Anti-NMDA receptor encephalitis in Japan: long-term outcome without tumor removal

Autoimmune channelopathies of the nervous system

Ion channels are complex transmembrane proteins that orchestrate the electrical signals necessary for normal function of excitable tissues, including the central nervous system, peripheral nerve, and both skeletal and cardiac muscle. Progress in molecular biology has allowed cloning and expression of genes that encode channel proteins, while comparable advances in biophysics, including patch-clamp electrophysiology and related techniques, have made the functional assessment of expressed proteins at the level of single channel molecules possible. The role of ion channel defects in the pathogenesis of numerous disorders has become increasingly apparent over the last two decades. Neurological channelopathies are frequently genetically determined but may also be acquired through autoimmune mechanisms. All of these autoimmune conditions can arise as paraneoplastic syndromes or independent from malignancies. The pathogenicity of autoantibodies to ion channels has been demonstrated in most of these conditions, and patients may respond well to immunotherapies that reduce the levels of the pathogenic autoantibodies. Autoimmune channelopathies may have a good prognosis, especially if diagnosed and treated early, and if they are non-paraneoplastic. This review focuses on clinical, pathophysiologic and therapeutic aspects of autoimmune ion channel disorders of the nervous system.

Not hysteria: ovarian teratoma-associated anti-N-methyl-D-aspartate receptor encephalitis

We report a case of a 33-year-old nulliparous woman who, following a short prodromal illness, experienced a series of psychiatric and behavioural symptoms. These included states of terror, insomnia, delirium, self-harm and suicidal ideation, facial dyskinesias, verbigeration, cognitive impairment, reduced responsiveness, violence and paranoia. A diagnosis of anti-N-methyl-d-aspartate (NMDAR) encephalitis was made 50 days after symptom onset. Early tumour removal is associated with an improved prognosis and a laparoscopic oophorectomy was performed following detection of a dermoid cyst. Within 24 hours of the operation there was marked improvement in cognitive function and appetite.

Anti-N-methyl-D-aspartate receptor encephalitis presenting with acute psychosis in a preteenage girl: a case report

Introduction

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a rare, newly defined autoimmune clinical entity that presents with atypical clinical manifestations. Most patients with anti-N-methyl-D-aspartate receptor encephalitis develop a progressive illness from psychosis into a state of unresponsiveness, with catatonic features often associated with abnormal movements and autonomic instability. This is the first report of anti-N-methyl-D-aspartate receptor encephalitis in a Greek pediatric hospital.

Case presentation

An 11-year-old Greek girl presented with clinical manifestations of acute psychosis. The differential diagnosis included viral encephalitis. The presence of a tumor usually an ovarian teratoma, a common clinical finding in many patients, was excluded. Early diagnosis and prompt immunotherapy resulted in full recovery up to one year after the initial diagnosis.

Conclusion

Acute psychosis is a rare psychiatric presentation in children, diagnosed only after possible organic syndromes that mimic acute psychosis are excluded, including anti-N-methyl-D-aspartate receptor receptor encephalitis. Pediatricians, neurologists and psychiatrists should consider this rare clinical syndrome, in order to make an early diagnosis and instigate appropriate treatment to maximize neurological recovery.

Fluorodeoxyglucose positron emission tomography in anti-N-methyl-D-aspartate receptor encephalitis: distinct pattern of disease

BACKGROUND

Patients with encephalitis associated with antibodies against N-methyl-D-aspartate-receptor antibody (NMDAR-ab) encephalitis frequently show psychotic symptoms, amnesia, seizures and movement disorders. While brain MRI in NMDAR-ab encephalitis is often normal, abnormalities of cerebral glucose metabolism have been demonstrated by positron emission tomography (PET) with 18F-fluorodeoxyglucose(FDG) in a few usually isolated case reports. However, a common pattern of FDG-PET abnormalities has not been reported.

METHODS

The authors retrospectively identified six patients with NMDAR-ab encephalitis in two large German centres who underwent at least one whole-body FDG-PET for tumour screening between January 2007 and July 2010. They analysed the pattern of cerebral uptake derived from whole-body PET data for characteristic changes of glucose metabolism compared with controls, and the changes of this pattern during the course of the disease.

RESULTS

Groupwise analysis revealed that patients with NMDAR-ab encephalitis showed relative frontal and temporal glucose hypermetabolism associated with occipital hypometabolism. Cross-sectional analysis of the group demonstrated that the extent of these changes is positively associated with clinical disease severity. Longitudinal analysis of two cases showed normalisation of the pattern of cerebral glucose metabolism with recovery.

CONCLUSIONS

A characteristic change in cerebral glucose metabolism during NMDAR-ab encephalitis is an increased frontotemporal-to-occipital gradient. This pattern correlates with disease severity. Similar changes have been observed in psychosis induced by NMDAR antagonists. Thus, this pattern might be a consequence of impaired NMDAR function.

Anti-NMDA-receptor encephalitis presenting as postpartum psychosis in a young woman, treated with rituximab

A severe paraneoplastic form of acute encephalitis associated with antibodies against the N-methyl D-aspartate (NMDA) receptor typically occurs in young individuals and is associated, but not always, with an underlying tumor. If diagnosed early, initiation of immunotherapy and tumor removal (if present) may result in recovery. We report a case in a 25-year-old young woman who presented to our medical center with postpartum psychosis. Treatment with rituximab (a chimeric monoclonal antibody against the protein CD20) resulted in gradual improvement in mental status and resolution of seizure activity episodes. A year after diagnosis and treatment, the patient was doing well without recurrences, and no tumors appeared. This is the first described case of anti-NMDA-receptor antibodies encephalitis that presented initially as a postpartum psychosis disorder and was successfully treated with rituximab.

Neuronal autoantigens--pathogenesis, associated disorders and antibody testing

The discovery of disorders that are associated with antibodies to neuronal cell-surface proteins has led to a paradigm shift in our understanding of CNS autoimmunity. These disorders can occur in patients with or without cancer-often children or young adults who develop psychosis, catatonic or autistic features, memory problems, abnormal movements, or seizures that were previously considered idiopathic. The autoantigens in such cases have crucial roles in synaptic transmission, plasticity and peripheral nerve excitability. Patients can be comatose or encephalopathic for months and yet fully recover with supportive care and immunotherapy. By contrast, disorders in which the antibodies target intracellular antigens, and in which T-cell-mediated irreversible neuronal degeneration occurs, show a considerably poorer response to treatment. In this article, we review the various targets of neuronal antibodies, focusing predominantly on autoantigens located on the cell surface or synapses-namely, N-methyl-D-aspartate receptors, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, γ-aminobutyric acid receptors, leucine-rich glioma-inactivated protein 1, contactin-associated protein-like 2, and metabotropic glutamate receptors. We also provide an algorithm to identify and assess antibodies that bind to cell-surface and synaptic antigens.

Anti-NMDA-receptor antibody detected in encephalitis, schizophrenia, and narcolepsy with psychotic features

BACKGROUND

Causative role of encephalitis in major psychotic features, dyskinesias (particularly orofacial), seizures, and autonomic and respiratory changes has been recently emphasized. These symptoms often occur in young females with ovarian teratomas and are frequently associated with serum and CSF autoantibodies to the NMDA receptor (NMDAR).

METHODS

The study included a total of 61 patients from age 15 to 61 and was carried out between January 1, 2005, and Dec 31, 2010. The patients were divided into the following three clinical groups for comparison. Group A; Patients with typical clinical characteristics of anti-NMDAR encephalitis. Group B; Patients with narcolepsy with severe psychosis. Group C; Patients with schizophrenia or schizo-affective disorders.

RESULTS

Ten out of 61 cases were anti-NMDAR antibody positive in typical encephalitis cases (group A: 3 of 5 cases) and cases in a broader range of psychiatric disorders including narcolepsy (group B: 3 of 5 cases) and schizophrenia (group C: 4 of 51 cases).

CONCLUSION

In addition to 3 typical cases, we found 7 cases with anti-NMDAR antibody associated with various psychotic and sleep symptoms, which lack any noticeable clinical signs of encephalitis (seizures and autonomic symptoms) throughout the course of the disease episodes; this result suggest that further discussion on the nosology and pathophysiology of autoimmune-mediated atypical psychosis and sleep disorders is required.

Epileptic encephalitis: the role of the innate and adaptive immune system

Seizures are a prominent clinical feature of encephalitis. Recent data suggest the adaptive as well as innate immune system to be involved directly in the pathomechanism of epileptogenesis. Cytotoxic T-cells and antibody-mediated complement activation are major components of the adaptive immune system, which can induce neurodegeneration, thereby probably contributing to epileptic encephalitis. The innate immune system operates via interleukin-1 and toll-like receptor-associated mechanisms and was shown to play a direct role in epileptogenesis. Here, we review neuropathology hallmarks of various encephalitis conditions such as Rasmussen encephalitis (RE) but also introduce the more recently discovered antibody-associated voltage-gated potassium channel complex (VGKC), N-methyl-D-aspartate receptor (NMDAR) or glutamic acid decarboxylase (GAD) 65 encephalitides. Neuropathological investigations are used to determine specific cellular components and molecular mechanisms used by the immune system to provoke neurodegeneration and to promote epileptogenesis. Based on recent findings, we propose concepts for the stratification of epileptic encephalitis. Knowledge of the role of the innate immunity has already translated into clinical treatment strategies and may help to discover novel drug targets for these epileptic disorders.

Anti-N-methyl-D-aspartate receptor encephalitis: an emerging cause of centrally mediated sinus node dysfunction

AIMS

Anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) is a recently recognized form of autoimmune encephalitis that typically affects young women, often as a paraneoplastic syndrome related to ovarian teratoma. Clinical features include psychiatric and neurological disturbances, central hypoventilation, autonomic instability, and cardiac dysrhythmias. The prevalence, nature, and outcomes of cardiac dysrhythmias in patients with NMDARE have not been well described.

METHODS AND RESULTS

Records of 10 consecutive patients with NMDARE were reviewed to obtain clinical, laboratory, echocardiographic, electrocardiographic, and radiological data. Patients were all female with an average age of 23 ± 5.5 years. Echocardiograms revealed structurally normal hearts with the exception of mild left ventricular hypertrophy in two cases. Eight patients had inappropriate sinus tachycardia. Six patients developed significant sinus bradycardia, which included periods of sinus arrest in four cases. Five patients manifested both sinus bradycardia and tachycardia. Bradycardia was often triggered by identifiable vagal stimuli. Temporary pacing was instituted in three patients, but permanent pacing was not required in any of the patients. Magnetic resonance imaging (MRI) scans revealed mesial temporal abnormalities in nine patients. In all cases, the dysrhythmias resolved with treatment of the underlying immune disorder with immunotherapy and/or teratoma resection. There was no evidence of dysrhythmia recurrence in any patient at follow-up.

CONCLUSION

Anti-N-methyl-D-aspartate receptor encephalitis is a recently recognized cause of autoimmune encephalitis with a predilection to cause severe sinus node abnormalities. Temporary pacing is occasionally required, but permanent pacing appears to be unnecessary. An analysis of the clinical syndrome coupled with MRI and experimental data may offer insight into central mechanisms of heart rate regulation.

Anti-N-methyl D-aspartate receptor encephalitis mimics viral encephalitis

We describe the clinical courses of 3 children with a psychochoreiform encephalitis associated with anti-N-methyl D-aspartate receptor autoantibodies. These cases, including the most severely medically complicated survivor to date, illustrate the challenges of diagnosis, supportive care, and immune-modulating therapy. Clinical and laboratory features are similar to those of viral encephalitis, and the condition is often reversible with appropriate diagnosis and treatment.

'Benign' ovarian teratoma and N-methyl-D-aspartate receptor (NMDAR) encephalitis in a child

N-methyl-D-aspartate receptor (NMDAR) encephalitis is a life-threatening paraneoplastic neuropsychiatric encephalitis that predominantly affects young women and has a strong association with ovarian teratomas. Removal of the ovarian teratomas improves the prognosis and decreases the risk of recurrence. We present an 11-year-old girl with NMDAR encephalitis with small bilateral teratomas not initially appreciated on abdominal CT or pelvic MRI. A 12-mm teratoma was identified in the right ovary and a 7-mm teratoma was identified in the left ovary on US follow-up at 5 months. Intraoperative sonography was used to localize the teratomas for excision. In NMDAR encephalitis, the ovarian teratomas can be very small, particularly in children, and easily missed on cross-sectional imaging. Awareness of the association of NMDAR encephalitis and ovarian teratomas will improve the diagnostic accuracy and imaging interpretation. Periodic sonography and MRI might be warranted in children if the initial study is negative.

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.

Anti-N-methyl-d-aspartate receptor encephalitis

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a treatment-responsive encephalitis associated with anti-NMDA receptor antibodies, which bind to the NR1/NR2 heteromers of the NMDA receptors. It is a highly characteristic syndrome evolving in five stages: the prodromal phase (viral infection-like symptoms), psychotic phase, unresponsive phase, hyperkinetic phase, and gradual recovery phase. It has been considered as a paraneoplastic syndrome usually affecting childbearing-age female with ovarian tumors; however, recent reports suggest a much higher incidence of nonparaneoplastic cases in children. We report a 14-year-old girl with anti-NMDA receptor encephalitis without a detectable tumor who showed a nearly complete recovery after intensive immunotherapy.

Anti-NMDA receptor encephalitis: an important differential diagnosis in psychosis

We present four cases of confirmed anti-NMDA receptor encephalitis; three presented initially with serious psychiatric symptoms and the other developed significant psychiatric symptoms during the initial phase of illness. Brain biopsy findings of one patient are also described. Psychiatrists should consider anti-NMDA receptor encephalitis in patients presenting with psychosis and additional features of dyskinesias, seizures and catatonia, particularly where there is no previous history of psychiatric disorder.

Autoimmune encephalitis: a case series and comprehensive review of the literature

Encephalitic syndromes are a common medical emergency. The importance of early diagnosis and appropriate treatment is paramount. If initial investigations for infectious agents prove negative, other diagnoses must be considered promptly. Autoimmune encephalitides are being increasingly recognized as important (and potentially reversible) non-infectious causes of an encephalitic syndrome. We describe four patients with autoimmune encephalitis--3 auto-antibody positive, 1 auto-antibody negative--treated during the last 18 months. A comprehensive review of the literature in this expanding area will be of interest to the infectious diseases, general medical and neurology community.

Anti-NMDA receptor encephalitis associated with ictal asystole

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis usually presents with psychiatric symptoms, behavioural changes, impaired consciousness, seizures and autonomic instability. Ictal asystole is a rare phenomenon associated with complex partial seizures. It is implicated as a potential cause of sudden unexpected death in epilepsy. We report a 41-year-old woman who presented with anti-NMDAR encephalitis. During continuous video electroencephalogram and cardiac monitoring, an episode of ictal asystole was detected. We discuss the potential link between anti-NMDAR encephalitis and ictal asystole. Treatment options for ictal asystole in the setting of anti-NMDAR encephalitis are also discussed.

Anti-N-methyl-D-aspartate receptor encephalitis complicating ovarian teratomas: a case report

Anti-N-methyl-D-aspartate receptor encephalitis is an emerging disease that affects young women. Its diagnosis can be delayed because of the neuropsychiatric symptoms in the foreground, but early removal of the associated teratoma improves the prognosis. We report the treatment of a patient with anti-N-methyl-D-aspartate receptor encephalitis that was related to an ovarian teratoma.

Novel FDG-PET findings in anti-NMDA receptor encephalitis: a case based report

The clinical manifestation and nuclear imaging findings in a 15-year-old boy with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis are described in this case report. The previously healthy patient presented with new onset hallucinations, seizure, and within a week, his mental status rapidly deteriorated to nonverbal with oro-lingual-facial dyskinesias. An extensive laboratory work-up for encephalopathy was negative. Repeated brain magnetic resonance imaging (MRI) studies were normal. On day 26 of admission, nuclear imaging using fluorodeoxyglucose positron emission tomography (FDG-PET) showed global hypometobolism with a prominent focally intense hypermetabolic lesion in the right cerebellar cortex. Diagnosis of anti-NMDAR encephalitis was confirmed with quantitative serology. The patient showed clinical signs of improvement after 2 courses of intravenous immunoglobulin therapy over 4 weeks. On day 46, repeat brain FDG-PET showed overall improvement but in contrast to the previous, the right cerebellar cortex showed focal hypometabolism. This is the first reported case of such findings using FDG-PET in anti-NMDAR encephalitis.

Paraneoplastic encephalomyelopathies: pathology and mechanisms

The last three decades have seen major advances in the understanding of paraneoplastic and idiopathic autoimmune disorders affecting the central nervous system (CNS). Neural-specific autoantibodies and their target antigens have been discovered, immunopathology and neuroimaging patterns recognized and pathogenic mechanisms elucidated. Disorders accompanied by autoantibody markers of neural peptide-specific cytotoxic effector T cells [such as anti-neuronal nuclear antibody type 1 (ANNA-1, aka anti-Hu), Purkinje cell antibody type 1 (PCA-1, aka anti-Yo) and CRMP-5 IgG] are generally poorly responsive to immunotherapy. Disorders accompanied by neural plasma membrane-reactive autoantibodies [the effectors of synaptic disorders, which include antibodies targeting voltage-gated potassium channel (VGKC) complex proteins, NMDA and GABA-B receptors] generally respond well to early immunotherapy. Here we describe in detail the neuropathological findings and pathophysiology of paraneoplastic CNS disorders with reference to antigen-specific serology and neurological and oncological contexts.

Encephalitis and antibodies to synaptic and neuronal cell surface proteins

The identification of encephalitis associated with antibodies against cell surface and synaptic proteins, although recent, has already had a substantial impact in clinical neurology and neuroscience. The target antigens are receptors and proteins that have critical roles in synaptic transmission and plasticity, including the NMDA receptor, the AMPA receptor, the GABA(B) receptor, and the glycine receptor. Other autoantigens, such as leucine-rich glioma-inactivated 1 and contactin-associated protein-like 2, form part of trans-synaptic complexes and neuronal cell adhesion molecules involved in fine-tuning synaptic transmission and nerve excitability. Syndromes resulting from these immune responses resemble those of pharmacologic or genetic models in which the antigens are disrupted. For some immune responses, there is evidence that the antibodies alter the structure and function of the antigen, suggesting a direct pathogenic effect. These disorders are important because they can affect children and young adults, are severe and protracted, occur with or without tumor association, and respond to treatment but may relapse. This review provides an update on these syndromes and autoantigens with special emphasis on clinical diagnosis and treatment.

[Dramatic improvement in two cases of anti-NMDA receptor encephalitis after immunomodulating therapy]

We report two patients with encephalitis associated with antibodies against NR1-NR2 heteromers of the NMDA receptor that showed dramatic improvement after immunomodulating therapies. A 38-year old woman (case 1) suddenly developed seizures and short term memory loss. Brain MRI appeared almost normal except for a small number of high intensity spots of white matter on T(2) weighted images. Cerebrospinal fluid examination (CFS) disclosed lymphocytic pleocytosis (61/µl) and Qualitative analysis of NR1-NR2 antibodies in both CFS and serum were positive. Although an initial treatment with high-dose methylprednisolone was not beneficial for clinical improvement, intravenous immunoglobulin (IVIg) therapy led to complete recovery from her neurological problems. Repeated general surveys showed no evidence of tumors including ovarian teratoma. A 71-year old man (case 2) suddenly developed seizures and short-term memory loss three days after receiving an influenza vaccination. Brain MRI appeared normal. CSF analysis revealed no pleocytosis and a slight elevation of protein value accompanying oligoclonal IgG band. Qualitative analysis of NR1-NR2 antibodies in both CFS and serum were positive. Intravenous high-dose methylprednisolone caused dramatic improvement and his neurological problems immediately disappeared. Repeated general surveys showed no evidence of tumors, as in case 1. These two cases showed relatively benign clinical courses with no evidence of tumors and were quite different from the well-known encephalitis associated with antibodies against NR1-NR2 heteromers of the NMDA receptor. Our clinical experience in these two cases suggests that the disease spectrum of anti-NMDA-receptor associated encephalitis might be broader than was once considered.

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.

Anti-NMDA Receptor Encephalitis in Psychiatry

Anti-NMDA receptor encephalitis is an autoimmune disorder in which antibodies attack NMDA (N-methyl-D-aspartate)-type glutamate receptors at central neuronal synapses. Symptoms include a highly characteristic set of neurologic deficits, but also prominent psychiatric manifestations that often bring mental health professionals into the course of care. Distinct phases of illness have become increasingly appreciated, and include a range of psychotic symptoms early in the course of the disease followed by more severe fluctuations in consciousness with neurologic involvement, and ultimately protracted cognitive and behavioral deficits. Young women are most commonly impacted and an ovarian teratoma is sometimes associated with the syndrome. Patients respond well to immunotherapy, but psychiatric symptoms can be challenging to manage. We provide an up to date review of this disorder and highlight the role of psychiatry in diagnosis, symptomatology, and treatment.

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-N-methyl-D-aspartate receptor encephalitis: a newly recognized inflammatory brain disease in children

OBJECTIVE

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a newly recognized antineuronal antibody-mediated inflammatory brain disease that causes severe psychiatric and neurologic deficits in previously healthy children. The present study was undertaken to describe characteristic clinical features and outcomes in children diagnosed as having anti-NMDAR encephalitis.

METHODS

Consecutive children presenting over a 12-month period with newly acquired psychiatric and/or neurologic deficits consistent with anti-NMDAR encephalitis and evidence of central nervous system (CNS) inflammation were screened. Children were included in the study if they had confirmatory evidence of anti-NMDAR antibodies in the serum and/or cerebrospinal fluid. Features at clinical presentation and results of investigations were recorded. Type and duration of treatment and outcomes at last followup were documented.

RESULTS

Seven children were screened, and 3 children with anti-NMDAR encephalitis were identified. All patients presented with neurologic and/or psychiatric abnormalities, seizures, speech disorder, sleep disturbance, and fluctuating level of consciousness. The 2 older patients had more prominent psychiatric features, while the younger child had significant autonomic instability and prominent involuntary movement disorder. None had an underlying tumor. Immunosuppressive therapy resulted in near or complete recovery; however, 2 of the patients had early relapse necessitating re-treatment.

CONCLUSION

Anti-NMDAR encephalitis is an important cause of neuropsychiatric deficits in children, which must be included in the differential diagnosis of CNS vasculitis and other inflammatory brain diseases. Early diagnosis and treatment are essential for neurologic recovery.

NMDA receptor encephalitis--expanding the clinical spectrum

A young woman presented with memory problems of subacute onset. Imaging was normal. She was admitted with severe complex partial status epilepticus requiring intensive care support and ventilation. Fits proved difficult to control requiring high dose anticonvulsants. She developed a profound amnesic syndrome. A clinical diagnosis of autoimmune encephalitis was considered and she was treated with intravenous steroids with an excellent cognitive outcome. She continues to have occasional seizures.

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.

[A case of anti-N-methyl-D-aspartate receptor encephalitis with ovarian teratoma showing excellent recovery with decreasing of anti-N-methyl-D-aspartate receptor antibody]

We report a case of a 17-year-old woman with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, who developed psychiatric symptoms. Pelvic MRI revealed a right ovarian tumor that was suspected of being an ovarian teratoma. On the 27th day after onset, the patient underwent right salpingo-oophorectomy. The histopathological diagnosis was immature ovarian teratoma. Subsequently, 4 double filtration plasmapheresises (DFPP) were performed from day 34 to day 43. Methylprednisolone (1,000 mg/day for 3 days) was started on day 38. With these treatments, consciousness disturbance completely improved, and the patient was discharged on day 50. The serum and cerebrospinal fluid were positive for antibodies against the GluRzeta1 (NR1)-EGFP/GluRepsilon2 (NR2B) heteromer and the GluRzeta1 (NR1) subunit of NMDAR. The patient was hence diagnosed as having anti-NMDAR encephalitis with ovarian teratoma Serial analysis show that the antibodies against NMDAR decreased with improvement of symptoms after the immunotherapy including DFPP treatment.

Anti-NMDA-receptor encephalitis: case report and literature review of an under-recognized condition

Anti-N-methyl-D-aspartate receptor (anti-NMDA-R) encephalitis is an immune-mediated syndrome that remains under-recognized despite a growing body of literature. This syndrome has been predominantly described in young females with a constellation of symptoms, including personality changes, autonomic dysfunction and neurologic decompensation. It is commonly associated with mature ovarian teratomas. We describe the classic presentation of anti-NMDA-R encephalitis in three dramatically different patients: Case A, a young woman with ovarian teratoma; Case B, the eldest case reported to date; and Case C, a young male with no identifiable tumor. We review the literature summarizing the differential diagnosis, investigative approach, treatment options and challenges inherent to this disorder. We advocate good supportive care, involvement of multiple health disciplines and use of immune-modulating therapies in patient management. These cases underscore the need for increased awareness and high diagnostic suspicion when approaching the patient with suspected viral encephalitis.

Behavior outbursts, orofacial dyskinesias, and CSF pleocytosis in a healthy child

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis represents a new category of immune-mediated neurologic disorders. Viral encephalitis is often the presumptive diagnosis because of the acute neurologic changes, cerebrospinal fluid lymphocytic pleocytosis, and occasional hyperthermia. We report here the case of a previously healthy 7-year-old boy with new-onset aggressive behavior, seizure activity, and orofacial dyskinesias with cerebrospinal fluid and serum that tested positive for anti-NMDA receptors.

Paraneoplastic syndromes causing movement disorders

Paraneoplastic neurological disorders are an extensive group of neurological syndromes that occur in patients with cancer and often present before the presence of an underlying tumor is known. Many of these disorders appear to be immune-mediated, with targets throughout the nervous system, including basal ganglia and brainstem, in which case they may result in movement disorders. Recent descriptions of new immune-mediated encephalitides in children and adults have substantially increased the number of patients with paraneoplastic movement disorders. There are several key concepts that assist in the identification of a movement disorder as likely paraneoplastic, including a rapid onset, the presence of cerebrospinal fluid inflammatory changes, and in some patients the identification of specific serum and cerebrospinal fluid antineuronal antibodies. Once identified, prompt diagnosis and treatment of the tumor can result in neurological symptom improvement or stabilization, although some patients may require immunotherapy only. Understanding the natural course of each immune-mediated paraneoplastic movement disorder minimizes unnecessary testing and the use of potentially toxic therapies.

[Encephalitis associated with positive anti-GluR antibodies showing abnormal appearance in basal ganglia, pulvinar and gray matter on MRI--case report]

We treated a 25-year-old woman with encephalitis. Following delivery, the patient developed fever, consciousness disturbance, cognitive dysfunction, and progressive motor dysfunction. In addition, mycobacterium tuberculosis was found in the lung, though there was no evidence of such infection in the central nervous system. Cerebrospinal fluid analysis revealed a slight elevation of mononuclear cells with a normal protein level indicating a possible viral infection. We could not find the origin of the infection, though the serum anti-glutamate epsilon2 receptor antibody was positive. Intravenous administration of methylprednisolone (1000 mg/day for 3 days) was temporarily effective for improvement of the clinical signs and symptoms. However, she finally demonstrated rapid deterioration resulting in death. Diffusion-weighted brain magnetic resonance imaging demonstrated abnormal high intensity lesions in the bilateral pulvinar and gray matter, with an abnormal appearance mimicking pulvinar sign.

Anaesthesia for a patient with paraneoplastic limbic encephalitis with ovarian teratoma: relationship to anti-N-methyl-D-aspartate receptor antibodies

Paraneoplastic limbic encephalitis associated with ovarian teratoma has recently been related to the development of antibodies to specific heteromers of the N-methyl-d-aspartate receptor and exhibits various manifestations including psychiatric symptoms, hypoventilation, seizures and derangement of autonomic nervous system function. Although recovery can sometimes occur spontaneously, early tumour resection with immunotherapy facilitates earlier recovery. Herein, we describe anaesthetic management of a 20-year-old woman who developed general convulsions and decreased level of consciousness, whom we suspected of having paraneoplastic limbic encephalitis and was scheduled for left ovarian tumour resection. Anaesthetic management was successful with no complications but the case acts as focus of discussion for the potential interaction of N-methyl-D-aspartate receptors and anaesthetic sensitivity.

Autoimmune limbic encephalitis as an emerging pediatric condition: case report and review of the literature

Limbic encephalitis, first described in the 1960s as a paraneoplastic condition, has emerged as an autoimmune condition, occurring often without evidence of an underlying tumor. Many novel autoantibodies have been identified, and this diagnosis is increasingly being made in the pediatric population. This article reports the case of a 16-year-old boy who presented following gastrointestinal illness with subacute evolution of neuropsychiatric symptoms. Brain magnetic resonance imaging revealed progressive hippocampal signal abnormality and swelling. N-methyl-D-aspartate (NMDA) receptor antibody was detected in serum. The patient responded well to pharmacological immunotherapy but has residual cognitive deficits. The available literature on this condition is reviewed. Limbic encephalitis should be considered in the differential diagnosis in children presenting with encephalopathy, particularly with neuropsychiatric manifestations. Long-term surveillance and close follow-up are required to accurately clarify tumor risk and natural history of this condition in children and balance these factors with risks of radiation exposure through imaging.

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.

A Young Man with Anti-NMDAR Encephalitis following Guillain-Barré Syndrome

A 19-year-old man developed rapidly progressive muscle weakness and dysesthesia in the extremities, and dyspnea after a flu-like episode. Nerve conduction studies showed reduced motor nerve conduction velocities with conduction block, and sensory nerve action potentials could not be evoked. The patient was diagnosed as having Guillain-Barré syndrome (GBS), and was treated with 2 cycles of intravenous immunoglobulin (IVIg) therapy and was assisted by mechanical ventilation. During the recovery course of the illness, he experienced several attacks of psychomotor agitation from the 37th hospital day, and generalized tonic convulsive seizures suddenly developed on the 42nd hospital day. Brain MRI showed high-intensity lesions in the bilateral thalamus and medial temporal lobes. The convulsions were controlled by continuous thiopental infusion (until the 50th hospital day) and mechanical ventilation (until the 84th hospital day). Intravenous methylprednisolone pulse therapy (1,000 mg/day) for 3 days followed by dexamethasone (16 mg/day) was added. After relief of convulsive seizures, prominent orolingual dyskinesia appeared, and on MRI marked atrophy of the bilateral medial temporal lobes was seen. Anti-N-methyl-D-aspartate receptor (NMDAR) antibodies in serum and cerebrospinal fluid were positive on the 92nd hospital day. Anti-NMDAR encephalitis usually affects young females but a small number of male cases with this disease have been reported. Our male patient was unique in having GBS, a post-infectious autoimmune disease, as a preceding disease, suggesting that anti-NMDAR encephalitis itself is caused by a parainfectious autoimmune mechanism.

Pseudo-piano playing motions and nocturnal hypoventilation in anti-NMDA receptor encephalitis: response to prompt tumor removal and immunotherapy

Tumor resection is recommended in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, however it is often difficult during an early stage of the disease. We report here the efficacy of early tumor removal in a patient with anti-NMDAR encephalitis. This 21-year-old woman was admitted to another hospital with rapidly progressive psychiatric symptoms, a decreased level of consciousness, and seizures. Abdominal CT showed a pelvic mass. On day 1 of admission to our center, she developed hypoventilation requiring mechanical support. She had orofacial dyskinesias with well-coordinated, pseudo-piano playing involuntary finger movements. Based on these clinical features, she was immediately scheduled for tumor resection on day 3. While awaiting surgery, she began to receive high-dose intravenous methylprednisolone. After tumor removal, she received plasma exchange, followed by intravenous immunoglobulin and additional high-dose methylprednisolone. Two weeks after tumor removal, she started following simple commands and progressive improvement, although she remained on mechanical ventilation for 10 weeks due to nocturnal central hypoventilation. Anti-NMDAR antibodies in serum/CSF were detected. Pathological examination showed immature teratoma with foci of infiltrates of B- and T-cells. Early tumor resection with immunotherapy facilitates recovery from this disease, but central hypoventilation may require long mechanical support. Non-jerky elaborate finger movements suggest antibody-mediated disinhibition of the cortico-striatal systems.

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.