A case of NMDAR Encephalitis with muscular pain as the main presentation.

BACKGROUND: Persistent somatoform pain disorder (PSPD) is often the initial diagnosis in patients seeking treatment in psychiatric departments, making it challenging to consider organic nervous system diseases. However, autoimmune encephalitis can present with atypical initial symptoms, leading to misdiagnosis or missed diagnosis. Lumbar puncture, with antibody support, plays a crucial role in diagnosing autoimmune encephalitis. CASE PRESENTATION: This report describes a 40-year-old male adult patient who was initially diagnosed with persistent somatoform pain disorder in 2022. The patient reported a reduction in pain while resting on his back. There were no fever or relevant medical history. Despite 8 months of symptomatic treatment, the symptoms did not improve. Moreover, the patient developed confusion, gibberish speech, non-cooperation during questioning, and increased frequency and amplitude of upper limb convulsions. Lumbar puncture revealed elevated protein levels and protein-cell dissociation. The autoimmune encephalitis antibody NMDAR (+) was detected, leading to a diagnosis of autoimmune encephalitis (NMDAR). CONCLUSION: Autoimmune encephalitis (NMDAR), starting with persistent somatoform pain (PSPD), often presents with atypical symptoms and can be easily misdiagnosed. Therefore, it is important to consider the possibility of organic nervous system disease in time, and to test serum or cerebrospinal fluid antibodies to rule out organic nervous system disease after symptomatic treatment of mental disorders is ineffective. This approach facilitates the early diagnosis of autoimmune encephalitis and other underlying organic neurological disorders.

Very Long-Term Functional Outcomes and Dependency in Children With Anti-NMDA Receptor Encephalitis.

OBJECTIVES: To assess the daily function of children with anti-N-methyl-d-aspartate receptor encephalitis (NMDARe) after a minimal follow-up of 5 years. METHODS: Patients 18 years and younger by the time of disease onset, whose serum and CSF were studied in our center between 2013 and 2017, were included in the study. Patients' daily life function was assessed by their physicians using a 15-domain question format (Liverpool Outcome Score). RESULTS: Of 76 patients, 8 (11%) died and 68 were followed for a mean of 7.1 years (SD 1.5 years, range: 5.0-10.1). Three outcome patterns were identified: full recovery (50; 73%); behavioral and school/working deficits (12; 18%); and multidomain deficits (6; 9%) involving self-care ability, behavioral-cognitive impairment, and seizures. Younger age of disease onset was significantly associated with multidomain deficits (OR 1.6, 95% CI 1.02-2.4, p = 0.04), particularly in children younger than 6 years, among whom 8 of 23 (35%) remained sociofamiliar dependent. DISCUSSION: After a minimal follow-up of 5 years, most children with NMDARe had substantial or full functional recovery, but approximately one-fifth remained with behavioral and school/working deficits. The younger the patient at disease onset, the more probable it was to remain with multidomain deficits and dependent on sociofamiliar support.

Movement disorders associated with pediatric encephalitis.

New onset movement disorders are a common clinical problem in pediatric neurology and can be infectious, inflammatory, metabolic, or functional in origin. Encephalitis is one of the more important causes of new onset movement disorders, and movement disorders are a common feature (~25%) of all encephalitis. However, all encephalitides are not the same, and movement disorders are a key diagnostic feature that can help the clinician identify the etiology of the encephalitis, and therefore appropriate treatment is required. Movement disorders are a characteristic feature of autoimmune encephalitis such as anti-NMDAR encephalitis, herpes simplex virus encephalitis-induced autoimmune encephalitis, and basal ganglia encephalitis. Other rarer autoantibody-associated encephalitis syndromes with movement disorder associations include encephalitis associated with glycine receptor, DPPX, and neurexin-3 alpha autoantibodies. In addition, movement disorders can accompany acute disseminated encephalomyelitis with and without myelin oligodendrocyte glycoprotein antibodies. Extremely important infectious encephalitides that have characteristic movement disorder associations include Japanese encephalitis, dengue fever, West Nile virus, subacute sclerosing panencephalitis (SSPE), and SARS-CoV-2 (COVID-19). This chapter discusses how specific movement disorder phenomenology can aid clinician diagnostic suspicion, such as stereotypy, perseveration, and catatonia in anti-NMDAR encephalitis, dystonia-Parkinsonism in basal ganglia encephalitis, and myoclonus in SSPE. In addition, the chapter discusses how the age of the patients can influence the movement disorder phenomenology, such as in anti-NMDAR encephalitis where chorea is typical in young children, even though catatonia and akinesia is more common in adolescents and adults.

Case report: Rapid recovery after intrathecal rituximab administration in refractory anti-NMDA receptor encephalitis: report of two cases.

Background: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is one of the most prevalent etiologies of autoimmune encephalitis. Approximately 25% of anti-NMDAR encephalitis cases prove refractory to both first- and second-line treatments, posing a therapeutic dilemma due to the scarcity of evidence-based data for informed decision-making. Intravenous rituximab is commonly administered as a second-line agent; however, the efficacy of its intrathecal administration has rarely been reported. Case summary: We report two cases of severe anti-NMDAR encephalitis refractory to conventional therapies. These patients presented with acute-onset psychosis progressing to a fulminant picture of encephalitis manifesting with seizures, dyskinesia, and dysautonomia refractory to early initiation of first- and second-line therapeutic agents. Both patients received 25 mg of rituximab administered intrathecally, repeated weekly for a total of four doses, with no reported adverse effects. Improvement began 2-3 days after the first intrathecal administration, leading to a dramatic recovery in clinical status and functional performance. At the last follow-up of 6 months, both patients remain in remission without the need for maintenance immunosuppression. Conclusion: Our cases provide evidence supporting the intrathecal administration of rituximab as a therapeutic option for patients with refractory anti-NMDAR encephalitis. Considering the limited penetration of intravenous rituximab into the central nervous system, a plausible argument can be made favoring intrathecal administration as the preferred route or the simultaneous administration of intravenous and intrathecal rituximab. This proposition warrants thorough investigation in subsequent clinical trials.

Possible temporal relationship between SARS-CoV-2 infection and anti-NMDA receptor encephalitis: a meta-analysis.

The global impact of SARS-CoV-2 infection has raised concerns about secondary diseases beyond acute illness. This review explores the significance and potential underlying mechanisms of how SARS-CoV-2 infection might elicit an immune response targeting N-methyl-D-aspartate (NMDA) receptors, and its implications for autoimmune-driven neuropsychiatric manifestations. We identified 19 published case reports of NMDA receptor encephalitis associated with SARS-CoV-2 infection or vaccination by a systematic literature search. The significance of these reports was limited since it is not clear if a coincidental or causal relationship exists between SARS-CoV-2 infection or vaccination and manifestation of NMDA receptor encephalitis. The included studies were hampered by difficulties in establishing if these patients had pre-existing NMDA receptor antibodies which entered the brain by infection- or vaccination-associated transient blood-brain barrier leakage. In addition, four cases had comorbid ovarian teratoma, which is a known trigger for development of NMDA receptor encephalitis. Considering that billions of people have contracted COVID-19 or have been vaccinated against this virus, the publication of only 19 case reports with a possible link to NMDA receptor encephalitis, indicates that it is rare. In conclusion, these findings do not support the case that SARS-CoV-2 infection or vaccination led to an increase of existing or de novo encephalitis mediated by an autoimmune response targeting NMDA receptor function. Nevertheless, this work underscores the importance of ongoing vigilance in monitoring viral outbreaks and their potential impact on the central nervous system through basic, epidemiological and translational research.

[Paraneoplastic Anti-N-methyl-D-aspartate Receptor Encephalitis Associated with Anterior Mediastinal Mature Teratoma].

We report a 27 years-old previously healthy male admitted to a psychiatric hospital because of abnormal behavior. He was suspected meningoencephalitis with fever, abnormal sweating, muscle tone, confusion, and introduced to the neurology department of our hospital. After admission, increasing convulsions and apnea attack required mechanical ventilation therapy. Anti-N-methyl-D-aspartate( NMDA) - receptor encephalitis was diagnosed based on positive (20-fold) anti-NMDA antibody in cerebrospinal fluid examination. An enhanced chest computed tomography (CT) showed a 43 mm cystic mass with calcification of the anterior mediastinum. He underwent the tumor resection under median sternotomy on the 18th hospital day. The plasmapheresis and steroid therapies were treated after the operation. The consciousness level gradually improved, the patient was withdrawn from the respirator on the post operative day( POD) 35, and transferred to a rehabilitation hospital on POD 60. The pathological result was mature teratoma. However, no specific findings such as inflammatory cell infiltration into nerve components were observed. Anti-NMDA receptor encephalitis was established by Dalmau in 2007 as encephalitis associated with ovarian teratoma. It presents mainly in young adult women with psychiatric symptoms, and requires mechanical ventilation management due to disturbance of consciousness, convulsions, and central hypoventilation in a short period of time. It presents severe symptoms in the acute phase and shows a unique clinical finding with a good prognosis even though it shows a protracted course. Treatment requires prompt tumor detection and early resection, as well as methylprednisolone (mPSL) pulse, plasmapheresis, and high-dose gamma globulin therapy. It is a neurological disease that requires emergency response, and the understanding and prompt response of related departments is important.

White matter microstructural alterations in patients with anti-N-methyl-D-aspartate receptor encephalitis: A tract-based spatial statistics study.

BACKGROUND: Cognitive impairment is common in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis; however, neural mechanisms underlying this impairment remain unclear. Diffusion tensor imaging (DTI) is a potential method for studying the condition of white matter fibers in patients with anti-NMDAR encephalitis, allowing for an analysis of the neuroimaging mechanisms of cognitive impairment in conjunction with cognitive scales. This study aimed to explore white matter microstructural alterations and their correlation with cognitive function in patients with anti-NMDAR encephalitis. METHODS: DTI data were collected from 22 patients with anti-NMDAR encephalitis (aged 29.00(19.75, 39.50) years; 12 males, 10 females) and 20 healthy controls (HCs) (aged 24.50(21.25, 32.00); 12 males, 8 females) matched for age, sex, and educational level. Changes in the white matter microstructure were analyzed using tract-based spatial statistics. Pearson correlation analysis was used to explore the correlation between white matter integrity and neuropsychological scores. RESULTS: Compared with HCs, patients with anti-NMDAR encephalitis showed decreased fractional anisotropy and increased mean diffusivity values in extensive white matter regions, which were associated with disease severity, memory, and executive and visuospatial functions. CONCLUSION: Widespread impairment of the structural integrity of the white matter in the brain is significantly associated with cognitive dysfunction in patients with anti-NMDAR encephalitis, providing neuroimaging evidence for studying the underlying mechanisms.

Ovarian teratoma-associated anti-NMDA receptor encephalitis with severe features.

Anti-N-methyl-D-aspartame receptor (NMDAR) encephalitis is an uncommon clinical entity for the general intensivist or neurologist. Diagnosis can be made by the presence of cerebrospinal fluid IgG antibody against the GluNR1 and GluNR2 subunits of the NMDAR. We present a case of anti-NMDAR encephalitis in a young woman with an ovarian teratoma treated with surgical resection and multiple immunomodulatory therapies.

Pediatric anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis: Exploring psychosis, related risk factors, and hospital outcomes in a nationwide inpatient sample: A cross-sectional study.

OBJECTIVE: Our study aims to examine the risk factors for comorbid psychosis in pediatric patients hospitalized for anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis and its impact on hospital outcomes. METHODS: We conducted a cross-sectional study using the nationwide inpatient sample (NIS 2018-2019). We included 3,405 pediatric inpatients (age 6-17 years) with a primary discharge diagnosis of anti-NMDAR encephalitis. We used binomial logistic regression model to evaluate the odds ratio (OR) of variables (demographic and comorbidities) associated with comorbid psychosis. RESULTS: The prevalence of comorbid psychosis in anti-NMDAR encephalitis inpatients was 5.3%, and majorly constituted of adolescents (72.2%) and females (58.3%). In terms of race, Blacks (OR 2.41), and Hispanics (OR 1.80) had a higher risk of comorbid psychosis compared to Whites. Among comorbidities, encephalitis inpatients with depressive disorders (OR 4.60), sleep-wake disorders (OR 3.16), anxiety disorders (OR 2.11), neurodevelopmental disorders (OR 1.95), and disruptive behavior disorders (OR 2.15) had a higher risk of comorbid psychosis. Anti-NMDAR encephalitis inpatients with comorbid psychosis had a longer median length of stay at 24.6 days (vs. 9.8 days) and higher median charges at $262,796 (vs. $135,323) compared to those without psychotic presentation. CONCLUSION: Adolescents, females, and Blacks with encephalitis have a higher risk of psychotic presentation leading to hospitalization for anti-NMDAR encephalitis. Identification of demographic predictors and comorbidities can aid in early recognition and intervention to optimize care and potentially reduce the healthcare burden.

Refractory Anti- N -Methyl- d -Aspartate Receptor Autoimmune Encephalitis Induced by Ovarian Teratoma: A Case Report.

OBJECTIVE: Teratoma is a type of germ cell tumor that derived from early embryonic stem cells and germ cell lines, which can lead to a rare complication known as paraneoplastic encephalitis syndrome. Delayed removal of teratoma allows for continuing antigen presentation, inducing affinity maturation of the antibody and the generation of long-lived plasma cells that infiltrate both bone marrow and brain, which makes the patient nonresponsive to later removal of teratoma and refractory to immunotherapy. We present this rare case to remind clinicians to be vigilant for the recognition and removal of teratoma during the treatment of autoimmune encephalitis. METHODS: We retrospectively reviewed the clinical record of this 12-year 5-month-old female patient diagnosed with anti- N -methyl- d -aspartate receptor (anti-NMDAR) autoimmune encephalitis; her ovarian teratoma was unidentified on admission. She did not respond to immunosuppressive therapy until the mature ovarian teratoma identified 45 days after admission and removed the following day, nearly 2 months after symptom onset. This patient experienced nearly complete resolution of symptoms within the subsequent 2 weeks. In addition, we conducted a literature review of the clinical presentations and treatment of anti-NMDAR autoimmune encephalitis associated with ovarian teratoma in the pediatric population. RESULTS: Our findings suggest that clinicians should be vigilant for the recognition and removal of teratoma during the treatment of autoimmune encephalitis. CONCLUSION: Female pediatric patients with suspected anti-NMDAR encephalitis should be screened for ovarian tumors immediately and treated in a multidisciplinary setting including neurology and obstetrics and gynecology.

Longitudinal Disability, Cognitive Impairment, and Mood Symptoms in Patients With Anti-NMDA Receptor Encephalitis.

BACKGROUND AND OBJECTIVES: Longitudinal outcomes in anti-NMDA receptor encephalitis (anti-NMDARe) are still not fully understood and may not be adequately captured with the modified Rankin Scale (mRS), often the sole reported outcome. We aim to characterize longitudinal outcomes in anti-NMDARe using multiple outcome measures. METHODS: This single-center, retrospective, observational study examined outcome measures (mRS and Clinical Assessment Scale in Autoimmune Encephalitis [CASE]) in adults with NMDA receptor-IgG in CSF at short- and long-term follow-ups using linear and logistic regression modeling. Patients with evaluations for cognitive impairment (Montreal Cognitive Assessment/Mini-Mental State Examination), depression (Patient Health Questionnaire-9), and anxiety (General Anxiety Disorder-7) >6 months from symptom onset were correlated with final CASE scores. RESULTS: Thirty-eight patients (76% female, median disease onset age = 28 years, range = 1-75 years) were included. The majority received first-line immunosuppressants (97%) at a median of 3.9 weeks (interquartile range [IQR] = 2.1-9.7) from symptom onset and 68% received second-line therapies. At baseline, median/mean mRS and CASE were 4 (IQR = 3-5) and 12.9 (SD = 7.2), respectively. At short-term follow-up (median = 10 weeks, IQR = 6-17), factors associated with higher CASE and mRS included dysautonomia, coma/lethargy, seizures/status epilepticus, and intensive care unit admission (p < 0.05). At long-term follow-up (median = 70 weeks, IQR = 51-174), median/mean mRS and CASE were 2 (IQR = 1-3) and 4.4 (SD = 4.2), respectively. Only weakness at symptom onset predicted higher mRS scores (odds ratio = 5.6, 95% confidence interval 1.02-30.9, p = 0.047). Despite both mRS and CASE improving from baseline (p < 0.001), only 9 patients (31%) returned to their premorbid function. Among patients with cognitive and mood evaluations >6 months from onset, moderate-severe cognitive impairment (42%), depression (28%), and anxiety (30%) were frequent. Cognitive and depression measures were associated with final CASE subscores (including memory, language, weakness, and psychiatric). DISCUSSION: Multiple clinical factors influenced short-term outcomes, but only onset weakness influenced long-term mRS, highlighting that mRS is predominantly affected by global motor function. Although mRS and CASE improved over time for most patients, these outcome measures did not capture the full extent of long-term functional impairment in terms of mood, cognition, and the ability to return to premorbid function. This emphasizes the need for increased utilization of more nuanced cognitive and mood outcome measures.

Single-cell RNA sequencing reveals diverse B cell phenotypes in patients with anti-NMDAR encephalitis.

BACKGROUNDS: Anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E) is a severe autoimmune disorder characterized by prominent psychiatric symptoms. Although the role of NMDAR antibodies in the disease has been extensively studied, the phenotype of B cell subsets is still not fully understood. METHODS: We utilized single-cell RNA sequencing, single-cell B cell receptor sequencing (scBCR-seq), bulk BCR sequencing, flow cytometry, and enzyme-linked immunosorbent assay to analyze samples from both NMDAR-E patients and control individuals. RESULTS: The cerebrospinal fluid (CSF) of NMDAR-E patients showed significantly increased B cell counts, predominantly memory B (Bm) cells. CSF Bm cells in NMDAR-E patients exhibited upregulated expression of differential expression genes (DEGs) associated with immune regulatory function (TNFRSF13B and ITGB1), whereas peripheral B cells upregulated DEGs related to antigen presentation. Additionally, NMDAR-E patients displayed higher levels of IgD- CD27- double negative (DN) cells and DN3 cells in peripheral blood (PB). In vitro, DN1 cell subsets from NMDAR-E patients differentiated into DN2 and DN3 cells, while CD27+ and/or IgD+ B cells (non-DN) differentiated into antibody-secreting cells (ASCs) and DN cells. NR1-IgG antibodies were found in B cell culture supernatants from patients. Differential expression of B cell IGHV genes in CSF and PB of NMDAR-E patients suggests potential antigen class switching. CONCLUSION: B cell subpopulations in the CSF and PB of NMDAR-E patients exhibit distinct compositions and transcriptomic features. In vitro, non-DN cells from NMDAR-E can differentiate into DN cells and ASCs, potentially producing NR1-IgG antibodies. Further research is necessary to investigate the potential contribution of DN cell subpopulations to NR1-IgG antibody production.

Acute Symptomatic Seizures and Risk of Seizure Recurrence in Patients with Anti-NMDAR, Anti-LGI1, and Anti-GABABR Encephalitis.

AIMS: To analyze the clinical characteristics of acute symptomatic seizures and predict the risk factors for seizure recurrence in patients with anti-N-methyl-D-aspartate receptor (NMDAR), anti-leucine-rich glioma-inactivated 1 (LGI1), and anti-gamma-aminobutyric acid B receptor (GABABR) encephalitis. METHODS: In this retrospective study, we included hospitalized patients who had been diagnosed with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis between November 2014 and April 2021. Binary logistic regression analysis was performed to identify the potential risk factors for seizure recurrence. RESULTS: In total, 262 patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis were included, 197 (75.2%) of whom presented with acute symptomatic seizures. During follow-up, 42 patients exhibited seizure recurrence. In anti-NMDAR encephalitis, frontal lobe abnormality on brain magnetic resonance imaging, delayed immunotherapy, early seizures, and focal motor onset were associated with seizure recurrence. CONCLUSIONS: Acute symptomatic seizure is a common clinical feature observed in patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis, with 50% of patients presenting with seizures as an initial symptom. The prognosis of patients with acute symptomatic seizures can be improved after receiving immunotherapy. Nevertheless, a minority of patients will experience seizure recurrence; therefore, restarting immunotherapy is recommended.

Unmasking bipolarity in recurrent depressive disorder following herpes simplex virus triggered n-methyl-D-aspartate encephalitis.

OBJECTIVE: Herpes simplex virus (HSV) infection triggered n-methyl-D-aspartate (NMDA) encephalitis can lead to varied neuropsychiatric manifestations, including movement disorders and manic symptoms. HSV is known to affect the same brain regions as in secondary mania. METHOD: We present a 35-year-old female diagnosed with recurrent depressive disorder (RDD) who developed NMDA encephalitis triggered by HSV infection. RESULT: HSV-triggered NMDA encephalitis led to a manic switch in a woman with RDD on antidepressants, along with the new onset of dyskinetic movements. CONCLUSION: A neurological insult predisposed our patient to the variable effects of antidepressant drugs.

Glucocorticoid-dependent multiple sclerosis overlapping anti-NMDA receptor encephalitis: a case report and literature review update.

BACKGROUND: Previous studies suggest a relationship between central nervous system inflammatory demyelinating diseases and anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. Also, the overlap between anti-NMDAR encephalitis and multiple sclerosis (MS) has been reported. However, the pathogenesis and clinical characteristics are still obscure. CASE PRESENTATION: A 33-year-old woman presented with diplopia and sensory ataxia at the onset. The cerebrospinal fluid (CSF) anti-NMDAR antibodies were positive (1:3.2), and nuclear magnetic resonance imaging (MRI) showed bilateral centrum ovale and lateral ventricle demyelinating lesions. Therefore, she was diagnosed with anti-NMDAR encephalitis. After administering intravenous immunoglobulin and oral prednisone, her lesions disappeared, and symptoms were relieved. The condition was maintained with a low dose of prednisone, but her lesions reappeared on MRI. Consequently, immunomodulatory therapy of mycophenolate mofetil was initiated. However, she developed dysarthria and right limb ataxia after 10 months with a positive CSF anti-NMDAR antibody (1:1) and positive oligoclonal band. The MRI showed symmetrical multiple demyelinating lesions. Considering the MS diagnosis, her neurological dysfunction again improved significantly after intravenous methylprednisolone. Unfortunately, her symptoms aggravated for the second time when teriflunomide was started. Finally, her condition was controlled again with oral prednisone. CONCLUSIONS: Consistent with previous cases of overlapping anti-NMDAR encephalitis and MS, patients often show atypical symptoms on MRIs and immunological tests. The overlap cannot be arbitrarily treated because of the recurrence of previous diseases. Long-term follow-up, dynamic antibody monitoring, and MRI examination are crucial for these patients. The special dependency of the patient on glucocorticoids in this study has been rarely reported, which may guide the treatment of insensitivity to disease-modifying therapy in recurrent overlapping anti-NMDAR encephalitis and MS.