Anti-N-methyl-d-aspartate receptor encephalitis in children: Incidence and experience in Hong Kong

Protocol on establishing a national disease registry-Swiss Pediatric Inflammatory Brain Disease Registry

BACKGROUND

Pediatric-onset inflammatory brain diseases are a group of potentially life-threatening central nervous system disorders. Overall, pediatric-onset inflammatory brain diseases are rare and therefore difficult to study. Patient registries are well suited to study the natural history of (rare) diseases and have markedly advanced the knowledge on pediatric-onset inflammatory brain diseases in other countries. Following their example, we established a national pediatric-onset inflammatory brain disease registry in Switzerland (Swiss-Ped-IBrainD).

AIMS

The Registry aims to describe epidemiology, demographics, diagnostics, management, and treatment, since these areas remain understudied in Switzerland. Additionally, we want to promote research by fostering the knowledge exchange between study centers and setting up studies such as national quality of life surveys. We further aim to facilitate the access to national and international studies for patients with a pediatric-onset inflammatory brain disease living and/or treated in Switzerland.

METHODS

The Swiss-Ped-IBrainD is a multicentric, population-based, observational cohort study (IRB number: 2019-00377) collaborating with 11 neuropediatric centers in Switzerland. Patient screening, information and recruitment is mainly conducted by the local principal investigators. The data collection is organized centrally by the Executive Office of the registry. The collected data is purely observational. Medical records are the primary data source. All patients who have been diagnosed with a pediatric-onset inflammatory brain disease since 2005 are eligible. We aim to include all pediatric-onset inflammatory brain disease patients living and/or treated in Switzerland who meet the inclusion criteria. Considering existing literature and our single-center experience we anticipate 300-400 eligible patients.

STATUS

Currently, all 11 neuropediatric centers have been initiated and are recruiting. As of the first of May 2023, we have identified 275 eligible participants and obtained informed consent from 101 patients and/or families. None of the informed patients and/or families have refused participation.

Spatial and Ecological Factors Modulate the Incidence of Anti-NMDAR Encephalitis-A Systematic Review

Anti-NMDAR encephalitis has been associated with multiple antigenic triggers (i.e., ovarian teratomas, prodromal viral infections) but whether geographic, climatic, and environmental factors might influence disease risk has not been explored yet. We performed a systematic review and a meta-analysis of all published papers reporting the incidence of anti-NMDAR encephalitis in a definite country or region. We performed several multivariate spatial autocorrelation analyses to analyze the spatial variations in the incidence of anti-NMDA encephalitis depending on its geographical localization and temperature. Finally, we performed seasonal analyses in two original datasets from France and Greece and assessed the impact of temperature using an exposure-lag-response model in the French dataset. The reported incidence of anti-NMDAR encephalitis varied considerably among studies and countries, being higher in Oceania and South America (0.2 and 0.16 per 100,000 persons-year, respectively) compared to Europe and North America (0.06 per 100,000 persons-year) (p < 0.01). Different regression models confirmed a strong negative correlation with latitude (Pearson's R = -0.88, p < 0.00001), with higher incidence in southern hemisphere countries far from the equator. Seasonal analyses showed a peak of cases during warm months. Exposure-lag-response models confirmed a positive correlation between extreme hot temperatures and the incidence of anti-NMDAR encephalitis in France (p = 0.03). Temperature analyses showed a significant association with higher mean temperatures and positive correlation with higher ultraviolet exposure worldwide. This study provides the first evidence that geographic and climatic factors including latitude, mean annual temperature, and ultraviolet exposure, might modify disease risk.

Neuropsychological functioning in children and adolescents with anti-NMDA receptor encephalitis (anti-NMDARE)

The objective of this study was to describe neuropsychological functioning and associated medical features in pediatric patients with anti-NMDA receptor encephalitis (anti-NMDARE). Retrospective data were collected from electronic medical records and neuropsychological reports of 15 children and adolescents with cerebral spinal fluid antibody-confirmed anti-NMDARE who were 7-21 years old at the time of the neuropsychological evaluation. The median time between treatment initiation for anti-NMDARE and neuropsychological testing was 228 days (IQR 431, range 41-927). Consistent with the limited literature, this pediatric sample with anti-NMDARE generally had average IQs, but had scores falling in the low average range on tests of verbal and visual memory as well as aspects of executive functioning (set shifting and phonemic verbal fluency). Other relative weaknesses were observed in visuo-constructional ability and reading comprehension. Future prospective studies are needed to replicate these data and explore disease and treatment variables that reduce or exacerbate the risk for neuropsychological sequelae, while longitudinal analyses are required to better characterize academic, vocational, and social outcomes.

A systematic review and quantitative synthesis of the long-term psychiatric sequelae of pediatric autoimmune encephalitis

BACKGROUND

Long-term neuropsychiatric sequelae of autoimmune encephalitis (AE) remain understudied, particularly in pediatric-onset AE. We aimed to synthesize the published data on ongoing psychiatric symptoms in pediatric-onset AE.

METHODS

The Pubmed, PyscINFO, Web of Science databases were searched from their inception years to August 23, 2021, and 29 studies were identified and analyzed. We also performed a quantitative synthesis of available patient data from the 29 studies combined with a cohort of anti-NMDA receptor (NMDAR) AE from our institution to examine the associations between acute treatment course and long-term psychiatric outcome.

RESULTS

At long-term follow up, 52.4% of the cases with pediatric-onset AE had any persistent symptom and 36.0% had at least one psychiatric symptom. Pooled data found that 36.3% of pediatric-onset anti-NMDAR AE had ongoing psychiatric symptoms. Using a univariate logistic regression analysis, we found that abnormal initial EEG, use of certain immunotherapies, and persistent cognitive impairments were associated with ongoing psychiatric symptoms.

LIMITATIONS

Limitations of the existing literature included a significant paucity of outcomes measured using consistent, objective methods. Limitations of the systematic review included the wide variability among the studies reviewed, which rendered a meta-analysis impossible and beyond the scope of the paper.

CONCLUSION

Chronic psychiatric and behavioral problems remain present in one-third of children months to years after onset of AE. Larger scaled prospective observational studies with a consistent standardized battery of testing are needed to examine impact of specific clinical features and immunotherapies on long-term mental health outcomes.

Anti-NMDAR Encephalitis in the Netherlands, Focusing on Late-Onset Patients and Antibody Test Accuracy

Background and Objectives

To describe the clinical features of anti-NMDAR encephalitis, emphasizing on late-onset patients and antibody test characteristics in serum and CSF.

Methods

Nationwide observational Dutch cohort study, in patients diagnosed with anti-NMDAR encephalitis between 2007 and 2019.

Results

One hundred twenty-six patients with anti-NMDAR encephalitis were included with a median age of 24 years (range 1–86 years). The mean annual incidence was 1.00/million (95% CI 0.62–1.59). Patients ≥45 years of age at onset (19%) had fewer seizures (46% vs 71%, p = 0.021), fewer symptoms during disease course (3 vs 6 symptoms, p = 0.020), and more often undetectable serum antibodies compared with younger patients (p = 0.031). In the late-onset group, outcome was worse, and all tumors were carcinomas (both p < 0.0001). CSF was more accurate than serum to detect anti-NMDAR encephalitis (sensitivity 99% vs 68%, p < 0.0001). Using cell-based assay (CBA), CSF provided an unconfirmed positive test result in 11/2,600 patients (0.4%); 6/11 had a neuroinflammatory disease (other than anti-NMDAR encephalitis). Patients with anti-NMDAR encephalitis, who tested positive in CSF only, had lower CSF antibody titers (p = 0.003), but appeared to have an equally severe disease course.

Discussion

Anti-NMDAR encephalitis occurs at all ages and is less rare in the elderly patients than initially anticipated. In older patients, the clinical phenotype is less outspoken, has different tumor association, and a less favorable recovery. Detection of antibodies in CSF is the gold standard, and although the CBA has very good validity, it is not perfect. The clinical phenotype should be leading, and confirmation in a research laboratory is recommended, when in doubt.

Clinical Characteristics and Follow-Up of Seizures in Children With Anti-NMDAR Encephalitis

Objective: To analyze the seizure characteristics of children with anti-NMDAR encephalitis.

Methods: This was a retrospective analysis of 50 children with anti-NMDAR encephalitis between July 1, 2013, and July 1, 2019.

Results: Fifty children with anti-NMDAR encephalitis were included in this study, of which 34 (68.0%) had seizures. During the follow-up, three patients with anti-NMDAR encephalitis secondary to herpes simplex virus encephalitis had persistent seizures. The average duration of seizures in the remaining patients was 14.6 days (range 1–47 days). Compared to patients without seizures, those with seizures were more likely to experience consciousness disturbances (p = 0.008) and epileptic form discharge on electroencephalograms (p = 0.002). The Glasgow coma scale scores (p = 0.014), and Rankin scale scores (p = 0.019) were also different. The cranial MRI findings of children were reviewed, and clinical characteristics were compared between children without cranial lesions and those with lesions in the limbic system and neocortex. Compared to children in the non-lesion group, children with lesions in the limbic system and neocortex had a higher incidence of status epilepticus. Further, children in the limbic system and neocortical lesions groups were more likely to be taking anti-seizure medications (ASMs) and receive second-line drugs.

Conclusion: Long-term oral ASMs are not recommended for most children with anti-NMDAR encephalitis. Children with involvement of the limbic system and neocortex are prone to status epilepticus, and sequelae of epilepsy may remain when the neocortex is involved.

Age-dependent characteristics and prognostic factors of pediatric anti-N-methyl-d-aspartate receptor encephalitis in a Chinese single-center study

OBJECTIVE

To describe the clinical features and prognosis of pediatric anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis from a single center in northern China.

METHODS

The clinical and laboratory characteristics of hospitalized patients with anti-NMDAR encephalitis, stratified by age, were retrospectively studied. Risk factors including relapse and long-term (follow-up ≥1 year) outcomes were analyzed.

RESULTS

A total of 273 patients were included between November 2011 and December 2019, and the average age of onset was 7.5 ± 4.0 years (0.5-15.8 years). Of them, 159（58.2%） were female, and the proportion of females increased with age. Seizures were the most common initial symptom. Movement disorders（86.1%） and psychiatric（82.4%） symptoms were most frequent in the acute phase. In the acute stage, the incidence of movement disorders decreased with age (χ² = 10.676, p = 0.011), while the proportion of psychiatric symptoms increased with age (χ² = 21.85, p < 0.001) The recurrence rate was 9.6% (24/250). Demyelination was an independent risk factor for relapse (p = 0.006, OR = 5.877, 95% CI: 1.658-20.835). Among the 210 patients who were followed up for more than one year, 28 patients had a poor prognosis (mRS ≥3). Onset age (p = 0.038，OR = 0.844, 95% CI: 0.720-0.991), precursor of viral encephalitis (p = 0.007，OR = 9.876, 95% CI: 1.878-51.940), and ICU admission (p = 0.023，OR = 5.924, 95% CI: 1.280-27.064) significantly affected the prognosis. The mortality rate was 2.9%.

CONCLUSIONS

The characteristics of anti-NMDAR encephalitis in children are age-dependent. Early-onset, the precursor of viral encephalitis, and ICU admission may indicate poor prognosis. Demyelination may be a risk factor for recurrence.

Neuropsychological outcomes in children and adolescents following anti-NMDA receptor encephalitis

Anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE) is a neurologic disorder that is becoming more recognized in children and adolescents. Early studies suggested that patients typically recover well, but more recent data suggests that children may experience persistent cognitive deficits, especially in verbal memory and executive functioning. The aims of this study are to evaluate areas of impairment and to characterize neuropsychological outcomes in pediatric patients with ANMDARE. This was a multi-centered retrospective chart review. We identified 23 pediatric patients who were, on average, 18.5 months from diagnosis. Patients underwent comprehensive neuropsychological assessment, including measures of intellectual functioning, memory, reading, verbal fluency, visuomotor skills, attention, and working memory. Caregiver ratings and information regarding resource utilization were also collected (e.g., formal school services, outpatient rehabilitation, psychological support). Neuropsychological impairment index (NPI) scores were calculated for each patient. Neuropsychological outcomes highlighted variability across individuals. Memory and fine motor dexterity were particularly impacted. Almost 90% of caregivers reported more concerns than average on at least one measure of emotional-behavioral, adaptive, or executive functioning. More than two-thirds of the sample were considered impaired based on NPI scores on performance measures. More than three quarters of the sample received outpatient intervention, most often consisting of school-based services. Our findings provide additional quantitative evidence that pediatric patients recovering from ANMDARE demonstrate ongoing cognitive concerns. While most patients experience remarkable recoveries following appropriate diagnosis and treatment, ongoing monitoring and support is recommended over time for these patients.

Pediatric Autoimmune Encephalitis and Its Relationship With Infection

Autoimmune encephalitis (AE) is an increasingly recognized inflammatory disorder of the central nervous system and is most often characterized by antibodies against intracellular and neuronal surface antigens. AE is a devastating disease that may result in developmental delay or regression in children. However, the pathogenesis of AE is not clear, and immune system disorders after infection likely play an important role in AE. Many studies have reported that patients with herpes simplex virus encephalitis develop anti-N-methyl-d-aspartate receptor encephalitis after antiviral treatment. It is critical to recognize pediatric AE early and to distinguish it from infectious forms because AE is treatable and responsive to immunotherapies. In this review, we discuss the clinical features of pediatric AE and focus on the relationship between AE and postinfection status. In addition, we review the probable mechanisms underlying infection-triggered AE, which include molecular mimicry, bystander activation, epitope spreading, immune system disorder, and genetic susceptibility.

Autoimmune encephalitis in a tertiary hospital in the Philippines

BACKGROUND

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

OBJECTIVE

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

METHODS

Retrospective case series of patients with definite AE.

RESULTS

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

CONCLUSION

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

High incidence of NMDAR encephalitis among Austronesians: A population-based study in Sabah, Malaysia

NMDAR encephalitis may be more common among non-Caucasians. A population-based study was conducted to estimate its incidence in Sabah, Malaysia, where the population consists predominantly of Austronesians (84%), and with a Chinese minority. Registries of NMDAR encephalitis at neurology referral centers were reviewed for case ascertainment. The annual incidence was 2.29/million (Austronesians: 2.56/million, Chinese: 1.31/million). Among pediatric population, the incidence was: Austronesians: 3.63/million, Chinese: 2.59/million. Our study demonstrated a higher incidence of NMDAR encephalitis among Austronesians than the predominantly Caucasian populations in Europe (0.5-0.9/million; pediatric: 0.7-1.5/million). Racial and genetic factors may contribute to risks of developing NMDAR encephalitis.

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

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

Management of pediatric post-infectious neurological syndromes

BACKGROUND

Post-Infectious Neurological Syndromes (PINS) are heterogeneous neurological disorders with post or para-infectious onset. PINS diagnosis is complex, mainly related to the absence of any recognized guidelines and a univocal definition.

AIM OF THE STUDY

To elaborate a diagnostic guide for PINS.

MATERIALS AND METHODS

We retrospectively analysed patients younger than 14 years old admitted to Bambino Gesù Children's Hospital in Rome for PINS from December 2005 to March 2018. Scientific literature using PubMed as research platform was analysed: the key words "Post-Infectious Neurological Syndromes" were used.

RESULTS

A polysymptomatic presentation occurred in a percentage of 88% of the children. Motor signs and visual disturbances the most observed symptoms/signs were the most detached, followed by fever, speech disturbances, sleepiness, headache and bradipsychism. Blood investigations are compatible with inflammation, as a prodromal illnesses was documented in most cases. Normal cerebral spinal fluid (CSF) characteristics has been found in the majority of the study population. Magnetic resonance imaging (MRI) was positive for demyelinating lesions. Antibiotics, acyclovir and steroids have been given as treatment.

DISCUSSION

We suggest diagnostic criteria for diagnosis of PINS, considering the following parameters: neurological symptoms, timing of disease onset, blood and CSF laboratory tests, MRI imaging.

CONCLUSIONS

We propose criteria to guide clinician to diagnose PINS as definitive, probable or possible. Further studies are required to validate diagnostic criteria.

Pediatric anti-N-methyl-d-aspartate receptor encephalitis in southern China: Analysis of 111 cases

OBJECTIVE

To study the clinical features of children diagnosed with anti-NMDAR encephalitis in southern China.

METHODS

Clinical data of children diagnosed with anti-NMDAR encephalitis from October 2014 to June 2020 from one national regional medical center were analyzed. Neurological disability was assessed by modified Rankin Scale (mRS) throughout the course of disease.

RESULTS

111 children (M/F = 49/62; mean onset age = 6.8 y) with anti-NMDAR encephalitis were involved. Prodromal events occurred in 34.2% of patients with infectious events being the most common. Seizure was the most common initial symptom, though movement disorder served as the most common event throughout the course of disease. 9.9% of patients had overlapped with other neuronal autoantibodies. Electroencephalogram showed abnormalities with slow wave (100.0%), epileptic discharge (31.5%) and delta brush (8.1%) respectively. 41.4% of patients had abnormal brain MRI, with focal lesions being the most common. None patients had tumor. 80.9% of patients had good response to first line therapy (steroid plus immunoglobulin), while 14 patients accepted second-line therapy (Rituximab) and all had a good response. Boys were significantly more likely to need more course of steroid. 13.8% of patients relapsed. 2 male patients died. mRS score was significantly improved after treatment. 51.4% of patients had a full recovery and 81.7% had mRS score ≤ 2. The median mRS score of boys after treatment was higher than that of girls. Non-infectious prodromal event, past medical history, perivascular lesions in brain MRI, hospital stay, initial mRS score higher than 3, and RTX treatment were independent risk factors associated with poor prognosis, defined as mRS score > 2.

CONCLUSION

Of pediatric anti-NMDAR encephalitis in southern China: median onset age around 7 years; girls more common; boys might have poor outcome than girls; seizure or movement disorder respectively being most common onset or course symptom; a few overlapped with other neuronal autoantibodies; rare combined with tumor; most had a good response to immunotherapy and a good prognosis; relapse rate relatively high; fatality rate relatively low; some risk factors associated with poor prognosis.

Clinical analysis of a patient simultaneously positive for antibodies of myelin oligodendrocyte glycoprotein and anti-N-methyl-D-aspartate receptor: A case report

RATIONALE

Myelin oligodendrocyte glycoprotein (MOG) antibody (MOG-Ab) disease (MOG-AD) is a type of demyelinating disease of the central nervous system characterized by a high frequency of optic neuritis (ON) attacks. anti-Nmethyl-D-aspartate receptor (NMDAR) encephalitis (anti-NMDARe) is an autoimmune disorder characterized by memory deficits, conscious disturbance, and seizures. Cases of simultaneous occurrence of MOG-Ab and anti-NMDARe antibody (anti-NMDARe-Ab) are rarely reported and could be mistaken for overlapping MOG-antibody disease (MOG-AD) and NMDARe. The diagnosis of such patients is challenging.

PATIENT CONCERNS

We report the case of a 37-year-old man who presented with recurrent headaches for 3 months and worsening symptoms over 2 weeks. He had a history of ON. He had a generalized seizure after 7 days in the hospital.

DIAGNOSIS

Brain magnetic resonance imaging (MRI) and cerebrospinal fluid tests showed no apparent abnormalities. Repeat MRI showed slight lesions 7 days later, and cerebrospinal fluid tests showed the simultaneous occurrence of MOG-Ab and anti-NMDARe-Ab.

INTERVENTIONS

He completely recovered after treatment with low doses of oral corticosteroids.

OUTCOMES

Two months and 2 years follow-up showed that his condition was stable.

LESSONS

The co-occurrence of MOG-Ab and anti-NMDAR-Ab does not indicate the co-occurrence of MOG-AD and anti-NMDARe. Laboratory findings should be combined with the clinical features to achieve an accurate and suitable diagnosis.

Efficacy and safety of rituximab in autoimmune encephalitis: A meta-analysis

BACKGROUND

Autoimmune encephalitis (AE) is a rare but debilitating neurological disease where the body develops antibodies against neuronal cell surface/synaptic proteins. Rituximab is an anti-CD20 chimeric monoclonal antibody which shows promise in AE treatment observational studies. To our knowledge, there has been no previous meta-analysis providing robust evidence on the effectiveness and safety of rituximab as second-line therapy for the treatment for AE.

METHODS

This study was conducted according to the PRISMA (Preferred Reporting Items for Systematic review and Meta-Analysis) statement. Investigators independently searched PubMed, Web of Science, Google Scholar, WANFANG, CNKI, and J-STAGE for studies. Meta-analysis via representative forest plots was conducted for good functional outcome (mRS ≤ 2), proportion of relapse, and mRS score change pre- and post-treatment.

RESULTS

Good functional outcome at last follow-up following rituximab therapy occurred in 72.2% of patients (95% CI: 66.3%-77.4%). Mean mRS score decreased by 2.67 (95% CI: 2.04-3.3; P < .001). Relapses following the rituximab therapy occurred in only 14.2% of patients (95% CI: 9.5%-20.8%). Infusion related reactions, pneumonia, and severe sepsis were seen in 29 (15.7%), 11 (6.0%), and two patients (1.1%), respectively. The efficacy and side effect profile of rituximab are comparable to outcomes seen in rituximab use in other autoimmune and inflammatory CNS disease.

CONCLUSION

Our meta-analysis showed that rituximab is an effective second-line agent for AE with an acceptable toxicity profile.

Epidemiology of paraneoplastic neurologic syndromes and autoimmune encephalitides in France

OBJECTIVE

To determine the observed and expected incidence rates of paraneoplastic neurologic syndromes (PNSs) and autoimmune encephalitides (AEs) diagnosed in France between 2016 and 2018, we conducted a population-based epidemiologic study.

METHODS

Observed incidence rates were stratified by sex, age groups, region of care, year of diagnosis, and disease subgroups. National expected incidence rates were calculated based on rates obtained in the area directly adjacent to the Reference Center using a mixed Poisson model and compared with observed incidence rates.

RESULTS

Six hundred thirty-two patients with definite PNS or AE met the inclusion criteria. The observed incidence rate of definite PNS and AE in France was 3.2 per million person-years (CI_95%: 2.9-3.4) compared with an expected incidence rate of 7.1 per million person-years (CI_95%: 3.9-11.4). The national observed incidence rate for the antibody-positive AE subgroup increased from 1.4 per million person-years (CI_95%: 1.2-1.7) in 2016 to 2.1 per million person-years (CI_95%: 1.7-2.4) in 2018, thus surpassing the incidence rate of classical PNS (1.2 per million person-years [CI_95%: 1.0-1.5]) of 2018.

CONCLUSIONS

There was a significant widespread year-to-year increase in the incidence of diagnoses registered with the Reference Center for all subgroups of PNS and AE studied. The national observed incidence rate is likely underestimated due to underdiagnosis and underreporting.

Pulmonary embolism complicated the course of anti-N-methyl-D aspartate receptor encephalitis in a pediatric intensive care unit setting: a case report

INTRODUCTION

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, an autoimmune neurological disorder resultant from the autoantibodies directed to the NR1 subunit of the NMDAR, is mainly characterized by neuropsychiatric symptoms, including behavior changes, paranoia, delusions, epileptic seizures, movement disorders, aphasia, insomnia, dysautonomia, and altered consciousness. Pulmonary embolism (PE) presents with pleuritic chest pain, hemoptysis, and respiratory distress by obstruction of the pulmonary circulation. Unlike adults, pediatric PE usually related to obvious risk factors, including central venous line, malignancy, lupus erythematosus, renal disease, congenital thrombophilia, surgery, and major trauma. Besides, PE has rarely been encountered in adult patients with anti-NMDAR encephalitis even in the absence of these risk factors.

CASE PRESENTATION

A 16-year-old male patient, with acute psychosis, epileptic seizure, and altered consciousness, was diagnosed as having anti-NMDAR encephalitis and treated by intravenous immunoglobulin and high-dose pulse intravenous methylprednisolone. During follow-up, on the 11^th day of hospitalization, the disease course was complicated by the occurrence of pulmonary embolism, presenting with acute onset respiratory distress and the need for supplementary oxygen treatment. PE improved with low-molecular-weight heparin treatment.

CONCLUSION

Pulmonary embolism should be kept in mind as a possible cause of respiratory insufficiency in pediatric anti-NMDAR encephalitis patients along with altered consciousness, breathing instability, hypersalivation, status epilepticus or dystonia, and their treatment.

Pathophysiology of paraneoplastic and autoimmune encephalitis: genes, infections, and checkpoint inhibitors

Paraneoplastic neurological syndromes (PNSs) are rare complications of systemic cancers that can affect all parts of the central and/or peripheral nervous system. A body of experimental and clinical data has demonstrated that the pathogenesis of PNSs is immune-mediated. Nevertheless, the mechanisms leading to immune tolerance breakdown in these conditions remain to be elucidated. Despite their rarity, PNSs offer a unique perspective to understand the complex interplay between cancer immunity, effect of immune checkpoint inhibitors (ICIs), and mechanisms underlying the attack of neurons in antibody-mediated neurological disorders, with potentially relevant therapeutic implications. In particular, it is reported that ICI treatment can unleash PNSs and that the immunopathological features of PNS-related tumors are distinctive, showing prominent tumor-infiltrating lymphocytes and germinal center reactions. Intriguingly, similar pathological substrates have gained further attention as potential biomarkers of ICI-sensitivity and oncological prognosis. Moreover, the genetic analysis of PNS-associated tumors has revealed specific molecular signatures and mutations in genes encoding onconeural proteins, leading to the production of highly immunogenic neoantigens. Other than PNSs, autoimmune encephalitides (AEs) comprise a recently described group of disorders characterized by prominent neuropsychiatric symptoms, diverse antibody spectrum, and less tight association with cancer. Other triggering factors seem to be involved in AEs. Recent data have shed light on the importance of preceding infections (in particular, herpes simplex virus encephalitis) in inducing neurological autoimmune disorders in susceptible individuals (those with a selective deficiency in the innate immune system). In addition, in some AEs (e.g. LGI1-antibody encephalitis) an association with specific host-related factors [e.g., human leukocyte antigen (HLA)] was clearly demonstrated. We provide herein a comprehensive review of the most recent findings in the field of PNSs and AEs, with particular focus on their triggering factors and immunopathogenesis.

Analysis of Risk Factors for a Poor Prognosis in Patients with Anti-N-Methyl-D-Aspartate Receptor Encephalitis and Construction of a Prognostic Composite Score

BACKGROUND AND PURPOSE

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most-common form of autoimmune encephalitis, but its early diagnosis is challenging. This study aimed to identify the risk factors for a poor prognosis in anti-NMDAR encephalitis and construct a prognostic composite score for obtaining earlier predictions of a poor prognosis.

METHODS

We retrospectively analyzed the clinical data, laboratory indexes, imaging findings, and electroencephalogram (EEG) data of 60 patients with anti-NMDAR encephalitis. The modified Rankin Scale (mRS) scores of patients were collected when they were discharged from the hospital. The mRS scores were used to divide the patients into two groups, with mRS scores of 3-6 defined as a poor prognosis. Logistic regression analysis was used to analyze independent risk factors related to a poor prognosis.

RESULTS

This study found that 23 (38.3%) and 37 (61.7%) patients had good and poor prognoses, respectively. Logistic regression analysis showed that age, disturbance of consciousness at admission, and ≥50% slow waves on the EEG were significantly associated with patient outcomes. An age, consciousness, and slow waves (ACS) composite score was constructed to predict the prognosis of patients with anti-NMDAR encephalitis at an early stage based on regression coefficients.

CONCLUSIONS

Age, disturbance of consciousness at admission, and ≥50% slow waves on the EEG were independent risk factors for a poor prognosis. The ACS prognostic composite score could play a role in facilitating early predictions of the prognosis of anti-NMDAR encephalitis.

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

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

Clinical manifestations, treatment outcomes, and prognostic factors of pediatric anti-NMDAR encephalitis in tertiary care hospitals: A multicenter retrospective/prospective cohort study

OBJECTIVE

Anti-NMDAR encephalitis is an acute autoimmune neurological disorder that is increasingly recognized in pediatric populations. Several studies of the disorder have been conducted worldwide but there are few publications in Thailand. Here, we describe the clinical manifestations, treatment outcomes, and prognostic factors in children with anti-NMDAR encephalitis.

METHODS

Between January 2007 and September 2017, we conducted a retrospective/prospective cohort study of children diagnosed with anti-NMDAR encephalitis from three tertiary care hospitals in Thailand: King Chulalongkorn Memorial Hospital, Chonburi Hospital, and Prapokklao Hospital. We assessed the Modified Rankin Score (mRS) score for each participant to measure severity of disease and treatment outcome at baseline, 12, and 24 months.

RESULTS

We recruited 14 participants (1-13 years with median age 8.4 years). Participants were followed up for a median of 20.5 months. Clinical manifestations included behavioral dysfunction (100%), movement disorder (93%), speech disorder (79%), sleep disorder (79%), and seizures (79%). All patients received first-line immunotherapy (corticosteroids: 100%, intravenous immunoglobulin: 79%, plasma exchange: 21%). Second-line immunotherapy (cyclophosphamide) was administered to 57% of patients. During the first 12 months, 8 patients (62%) achieved a good outcome (mRS ≤ 2). At 24 months, 9 patients (81%) had achieved a good outcome. Altered consciousness and central hypoventilation were predictors of poor outcome. (p < 0.05).

CONCLUSIONS

We observed similar clinical manifestation of anti-NMDAR encephalitis in Thai children to those reported in other countries. Furthermore, the percentage of patients with good outcomes in our study was comparable with previous studies. Further studies are required to investigate other populations in other regions of Thailand.

A review of EEG in anti-NMDA receptor encephalitis

Anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE) is common among autoimmune encephalitides (AE) and can present with protean features and nonspecific laboratory and neuroimaging results. Antibody testing is specific, but results are often delayed, and prompt diagnosis and treatment is vital given associated morbidity and mortality. Electroencephalography (EEG) may be a useful tool given ease of performance and short turn-around time for results. As such, we performed a systematic review of the literature on anti-NMDARE and EEG characteristics. We found that EEG is often pathologic in anti-NMDAR encephalitis, though at times nonspecific. A stronger focus on common EEG features in patient with this type of encephalitis and an effort to identify when these features are present in the course of the disease may allow for improved diagnosis, description and differentiation of anti-NMDARE.

Clinical variability of children with anti-N-methyl-D-aspartate receptor encephalitis in southern Brazil: a cases series and review of the literature

PURPOSE

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an immune-mediated disease of the central nervous system (CNS). The aim of this study was to describe the variability of clinical presentation in anti-NMDAR encephalitis, treatment and outcomes in a case series of children and adolescents.

METHODS

Retrospectively analyse patients diagnosed with anti-NMDAR encephalitis, from 2010 to 2018.

RESULTS

The study population consisted of nine children with anti-NMDAR encephalitis from southern Brazil, six females and three males, aged 5 months to 16 years (mean 5 years). The time of follow-up varied between 1 and 7 years, with a mean of 3 years. The most frequent first manifestation consisted of seizures. All patients described had psychiatric symptoms and a wide spectrum of neurologic findings. Five patients had unilateral symptoms. Magnetic resonance imaging and electroencephalogram were normal in most patients. Cerebrospinal fluid pleocytosis occurred in five patients. All patients were administered immunoglobulin and/or steroids. Seven patients (78%) required cyclophosphamide and/or rituximab. Almost half of the patients fully recovered from all symptoms.

CONCLUSIONS

A wide variety of symptoms were observed in this study and, although unilateral symptoms are rarely reported in the literature, a high frequency was observed among Brazilian children. Alternatives to first-line therapy should be considered in patients with clinical suspicion, even if they have not had a good response with first-line therapy.

Frequency, symptoms, risk factors, and outcomes of autoimmune encephalitis after herpes simplex encephalitis: a prospective observational study and retrospective analysis

BACKGROUND

Herpes simplex encephalitis can trigger autoimmune encephalitis that leads to neurological worsening. We aimed to assess the frequency, symptoms, risk factors, and outcomes of this complication.

METHODS

We did a prospective observational study and retrospective analysis. In the prospective observational part of this study, we included patients with herpes simplex encephalitis diagnosed by neurologists, paediatricians, or infectious disease specialists in 19 secondary and tertiary Spanish centres (Cohort A). Outpatient follow-up was at 2, 6, and 12 months from onset of herpes simplex encephalitis. We studied another group of patients retrospectively, when they developed autoimmune encephalitis after herpes simplex encephalitis (Cohort B). We compared demographics and clinical features of patients who developed autoimmune encephalitis with those who did not, and in patients who developed autoimmune encephalitis we compared these features by age group (patients ≤4 years compared with patients >4 years). We also used multivariable binary logistic regression models to assess risk factors for autoimmune encephalitis after herpes simplex encephalitis.

FINDINGS

Between Jan 1, 2014, and Oct 31, 2017, 54 patients with herpes simplex encephalitis were recruited to Cohort A, and 51 were included in the analysis (median age 50 years [IQR 5-68]). At onset of herpes simplex encephalitis, none of the 51 patients had antibodies to neuronal antigens; during follow-up, 14 (27%) patients developed autoimmune encephalitis and all 14 (100%) had neuronal antibodies (nine [64%] had NMDA receptor [NMDAR] antibodies and five [36%] had other antibodies) at or before onset of symptoms. The other 37 patients did not develop autoimmune encephalitis, although 11 (30%) developed antibodies (n=3 to NMDAR, n=8 to unknown antigens; p<0·001). Antibody detection within 3 weeks of herpes simplex encephalitis was a risk factor for autoimmune encephalitis (odds ratio [OR] 11·5, 95% CI 2·7-48·8; p<0·001). Between Oct 7, 2011, and Oct 31, 2017, there were 48 patients in Cohort B with new-onset or worsening neurological symptoms not caused by herpes simplex virus reactivation (median age 8·8 years [IQR 1·1-44·2]; n=27 male); 44 (92%) patients had antibody-confirmed autoimmune encephalitis (34 had NMDAR antibodies and ten had other antibodies). In both cohorts (n=58 patients with antibody-confirmed autoimmune encephalitis), patients older than 4 years frequently presented with psychosis (18 [58%] of 31; younger children not assessable). Compared with patients older than 4 years, patients aged 4 years or younger (n=27) were more likely to have shorter intervals between onset of herpes simplex encephalitis and onset of autoimmune encephalitis (median 26 days [IQR 24-32] vs 43 days [25-54]; p=0·0073), choreoathetosis (27 [100%] of 27 vs 0 of 31; p<0·001), decreased level of consciousness (26 [96%] of 27 vs seven [23%] of 31; p<0·001), NMDAR antibodies (24 [89%] of 27 vs 19 [61%] of 31; p=0·033), and worse outcome at 1 year (median modified Rankin Scale 4 [IQR 4-4] vs 2 [2-3]; p<0·0010; seizures 12 [63%] of 19 vs three [13%] of 23; p=0·001).

INTERPRETATION

The results of our prospective study show that autoimmune encephalitis occurred in 27% of patients with herpes simplex encephalitis. It was associated with development of neuronal antibodies and usually presented within 2 months after treatment of herpes simplex encephalitis; the symptoms were age-dependent, and the neurological outcome was worse in young children. Prompt diagnosis is important because patients, primarily those older than 4 years, can respond to immunotherapy.

FUNDING

Mutua Madrileña Foundation, Fondation de l'Université de Lausanne et Centre Hospitalier Universitaire Vaudois, Instituto Carlos III, CIBERER, National Institutes of Health, Generalitat de Catalunya, Fundació CELLEX.