in a cohort of Tunisian children with AE.

Methods

We conducted a retrospective review of the medical records of all children attending the Department of Child and Adolescent Neurology (Tunis) with autoimmune encephalitis between 2004 and 2020. Clinical, neuroimaging, laboratory features, therapeutic data, and outcome were analyzed.

Results

Nineteen children were included in the study (12 girls and 7 boys). The median age at diagnosis was 7.68 years (range: 10 months-13 years). The most frequent manifestations were seizures and behavioral disorders. Eleven cases were diagnosed with anti-NMDA receptor encephalitis, 4 cases with anti-Ma2 encephalitis, 3 cases with anti-GAD encephalitis, and 1 case with anti-SOX1 encephalitis. Brain MRI showed increased T2 and fluid-attenuated inversion recovery (FLAIR) signal of the temporal lobe in 5 patients. Eighteen patients showed improvement following first-line immunotherapy (high-dose corticosteroids, intravenous immunoglobulin). One patient with anti-GAD encephalitis died despite escalating immunotherapy.

Conclusion

Diagnosis of autoimmune encephalitis is challenging in children, because of misleading presentations. An early and accurate diagnosis is important to enable proper therapeutic interventions.

Antibody-Mediated Encephalitis in Children: Focus on Diagnostic Clues and Acute Symptom Management

Antibody-mediated encephalitis is a treatable cause of encephalitis that manifests over days to weeks as changes in behavior and cognition, seizures, movement disorders, and autonomic dysfunction. Patients with autoimmune encephalitis develop a variety of symptoms. As such, they require a multidisciplinary approach to care. In this review we summarize the clinical presentation and practical diagnostic approach to pediatric autoimmune encephalitis, review treatments of the autoimmune process, and discuss the management of the acute symptoms encountered in children.

Clinical Features, Treatment Strategies, and Outcomes in Hospitalized Children With Immune-Mediated Encephalopathies

BACKGROUND

Autoimmune encephalitis (AE) and acute disseminated encephalomyelitis (ADEM) are immune-mediated brain conditions that can cause substantial neurological sequalae. Data describing the clinical characteristics, treatments, and neurological outcomes for these conditions are needed.

METHODS

This is a single-center retrospective review of children diagnosed with AE or ADEM over a nine-year period with discharge outcomes measured by the Modified Rankin Score.

RESULTS

Seventy-five patients (23 with ADEM and 52 with AE) were identified. Patients with ADEM had a higher percentage of abnormal magnetic resonance imaging findings (100% vs 60.8%; P < 0.001) and a shorter time from symptom onset to diagnosis (6 vs 14 days; P = 0.024). Oligoclonal bands and serum and cerebrospinal fluid inflammatory indices were higher in patients with AE. Nearly all patients received corticosteroids followed by plasmapheresis or intravenous immunoglobulin, and treatment strategies did not differ significantly between groups. Second-line immune therapies were commonly used in patients with AE. Finally, patients with AE had trends toward longer hospital lengths of stay (21 vs 13 days) and a higher percentage of neurological disability at hospital discharge (59.6% vs 34.8%).

CONCLUSIONS

Although patients with ADEM and AE may have similar presenting symptoms, we found significant differences in the frequency of imaging findings, symptom duration, and laboratory and cerebrospinal fluid profiles, which can assist in distinguishing between the diagnoses. Patients in both groups were treated with a combination of immunomodulating therapies, and neurological disability was common at hospital discharge.

Psychiatric autoimmune conditions in children and adolescents: Is catatonia a severity marker?

OBJECTIVES

Patients with autoimmune encephalitis (AE) are likely to exhibit an acute onset of severe psychiatric features, including psychosis and/or catatonia. Based on the high prevalence of catatonia in AE and our clinical experience, we hypothesized that catatonia might be a marker of severity requiring more aggressive treatment approaches.

METHODS

To reach a sufficient number of cases with brain-autoimmune conditions, we pooled two samples (N = 58): the first from the French National Network of Rare Psychiatric diseases and the second from the largest Italian neuro-pediatrics center for encephalopathies. Autoimmune conditions were diagnosed using a multidisciplinary approach and numerous paraclinical investigations. We retrospectively compared patients with and without catatonia for psychiatric and non-psychiatric clinical features, biological and imaging assessments, type of immunotherapy used and outcomes.

RESULTS

The sample included 25 patients (43%) with catatonia and 33 (57%) without catatonia. Forty-two patients (72.4%) had a definite AE (including 27 anti-NMDA receptor encephalitis) and 16 (27.6%) suspected autoimmune encephalitis. Patients with catatonia showed significantly more psychotic features [18 (72%) vs 9 (27.3%), p < 0.001)] and more movement disorders [25 (100%) vs 20 (60.6%), p < 0.001] than patients without catatonia. First line (corticoids, immunoglobulin and plasma exchanges) and second line (e.g., rituximab) therapies were more effective in patients with catatonia, with 24 (96%) vs 22 (66.7%) (p = 0.006) and 17 (68%) vs 9 (27.3%) (p = 0.002), respectively. However, those with catatonia received more combinations of first and second line treatments and had more relapses during outcomes.

CONCLUSION

Despite its exploratory design, the study supports the idea that autoimmune catatonia may be a marker of severity and morbidity in terms of initial presentation and relapses, requiring the need for early and aggressive treatment.

Developing Consensus in the Assessment and Treatment Pathways for Autoimmune Encephalitis in Child and Adolescent Psychiatry

Children with a diagnosis of Autoimmune Encephalitis (AE) frequently require multi-disciplinary care in order to mobilize the assessment and treatment necessary for recovery. Institutional and provider practice differences often influence the diagnostic workup and treatment pathways made available to patients. There are a variety of provider coalitions in pediatric rheumatology, internal medicine, and neurology that have been making meaningful progress toward the development of consensus in assessment and treatment approaches to patient care. However, child psychiatry is currently underrepresented in this work in spite of the high psychiatric symptom burden seen in some young patients. The need for consensus is often made visible only with inter-institutional dialogue regarding patient care trajectories. We aim to review key updates in the assessment and treatment of children and adolescents with autoimmune encephalitis during the acute phase, with or without catatonia, and to outline provider perspectives by comparing current treatment models in the United States, Canada, and Europe.

Clinical Features and Treatment Outcomes of Seronegative Pediatric Autoimmune Encephalitis

Background and Purpose

New diagnostic criteria for pediatric autoimmune encephalitis (AIE) have been introduced recently. A substantial proportion of cases of pediatric AIE are diagnosed as seronegative based on these criteria, and so the clinical characteristics of this group remain to be investigated.

Methods

This study included 46 pediatric patients younger than 18 years with suspected AIE. Clinical features, laboratory or radiological findings, and treatment outcomes were compared between seronegative and seropositive patients.

Results

Nine (19.6%) of the 46 patients were diagnosed as seropositive AIE. All of the patients with seropositive AIE had anti-N-methyl-D-aspartate receptor antibodies. Commonly identified neuropsychiatric symptoms were altered mental status, cognitive dysfunction, seizure, speech dysfunction, and psychotic disorder in both the seronegative and seropositive groups. Immunotherapy produced favorable treatment outcomes in both the seropositive (n=7, 77.8%) and seronegative (n=35, 94.6%) AIE patients. Treatment outcomes for first-line immunotherapy were better in seronegative AIE than seropositive AIE patients (p=0.003), and hence a smaller proportion of seronegative patients required second-line treatment (p=0.015).

Conclusions

Pediatric seronegative AIE patients showed clinical presentations similar to those of seropositive AIE patients, with favorable treatment outcomes after immunotherapy.

Clinical Characteristics and Prognostic Factors of Children With Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Objective: Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is the most common autoimmune encephalitis in pediatric patients. The study aimed to investigate the clinical characteristics and prognostic factors of anti-NMDA receptor encephalitis in children in South China. Methods: This was a retrospective study of children diagnosed with anti-NMDA receptor encephalitis between 01/2014 and 12/2017 at Hunan Children's Hospital. Laboratory, brain magnetic resonance imaging (MRI), and electroencephalography data were collected. The short-term (6-month) outcomes were assessed using the Liverpool score by the same pediatric neurologist. The children were divided into good (scores 4-5) and poor (score <3) clinical outcomes. Results: Among the 51 patients, 21 (41.2%) were male. The most common clinical symptoms were dyskinesia (88.2%), personality change (84.3%), seizure (82.4%), and cognitive disorder (31.4%). Two were transferred to another hospital, 45 (91.8%) received intravenous immunoglobulins, 41 (83.7%) received methylprednisolone, and 8 (16.3%) received plasma exchange. Eight (16.3%) received rituximab for second-line treatment, six after intravenous immunoglobulin and methylprednisolone treatment, and two after plasma exchange therapy failed. Seven were lost to follow-up. The short-term outcome was good in 23 patients. Cognitive disorder [odds ratio (OR): 23.97, 95% confidence interval (CI): 1.12-513.30, P = 0.042) and abnormal brain MRI (OR: 14.29, 95% CI: 1.36-150.10, P = 0.027] were independently associated with a poor short-term outcome after adjustment for age, GCS, and rituximab use. Conclusions: MRI abnormalities and cognitive disorders are independently associated with poor short-term outcomes in children with anti-NMDA receptor encephalitis. The use of rituximab is not associated with the 6-month outcomes.

Neuropsychiatric Disorders Due to Limbic Encephalitis: Immunologic Aspect

Limbic encephalitis (LE) is a rare cause of encephalitis presenting as an acute and subacute onset of neuropsychiatric manifestations, particularly with memory deficits and confusion as core features, along with seizure occurrence, movement disorders, or autonomic dysfunctions. LE is caused by neuronal antibodies targeting the cellular surface, synaptic, and intracellular antigens, which alter the synaptic transmission, especially in the limbic area. Immunologic mechanisms involve antibodies, complements, or T-cell-mediated immune responses in different degree according to different autoantibodies. Sensitive cerebrospinal fluid markers of LE are unavailable, and radiographic findings may not reveal a typical mesiotemporal involvement at neurologic presentations; therefore, a high clinical index of suspicions is pivotal, and a neuronal antibody testing is necessary to make early diagnosis. Some patients have concomitant tumors, causing paraneoplastic LE; therefore, tumor survey and treatment are required in addition to immunotherapy. In this study, a review on the molecular and immunologic aspects of LE was conducted to gain awareness of its peculiarity, which we found quite different from our knowledge on traditional psychiatric illness.

Pro-inflammatory dopamine-2 receptor-specific T cells in paediatric movement and psychiatric disorders

Objectives

A dysregulated inflammatory response against the dopamine‐2 receptor (D2R) has been implicated in movement and psychiatric disorders. D2R antibodies were previously reported in a subset of these patients; however, the role of T cells in these disorders remains unknown. Our objective was to identify and characterise pro‐inflammatory D2R‐specific T cells in movement and psychiatric disorders.

Methods

Blood from paediatric patients with movement and psychiatric disorders of suspected autoimmune and neurodevelopmental aetiology (n = 24) and controls (n = 16) was cultured in vitro with a human D2R peptide library, and D2R‐specific T cells were identified by flow cytometric quantification of CD4⁺CD25⁺CD134⁺ T cells. Cytokine secretion was analysed using a cytometric bead array and ELISA. HLA genotypes were examined in D2R‐specific T‐cell‐positive patients. D2R antibody seropositivity was determined using a flow cytometry live cell‐based assay.

Results

Three immunodominant regions of D2R, amino acid (aa)121–131, aa171–181 and aa396–416, specifically activated CD4⁺ T cells in 8/24 patients. Peptides corresponding to these regions were predicted to bind with high affinity to the HLA of the eight positive patients and had also elicited the secretion of pro‐inflammatory cytokines IL‐2, IFN‐ γ, TNF, IL‐6, IL‐17A and IL‐17F. All eight patients were seronegative for D2R antibodies.

Conclusion

Autoreactive D2R‐specific T cells and a pro‐inflammatory Th1 and Th17 cytokine profile characterise a subset of paediatric patients with movement and psychiatric disorders, further underpinning the theory of immune dysregulation in these disorders. These findings offer new perspectives into the neuroinflammatory mechanisms of movement and psychiatric disorders and can influence patient diagnosis and treatment.

Neuronal antibody prevalence in children with seizures under 3 years: A prospective national cohort

OBJECTIVE

To report the prevalence of anti-neuronal antibodies in a prospective whole-nation cohort of children presenting with seizures before their third birthday.

METHODS

This was a prospective population-based national cohort study involving all children presenting with new-onset epilepsy or complex febrile seizures before their third birthday over a 3-year period. Patients with previously identified structural, metabolic, or infectious cause for seizures were excluded. Serum samples were obtained at first presentation and tested for 7 neuronal antibodies using live cell-based assays. Clinical data were collected with structured proformas at recruitment and 24 months after presentation. In addition, patients with seizures and clinically suspected autoimmune encephalitis were independently identified by a review of the case records of all children <3 years of age in Scotland who had undergone EEG.

RESULTS

Two hundred ninety-eight patients were identified and recruited and underwent autoantibody testing. Antibody positivity was identified in 18 of 298 (6.0%). The antibodies identified were GABA receptor B (n = 8, 2.7%), contactin-associated protein 2 (n = 4, 1.3%), glycine receptor (n = 3, 1.0%), leucine-rich glioma inactivated 1 (n = 2, 0.7%), NMDA receptor (n = 1, 0.3%), and GABA receptor A (n = 1, 0.3%). None of these patients had a clinical picture of autoimmune encephalitis. Seizure classification and clinical phenotype did not correlate with antibody positivity.

CONCLUSIONS

Autoimmune encephalitis is very rare in early childhood. However serum neuronal antibodies are identified in 6.4% of children presenting with seizures at <3 years of age. Antibody testing should not be a routine clinical test in early childhood-onset epilepsy because, in the absence of other features of autoimmune encephalitis, antibody positivity is of doubtful clinical significance. Antibody testing should be reserved for patients with additional features of encephalitis.

Anti-Dopamine Receptor 2 Antibody-Positive Encephalitis in Adolescent

Autoimmune encephalitic syndromes include mutism, somnolence, movement disorder, and behavioral, or psychiatric symptoms. When paired with bilateral basal ganglia lesions on magnetic resonance imaging, these support the diagnosis of basal ganglia encephalitis (BGE). BGE is a rare but distinct entity of putative autoimmune etiology, with specific basal ganglia inflammation and acute movement disorders. A previous study identified dopamine-2 receptors (D2R) antibody to be positive in most BGE children, indicating that the D2R antibody may trigger the downstream pathological process in BGE patients. The highest levels of D2R are found in the striatum, the nucleus accumbens, and the olfactory tubercle. D2R antibody-positive BGE is widely reported in children. Here we present a 17-year-old girl with a typical clinical feature of basal ganglia encephalitis, who benefited from immune therapy.

Immune mediated pediatric encephalitis - need for comprehensive evaluation and consensus guidelines

Background

Autoimmune encephalitis is characterized by neuropsychiatric symptoms associated with brain inflammation. The differential is usually broad and Psychiatry often collaborates with Neurology in diagnostic clarification and symptom management. At least 40% of neuroencephalitis cases are of unknown etiology which adds to difficulties in making the right diagnosis and deciding on the appropriate treatment (Granerod et al., Lancet Infect Dis 10:835-44, 2010). The aim of this case series was to present four cases with complicated psychiatric symptomatology and isolated neurologic signs and symptoms, evaluated at a large tertiary medical center and treated for suspected autoimmune encephalitis, demonstrating the complexity of diagnosis and treatment.

Case presentation

Four diagnostically challenging and heterogeneous cases displayed clinical symptomatology suggestive of autoimmune encephalitis. All cases presented with neurologic and psychiatric symptoms, but had negative autoantibody panels, normal or inconclusive magnetic resonance imaging results and non-specific cerebrospinal fluid changes. All were challenged with immunosuppressive/immunomodulatory treatments with overall poor response rates.

Conclusions

There is a heterogeneous presentation of autoimmune encephalitis in pediatric populations. In the absence of positive findings on testing, individuals who do not meet proposed criteria for seronegative encephalitis may be misdiagnosed, and/or may not respond adequately to treatment. In those cases, comprehensive evaluation and stringent application of consensus guidelines is necessary.

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.

Evaluation of the Cunningham Panel™ in pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS) and pediatric acute-onset neuropsychiatric syndrome (PANS): Changes in antineuronal antibody titers parallel changes in patient symptoms

OBJECTIVE

This retrospective study examined whether changes in patient pre- and post-treatment symptoms correlated with changes in anti-neuronal autoantibody titers and the neuronal cell stimulation assay in the Cunningham Panel in patients with Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection (PANDAS), and Pediatric Acute-onset Neuropsychiatric Syndrome (PANS).

METHODS

In an analysis of all tests consecutively performed in Moleculera Labs' clinical laboratory from April 22, 2013 to December 31, 2016, we identified 206 patients who were prescribed at least one panel prior to and following treatment, and who met the PANDAS/PANS diagnostic criteria. Patient follow-up was performed to collect symptoms and treatment or medical intervention. Of the 206 patients, 58 met the inclusion criteria of providing informed consent/assent and documented pre- and post-treatment symptoms. Clinician and parent-reported symptoms after treatment or medical intervention were categorized as "Improved/Resolved" (n = 34) or "Not-Improved/Worsened" (n = 24). These were analyzed for any association between changes in clinical status and changes in Cunningham panel test results. Clinical assay performance was also evaluated for reproducibility and reliability.

RESULTS

Comparison of pre- and post-treatment status revealed that the Cunningham Panel results correlated with changes in patient's neuropsychiatric symptoms. Based upon the change in the number of positive tests, the overall accuracy was 86%, the sensitivity and specificity were 88% and 83% respectively, and the Area Under the Curve (AUC) was 93.4%. When evaluated by changes in autoantibody levels, we observed an overall accuracy of 90%, a sensitivity of 88%, a specificity of 92% and an AUC of 95.7%. Assay reproducibility for the calcium/calmodulin-dependent protein kinase II (CaMKII) revealed a correlation coefficient of 0.90 (p < 1.67 × 10^-6) and the ELISA assays demonstrated test-retest reproducibility comparable with other ELISA assays.

CONCLUSION

This study revealed a strong positive association between changes in neuropsychiatric symptoms and changes in the level of anti-neuronal antibodies and antibody-mediated CaMKII human neuronal cell activation. These results suggest there may be clinical utility in monitoring autoantibody levels and stimulatory activity against these five neuronal antigen targets as an aid in the diagnosis and treatment of infection-triggered autoimmune neuropsychiatric disorders. Future prospective studies should examine the feasibility of predicting antimicrobial and immunotherapy responses with the Cunningham Panel.

Atypical presentation of MOG-related disease: Slowly progressive behavioral and personality changes following a seizure

BACKGROUND

Myelin Oligodendrocyte Glycoprotein (MOG) antibodies-related disease is mainly presented with acute disseminated encephalomyelitis (ADEM), recurrent optic neuritis, and neuromyelitis optica spectrum disorders (NMOSDs), however the complete clinical spectrum has not yet been defined. We describe an unusual presentation of MOG- related disease. A previously well 10-year-old girl admitted with a focal onset seizure. Neurological examination, electroencephalography, and brain magnetic resonance imaging (MRI) were normal. Following seizure episode she developed gradually increased behavioral and personality changes during a period of 2.5 months. Neurological examination was unremarkable except for drowsiness and minimal ataxia on tandem walking. Repeated brain MRI revealed hazy and poorly demarcated lesions with gadolinium enhancement in the basal ganglia, supratentorial white matter, cerebral peduncles, cerebellum, and servical spinal cord. Cerebrospinal fluid analyses (CSF) revealed 10 lymphocytes /µL, normal protein concentration and IgG index, and negative oligoclonal bands. Auto-antibodies against N-methyl-d-aspartate receptor and CASPR2 in CSF, and antibodies against aquaporin 4 in serum were negative. Analysis with a cell-based assay identified high serum titer of MOG antibodies (1:320). Following IVIG therapy, the patient showed complete clinical recovery within a week with no further relaps for the following 6-month period.

CONCLUSION

Slowly progressive behavioral and personality changes following a seizure may be a manifestation of MOG-related disease in children.

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

Background and purpose: We retrospectively analyzed the clinical characteristics of children with autoimmune encephalitis (AE) in two Chinese tertiary pediatric neurology centers. We also compared anti-NMDAR encephalitis with and without co-positive MOG antibody, as well as specific autoantibody-positive AE and autoantibody-negative but probable AE. Methods: A retrospective study of children (0-18 years old) with AE in Peking University First Hospital and Children's Hospital Affiliated to Capital Institute of Pediatrics was carried out from May 2012 to January 2017. Demographics, clinical features, laboratory, and imaging findings, outcome, and co-positivity with MOG antibody were analyzed. Results: A total of 103 children had AE, 89 (86.4%) had anti-NMDAR encephalitis, 2 (1.9%) had anti-LGI1 encephalitis, 1 (0.9%) had anti-CASPR2 encephalitis, and 11 (10.7%) were diagnosed as autoantibody-negative but probable AE. Among the 89 children with anti-NMDAR encephalitis, 35 were males and 54 were females. The follow-up time was 1-3 years. A total of 15 cases (15/89, 16.9%) with anti-NMDAR encephalitis had co-positive MOG antibody (serum or cerebrospinal fluid or both). These patients were more likely to experience relapse later in life (P = 0.014). We had two cases with anti-LGI1 encephalitis, that is, one with sleep disorder onset, and the other one with seizure onset, both of whom recovered after treatment. One case with anti-CASPR2 encephalitis was treated with an antiepileptic drug and fully recovered. There were 11 cases diagnosed as autoantibody-negative but probable AE who had relatively poorer outcome than those with autoantibody-positive AE (15.2%, 14/89). However, the difference was not significant (P = 0.08). Only one 12-year-old girl with NMDAR-antibody AE had ovarian teratoma. Conclusion: Most subjects with AE in our Chinese cohort had anti-NMDAR AE, which had relatively good prognosis. Children with anti-LGI1 or anti-CASPR2 encephalitis were rare and showed good response on immunotherapy. Co-positive MOG antibody was relatively common in anti-NMDAR encephalitis, which was related to high relapse rate. In our study, the prognosis of autoantibody-negative but probable AE seemed worse than that of specific autoantibody-positive AE.

LGI1 and CASPR2 neurological autoimmunity in children

The clinical phenotype of leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated proteinlike 2 (CASPR2) autoimmunity is well defined in adults. Data for children are limited (<10 cases). Among 13,319 pediatric patients serologically tested for autoimmune neurological disorders (2010-2017), 264 were seropositive for voltage-gated potassium channel-complex-IgG (radioimmunoprecipitation). Only 13 (4.9%) were positive by transfected cell-binding assay for LGI1-IgG (n = 7), CASPR2-IgG (n = 3), or both (n = 3). This is significantly less than in adults. Encephalopathy, seizures, and peripheral nerve hyperexcitability were common, as was coexisting autoimmunity. No faciobrachial dystonic seizures or cancers were identified. Functional neurologic disorders were frequently the initial diagnosis, and immunotherapy appeared beneficial. Ann Neurol 2018;84:473-480.

Management of antibody-mediated autoimmune encephalitis in adults and children: literature review and consensus-based practical recommendations

Autoimmune encephalitis associated with antibodies against neuronal surface targets (NSAE) are rare but still underrecognized conditions that affect adult and pediatric patients. Clinical guidelines have recently been published with the aim of providing diagnostic clues regardless of antibody status. These syndromes are potentially treatable but the choice of treatment and its timing, as well as differential diagnoses, long-term management, and clinical and paraclinical follow-up, remain major challenges. In the absence of evidence-based guidelines, management of these conditions is commonly based on single-center expertise.Taking into account different published expert recommendations in addition to the multicenter experience of the Italian Working Group on Autoimmune Encephalitis, both widely accepted and critical aspects of diagnosis, management and particularly of immunotherapy for NSAE have been reviewed and are discussed.Finally, we provide consensus-based practical advice for managing hospitalization and follow-up of patients with NSAE.

Utility and safety of plasma exchange in paediatric neuroimmune disorders

AIM

Our aim was to ascertain the indications, side effects, and outcomes in children receiving therapeutic plasma exchange (TPE) for neurological disorders.

METHOD

Medical records were retrospectively reviewed for 58 consecutive children (age ≤16y) undergoing 67 courses of TPE across four tertiary centres. Patient characteristics, treatment schedules, complications, and outcomes were analysed.

RESULTS

Median age at initiation of TPE was 9 years (range 1-15y). Indications included peripheral nervous system (PNS; n=18) and central nervous system (CNS; n=40) disorders. Courses comprised a median six exchanges (range 2-179) over 8 days (range 3-466). Forty-two out of 58 (73%) children were severely disabled (bedridden) at initiation and 24 out of 58 (41%) were admitted to intensive care units. Treating clinicians' impression of response was positive in 16 out of 18 of those with PNS disorders versus 22 out of 40 with CNS disorders (p=0.016). Improvements in disability (modified Rankin Scale) occurred in 13 out of 58 (22%) children by completion of TPE (p=0.003). Complications occurred in 40 out of 67 (60%) courses, of which 16 out of 67 (24%) were line related. Potentially life-threatening complications occurred in 2 out of 67 (3%) courses.

INTERPRETATION

This cohort study provides safety and efficacy information for clinicians and families and a basis for future prospective studies.

WHAT THIS PAPER ADDS

Disability scores for severe neuroimmune disorders remained stable or improved during therapeutic plasma exchange treatment. Complications occurred frequently but were typically mild and correctable.

Standardised guidelines and reference networks for treating neuroinflammatory conditions in children are lacking

AIM

To investigate whether local or national guidelines are used in treating neuroinflammatory conditions in children and if there is a perceived need for more guidelines and forums of cooperation.

METHODS

A web-based questionnaire sent to all university hospitals in the Nordic countries (n = 21) between March and July 2015.

RESULTS

All 21 centres replied to the survey. Markers of neuronal or glial damage and markers of inflammation were used at varying rates. Neuronal antibodies were used at all sites except two. Only three hospitals collaborated with their laboratories in developing new assays for biomarkers. Although most centres used some form of guideline for neuroinflammatory conditions, no single disease had a guideline prevalence over 60%. For some diagnoses, access to guidelines was as low as 10%. Standardised follow-up programs were lacking in 50-95%. A clear majority of the centres perceived a need for more guidelines. Also, forums of cooperation were few. However, there was a great interest in developing paediatric neuroinflammatory guidelines and to create platforms for further consensus work and discussion.

CONCLUSION

There is a need for developing treatment guidelines within the field of paediatric neuroinflammation to aid in clinical decision-making, and to establish forums of cooperation.

Mycophenolate mofetil in paediatric autoimmune or immune-mediated diseases of the central nervous system: clinical experience and recommendations

AIM

To gather data on mycophenolate mofetil (MMF) in paediatric autoimmune/immune-mediated central nervous system (CNS) conditions, focusing on safety and factors that may affect MMF efficacy.

METHOD

Retrospective, multicentre study based on four paediatric neurology centres.

RESULTS

Forty-four children were included (30 females, 14 males): 19 had proven/suspected autoimmune encephalitis, 14 had inflammatory demyelinating CNS diseases, and 11 had other autoimmune/immune-mediated CNS conditions. Before MMF, all received first-line immune therapies, and 17 had second-line rituximab and/or cyclophosphamide. MMF was started at a median of 9.5 months from disease onset (range 1-127mo) (median age 9y 4mo, range 1y 5mo-16y 5mo), and was used for median 18 months (range 0.3-73mo). On MMF, 31 patients were relapse-free, whereas eight relapsed (excluding patients with chronic-progressive course). Relapses on MMF were associated with medication weaning/cessation, or with suboptimal MMF dosage/duration. Adverse events of MMF occurred in eight patients: six moderate (gastrointestinal, movement disorder, dermatological) and two severe (infectious).

INTERPRETATION

MMF use in paediatric neuroimmunology is heterogeneous, although relatively safe. We have identified factors that may affect MMF efficacy and provide recommendations on MMF usage.

WHAT THIS PAPER ADDS

Mycophenolate mofetil (MMF) use was heterogeneous with relatively common adverse events, although mostly not severe. MMF treatment reduced median annualized relapse rate, although 20% of patients relapsed on MMF. A high relapse rate pre-MMF and late MMF start were associated with higher probability of relapsing on MMF. Most relapses were associated with suboptimal MMF dosage, short MMF duration, or concurrent medication weaning/discontinuation.

Limited preventive effect of prednisone on neuropsychiatric symptoms in murine systemic lupus erythematosus

OBJECTIVE

To investigate whether glucocorticoids, the hallmark medication for systemic lupus erythematosus (SLE), could prevent the development of neuropsychiatric SLE (NPSLE).

METHODS

The protective effects of prednisone on NPSLE were tested using the open field, object recognition/placement, forced swim, tail suspension, and sucrose preference tests in MRL/lpr mice. Auto-antibody titres and the weight of lymph nodes were also measured.

RESULTS

MRL/lpr mice exhibited mild depression at the age of 8 weeks before progressing with spatial cognitive impairment and severe depression-like behaviour at the age of 16 weeks. Treating MRL/lpr mice with prednisone (5 mg/kg) from the age of 8 weeks decreased anti-cardiolipin and anti-N-methyl-D-aspartate (NMDA) receptor antibody titres in the brain, reduced the weight of lymph nodes, and prolonged the floating latency in the forced swim test. However, prednisone (3 or 5 mg/kg) had no preventive effect on the development of spatial cognitive impairment and other depression-like behaviours in MRL/lpr mice. The dose of prednisone had a positive correlation with the floating latency in the forced swim test, while it offered no effects on all other behavioural tests.

CONCLUSION

Our results provide evidence that early treatment with prednisone had a limited effect on the development of neuropsychiatric symptoms in MRL/lpr mice. Further work is needed in other models beyond NPSLE in MRL/lpr mice before any definitive conclusions are made on the efficacy of prednisone in human NPSLE.