Clinical Characteristics and Prognostic Factors of Children With Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Pediatric Autoimmune Encephalitis: A Nationwide Study in Latvia

BACKGROUND

 Autoimmune encephalitis (AE) is the third most common encephalitis in children. Diagnosis can be challenging due to overlapping and diverse clinical presentations as well as various investigation results. This study aims to characterize the clinical, diagnostic features, as well as treatment and outcomes of AE in children and determine the incidence of pediatric AE in Latvia.

METHODS

 The study was conducted at the Children's Clinical University Hospital in Riga. The study participants were patients under the age of 18 years diagnosed with AE from 2014 to 2022. Data regarding clinical characteristics, investigation findings, treatment strategy, and outcomes were retrospectively collected from the medical history data system.

RESULTS

 We included 18 pediatric patients diagnosed with AE. The mean incidence of pediatric AE in Latvia was 0.56 per 100,000 children. Most patients (66.6%) had seronegative AE. In the seropositive group, the most common was anti-methyl-D-aspartate receptor AE, with two patients having other antibodies. The most prevalent clinical features were personality change, cognitive impairment, autonomic dysfunction, and movement disorders. The majority of patients (58.8%) received first-line treatment only. More than half (55.6%) of our AE patient group had long-term sequelae.

CONCLUSIONS

 Our study shows that the pediatric AE incidence in Latvia is similar to what has been previously reported in other studies. A relatively high proportion of seronegative AE was present in our cohort, indicating that awareness of possible misdiagnosis should be raised. Further research is needed to better understand the underlying mechanisms, characterize clinical features, and determine the treatment of choice in different situations to improve long-term outcomes.

Pediatric anti-NMDAR encephalitis with demyelination on brain MRI: A single center study

OBJECTIVE

To explore the clinical characteristics, immunotherapy response, and prognosis of pediatric anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis associated with demyelination on brain magnetic resonance (MRI).

METHODS

We retrospectively reviewed the medical records of children diagnosed with anti-NMDAR encephalitis in our hospital between January 2016 and December 2021. All children with evidence of demyelination on brain MRI were included.

RESULTS

A total of 183 anti-NMDAR encephalitis children were included; 8.7 % (16/183) of them had demyelination on brain MRI. Nine were positive for myelin oligodendrocyte glycoprotein (MOG)-IgG, while two were positive for both MOG-IgG and glial fibrillary acidic protein (GFAP)-IgG. Four patients had a history of acquired demyelinating syndromes and encephalitis, respectively, while nine (56.3 %) had atypical symptoms of anti-NMDAR encephalitis. All children had supratentorial demyelination on brain MRI; four of them had additional infratentorial lesions. All children received first-line immunotherapy; four were administered repeated first-line immunotherapy and/or rituximab because of poor initial response. During the follow-up, 37.5 % (6/16) of the children relapsed, but all responded well to immunotherapy. There were no significant differences in mRS score before immunotherapy, response to first-line immunotherapy, and long-term prognosis between anti-NMDAR encephalitis children with and without demyelination. However, patients with demyelination were more likely to have a history of acquired demyelinating syndromes or unexplained cortical encephalitis and to relapse.

CONCLUSION

Pediatric anti-NMDAR encephalitis can co-occur with demyelination and has a high rate of MOG-IgG positivity. A history of acquired demyelinating syndromes or unexplained cortical encephalitis and atypical symptoms may indicate demyelination in children with anti-NMDAR encephalitis. Pediatric anti-NMDAR encephalitis with demyelination is more likely to relapse and needs a closer follow-up. However, it remains unknown whether more intensive immunotherapy is required in these patients.

Effectiveness of intra-thecal methotrexate in refractory Anti-N-methyl-d-aspartate receptor encephalitis

BACKGROUND

Anti-N-methyl-d-aspartate "anti-NMDA" receptor encephalitis is one of the most common autoimmune encephalitis for which first- and second-line therapies have been recommended following international consensus. However, some refractory cases do not respond to the first- and second-line therapy and require further immune-modulatory therapies such as intra-thecal methotrexate. In this study, we reviewed six confirmed cases of refractory anti-NMDA receptor encephalitis from two tertiary centers in Saudi Arabia that required escalation of treatment and received a six-month course of intra-thecal methotrexate. The aim of this study was to evaluate the effectiveness of intra-thecal methotrexate as immunomodulatory therapy for refractory anti-NMDA receptor encephalitis.

METHODS

We retrospectively evaluated six confirmed cases of refractory anti-NMDA receptor encephalitis who did not improve after first- and second-line therapy and received monthly intra-thecal methotrexate treatment course for six consecutive months. We reviewed patient demography, underlying etiologies, and compared their modified Rankin score prior to receiving intra-thecal methotrexate and six months after completing the treatment.

RESULTS

Three of the six patients showed a marked response to intra-thecal methotrexate with a modified Rankin scale of 0-1 at 6-month follow-up. None of the patients experienced any side effects during or after intra-thecal methotrexate treatment, and no flareups were observed.

CONCLUSION

Intra-thecal methotrexate may be a potentially effective and relatively safe escalation option for immunomodulatory therapy of refractory anti-NMDA receptor encephalitis. Future studies on intra-thecal methotrexate -specific treatment regimens may further support its utility, efficacy, and safety in treating refractory anti-NMDA receptor encephalitis.

Validity and prognostic utility of clinical assessment scale for autoimmune encephalitis (CASE) score in children with autoimmune encephalitis

INTRODUCTION

The clinical assessment scale for autoimmune encephalitis (CASE) is a recently developed and validated scale to rate the severity of autoimmune encephalitis (AE) in adults. But it is yet to be validated in pediatric AE cases.

METHODS

In a prospective observational study, we determined the validity and prognostic utility of CASE in the pediatric population with a diagnosis of probable or definite AE. We also determined clinical, neuroimaging, or laboratory-based prognostic factors for favorable clinical outcomes at 3 months after presentation. We used weighted kappa statistics and the intra-class correlation coefficient of individual item scores and total scores for determining inter-observer and intra-observer reliability respectively.

RESULTS

We enrolled a total of 54 patients (28 girls, probable [45%] or definite [55%] AE). Functional status score (FSS), CASE score, and other scores showed significant improvement at the time of discharge and 3-months, as compared to baseline (p < 0.0001). The intra-observer and interobserver reliability of the total scores was excellent (k = 0.94 and 0.95 respectively). CASE was also found to have good internal consistency (Cronbach-α = 0.83). The corrected item-total correlations of all items were >0.40. The correlation between the total CASE score and FSS score at admission, at discharge, and at 3 months was strong (r = 0.90, 0.92, and 0.94, p < 0.001). In multivariate analysis, only seropositivity or definite AE and CASE score at baseline was found to be significant predictive factors for functional status at 3 months (p = 0.03, 0.01).

CONCLUSION

CASE score can be used for monitoring the severity of pediatric AE patients. It also has prognostic usefulness for predicting functional independence on follow-up.

Recent research on immunotherapy for anti-N-methyl-D-aspartate receptor encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a central nervous system disease characterized by neurological and psychiatric symptoms. Immunotherapy is the basic treatment for this disease, including first- and second-line therapies for the acute stage and the long-course therapy for the chronic stage. Anti-NMDAR encephalitis often has a good prognosis, but some patients may still have neurological dysfunction due to poor response to current immunotherapy. In addition, the adverse reactions and economic burden of drugs are practical problems in clinical practice. To solve the above problems, continuous improvements have been made in immunotherapy regimens in terms of dose, route of administration, and course of treatment, and some new immunotherapy drugs have emerged. This article reviews the recent research on immunotherapy for anti-NMDAR encephalitis.

Autoimmune Encephalitis

Autoimmune encephalitis is a common and treatable cause of encephalitis in children and adults. Individuals present with a variety of symptoms, including altered mental status, behavioral changes, irritability, insomnia, developmental regression, seizures, dyskinetic movements, and autonomic instability. Evaluation includes electroencephalography, magnetic resonance imaging, and lumbar puncture. Once infectious and other causes are reasonably ruled out, treatment should be started empirically without waiting for antibody confirmation. Early clinical suspicion is key, as the outcome depends on early initiation of immunotherapy, including corticosteroids, intravenous immunoglobulin, and/or plasmapheresis. Severe or refractory cases require other treatments, such as rituximab, cyclophosphamide, or other immunotherapies using novel monoclonal antibodies. Psychiatry should be involved early for the management of behavioral issues. Additional considerations include management of seizures and dyskinesias. ICU admission may be required for management of hypoventilation necessitating mechanical ventilation (either intrinsic or iatrogenic, eg, from sedatives), refractory seizures, and dysautonomia. Anti-N-methyl-d-aspartate receptor and other forms of autoimmune encephalitis are less often associated with neoplasia (such as ovarian teratoma) in children compared with adults, but screening and removal of tumor if present should be performed.

A Systematic Review of Severe Neurological Manifestations in Pediatric Patients with Coexisting SARS-CoV-2 Infection

SARS-CoV-2 infection in children produces mild respiratory symptoms or no symptoms at all in most cases. Some pediatric patients develop a severe complication associated with high mortality, the multisystem inflammatory syndrome in children (MIS-C). In both scenarios, there are reports of neurological manifestations. This article aims to review the cases of pediatric patients with severe neurological issues and a coexisting positive SARS-CoV-2 test. A literature search was performed between March 2020 and May 2021. The results included the data from 41 studies, with 159 children with severe neurological manifestations, within an age range from 24 h to 17 years. The neurological disorders included 38 cases with stroke, 32 with encephalitis, 22 with encephalopathy, and 10 with Guillain–Barre syndrome. Sixty-five out of 159 cases with severe neurological manifestations were diagnosed with MIS-C. Direct neuroinvasion and the exaggerated immune response in some patients seem to be the most critical factors triggering these manifestations. Further research in the ongoing pandemic is needed to elucidate the precise mechanism.