Anti-NMDA Receptor Autoimmune Encephalitis: Diagnosis and Management Strategies

Case Report: Efficacy of ofatumumab in refractory anti-NMDAR encephalitis: case series and literature review

Anti-NMDAR encephalitis is the most common autoimmune encephalitis. When first-line treatments fail, second-line therapies are employed. However, a standardized approach for second-line treatment has yet to be established. We presented three cases of anti-NMDAR encephalitis with seizures and psychosis as the primary symptom. These patients showed inadequate response to initial treatments, including intravenous immunoglobulin, methylprednisolone, and plasma exchange. However, their symptoms were effectively controlled following subcutaneous administration of ofatumumab. Previous studies have reported that twelve cases of anti-NMDAR encephalitis were effectively treated with ofatumumab. In this study, the modified Rankin scale (mRS) scores at the last follow-up for all fifteen patients (including our three cases) were significantly lower compared to scores at the peak of the disease (p < 0.001). Thirteen patients achieved full recovery. These findings suggest that CD20 monoclonal antibodies, particularly ofatumumab, may offer a promising treatment option for anti-NMDAR encephalitis.

Cognitive disorders in patients with neuroimmunological disease

PURPOSE OF REVIEW

Autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), and autoimmune encephalitis can directly and indirectly affect brain function, leading to cognitive dysfunction or well characterized neurocognitive syndromes. However, these are often poorly characterized in the literature. Here, we review evidence on clinical manifestations, risk factors, their assessment and outcomes, and evidence for underlying mechanisms and associated biomarkers, if available.

RECENT FINDINGS

Significant advances have been made in neurocognitive disorders associated with four categories of autoimmune disease: neurocognitive disorders due to autoimmune connective tissue diseases, neurocognitive disorders due to autoimmune demyelinating diseases of the CNS, neurocognitive disorders due to autoimmune encephalitis, and neurocognitive disorders due to cerebrovascular disease of autoimmune origin.

SUMMARY

Autoimmune diseases should be considered as critical causal factors underlying new cases of neurocognitive disorder, especially in young patients. These diseases are mediated by immune system reactions involving antibody production, T-cell-mediated damage, and demyelination. Although the prognosis seems favourable in most conditions after immunotherapy, the magnitude of the therapeutic effect of immunotherapy on cognitive functioning remains unclear.

Lyme Disease as a Potential Precursor to Anti-N-Methyl-D-Aspartate Receptor Encephalitis: A Case Report

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a complex neuroinflammatory condition often triggered by underlying factors such as viral infections or malignancies, although idiopathic cases are not uncommon. Here, we present a unique case of a 27-year-old female patient diagnosed with anti-NMDAR encephalitis, where Lyme disease emerges as a plausible yet underrecognized trigger. The patient initially presented to the emergency department (ED) with acute psychosis and was later found to have positive Borrelia burgdorferi immunoglobulin G (IgG) titers, antibodies against the NR1 subunit of NMDA, and subacute thyroiditis. A detailed investigation ruled out other paraneoplastic or infectious causes, pointing to Lyme disease as the most likely precipitant. Notably, her exposure to B. burgdorferi preceded the onset of encephalitis by two years. Treatment with immunotherapy and antibiotics resulted in significant clinical improvement. This case highlights the importance of a thorough evaluation of potential triggers of anti-NMDAR encephalitis, emphasizing that it should not be presumed idiopathic without exhaustive investigation. Awareness of Lyme disease as a possible etiological factor may facilitate more targeted management, reduce prolonged hospital stays, and mitigate the burden of extensive diagnostic workups. By addressing the root cause, clinicians can improve patient outcomes and prevent disease recurrence or complications associated with empiric treatment alone.

Diagnostic testing in psychiatry: insights and examples from a Bayesian perspective

OBJECTIVE

To demonstrate the application of Bayes' theorem to diagnostic testing in clinical settings, especially with respect to rare diseases, enhancing an understanding of pre-test probability and its implications.

CONCLUSION

Bayes' theorem enables the revision of the conditional probabilities of an event occurring when new information is acquired. It demonstrates that when the prevalence of a disease is very low, there are a high number of false positives, thereby reducing the clinical utility and cost benefit profile of the diagnostic test, even in the presence of relatively high sensitivities and specificities of the chosen test.

A Complex Case of Triumphantly Treated ​​​​​​Anti-N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare autoimmune disorder characterized by neuropsychiatric symptoms and the presence of immunoglobulin G (IgG) antibodies against the N-methyl-D-aspartate receptor 1 (NR1) subunit of NMDA receptors. It is often triggered by ovarian teratomas, especially in young women, and presents with a combination of psychiatric and neurological symptoms. Here, we present a case of a 25-year-old woman with a history of schizoaffective disorder and post-partum depression who presented with two months of bizarre behavior, agitation, and decreased sleep. Initially admitted for suspected psychosis, her condition worsened with episodes of loss of consciousness and failure to respond to psychiatric medications. After extensive investigations, including computed tomography (CT), magnetic resonance imaging (MRI), and electroencephalogram (EEG), NMDA receptor encephalitis was suspected and confirmed by positive autoantibodies. Imaging revealed bilateral ovarian teratomas, and she underwent a cystectomy. The patient was treated with intravenous immunoglobulin (IVIG), which led to complications, including desaturation and the need for intubation. Initially, five IVIG sessions were given. Based on their experience, and due to sub-optimal recovery, a shared decision was made between the neurology team and the intensive care unit (ICU) team to administer two additional IVIG sessions. The single dose of each IVIG session was 35 g (0.4 g/kg). After seven sessions of IVIG, she showed gradual improvement. This case underscores the importance of considering NMDA receptor encephalitis in patients with unexplained neuropsychiatric symptoms and highlights the critical roles of autoantibody testing, tumor resection, and immunotherapy in the management of this condition.

Coexistence of Anti-GAD and Anti-GABAAR Antibodies in an Autoimmune Encephalitis Patient: A Case Report

Background

Coexistence of autoimmune encephalitis (AE) with multiple autoantibodies is of particular concern because overlying antibodies may cause variation of clinical manifestations. Coexistence of anti-glutamic acid decarboxylase (GAD) and anti-Gamma-aminobutyric acid-α-receptor (GABAAR) antibodies in AE was rare.

Case Presentation

A 44-year-old female patient presented to our hospital due to cognitive decline for 4 years, seizures, slowed speech and depression for 2 months. Based on her clinical manifestations and laboratory assessment results (positive anti-GAD and anti-GABAAR antibodies), she was diagnosed as AE with coexisting anti-GAD and anti-GABAAR antibodies. After treatment with intravenous methylprednisolone (at dose of 1000mg/d, 500mg/d, 250mg/d, 120mg/d, 80mg/d for 3 days respectively) and intravenous immunoglobulin (400 mg/kg/d for 5 days), her symptoms gradually improved with exception for the slowed speech. Oral prednisone acetate was continued after discharge, her symptoms of slowed speech improved at 6-month follow-up.

Conclusion

We report a case of AE co-existing with anti-GAD and anti-GABAAR antibodies, which has different characteristics from previous cases. Coexistence of neural auto-antibodies should be considered when patients suspected with autoimmune encephalitis.

Precision Assessment of Anti-NMDA Receptor Encephalitis: A Case Report on Integrating Clinical Course, Immunophenotyping, and Comprehensive Symptomatology in a Pediatric Patient With Adjunctive Hydrogen Therapy

BACKGROUND/AIM

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, though rare, is the most common form of autoimmune encephalitis, predominantly affecting young individuals, particularly females. Standard treatments include corticosteroids, intravenous immunoglobulins (IVIG), and plasmapheresis, with rituximab recommended for those unresponsive to first-line therapies. However, reliable biomarkers for clinical assessment remain elusive. This study investigated the efficacy of adjunctive hydrogen therapy in a patient with anti-NMDAR encephalitis.

CASE REPORT

This case report describes a 14-year-old boy with anti-NMDAR encephalitis who exhibited poor response to initial treatment, but showed significant improvement with rituximab and adjunctive hydrogen therapy. Immunophenotyping revealed correlations between treatment outcomes and shifts in B cell subsets, PD-1+ cytotoxic T cells, and regulatory T cell subtypes.

CONCLUSION

This case underscores the importance of integration traditional clinical assessments with advanced diagnostics such as flow cytometry-based immunophenotyping, and suggests a potential role for hydrogen therapy in modulating immune response in this complex autoimmune condition.

Peptide-Purified Anti-N-methyl-D-aspartate Receptor (NMDAR) Autoantibodies Have Inhibitory Effect on Long-Term Synaptic Plasticity

Background/Objectives: Recent studies, typically using patient cerebrospinal fluid (CSF), have suggested that different autoantibodies (Aabs) acting on their respective receptors, may underlie neuropsychiatric disorders. The GluN1 (NR1) subunit of the N-methyl-D-aspartate receptor (NMDAR) has been identified as a target of anti-NMDAR Aabs in a number of central nervous system (CNS) diseases, including encephalitis and autoimmune epilepsy. However, the role or the nature of Aabs responsible for effects on neuronal excitability and synaptic plasticity is yet to be established fully. Methods: Peptide immunisation was used to generate Aabs against selected specific GluN1 extracellular sequences based on patient-derived anti-NMDAR Aabs that have been shown to bind to specific regions within the GluN1 subunit. 'Protein A' purification was used to obtain the total IgG, and further peptide purification was used to obtain a greater percentage of NMDAR-target specific IgG Aabs. The binding and specificity of these anti-NMDAR Aabs were determined using a range of methodologies including enzyme-linked immunosorbent assays, immunocytochemistry and immunoblotting. Functional effects were determined using different in vitro electrophysiology techniques: two-electrode voltage-clamps in Xenopus oocytes and measures of long-term potentiation (LTP) in ex vivo hippocampal brain slices using multi-electrode arrays (MEAs). Results: We show that anti-NMDAR Aabs generated from peptide immunisation had specificity for GluN1 immunisation peptides as well as target-specific binding to the native protein. Anti-NMDAR Aabs had no clear effect on isolated NMDARs in an oocyte expression system. However, peptide-purified anti-NMDAR Aabs prevented the induction of LTP at Schaffer collateral-CA1 synapses in ex vivo brain slices, consistent with causing synaptic NMDAR hypofunction at a network level. Conclusions: This work provides a solid basis to address outstanding questions regarding anti-NMDAR Aab mechanisms of action and, potentially, the development of therapies against CNS diseases.

Decoding Dystonia in Autoimmune Disorders: A Scoping Review

Background

Dystonia is a common hyperkinetic movement disorder observed in various genetic, infective, drug-induced, and autoimmune disorders. Autoimmune disorders can present with isolated or combined acute or subacute dystonia. The pattern and approach to dystonia in autoimmune disorders are poorly described and have never been established in a structured manner.

Objective

This scoping review aims to summarize all available clinical literature and formulate a pattern and approach to dystonia in different autoimmune disorders.

Methods

We included one hundred and three articles in this scoping review. Most articles identified were case reports or case series.

Results

In this review, we analysed data from 103 articles and summarized the epidemiological, clinical, and diagnostic features of dystonia associated with different autoimmune diseases. We highlight that dystonia can be isolated or combined in various autoimmune conditions and is responsive to immunotherapy. We point out the patterns of dystonia and associated neurological features and investigations that can suggest the underlying autoimmune nature, which can guide the most appropriate treatment.

Discussion

The clinical pattern of dystonia can be a unique feature in many autoimmune disorders. In isolated subacute dystonia, the presence of autoantibodies could have a temporal association, or this is just an epiphenomenon to be evaluated in further research.

Highlights

Many autoimmune disorders can present with isolated or combined dystonia.Subacute onset focal or segmental dystonia (craniocervical dystonia or limb dystonia) or hemidystonia could be secondary to an autoimmune condition and warrants investigations.They have a relapsing or progressive course.They usually have a good response to early immunotherapy.Symptomatic treatment, including botulinum toxin, can be useful in focal dystonia.

Immediate Postoperative Activation of Vagus Nerve Stimulation (VNS) for Super-refractory Status Epilepticus: A Case Report

Anti-NMDA (N-methyl-D-aspartate) receptor encephalitis (ANRE) is a rare autoimmune condition targeting brain receptors, often linked to ovarian tumors in young women. In severe cases, it can lead to status epilepticus, but in sporadic cases, it may progress to super-refractory status epilepticus (SRSE), a dangerous state of continuous or repetitive seizures demanding urgent medical attention that continues or recurs more than 24 hours after the initiation of anesthetic therapy. We present a case report of anti-NMDA receptor limbic encephalitis-triggered SRSE terminated with vagus nerve stimulation (VNS) and titrated to high stimulation parameters in the immediate postoperative period. Titrating VNS to high stimulation parameters immediately postoperatively under specialized neuroanesthesia is a safe and effective treatment for nonconvulsive SRSE in anti-NMDA receptor limbic encephalitis. However, further research is needed to solidify this approach as a standard treatment option in these circumstances since the SRSE is rare. Expanding the evidence base will help improve patient outcomes and reduce morbidity and mortality associated with this condition.

Late relapse of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis: a case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is a sporadic autoimmune disorder of the brain that presents in a variety of neuropsychiatric manifestations, including seizures, psychosis, and alterations in behavior. N-methyl-D-aspartate receptor is primarily seen in young females. Although this disease can be treated, it can relapse in rare cases. Relapsing typically occurs within the early years following the initial episode and is exceedingly rare after 5 years.

CASE PRESENTATION

In this case study, we report on a 16-year-old Iranian female experiencing a relapse of anti-N-methyl-D-aspartate receptor encephalitis 8 years after her initial diagnosis. She was admitted to the hospital with dysphasia (a speech disorder) and dyslexia (reading and writing impairment). A thorough clinical evaluation revealed the presence of anti-glutamate receptor type N-methyl-D-aspartate receptor antibodies in her serum and cerebrospinal fluid, confirming the diagnosis. Following treatment with immunotherapy and plasmapheresis, she made a complete recovery.

CONCLUSION

This case of relapsing anti-N-methyl-D-aspartate receptor encephalitis, occurring more than 5 years after the initial episode, is exceptionally rare. This late relapse underscores the importance of long-term follow-up for patients with this condition.

Association of ovarian teratoma with anti-N-methyl-D-aspartate receptor encephalitis: a case report and narrative review

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a potentially life-threatening autoimmune disorder which is strongly associated with ovarian teratomas in young female patients. The primary aim is to highlight the importance of considering NMDAR encephalitis in the differential diagnosis of young female patients presenting with acute or subacute neuropsychiatric symptoms, especially when accompanied by ovarian teratomas.

CASE DESCRIPTION

This case report and literature review detail the presentation, diagnosis, and treatment of a 35-year-old G4P3 Indigenous woman who initially presented with neuropsychiatric symptoms and fever, having a history of extensive drug and alcohol use. Misdiagnosed initially, the patient's lack of response to standard treatments led to further investigations, revealing paraneoplastic anti-NMDAR encephalitis secondary to a left ovarian teratoma. The report examines the treatment regimen followed, including prednisolone, intravenous immunoglobulin, rituximab injections, and laparoscopic bilateral salpingo-oophorectomy.

CONCLUSIONS

This case underscores the critical need for increased clinical vigilance for anti-NMDAR encephalitis in patients, particularly young females, presenting with neuropsychiatric symptoms and potential ovarian teratomas. The literature review accompanying the case report provides valuable insights into the presentation, diagnosis, and management of this complex condition. Lastly, this study emphasised the diagnostic challenges inherent in paraneoplastic neuropsychiatric syndromes, advocating for a multidisciplinary approach in similar clinical scenarios.

Anti-N-Methyl-D-Aspartate Receptor (Anti-NMDAR) Encephalitis in Small Cell Lung Cancer: A Case Report

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune encephalitis characterized by psychiatric and neurological symptoms. It often presents as a paraneoplastic manifestation and is rarely associated with small cell lung cancer. While treatment usually involves immunotherapy and treatment of underlying malignancy, the patient's condition can complicate treatment decisions. A 66-year-old man presented to the emergency department with a chief complaint of fever and impaired consciousness. Tests revealed anti-NMDAR encephalitis and small cell lung cancer. Despite immunotherapy, including steroids, intravenous immunoglobulin, and rituximab, chemotherapy was not possible due to the patient's poor condition. Immunotherapy treatment was continued, but there was no improvement in his state of consciousness, and death was confirmed on the 101st day of hospitalization. Anti-NMDAR encephalitis caused by small cell carcinoma is treated with immunotherapy and cancer therapy; only immunotherapy is not enough.

Efficacy and safety of different oral prednisone tapering courses in adult anti-NMDAR encephalitis: A multicenter prospective cohort study

OBJECTIVE

In adult anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, corticosteroids are commonly used as first-line treatment. However, the optimal oral prednisone tapering (OPT) following intravenous methylprednisolone pulse therapy remains unclear. We aim to compare the efficacy and safety of different OPT courses in anti-NMDAR encephalitis.

METHODS

The CHASE study, a multicenter prospective observational cohort study, enrolled patients with autoimmune encephalitis from October 2011 to March 2023. Patients were grouped based on oral prednisone tapering course: ≤3 months (Group ≤3 month), 3-6 months (Group 3-6 months, including 3 months), and >6 months (Group > 6 months). Kaplan-Meier plots were used to analyze time to relapse and time to total recovery within 2 years.

RESULTS

Among 666 screened patients, 171 (median [IQR] age 27 [21.0-36.5] years, 55.0% female) met selection criteria. Responders at 3 months were prevalent in Group ≤3 months (OR 7.251 [95% CI 2.252 to 23.344] and Group 3-6 months (OR, 3.857 [95% CI 1.107 to 13.440] than in Group >6 months. Clinical Assessment Scale for Autoimmune Encephalitis (CASE) scores at 12 months were higher in Group >6 months than in Group ≤3 months and Group 3-6 months (β, -2.329 [95% CI -3.784 to -.875]; β, -2.871 [95% CI -4.490, -1.253]). CASE seizures subscore was higher in Group >6 months than in Group 3-6 months (β, -.452 [95% CI -.788 to -.116]). No significant difference in seizure freedom rates among the groups. Adverse events were higher in Group 3-6 months and Group >6 months than in Group ≤3 months (OR 6.045 [95% CI 2.352 to 15.538]; OR 6.782 [95% CI 1.911 to 24.073]).

SIGNIFICANCE

Longer oral prednisone courses for adult patients with anti-NMDAR encephalitis did not show superior effects compared to shorter courses in improving modified Rankin Scale (mRS) scores and CASE scores, reducing the risk of relapse within 2 years, or achieving seizure freedom. Instead, extended prednisone courses may lead to more side effects- particularly weight gain. This outcome recommends evaluating the possibility of shortening the duration of oral prednisone after a thorough patient assessment.

Anti-NMDAR encephalitis with delayed ovarian teratoma in a young woman: a case report with 5 years of follow-up

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder with a variety of clinical manifestations. It has been established that anti-NMDAR encephalitis may be related to ovarian teratoma in female patients. However, a considerable number of patients have no obvious evidence of ovarian teratoma during the onset of the disease.

CASE

A 25-year-old previously-healthy female experienced a series of acute symptoms within two days, including confusion, disorientation, short-term memory loss, auditory hallucinations, abnormal behavior, refractory status epilepticus, etc. Her brain MRI and abdominal imaging showed no definite abnormality while her electroencephalogram exhibited the presence of low to moderate amplitude sharp, spike, and multi-spike waves. Serum and cerebrospinal fluid tests yielded positive results for anti-NMDAR antibodies. However, an ultrasound scan failed to identify an ovarian teratoma. Consequently, the diagnosis of anti-NMDAR encephalitis without teratoma was made after 4 days onset. After the plasma exchange and immunoglobulin therapy, her neurological symptoms improved and obtained a clinical cure. In the next eight months of follow-up, the patient accidentally touched a lump in the lower abdomen without any symptoms, and abdominal ultrasound and CT scan revealed a left ovarian tumor. Then she underwent left ovarian teratoma resection surgery and histopathology showed a mature cystic teratoma with neural components. The patient continued to receive five years of follow-up, and her condition remained stable without any recurrence, except that there had been a low titer of anti-NMDAR antibody in her serum.

CONCLUSION

Our case demonstrated the importance of long-term follow-up for female patients with anti-NMDAR encephalitis, since anti-NMDAR encephalitis-associated ovarian teratomas may develop in a delayed manner, even without any symptoms.

Assessment of long-term psychosocial outcomes in N-methyl-D-aspartate receptor encephalitis - the SAPIENCE study protocol

BACKGROUND

N-methyl-D-aspartate-receptor (NMDAR) encephalitis is a rare neurological autoimmune disease with severe neuropsychiatric symptoms during the acute phase. Despite good functional neurological recovery, most patients continue to experience cognitive, psychiatric, psychological, and social impairments years after the acute phase. However, the precise nature and evolving patterns over time of these long-term consequences remain unclear, and their implications for the well-being and quality of life of predominantly young patients have yet to be thoroughly examined.

METHODS

SAPIENCE is a European multi-center (n = 3) prospective observational cohort study studying the long-term cognitive, psychiatric, psychological, and social outcome in patients with NMDAR encephalitis. The study consists of three interconnected levels. Level 1 comprises a qualitative interview and focus groups with patients and their caregivers. Level 2 consists of a condensed form of the interview, standardized questionnaires, and a detailed neuropsychological examination of patients. Level 3 involves an online survey that will be open to patients world-wide and explores patient-reported outcomes (PROMs), and patient-reported experiences (PREMs) in association with clinical and cognitive outcomes. Levels 1 to 3 will progressively contribute developing of structured interviews, survey questions, and treatment guidelines by informing one another.

DISCUSSION

SAPIENCE is an in-depth study of the long-term effects of NMDAR encephalitis and bridges the gap between standardized assessments and individual patient experiences, intending to improve patient care and to increase awareness of the psychosocial long-term consequences of the disease. Through collaboration of experts in clinical neurology and social and health psychology across Europe, SAPIENCE aims to create online assessment tools and formulate guidelines for patient-centered post-acute care that will help enhance the quality of life for patients and caregivers.

Emerging Biomarkers for the Early Detection of Autoimmune Encephalitis: A Narrative Review

Autoimmune encephalitis (AE) is a rare yet critical neurological disorder characterized by inflammation of the brain, typically triggered by an abnormal immune response. The early detection and diagnosis of AE are crucial for effective treatment and improved patient outcomes. However, the diagnostic process is often complicated by the diverse clinical presentations of AE, which can mimic other neurological and psychiatric conditions. Currently, diagnosis relies on a combination of clinical evaluation, neuroimaging, cerebrospinal fluid analysis, and the detection of specific autoantibodies. Despite advances in these areas, challenges remain, particularly in cases where patients are seronegative or present with nonspecific symptoms. This narrative review provides a comprehensive overview of emerging biomarkers for the early detection of AE, highlighting their potential to enhance diagnostic accuracy and speed. We explore a variety of biomarkers, including novel autoantibodies, inflammatory markers, cytokines, and neuronal damage indicators, and discuss their clinical implications. This review emphasizes the need for biomarkers that are not only sensitive and specific but also accessible and rapid to facilitate earlier diagnosis and treatment. By synthesizing current research, this review aims to contribute to the ongoing efforts to refine the diagnostic approach to AE, ultimately improving outcomes for patients affected by this challenging condition.

From Psychosis to Recovery: A Case Report of N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis

Autoimmune N-methyl-D-aspartate (NMDA) receptor encephalitis is an increasingly recognized cause of severe neuropsychiatric illness, particularly in young individuals. This case report presents a detailed account of a patient diagnosed with NMDA receptor encephalitis, highlighting the clinical presentation, diagnostic challenges, and treatment approach. The patient exhibited initial symptoms of psychosis and memory disturbances, which rapidly progressed to seizures and autonomic instability, reflecting the characteristic progression of the disorder.

Occult Lung Cancer-Associated Autoimmune Encephalitis Presenting as Acute Psychosis

During deployment, a 52-year-old male developed acute behavioral changes. Though initially considered to have PTSD and related agitation and confusional state, his evaluation was consistent with acute encephalopathy. Magnetic resonance imaging of the brain showed T2 hyperintensities, and CSF analysis was positive for anti-N-methyl-D-aspartate receptor antibody. A nuclear protein in testis carcinoma midline carcinoma was discovered in the lung. Immunotherapy and surgical resection led to steady improvement prior to adjuvant chemotherapy. Autoimmune encephalitis due to anti-N-methyl-D-aspartate receptor antibodies is increasingly being recognized as causal of acute behavioral change.

Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations

BACKGROUND

 Autoimmune encephalitis (AIE) is a group of inflammatory diseases characterized by the presence of antibodies against neuronal and glial antigens, leading to subacute psychiatric symptoms, memory complaints, and movement disorders. The patients are predominantly young, and delays in treatment are associated with worse prognosis.

OBJECTIVE

 With the support of the Brazilian Academy of Neurology (Academia Brasileira de Neurologia, ABN) and the Brazilian Society of Child Neurology (Sociedade Brasileira de Neurologia Infantil, SBNI), a consensus on the diagnosis and treatment of AIE in Brazil was developed using the Delphi method.

METHODS

 A total of 25 panelists, including adult and child neurologists, participated in the study.

RESULTS

 The panelists agreed that patients fulfilling criteria for possible AIE should be screened for antineuronal antibodies in the serum and cerebrospinal fluid (CSF) using the tissue-based assay (TBA) and cell-based assay (CBA) techniques. Children should also be screened for anti-myelin oligodendrocyte glucoprotein antibodies (anti-MOG). Treatment should be started within the first 4 weeks of symptoms. The first-line option is methylprednisolone plus intravenous immunoglobulin (IVIG) or plasmapheresis, the second-line includes rituximab and/or cyclophosphamide, while third-line treatment options are bortezomib and tocilizumab. Most seizures in AIE are symptomatic, and antiseizure medications may be weaned after the acute stage. In anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, the panelists have agreed that oral immunosuppressant agents should not be used. Patients should be evaluated at the acute and postacute stages using functional and cognitive scales, such as the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Modified Rankin Scale (mRS), and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).

CONCLUSION

 The present study provides tangible evidence for the effective management of AIE patients within the Brazilian healthcare system.

The split apparent diffusion coefficient sign: A novel magnetic resonance imaging biomarker for cortical pathology with possible implications in autoimmune encephalitis

INTRODUCTION

MRI is the imaging modality of choice for assessing patients with encephalopathy. In this context, we discuss a novel biomarker, the "split ADC sign," where the cerebral cortex demonstrates restricted diffusion (high DWI signal and low ADC) and the underlying white matter demonstrates facilitated diffusion (high or low DWI signal and high ADC). We hypothesize that this sign can be used as a biomarker to suggest either acute encephalitis onset or to raise the possibility of an autoimmune etiology.

MATERIALS AND METHODS

A full-text radiological information system search of radiological reports was performed for all entities known to produce restricted diffusion in the cortex excluding stroke between January 2012 and June 2022. Initial MRI studies performed upon onset of clinical symptoms were screened for the split ADC sign.

RESULTS

25 subjects were encountered with a positive split ADC sign (15 female; median age = 57 years, range 18-82). Diagnosis included six herpes simplex encephalitis, three peri-ictal MRI changes, eight PRES, two MELAS, and six autoimmune (3 anti-GABAAR, two seronegative, and one anti-Ma2/Ta). Subjects were imaged at a mean 1.8 days after the onset of symptoms (range 0-8).

DISCUSSION

We present a novel visual MRI biomarker, the split ADC sign, and highlight its potential usefulness in subjects with encephalopathy to suggest acute disease onset or to raise the possibility of an autoimmune etiology when location-based criteria are applied. When positive, the sign was present on the initial MRI and can therefore be used to help focus further clinical and laboratory workup.

Case report: Successful treatment of an anti-D2R and DPPX antibody-associated autoimmune encephalitis patient with high-dose methylprednisolone and intravenous immunoglobulin

Background

Autoimmune encephalitis is a neurological condition caused by abnormal immune responses, manifesting as cognitive impairments, behavioral abnormalities, and seizures. Its diagnosis depends on the detecting neuronal surface antibodies in serum or cerebrospinal fluid. Despite recent advances in understanding, clinical recognition remains challenging, especially with rare antibodies such as anti-dopamine D2 receptor (D2R) and anti-dipeptidyl-peptidase-like protein 6 (DPPX) antibodies. Delayed diagnosis can lead to severe complications. This case presentation emphasizes the diagnostic intricacies and effective treatment of the anti-D2R and DPPX antibody-associated autoimmune encephalitis.

Case description

The patient presented with a 3-day history of fatigue and limb soreness followed by a 3-h episode of confusion and limb convulsions. Upon admission to our facility, the initial diagnosis included status epilepticus, aspiration pneumonia, metabolic acidosis, respiratory alkalosis, and suspected encephalitis. Despite receiving antiepileptic, anti-infection, and antivirus therapy, the patient's condition deteriorated. Both computed tomography (CT) scan and magnetic resonance imaging (MRI) of the brain showed no significant abnormalities. No pathogen was identified in the cerebrospinal fluid (CSF). However, further CSF and serum examination revealed positive results of anti-D2R and anti-DPPX antibodies, confirming a diagnosis of anti-D2R and DPPX antibody-associated autoimmune encephalitis. The patient underwent a comprehensive treatment regimen, including high-dose methylprednisolone pulse therapy combined with intravenous immunoglobulin (IVIG), antiviral and anti-infection treatments, and antiepileptic medications. Significant clinical improvement was observed, and by the 18th day of admission, the patient was stable and coherent.

Conclusions

The current patient represents the first reported case of double-positive autoimmune encephalitis for anti-D2R and DPPX antibodies, with epilepsy as a prominent feature. High-dose methylprednisolone pulse therapy combined with IVIG has shown significant safety and efficacy in treating anti-D2R and DPPX antibody-positive autoimmune encephalitis-associated epilepsy.

Unveiled: A Case of N-Methyl-D-Aspartate Receptor Antibody Encephalitis With Delayed Diagnosis of Ovarian Teratoma

N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is an autoimmune syndrome with potentially fatal sequelae causing profound dysregulation of neurotransmission. Patients most often present with a constellation of neuropsychiatric signs and symptoms, including behavioral changes, motor disturbances, and seizures. Frequently, the development of anti-NMDAR antibodies has been linked to specific malignancies, although the exact event that triggers the production of these antibodies remains unknown. We present a case of a 25-year-old female who came into the emergency room with behavioral changes and fever. The patient had non-convulsive seizures, catatonia, and orofacial dyskinesias during the course of the admission and was treated as a case of autoimmune anti-NMDAR encephalitis. Cranial and abdominal MRI with contrast initially showed negative results, while the serum and cerebrospinal fluid studies were positive for anti-NMDAR antibodies. The patient was noted to have significant clinical improvement after being treated with high-dose intravenous steroid therapy followed by intravenous immunoglobulin (IVIg) and rituximab infusion. She was discharged stable with the resolution of neurologic symptoms four months after the diagnosis. On follow-up with her neurologist two years later, an abdominal CT scan was done and showed mature cystic teratoma. This is one of the few documented cases of anti-NMDAR encephalitis with a good response to medical treatment but had a delayed diagnosis of ovarian teratoma seen on surveillance work-up years after the diagnosis. A high index of suspicion is warranted for the diagnosis, and treatment should be started early as soon as there is clinical suspicion of the disease. Also, surveillance pelvic or abdominal imaging is important in patients who have negative initial screening but have high risks for teratomas.

Immunopathology of herpes simplex virus-associated neuroinflammation: Unveiling the mysteries

The immunopathology of herpes simplex virus (HSV)-associated neuroinflammation is a captivating and intricate field of study within the scientific community. HSV, renowned for its latent infection capability, gives rise to a spectrum of neurological expressions, ranging from mild symptoms to severe encephalitis. The enigmatic interplay between the virus and the host's immune responses profoundly shapes the outcome of these infections. This review delves into the multifaceted immune reactions triggered by HSV within neural tissues, intricately encompassing the interplay between innate and adaptive immunity. Furthermore, this analysis delves into the delicate equilibrium between immune defence and the potential for immunopathology-induced neural damage. It meticulously dissects the roles of diverse immune cells, cytokines, and chemokines, unravelling the intricacies of neuroinflammation modulation and its subsequent effects. By exploring HSV's immune manipulation and exploitation mechanisms, this review endeavours to unveil the enigmas surrounding the immunopathology of HSV-associated neuroinflammation. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of HSV infections.

The specifics of encephalitis after COVID-19

Encephalitis is a group of acute infectious diseases affecting the substance of the brain. They often lead to disability or death, and, therefore, require urgent medical attention. The article discusses the etiology, pathogenesis, and clinical picture of encephalitis, with special attention to the course of this disease after the COVID-19 pandemic. We note the growing number of encephalitis cases, especially of autoimmune variety and those caused by herpes. The possible reason behind this trend is the disruption of operation of the immune system brought by COVID-19, which manifests as a cytokine storm, neuroinflammation, and autoimmune reactions. There are cases of COVID-19-dependent encephalitis described. The pathways taken by SARS-CoV-2 to penetrate into the cells of the central nervous system have not yet been fully studied, although there are hypotheses that this happens both trans-synaptically through mechanoreceptors and chemoreceptors of the respiratory system into the medulla oblongata, and through receptors of the angiotensin converting enzyme 2.

VH2+ Antigen-Experienced B Cells in the Cerebrospinal Fluid Are Expanded and Enriched in Pediatric Anti-NMDA Receptor Encephalitis

Pediatric and adult autoimmune encephalitis (AE) are often associated with Abs to the NR1 subunit of the N-methyl-d-aspartate (NMDA) receptor (NMDAR). Very little is known regarding the cerebrospinal fluid humoral immune profile and Ab genetics associated with pediatric anti-NMDAR-AE. Using a combination of cellular, molecular, and immunogenetics tools, we collected cerebrospinal fluid from pediatric subjects and generated 1) flow cytometry data to calculate the frequency of B cell subtypes in the cerebrospinal fluid of pediatric subjects with anti-NMDAR-AE and controls, 2) a panel of recombinant human Abs from a pediatric case of anti-NMDAR-AE that was refractory to treatment, and 3) a detailed analysis of the Ab genes that bound the NR1 subunit of the NMDAR. Ag-experienced B cells including memory cells, plasmablasts, and Ab-secreting cells were expanded in the pediatric anti-NMDAR-AE cohort, but not in the controls. These Ag-experienced B cells in the cerebrospinal fluid of a pediatric case of NMDAR-AE that was refractory to treatment had expanded use of variable H chain family 2 (VH2) genes with high somatic hypermutation that all bound to the NR1 subunit of the NMDAR. A CDR3 motif was identified in this refractory case that likely drove early stage activation and expansion of naive B cells to Ab-secreting cells, facilitating autoimmunity associated with pediatric anti-NMDAR-AE through the production of Abs that bind NR1. These features of humoral immune responses in the cerebrospinal fluid of pediatric anti-NMDAR-AE patients may be relevant for clinical diagnosis and treatment.

Anti-NMDA receptor encephalitis in a 73-year-old female with secondary progressive multiple sclerosis: A case report

Anti-NMDA receptor (Anti-NMDAR) encephalitis is an autoimmune disease that presents with diverse symptoms. Since literature is scarce on the overlap with multiple sclerosis (MS), this report aims to elucidate the distinctive clinical presentation and diagnostic challenges of anti-NMDAR encephalitis in MS patients. A 73-year-old woman with secondary progressive multiple sclerosis, after experiencing status epilepticus and subsequent non-convulsive status epilepticus, presented with neuropsychiatric symptoms and autonomic nervous dysfunction. Notably, the patient had not received any immunomodulatory therapy. The clinical picture together with diagnostics (MRI, EEG, cerebro-spinal fluid) let us suspect HSV-meningoencephalitis and empirically treat the patient with IV acyclovir. Due to a lack of clinical improvement, we reconsidered the diagnosis and found the diagnostic criteria for autoimmune encephalitis to be met. Antibodies in blood and CSF were positive and we diagnosed the patient with anti-NMDAR encephalitis. The patient responded well to IV prednisolone treatment, leading to a stable outcome in a six-month follow-up. This case highlights the difficulties in diagnosing anti-NMDAR encephalitis in patients with multiple sclerosis. The presence of epileptic seizures can serve as a crucial diagnostic indicator to distinguish between an MS relapse and an overlapping disease. Compared to patients with other demyelinating diseases, patients with overlapping MS appear to have a higher risk of motor seizures.

Anti-N-methyl-D-aspartate receptor encephalitis and positive human herpesvirus-7 deoxyribonucleic acid in cerebrospinal fluid: a case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is a neuroautoimmune syndrome typically presenting with seizures, psychiatric symptoms, and autonomic dysfunction. Human herpesvirus-7 is often found with human herpesvirus-6 and infects leukocytes such as T-cells, monocytes-macrophages, epithelial cells, and central nervous system cells. The pathogenicity of human herpesvirus-7 is unclear. Cases of anti-N-methyl-D-aspartate receptor encephalitis with human herpesvirus-7 present in cerebrospinal fluid have been documented, but the clinical significance of this finding remains unclear.

CASE PRESENTATION

An 11-year-old Caucasian boy was admitted to hospital after a generalized tonic-clonic seizure. Generalized tonic seizures repeated three more times during the day of hospitalization. Blood tests showed minor ongoing inflammation, while brain computed tomography yielded normal results. Brain magnetic resonance imaging showed hyperintense focal alterations in both temporal lobes, hippocampi, and at the base of the right frontal lobe. Positive anti-N-methyl-D-aspartate receptor antibodies were found in both serum and cerebrospinal fluid. Positive novel coronavirus 2 (severe acute respiratory syndrome coronavirus 2) immunoglobulin G antibodies were found in serum. Polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2 was negative. Furthermore, positive human herpesvirus-7 deoxyribonucleic acid was found in cerebrospinal fluid. The patient was treated with acyclovir, human immunoglobulin, and methylprednisolone. The seizures did not repeat, and no psychiatric symptoms were present. The patient made a full recovery.

CONCLUSIONS

We present a pediatric case of anti-N-methyl-D-aspartate receptor encephalitis with atypical clinical presentation. The role of human herpesvirus-7 in neurological disorders remains unclear in immunocompetent patients.

The Leading Role of Brain and Abdominal Radiological Features in the Work-Up of Anti-NMDAR Encephalitis in Children: An Up-To-Date Review

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis (NMDARe) is the most common cause of nonviral encephalitis, mostly affecting young women and adolescents with a strong female predominance (F/M ratio of around 4:1). NMDARe is characterized by the presence of cerebrospinal fluid (CSF) antibodies against NMDARs, even though its pathophysiological mechanisms have not totally been clarified. The clinical phenotype of NMDARe is composed of both severe neurological and neuropsychiatric symptoms, including generalized seizures with desaturations, behavioral abnormalities, and movement disorders. NMDARe is often a paraneoplastic illness, mainly due to the common presence of concomitant ovarian teratomas in young women. Abdominal ultrasonography (US) is a key imaging technique that should always be performed in suspected patients. The timely use of abdominal US and the peculiar radiological features observed in NMDARe may allow for a quick diagnosis and a good prognosis, with rapid improvement after the resection of the tumor and the correct drug therapy.

The Emerging Role of N-Methyl-D-Aspartate (NMDA) Receptors in the Cardiovascular System: Physiological Implications, Pathological Consequences, and Therapeutic Perspectives

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ion channels that are activated by the neurotransmitter glutamate, mediate the slow component of excitatory neurotransmission in the central nervous system (CNS), and induce long-term changes in synaptic plasticity. NMDARs are non-selective cation channels that allow the influx of extracellular Na⁺ and Ca²⁺ and control cellular activity via both membrane depolarization and an increase in intracellular Ca²⁺ concentration. The distribution, structure, and role of neuronal NMDARs have been extensively investigated and it is now known that they also regulate crucial functions in the non-neuronal cellular component of the CNS, i.e., astrocytes and cerebrovascular endothelial cells. In addition, NMDARs are expressed in multiple peripheral organs, including heart and systemic and pulmonary circulations. Herein, we survey the most recent information available regarding the distribution and function of NMDARs within the cardiovascular system. We describe the involvement of NMDARs in the modulation of heart rate and cardiac rhythm, in the regulation of arterial blood pressure, in the regulation of cerebral blood flow, and in the blood-brain barrier (BBB) permeability. In parallel, we describe how enhanced NMDAR activity could promote ventricular arrhythmias, heart failure, pulmonary artery hypertension (PAH), and BBB dysfunction. Targeting NMDARs could represent an unexpected pharmacological strategy to reduce the growing burden of several life-threatening cardiovascular disorders.