Response to immunotherapy in a 20-month-old boy with anti-NMDA receptor encephalitis

Differentiating rhythmic high-amplitude delta with superimposed (poly) spikes from extreme delta brushes: limitations of standardized nomenclature and implications for patient management

BACKGROUND

Following the standardized nomenclature proposed by the American Clinical Neurophysiology Society (ACNS), rhythmic high-amplitude delta activity with superimposed spikes (RHADS) can be reported as an extreme delta brush (EDB). The clinical implications of similar electrographic patterns being reported as RHADS versus EDB are important to highlight. We aim to review the electrographic characteristics of RHADS, evaluate whether RHADS is seen in other neurological disorders, and identify the similar and unique characteristics between RHADS and EDB to ultimately determine the most accurate way to differentiate and report these patterns. We believe that the differentiation of RHADS and EDB is important as there is a vast difference in the diagnostic approach and the medical management of associated underlying etiologies.

DATA SOURCE

We conducted an extensive search on MEDLINE and Pubmed utilizing various combinations of keywords. Searching for "gamma polymerase and EEG", or "RHADS" or "Alpers syndrome and EEG" or "EEG" AND "Alpers-Huttenlocher syndrome".

RESULTS

Three articles were found to be focused on the description of "RHADS" pattern in Alpers Syndrome. No publication to date were found when searching for the terms "EDB" AND "children", AND "infant" AND "adolescent" excluding "encephalitis" and "neonate". Although RHADS and EDB appear as similar EEG patterns, meticulous analysis can differentiate them. RHADS is not exclusive to patients with Alpers-Huttenlocher syndrome and may manifest in regions beyond the posterior head region. Reactivity to eye-opening and response to anesthesia can be two other elements that help in the differentiation of these patterns.

CONCLUSION

RHADS is not exclusive to patients with AHS and may manifest in regions beyond the posterior head region. Reactivity to eye-opening and response to anesthesia are features that help in the differentiation of these patterns.

Pharmacological Treatments and Therapeutic Targets in Muscle Dystrophies Generated by Alterations in Dystrophin-Associated Proteins

Muscular dystrophies (MDs) are a heterogeneous group of diseases of genetic origin characterized by progressive skeletal muscle degeneration and weakness. There are several types of MDs, varying in terms of age of onset, severity, and pattern of the affected muscles. However, all of them worsen over time, and many patients will eventually lose their ability to walk. In addition to skeletal muscle effects, patients with MDs may present cardiac and respiratory disorders, generating complications that could lead to death. Interdisciplinary management is required to improve the surveillance and quality of life of patients with an MD. At present, pharmacological therapy is only available for Duchene muscular dystrophy (DMD)-the most common type of MD-and is mainly based on the use of corticosteroids. Other MDs caused by alterations in dystrophin-associated proteins (DAPs) are less frequent but represent an important group within these diseases. Pharmacological alternatives with clinical potential in patients with MDs and other proteins associated with dystrophin have been scarcely explored. This review focuses on drugs and molecules that have shown beneficial effects, mainly in experimental models involving alterations in DAPs. The mechanisms associated with the effects leading to promising results regarding the recovery or maintenance of muscle strength and reduction in fibrosis in the less-common MDs (i.e., with respect to DMD) are explored, and other therapeutic targets that could contribute to maintaining the homeostasis of muscle fibers, involving different pathways, such as calcium regulation, hypertrophy, and maintenance of satellite cell function, are also examined. It is possible that some of the drugs explored here could be used to affordably improve the muscular function of patients until a definitive treatment for MDs is developed.

Speech, Language, and Communication Deficits and Intervention in a Single Case of Pediatric Autoimmune Encephalitis

Purpose The current literature on pediatric autoimmune encephalitis (AE) focuses on medical identification/diagnosis and medical treatments. Data about the identification and treatment of communication disorders in these children are limited. This clinical focus article provides an example of the speech, language, and communication characteristics, intervention, and recovery of a single child with medical diagnoses of pediatric AE and pediatric acute-onset neuropsychiatric syndrome (PANS) and special education eligibility under the autism spectrum disorder category. Method This is an in-depth illustrative/descriptive case study. Medical, educational, and speech-language documentation of one child diagnosed with AE at age 7 years was reviewed. Methods included interviews with family members, teachers, and the school speech-language pathologist and reviews of documentation including evaluations, reports, and Individualized Education Programs. Results This child received special education and therapy services through his public school and a university speech-language clinic. He concurrently received medical treatment for AE and PANS. Comprehensive augmentative and alternative communication (AAC) intervention included the use of core words, modeling, parallel talk, self-talk, expansive recasts, shared book reading, family counseling, and collaboration with the parents and the school speech-language pathologist. The child made progress on all goals despite irregular attendance to therapy due to medical complications. Discussion Because experimental research including this population is currently limited, this descriptive case study provides valuable information to clinicians, educators, pediatricians, medical diagnosticians, and anyone providing services to a child with a complex neuropsychological disorder like AE. Future research is needed with more children who have AE, especially experimental investigations of the intervention methods utilized here. Additional research of more children with AE can provide information about the scope and severity of speech, language, and communication needs and the trajectory of recovery given AAC intervention.

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.

Anti-NMDA Receptor Encephalitis: Efficacy of Treatment for Male Patients and miRNA Biomarker

BACKGROUND

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an acute form of encephalitis. Treatments for the anti-NMDA receptor encephalitis usually include steroids, intravenous immunoglobulin, plasma exchange, plasmapheresis, rituximab, cyclophosphamide and tumor resection.

OBJECTIVE

We aimed to compare the efficacy of the treatments including intravenous immunoglobulin, plasma exchange, plasmapheresis, rituximab or cyclophosphamide for male anti- NMDA receptor encephalitis patients without tumor and to discuss potential biomarkers for this disease.

METHOD

The Fisher exact test and the contingency table analysis were used to analyze the treatment efficacy for 43 male and 76 female patients. In addition, a hierarchical tree method was adopted to analyze the difference in the treatment efficacy between male and female patients.

RESULTS

The p-values of testing whether the efficacy rate of plasmapheresis (or plasma exchange) for the male patient is greater than a threshold are significantly different from the pvalues for the other two treatments. In addition, the hierarchical tree method shows that the treatment strategy associating with early recovery is different for male and female patients.

CONCLUSION

The results revealed that the efficacy rate of plasmapheresis (or plasma exchange) is not inferior to that of intravenous immunoglobulin and rituximab (or cyclophosphamide) for male patients without tumor. In addition, B-cell attracting C-X-C motif chemokine 13 (CXCL13) and microRNA let-7b have the potential to be the treatment response biomarkers for anti-NMDA receptor encephalitis. They may not be useful prognostic biomarkers for this encephalitis unless they are not biomarkers for other autoimmune encephalitides.

Catatonia secondary to anti-N-methyl-D-aspartate receptor (NMDAr) encephalitis: a review

Anti-N-methyl-D-aspartate receptor (NMDAr) encephalitis is a relatively recent autoimmune entity, as it was first described in 2007. Given that it is a condition with neuropsychiatric symptoms, its initial symptom is frequently psychiatric in nature. Hence, psychiatrists are often the first physicians to assess these patients and, as so, must recognize this type of encephalitis as a possible cause. Catatonia may be inaugural or develop throughout the course of the disease. Management of patients with anti-NMDAr encephalitis is based on etiologic treatment with immunotherapy and removal of the associated tumor, if any. However, these catatonic patients may have variable responses to etiologic treatment, sometimes with refractory catatonic symptoms, which attests to the necessary urgency to know how to manage these patients. In the clinical setting, physicians appear to be using guidelines originally created to the management of catatonia due to primary psychiatric conditions. In this literature review, catatonia was historically contextualized and anti-NMDAr encephalitis overall described. Finally, catatonia secondary to this type of encephalitis was discussed.

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.

Neuronal Antibodies and Associated Syndromes

INTRODUCTION

Multiple well-recognized conditions, such as Lambert-Eaton myasthenic syndrome (LEMS) and myasthenia gravis (MG), have been associated with neuronal antibodies.

MATERIALS AND METHODS

A search was performed using Embase, PubMed, and CINAHL. An initial search of each database was conducted using keywords and terms related to the aim of the current review. Additional articles were obtained by examining the reference lists and citations in the selected records.

RESULTS

The studies identified through the search process used different designs and methods to explore neuronal antibodies and associated syndromes. Previous studies have shown that neurological and psychiatric disorders can be mediated and influenced by various antibodies. The identification of autoantibodies can help with the accurate diagnosis of conditions and commencement of early treatment.

DISCUSSION

A review of selected studies identified in the literature implicated that classic anti-neuronal antibodies, such as anti-Ri and anti-Hu, play a role in the development of neurological diseases. More recent studies have indicated that other novel antibodies act on neuronal cell surface antigens to contribute to the development of neurological disorders.

CONCLUSION

Existing research provides evidence revealing a spectrum of antibodies linked to the development and progression of neurological diseases. However, further antibody testing and studies should be performed to validate the relationship between conditions and antibodies.

Clinical variants of limbic encephalitis

The clinical picture of immunomediator disorders of the central nervous system resulting from autoimmune or paraneoplastic processes is often represented by the limbic symptom complex or limbic encephalitis. The article gives a brief description of these conditions, allocated to a separate nosological group in 2007. The symptoms of limbic encephalitis include mental disorders and epileptic seizures of both convulsive and non-convulsive spectrum, up to epileptic status. Four clinical cases representative of different variants of limbic encephalitis are presented in this study, along with the discussion of epidemiology, differential diagnostics, and generally accepted patient management strategies. The diagnosis of limbic encephalitis was made on clinical grounds alone in three cases and on the presence of antibodies to N-Methyl-d-aspartic acid receptors in one case. A combination of glucocorticoid pulse therapy with prolonged use of valproic acid was successfully applied for the treatment of limbic encephalitis with non-convulsive epileptic status. Plasmapheresis was used for the treatment of limbic encephalitis with recurrent focal non-motor attacks with and without loss of consciousness, as well as for limbic encephalitis with focal motor attacks. Presented cases emphasize the need to increase the awareness of physicians of various specialties to autoimmune disorders of the nervous system. In addition, it highlights the necessity of complete diagnostic workup for a patient with impaired consciousness of unclear etiology.

[Progress in immunotherapy for children with anti-N-methyl-D-aspartate receptor encephalitis]

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune encephalitis that was reported in recent years. At present, there remains no unified treatment regimen for the children and adolescents with this disease around the world. Immunotherapy is still the preferred way of treatment, mainly including first-line immunotherapy, second-line immunotherapy, and long-term immunotherapy. In recent years, some researchers have tried new immunosuppressants or modified immunotherapy regimens to improve the treatment outcome of the patients. This article summarizes related immunotherapy regimens, as well as the future direction of research on immunotherapy for anti-NMDAR encephalitis.

[Progress in immunotherapy for children with anti-N-methyl-D-aspartate receptor encephalitis]

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune encephalitis that was reported in recent years. At present, there remains no unified treatment regimen for the children and adolescents with this disease around the world. Immunotherapy is still the preferred way of treatment, mainly including first-line immunotherapy, second-line immunotherapy, and long-term immunotherapy. In recent years, some researchers have tried new immunosuppressants or modified immunotherapy regimens to improve the treatment outcome of the patients. This article summarizes related immunotherapy regimens, as well as the future direction of research on immunotherapy for anti-NMDAR encephalitis.

Anti-NMDA receptor encephalitis in a toddler: A diagnostic challenge

Anti N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder and is considered to be one of the most common causes of encephalitis in children. Despite the fact that around half of all reported cases are of children, the number of studies that report infants and toddlers is very small. Furthermore, reports on children from the Middle East particularly are extremely rare.

We report a 21-month-old Jordanian female toddler with NMDAR encephalitis, who initially presented with behavioral changes and some autistic features. She presented a diagnostic challenge due to a concurrent urinary tract infection and gastroenteritis. Multiple investigations were conducted and she was treated with methylprednisolone and intravenous immunoglobulin (IVIg) empirically as well as plasma exchange and rituximab once the diagnosis was confirmed. Her condition improved gradually. We discuss her clinical picture and the diagnostic challenges within this age group; we also review the current related literature.

Anti-NMDA-Receptor Encephalitis: From Bench to Clinic

NMDAR encephalitis is a common cause of autoimmune encephalitis, predominantly affecting young adults. Current data supports the idea that autoantibodies targeting NMDARs are responsible for disease pathogenesis. While these autoantibodies occur in the setting of underlying malignancy in approximately half of all patients, initiating factors for the autoimmune response in the remainder of patients are unclear. While there is increasing evidence supporting viral triggers such as herpes simplex encephalitis, this association and the mechanism of action have not yet been fully described. Although the majority of patients achieve good outcomes, those without an underlying tumor consistently show worse outcomes, prolonged recovery, and more frequent relapses. The cloning of patient-specific autoantibodies from affected individuals has raised important questions as to disease pathophysiology and clinical heterogeneity. Further advances in our understanding of this disease and underlying triggers are necessary to develop treatments which improve outcomes in patients presenting in the absence of tumors.

Rituximab for Treatment of Refractory Anti-NMDA Receptor Encephalitis in a Pediatric Patient

Anti-N-methyl d-aspartate receptor (anti-NMDAR) encephalitis is a devastating disease that is increasingly being identified in both children and adults with psychosis, language disturbances, behavioral changes, and motor deficits. Currently no consensus guidelines exist for the optimal management of patients with this disease, although intravenous immune globulin (IVIG) therapy is often considered first-line pharmacotherapy. We present a case of an otherwise healthy 4 year-old-child who presented with seizures, loss of age-appropriate language skills, and behavioral changes, in whom anti-NMDAR was subsequently diagnosed. After marked intolerance to corticosteroid therapy and inadequate clinical response to IVIG, immunotherapy with rituximab was initiated. The patient had rapid return of language skills and complete resolution of dyskinesia after a single rituximab infusion, with no residual deficits at her 6-month follow-up visit. Early intervention in patients with anti-NMDAR encephalitis is of paramount importance for successful outcomes and baseline recovery. Only approximately half of patients respond to first-line immunotherapy, necessitating further evaluation of alternative therapies and the development of a treatment algorithm for practitioners. This case report builds upon previous findings illustrating rapid symptom resolution after rituximab infusion and adds to the available body of evidence for management of pediatric patients with anti-NMDAR.

Clinical Characteristics and Follow-up of South Indian Children with Autoimmune Encephalopathy

OBJECTIVE

To describe the clinical characteristics of a cohort of south Indian children with probable autoimmune encephalopathy from a tertiary care academic hospital and to compare this data with the existing literature.

METHODS

Patients with encephalopathy plus one or more of neuropsychiatric symptoms, seizures, movement disorder or cognitive dysfunction were identified. Common infectious causes were excluded. Clinical characteristics, investigations, management and outcome were analyzed.

RESULTS

Thirteen patients were included in the study; 12 were females (92.3 %) and mean age was 9.6 y. Most common presentation was behavior change (13 patients) followed by seizures (11 patients). Three patients showed lymphocytic pleocytosis in CSF and one patient had oligoclonal bands. Initial MRI was normal in all patients except in one. Most common EEG abnormality was mild background slowing. Only one child had ovarian tumor. S.NMDA receptor antibody was positive in 10 patients (83 %), and all of them received immunotherapy. Six out of 13 children were followed up for more than 1 y (mean - 21 mo). Recurrence was noted in 4 out of 6 patients (66 %). On last follow-up, good recovery was seen in 2 children (33 %), moderate disability in 3 (50 %) and severe disability in 1 (16 %).

CONCLUSIONS

The clinical characteristics and outcome of one of the largest single center cohort of Indian children with autoimmune encephalopathy is reported. Autoimmune encephalopathy should be considered as a differential diagnosis in the acute and subacute encephalopathies of childhood and treating pediatrician should be aware of this entity.

Approach to the Management of Pediatric-Onset Anti-N-Methyl-d-Aspartate (Anti-NMDA) Receptor Encephalitis: A Case Series

Anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis is a treatable cause of autoimmune encephalitis. It remains unclear if the natural history of this disease is altered by choice of acute therapy or the employment of chronic immunotherapy. Chart review was undertaken for pediatric patients diagnosed with anti-NMDA receptor encephalitis. Data obtained included patient demographics, disease manifestations, treatment course, and clinical outcomes. Ten patients with anti-NMDA receptor encephalitis were identified. All patients were treated with immunotherapy in the acute period, and all patients experienced good recovery. Neurologic relapse did not occur in any patient. All patients received varied forms of chronic immunosuppression to prevent relapses. Complications of chronic immunotherapy occurred in 50% of patients. The benefits of chronic immunotherapy and the duration of use should be carefully weighed against the risks. Complications from immunotherapy are not uncommon and can be serious. Clinical trials assessing the benefit of long-term immunotherapy in this population are needed.

Antibody-Mediated Autoimmune Encephalitis in Childhood

BACKGROUND

The differential diagnosis of encephalitis in childhood is vast, and evaluation for an etiology is often unrevealing. Encephalitis by way of autoimmunity has long been suspected, as in cases of acute disseminated encephalomyelitis; however, researchers have only recently reported evidence of antibody-mediated immune dysregulation resulting in clinical encephalitis.

MAIN FINDINGS

These pathologic autoantibodies, aimed at specific neuronal targets, can result in a broad spectrum of symptoms including psychosis, catatonia, behavioral changes, memory loss, autonomic dysregulation, seizures, and abnormal movements. Autoimmune encephalitis in childhood is often quite different from adult-onset autoimmune encephalitis in clinical presentation, frequency of tumor association, and ultimate prognosis. As many of the autoimmune encephalitides are sensitive to immunotherapy, prompt diagnosis and initiation of appropriate treatment are paramount.

CONCLUSIONS

Here we review the currently recognized antibody-mediated encephalitides of childhood and will provide a framework for diagnosis and treatment considerations.

Utility of Plasmapheresis in Autoimmune-Mediated Encephalopathy in Children: Potentials and Challenges

Autoimmune-mediated encephalopathy in children continues to constitute a diagnostic and therapeutic challenge in pediatric population. Utility and usefulness in this clinical setting of plasmapheresis have seldom been evaluated in current pediatric literature. Children with immune-mediated encephalopathies represent a uniquely different group among patients presenting to intensive care units or neurological services worldwide. Arriving at a final diagnosis is not an easy task for treating physicians. It is very crucial to consider early use of first-line immunotherapy modalities, save those children's lives and improve outcomes. Plasmapheresis is an emerging, potentially beneficial first-line therapy in such patients. However, indications, value, logistics, and procedural difficulties are often faced. This study is mainly meant to review the current knowledge in regard to the clinical value of plasmapheresis in children with immune-mediated encephalopathy.

Three phenotypes of anti-N-methyl-D-aspartate receptor antibody encephalitis in children: prevalence of symptoms and prognosis

BACKGROUND

Anti-N-methyl-d-aspartate (NMDA) receptor antibody encephalitis is becoming an increasingly recognized cause of encephalopathy in individuals previously presumed to have viral encephalitis. Various manifestations of this disease include altered mental status, behavioral changes, seizures, and movement disorders. We have noted three distinct subtypes of this disease which appear to have differential responses to immunotherapies and differences in prognosis.

METHODS AND PATIENTS

We report eight patients observed at our children's hospital from 2009 through 2013 who appear to clearly fall into one of our three clinical categories. To find comparable articles reflecting this classification, we then performed a MEDLINE search of all articles involving the subject heading "anti-NMDA receptor encephalitis" or just the keyword phrase "NMDA encephalitis," and we found 162 articles to review. Twenty-two articles were eliminated due to basic science, and we were able to review 105 of the remaining articles, most of which were case reports or case series, although a few were larger reviews. For the sake of our review, we defined type 1 or "classic" anti-NMDA receptor antibody encephalitis as having a duration of <60 days and being characterized predominantly by a catatonic or stuporous state, type 2 or psychiatric-predominant anti-NMDA receptor antibody encephalitis as having no noteworthy catatonic or stuporous state in addition to the presence of predominantly behavioral and psychiatric symptoms, and type 3 or catatonia-predominant anti-NMDA receptor antibody encephalitis as having a duration of ≥60 days in a predominantly catatonic or stuporous state.

RESULTS

We note that the poorest responders, even to aggressive immunotherapies, are the patients with catatonia-persistent type anti-NMDA receptor antibody encephalitis, which has, as its hallmark, prolonged periods of severe encephalopathy. Patients with predominantly psychiatric symptoms, which we call the psychiatric-predominant anti-NMDA receptor antibody encephalitis, have had excellent responses to plasma exchange or other immunotherapies and appear to have the least residual deficits at follow-up. Patients with fairly equal representations of periods of altered mental status, behavioral problems, and movement disorders appear to have an intermediate prognosis and likely require early aggressive immunotherapy.

CONCLUSIONS

In our series, we discuss representative examples of these clinical subtypes and their associated outcomes, and we suggest that tracking these subtypes in future cases of anti-NMDA receptor antibody encephalitis might lead to better understanding and better risk stratification with regard to immunotherapy decisions.

Anti-N-methyl-D-aspartate receptor encephalitis with positive serum antithyroid antibodies, IgM antibodies against mycoplasma pneumoniae and human herpesvirus 7 PCR in the CSF

We report the case of a boy with an encephalopathy associated with extrapyramidal and psychiatric symptoms and anti-N-methyl-D-aspartate receptor antibodies. He had positive serum antithyroid antibodies, IgM antibodies against Mycoplasma pneumoniae and human herpesvirus 7 polymerase chain reaction in the cerebrospinal fluid. He was successfully treated with rituximab, after steroids, intravenous immunoglobulin and plasma exchange. The pathophysiology of this disorder may be post-infectious and autoimmune.

Pediatric anti-NMDA (N-methyl D-aspartate) receptor encephalitis

BACKGROUND

We report the clinical features and course of pediatric patients presenting with anti-N-methyl D-aspartate receptor (NMDA-R) encephalitis.

METHODS

Single-center 4-year observational study of pediatric encephalitis associated with NMDA-R antibodies in the serum and/or the cerebrospinal fluid.

RESULTS

Three girls with anti-NMDA-R encephalitis were identified. All presented with an acute hyperkinetic movement disorder and seizures, expressive aphasia, and emotional lability requiring inpatient treatment for 1-3 months. Imaging and electroencephalogram findings were nondiagnostic. None had an underlying tumor or ovarian teratoma. All received immune-modulatory therapy, including one or more of the following: high-dose methyl-prednisolone, plasma exchange, intravenous immunoglobulin or mycophenolate mofetil. Two of the three patients relapsed within 6 months of presentation and required retreatment with plasma exchange. All have remained in subsequent remission, with two of the three requiring second-line immunotherapy with rituximab.

CONCLUSIONS

Hyperkinetic movements in pediatric patients presenting with acute encephalopathy and prominent psychiatric symptoms should elicit a search for NMDA-R antibodies early in the evaluation. Relapses require aggressive immunomodulatory treatment for remission. This series highlights a unique positron emission tomography scan finding of hypermetabolism in one of the patients that correlated with her clinical symptoms. Recovery and rehabilitation can be prolonged, often taking years after the initial diagnosis. Early identification and treatment is likely to reduce relapses and limit morbidity associated with this potentially devastating but treatable encephalitis.

Identification of the N-Methyl-D-aspartate receptor (NMDAR)-related epitope, NR2B, in the normal human ovary: implication for the pathogenesis of anti-NMDAR encephalitis

N-methyl-D-aspartate receptors (NMDARs) are one type of ionotropic glutamate receptors (GluRs) and are heterotetrametric cation channels composed of NMDAR1 (NR1), NMDAR2 (NR2A, 2B, 2C or 2D) and NMDAR3 (NR3A or NR3B) subunits. The main subunits are NR1 and NR2 and their combinations are classified into several diverse forms including NR1/NR1/NR2A/NR2A, NR1/NR1/NR2B/NR2B and NR1/NR1/NR2A/NR2B. NMDARs are physiologically related to synapse development and synaptic plasticity in the central nervous system. Anti-NMDAR encephalitis is a form of autoimmune limbic encephalitis mainly affecting young women, with various manifestations including initial psychiatric symptoms, subsequent unresponsiveness, intractable generalized seizure, dysautonomia and orofacial dyskinesia. This disorder is often accompanied by ovarian teratoma that is originated from oocytes. Anti-neural antibody for the NR1/NR2 heteromer of NMDAR has been identified as a disease-specific hallmark. It has been emphasized that neural components in ovarian teratoma act as a trigger to produce anti-NMDAR antibodies, although about half of the patients with anti-NMDAR encephalitis are not associated with ovarian teratoma. To identify NMDAR-related epitopes located outside of the brain, we performed immunohistochemical examinations of normal human ovary and testis using specific antibodies against NR1, NR2A and NR2B, respectively, and found expression of the NR2B epitope in the cytoplasm of oocytes. In contrast, the testis showed no immunohistochemical reactivity. Therefore, oocytes contain NMDAR-related epitopes including NR2B. The NMDAR-related epitopes in normal oocytes may cause an antigen-antibody reaction in certain pathological conditions. The presence of NR2B immunoreactivity in oocytes may account for the fact that anti-NMDAR encephalitis predominantly affects young females.

Anti-N-methyl-D-aspartate receptor-mediated encephalitis in infants and toddlers: case report and review of the literature

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is an increasingly well-recognized inflammatory encephalitis in children and adults.

PATIENT

We report a previously healthy 21-month-old girl who presented with behavioral change, self-mutilatory behavior, and echolalia. Over the ensuing weeks, symptoms progressed to include unilateral upper extremity dystonia, gait impairment, dysphagia, and mutism. Magnetic resonance imaging of the brain showed a tiny area of signal abnormality in the subcortical white matter, but was otherwise normal. Continuous video electroencephalography showed slowing of the background rhythm, but was without epileptiform discharges. Lumbar puncture showed a mild pleocytosis of mixed cellularity; bacterial culture and testing for various viral encephalitides were negative. Serum and cerebrospinal fluid was positive for autoantibodies directed against the N-methyl-D-aspartate receptor, and she was diagnosed with anti-N-methyl-D-aspartate receptor encephalitis. The patient was successfully treated with a regimen of immunotherapy that included dexamethasone, intravenous immunoglobulin, and rituximab. One year after initial presentation, the patient remained symptom-free. We further review the clinical characteristics, results of diagnostic studies, treatment, and outcome of infants and toddlers diagnosed with anti-N-methyl-D-aspartate receptor encephalitis that have been previously reported in the literature.

CONCLUSION

Anti-N-methyl-D-aspartate receptor encephalitis is relatively common among infants and toddlers and often presents with a pattern of defining characteristics in this age group, particularly the absence of associated tumor.

Clinical case of anti-N-methyl-D-aspartate receptor encephalitis in an 8-month-old patient with hyperkinetic movement disorder

This article describes an 8-month-old boy with the full clinical spectrum anti-N-methyl-d-aspartate receptor encephalitis. He was admitted to the hospital with involuntary orofacial head movements, behavioral changes, and fluctuation in consciousness. His examination showed tongue thrusting, decreased responsiveness, and hypotonia without fever. Analysis of the cerebrospinal fluid revealed increased protein levels (62 mg/dL). The next day he developed oral dyskinesia and choreoathetosis. Video-electroencephalogram polygraphy showed coreo-dystonic movements without electrographic correlation. A putative diagnosis of autoimmune encephalopathy was made, and treatment with intravenous immunoglobulin and methylprednisolone was started, with improvement in the abnormal movements. Antibodies to the N-methyl-d-aspartate receptor were identified in the cerebrospinal fluid and blood. He began receiving immunoglobulin once a month for a year. Two months after the treatment had started, the involuntary movement disappeared and his development has been normal. N-methyl-d-aspartate receptor encephalitis is a recently identified disorder. This is the youngest case reported. Prompt diagnosis and treatment are important to obtain full recovery.

Fine mapping of a monoclonal antibody to the N-Methyl D-aspartate receptor reveals a short linear epitope

Anti-N-Methyl D-aspartate receptor encephalitis is an autoimmune disease in which autoantibodies are produced against extracellular regions of the N-Methyl D-aspartate receptor (NMDAR). In this study, we used resin-bound peptides equipped with a base labile linker to map the epitope of a monoclonal NMDAR antibody against the NMDAR NR1 subunit. The antigenicity of the synthesized resin-bound peptides was determined by enzyme-linked immunosorbent assay. Distinct reactivity was found to two extracellular overlapping peptides (amino acids, 658-687). Using N- and C-terminally truncated resin-bound peptides, the minimum functional epitope was identified as the NPSDK sequence. The peptide sequence RNPSDK (amino acids, 673-678) was identified as the complete epitope, which was found to be located in the extracellular S2 domain of the NR1 subunit. Especially, the N-terminal arginine residue was found to be essential for reactivity, whereas the remaining amino acids could be replaced with amino acids of similar side-chain functionality, indicating the importance of backbone interaction in antibody reactivity.

Anti-NMDA Receptor Encephalitis

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a severe but potentially reversible neurologic disorder that is clinically recognizable in children and adolescents. Prompt diagnosis and treatment are essential to facilitate recovery. Treatment consists of corticosteroids, intravenous immunoglobulin, or plasma exchange as first-line therapy followed by cyclophosphamide or rituximab, if necessary, as second-line immunotherapy. Patients with tumor-associated encephalitis benefit from tumor resection. More than 75% of patients make a substantial recovery, which occurs in the reverse order of symptom presentation associated with a decline in antibody titers.

Autoimmune encephalitis in children

The causes of encephalitis are numerous, and extensive investigations for infectious agents and other etiologies are often negative. The discovery that many of these encephalitis are immune mediated has changed the approach to the diagnosis and treatment of these disorders. Moreover, the broad spectrum of symptoms including, psychosis, catatonia, alterations of behavior and memory, seizures, abnormal movements, and autonomic dysregulation usually requires a multidisciplinary treatment approach. This review focuses in several forms of encephalitis that occur in children, and for which an autoimmune etiology has been demonstrated (eg, anti-N-methyl-d-aspartate receptor encephalitis) or is strongly suspected (eg, Rasmussen encephalitis, limbic encephalitis, opsoclonus-myoclonus). The authors also review several disorders that may be immune mediated, such as the rapid onset obesity with hypothalamic dysfunction, hypoventilation and autonomic dysregulation (ROHHAD) syndrome and some encephalopathies with fever and status epilepticus. Recognition of novel immune-mediated encephalitis is important because some of these disorders are highly responsive to immunotherapy.

The rehabilitation of children with anti-N-methyl-D-aspartate-receptor encephalitis: a case series

Anti-N-methyl-D-aspartate (NMDA)-receptor encephalitis is a serious, complex, and potentially fatal disease in children. Children with this condition frequently present with altered mental status, rapid functional deterioration, and seizures. Despite aggressive treatment with immune therapy such as corticosteroids, intravenous immunoglobin, and plasmapheresis, children often need extensive rehabilitative services and can be left with lasting deficits. In this case series, we report on six known consecutive pediatric cases of N-methyl-D-aspartate-receptor antibody encephalitis in Northern California requiring comprehensive inpatient rehabilitation. The children presented with a variety of symptoms and had waxing and waning clinical courses. All children progressed well through their rehabilitation programs but were discharged home with persistent functional deficits. At follow-up, all but one child had lasting deficits. Because of the complicated management and extensive rehabilitation needs of children with anti-N-methyl-D-aspartate-receptor encephalitis, physiatrists and other rehabilitation providers should be knowledgeable about this complex condition.

Autoimmune encephalopathies and epilepsies in children and teenagers

Recognition of autoimmune encephalopathies and epilepsies in children and teenagers with acute or subacute onset of central nervous system dysfunction, through detection of the pertinent antibody on serum or cerebral spinal fluid, or through a response to immunotherapy may lead to an early diagnosis, and thus expedited implementation of immunotherapy and improved neurological outcome. The epidemiology of pediatric autoimmune encephalopathy and epilepsy is not well established, but advances in disease-specific biomarker discovery have lead to identification of disorders with either a cytotoxic T cell mediated pathogenesis or (more recently) possible autoantibody mediated disorders. This review summarizes the clinical presentations and recommended evaluations and treatment of pediatric epileptic encephalopathy suspected to be of autoimmune etiology.

Metabolic encephalopathies

Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.

Rituximab used successfully in the treatment of anti-NMDA receptor encephalitis

We report the case of a young woman with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, without tumor, who was successfully treated with rituximab. Because conventional immunotherapy, including corticosteroids, immunoglobulin (IVIg), and plasma exchange showed little improvement in our patient, we introduced another treatment using rituximab. A week after the first administration of rituximab, her symptoms improved gradually and significantly. This case provides in vivo evidence that rituximab is an effective agent for treating anti-NMDAR encephalitis, even in those cases where conventional immunotherapies have been ineffective. Rituximab should be regarded as a beneficial therapeutic agent for this disease.

Management of suspected viral encephalitis in children - Association of British Neurologists and British Paediatric Allergy, Immunology and Infection Group national guidelines

In the 1980s the outcome of patients with herpes simplex encephalitis was shown to be dramatically improved with aciclovir treatment. Delays in starting treatment, particularly beyond 48 h after hospital admission, are associated with a worse prognosis. Several comprehensive reviews of the investigation and management of encephalitis have been published. However, their impact on day-to-day clinical practice appears to be limited. The emergency management of meningitis in children and adults was revolutionised by the introduction of a simple algorithm as part of management guidelines. In February 2008 a group of clinicians met in Liverpool to begin the development process for clinical care guidelines based around a similar simple algorithm, supported by an evidence base, whose implementation is hoped would improve the management of patients with suspected encephalitis.

Neurologic emergencies in patients who have cancer: diagnosis and management

The nervous system can be significantly affected by cancer. Neurologic symptoms are present in 30% to 50% of oncologic patients presenting to the emergency department or in neurologic consultation at teaching hospitals. Evaluation and treatment require collaborative effort between specialties. The causes of neurologic emergencies in patients with cancer are mostly related to effects of cancer, toxicities of treatments, infections, and paraneoplastic syndromes. These complications cause significant morbidity and mortality and require prompt and accurate diagnostic and treatment measures. This article reviews the common neurologic emergencies affecting patients with cancer and discusses epidemiology, clinical presentation, diagnosis, and treatment modalities.

Pediatric neurological complications associated with the A(H1N1)pdm09 influenza infection

BACKGROUND

Influenza-related neurological complications (INC) have been reported during seasonal flu in children.

OBJECTIVES

To investigate the types, outcomes and incidence of INC occurring during the 2009 A(H1N1) pandemic, a retrospective analyze was conducted in the single French pediatric hospital of Lyon from October 2009 to February 2010.

STUDY DESIGN

All children presenting with fever, influenza-like illness, respiratory distress or neurological symptoms were tested for influenza A(H1N1)pdm09 infection from respiratory specimens using real time RT-PCR.

RESULTS

INC occurred in 14 A(H1N1)pdm09 positive children (7.7% of A(H1N1)pdm09 positive children admitted to hospital) with a median age of 5.1 years. Admission to the intensive care unit (ICU) was required for nine children (64.3%). Half of the children with INC had comorbidity and three had coinfection, both characteristics mainly found in children requiring the ICU. All children received oral oseltamivir treatment. Febrile seizures were observed in eight children, half of them having a chronic comorbidity (2 epilepsy, 1 nonketotic hyperglycinemia, 1 anoxic encephalopathy). Other INC, less commonly reported, included 2 cases of encephalitis, 1 encephalopathy, 1 basilar artery thrombosis, 1 myasthenic crisis and 1 coma. Eleven of the 14 children (78.6%) recovered, one had a minor disability, one child developed a locked-in syndrome and one died from complications of an acute necrotizing encephalopathy.

DISCUSSION

INC can be observed even in children with no underlying disorder. It may lead to dramatic issue in a significant number of cases.

NMDA receptor antibody encephalitis

N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is a recently described immunotherapy-responsive panencephalitis with characteristic features that include a psychiatric onset and a later movement disorder. This entity was first described as a paraneoplastic phenomenon in young women with ovarian teratomata. However, more recently it has become clear that the majority of patients, particularly children, do not harbor a tumor and that males can also be affected. With the development of the NMDAR antibody assay, now available worldwide, a few patients with classical limbic encephalitis and early psychosis and epilepsy have also been found to harbor these antibodies. Early diagnosis followed by immunotherapies and tumor removal, when relevant, expedite recovery from the condition. Antibody levels correlate with the clinical severity of the disease in individual patients, and the antibodies have been shown to substantially reduce NMDA receptors on hippocampal neurons both in vitro and in vivo, supporting the likely direct pathogenicity of the NMDAR antibodies.

Movement disorders in paraneoplastic and autoimmune disease

PURPOSE OF REVIEW

The most relevant advances in immune-mediated movement disorders are described, with emphasis on the clinical--immunological associations, novel antigens, and treatment.

RECENT FINDINGS

Many movement disorders previously considered idiopathic or degenerative are now recognized as immune-mediated. Some disorders are paraneoplastic, such as anti-CRMP5-associated chorea, anti-Ma2 hypokinesis and rigidity, anti-Yo cerebellar ataxia and tremor, and anti-Hu ataxia and pesudoathetosis. Other disorders such as Sydenham's chorea, or chorea related to systemic lupus erythematosus and antiphospholipid syndrome occur in association with multiple antibodies, are not paraneoplastic, and are triggered by molecular mimicry or unknown mechanisms. Recent studies have revealed a new category of disorders that can be paraneoplastic or not, and associate with antibodies against cell-surface or synaptic proteins. They include anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, which may cause dyskinesias, chorea, ballismus or dystonia (NMDAR antibodies), the spectrum of Stiff-person syndrome/muscle rigidity (glutamic acid decarboxylase, amphiphysin, GABA(A)-receptor-associated protein, or glycine receptor antibodies), neuromyotonia (Caspr2 antibodies), and opsoclonus--myoclonus--ataxia (unknown antigens).

SUMMARY

Neurologists should be aware that many movement disorders are immune-mediated. Recognition of these disorders is important because it may lead to the diagnosis of an occult cancer, and a substantial number of patients, mainly those with antibodies to cell-surface or synaptic proteins, respond to immunotherapy.

Anti-NMDA-Receptor Encephalitis and Other Synaptic Autoimmune Disorders

OPINION STATEMENT

Synaptic autoimmunity may result in a wide variety of symptoms, including catatonia, psychosis, movement disorders, short-term memory deficits, and refractory seizures, so these patients are seen by a wide spectrum of practitioners, who need to be aware of these disorders. In some cases, these disorders occur as a paraneoplastic manifestation of an associated cancer. However, in contrast to the well-known paraneoplastic neurologic disorders of the central nervous system that predominate in older individuals, these novel disorders often affect children and young adults. Additionally, for some syndromes, the presence of a tumor does not necessarily indicate a poor prognosis. Successful treatment of the tumor and immunotherapy often result in recovery, supporting the use of surgery for severely ill patients. In all syndromes, deficits may be reversible despite the duration or severity of symptoms. For example, patients with anti-NMDA-receptor encephalitis who had been in a coma or ventilated for 6-10 months have had full recovery after appropriate treatment.

Current approaches to the treatment of paraneoplastic encephalitis

Paraneoplastic neurological syndromes (PNSs) cover a wide range of diseases and involve both the central nervous system (CNS) and peripheral nervous system. Paraneoplastic encephalitis comprises several diseases such as paraneoplastic cerebellar degeneration (PCD), limbic encephalitis (LE), paraneoplastic encephalomyelitis (PEM), brainstem encephalitis, opsomyoclonus syndrome, in addition to other even less frequently occurring entities. LE was the first historically identified CNS PNS, and similarities between other temporal lobe diseases such as herpes encephalitis have been elucidated. In the past few decades several autoantibodies have been described in association with LE. These encompass the classical 'onconeuronal' antibodies (abs) such as Hu, Yo, Ri and others, and now additionally abs towards either ion channels or surface antigens. The clinical core findings in LE are various mental changes such as amnesia or confusion, often associated with seizures. Careful characterization of psychiatric manifestations and/or associated neurological signs can help to characterize the syndrome and type of ab. The treatment options in LE depend on the aetiology. In LE caused by onconeuronal abs, the treatment options are poor. In two types of abs associated with LE, abs against ion channels and surface antigens (e.g. NMDA), immunomodulatory treatments seem effective, making these types of LE treatable conditions. However, LE can also occur without being associated with cancer, in which case only immunomodulation is required. Despite effective treatments, some patients' residual deficits remain, and recurrences have also been described.

Ictal asystole and anti-N-methyl-D-aspartate receptor antibody encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is a recently identified autoimmune disorder that is increasingly recognized in children. Most cases occur in girls and women and may be paraneoplastic with an associated ovarian teratoma. Characteristic clinical features include neuropsychiatric symptoms, dyskinesias, decreased consciousness, and autonomic instability. We report the first case of asystole associated with temporal lobe seizures in this disorder and highlight the need for careful monitoring for this potentially fatal complication. A 15-year-old previously healthy girl presented with focal seizures and personality changes that progressed to periods of agitation and confusion alternating with catatonia. Anti-NMDAR antibodies were detected in the cerebrospinal fluid and serum. Twenty-six days after initial presentation, new seizures developed characterized by bradycardia and oxygen desaturation. Continuous video-electroencephalogram monitoring captured 3 seizures with left-temporal onset and associated asystole. An ovarian teratoma was diagnosed by pelvic ultrasound and computed tomography, and surgical resection was followed by gradual improvement in her neuropsychiatric symptoms. Treatment with phenobarbital beginning on day 26 lead to the cessation of seizures. However, asymptomatic bradycardia and pauses of 3 seconds continued. After insertion of a demand pacemaker on day 46, there were no further cardiac events. The patient was also treated with 2 courses of intravenous immunoglobulin. Outpatient follow-up at 4 months revealed near-complete neurologic recovery and no cardiac events. To our knowledge, ictal asystole has not previously been described as a complication of anti-NMDAR encephalitis; it is a preventable cause of death in this emerging pediatric disorder, which presents with protean symptoms and is easily misdiagnosed.

The diagnosis of postencephalitic parkinsonism at the neurological unit of Boston City Hospital, 1930-1981

The objective of the study is to ascertain the rationale for the diagnosis of postencephalitic parkinsonism (PEP) at Boston City Hospital's Neurological Unit (1930-1981). 5,270 discharge summaries were evaluated for the diagnoses of PEP. Sixteen cases of PEP were identified; the diagnosis of PEP was justified in approximately half of these cases based on the published criteria for distinguishing PEP from Parkinson's disease (PD). In conclusions, the absence of a clear justification for the diagnosis of PEP in many of the 16 cases suggests that the accepted relationship between encephalitis lethargica and PEP may be less definitive than currently believed.

Clinical experience and laboratory investigations in patients with anti-NMDAR encephalitis

Since its discovery in 2007, the encephalitis associated with antibodies against the N-methyl-D-aspartate receptor (NMDAR) has entered the mainstream of neurology and other disciplines. Most patients with anti-NMDAR encephalitis develop a multistage illness that progresses from psychosis, memory deficits, seizures, and language disintegration into a state of unresponsiveness with catatonic features often associated with abnormal movements, and autonomic and breathing instability. The disorder predominantly affects children and young adults, occurs with or without tumour association, and responds to treatment but can relapse. The presence of a tumour (usually an ovarian teratoma) is dependent on age, sex, and ethnicity, being more frequent in women older than 18 years, and slightly more predominant in black women than it is in white women. Patients treated with tumour resection and immunotherapy (corticosteroids, intravenous immunoglobulin, or plasma exchange) respond faster to treatment and less frequently need second-line immunotherapy (cyclophosphamide or rituximab, or both) than do patients without a tumour who receive similar initial immunotherapy. More than 75% of all patients have substantial recovery that occurs in inverse order of symptom development and is associated with a decline of antibody titres. Patients' antibodies cause a titre-dependent, reversible decrease of synaptic NMDAR by a mechanism of crosslinking and internalisation. On the basis of models of pharmacological or genetic disruption of NMDAR, these antibody effects reveal a probable pathogenic relation between the depletion of receptors and the clinical features of anti-NMDAR encephalitis.

Pharmacologic agents for pediatric neuroimmune disorders

Autoimmune diseases make up a significant portion of the acute and chronic caseload of all pediatric neurologists. By comparing these diseases and their treatments side by side, common themes become evident. Therapeutic decisions follow patterns dependent on the clinical situation. Physicians must adapt therapy based on individual clinical responses. This article provides an overview of the current therapeutic options as they relate to the more common pediatric neuroimmune disorders.

Emerging concepts in pediatric-onset multiple sclerosis and related disorders

PURPOSE OF REVIEW

Pediatric-onset multiple sclerosis (MS) is increasingly recognized. Conversely, MS diagnosis in the pediatric population continues to be challenging, particularly in the youngest group of patients. An interesting amount of data has been recently published concerning immunopathogenesis, environmental factors, diagnosis, and treatment of MS in pediatric patients.

RECENT FINDINGS

Recent studies have demonstrated that brain MRI criteria may distinguish MS from acute disseminated encephalomyelitis, and from nondemyelinating disorders in children. The presence of native myelin oligodendrocyte glycoprotein antibodies strongly correlates with a particular pediatric MS phenotype. Vitamin D, Epstein-Barr virus infection, and cigarette smoke are risk factors likely to act at specific stages during life. Diffuse tissue damage was confirmed in normal-appearing white matter at early stages of disease in children with MS, pointing to the need for early treatment interventions. The cognitive involvement of MS in children is progressive.

SUMMARY

Pediatric-onset MS needs a prompt identification and early treatment. Further multinational research studies are still necessary to advance on genetic, immunologic, and imaging features on the initial and ongoing aspects of this disorder in the pediatric population.

Update on anti-N-methyl-D-aspartate receptor encephalitis in children and adolescents

PURPOSE OF REVIEW

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a recently identified disorder that is increasingly recognized in children and adolescents. Prompt diagnosis and treatment are important to obtain full recovery. We review here the main clinical features and differential diagnosis and provide algorithms of the clinical correlates of antibody-mediated decrease of NMDAR and a suggested treatment approach.

RECENT FINDINGS

The sharp increase of patients identified with anti-NMDAR encephalitis reveals a multistage disorder that usually presents with psychiatric manifestations progressing to a decrease of verbal output, catatonia, seizures, dyskinesias, and frequent autonomic instability and hypoventilation. In adults, the disorder often occurs in association with a tumor that expresses NMDAR (usually ovarian teratoma), but in male patients and children the presence of a tumor is rare. Given that patients' antibodies have pathogenic effects on the NMDAR, immunotherapy and tumor resection, when appropriate, are often effective. The outcome is usually good, but the recovery is slow with frequent protracted symptoms of frontal lobe dysfunction.

SUMMARY

Anti-NMDAR encephalitis is a severe but treatable disorder that frequently affects children and adolescents and is likely under-recognized. The syndrome is highly predictable, recognizable on clinical grounds and can be confirmed with the demonstration of NMDAR antibodies.

Anti-NMDA-receptor encephalitis: a severe, multistage, treatable disorder presenting with psychosis

Anti-NMDA-receptor encephalitis is a severe, treatable and potentially reversible disorder presenting with memory deficits, psychiatric symptoms and seizures. Initially described in young patients with ovarian teratoma, the disease is meanwhile increasingly recognized also in women without tumours, in men and in children. The presence of anti-glutamate receptor (type NMDA) autoantibodies in serum or cerebrospinal fluid is specific for this novel and widely underdiagnosed disorder. Early recognition is crucial since prognosis largely depends on adequate immunotherapy and, in paraneoplastic cases, complete tumour removal. Indirect immunofluorescence using NMDA-type glutamate receptors recombinantly expressed in human cells is a highly competent method for diagnosing anti-NMDA-receptor encephalitis.

Expression of various glutamate receptors including N-methyl-D-aspartate receptor (NMDAR) in an ovarian teratoma removed from a young woman with anti-NMDAR encephalitis

A 21-year-old woman developed psychiatric symptoms, progressive unresponsiveness, generalized seizures, severe dyskinesia, marked fluctuation of blood pressure, and hypersalivation after a flu-like episode. Anti-glutamate receptor (GluR)ε2 and anti-N-methyl-D-aspartate receptor (NMDAR) antibodies were positive in both her serum and CSF. After she recovered five months later she underwent surgery to remove a right ovarian teratoma. Immunohistochemical examinations of her teratoma disclosed abundant expression of various GluRs including NR2B subunit of NMDAR, GluR1, and GluR2/3. These immunoreactivities of GluRs were seen not only in small areas of neural tissue identified as anti-glial fibrillary acidic protein (GFAP)-immunoreactive areas but also in other large areas of undifferentiated neuroepithelial tissue without GFAP immunoreactivity. Our findings strongly support the recent idea that neural elements in ovarian teratoma play an important role in the production of antibodies to NMDARs in anti-NMDAR encephalitis. Additionally, the study of control ovaries clearly showed NR2B-related immunoreactivity in the cytoplasm of oocytes, indicating that the normal ovary itself has expression of NMDARs. This finding might provide a clue to understand the pathogenesis of this disease in female patients without ovarian teratoma.