Clinical Features and Outcomes of Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Infants and Toddlers

Clinical Presentation, Management, and Diagnostic Performance of 2021 Criteria for Paraneoplastic Neurologic Syndromes in Childhood

BACKGROUND AND OBJECTIVES

Paraneoplastic neurologic syndromes (PNSs) are remote neurologic immune-related effects of tumors. The clinical characteristics of pediatric PNSs remain unclear. We retrospectively examined the clinical characteristics of cases of pediatric PNSs and assessed the performance of the 2021 diagnostic criteria in children.

METHODS

Patients hospitalized in the Beijing Children's Hospital between June 2015 and June 2023 and fulfilling the description of definite by 2004 diagnostic criteria of PNSs were included. A retrospective analysis of clinical characteristics was conducted, and the 2021 diagnostic criteria were applied to rediagnostic stratification.

RESULTS

Among the 42 patients included, the most common neurologic syndrome was opsoclonus-myoclonus syndrome (OMS) (62%), followed by rapidly progressive cerebellar syndrome (26%). Most tumors were neuroblastomas (88%), with few being ovarian teratomas (10%). Approximately 71% (30/42) of patients were classified as definite and 24% (10/42) as probable according to the 2021 criteria. All cases judged as probable exhibited rapidly progressive cerebellar ataxia with neuroblastoma. For OMS, chemotherapy was administered based on the tumor's risk stage, accompanied by regular infusion of IV gamma globulin and oral steroids following tumor diagnosis. Twenty-one patients underwent regular follow-ups over 4.92 (0.58-7.58) years. The initial hospitalization recorded a median score of 12 (7-14) on the Mitchell and Pike OMS rating scale, decreasing to 0 (0-5) at the final follow-up. In cases of rapidly progressive cerebellar syndrome, a similar therapeutic regimen was used. Nine patients underwent regular follow-ups over 4.42 (1.17-7.50) years. The mean modified Rankin scale score at first hospitalization was 4 (3-4), reducing to 1 (0-4) at the final follow-up. Only 17% (5/30) of patients across both groups exhibited poor response to this regimen. Among these 5 patients, 4 belonged to the low-risk group (without chemotherapy).

DISCUSSION

OMS followed by rapidly progressive cerebellar ataxia are the most common forms of PNSs in children and are associated with neuroblastoma. An aggressive approach with multiple immunotherapies may improve the prognosis of neuroblastoma-associated PNSs. The 2021 criteria perform well in pediatric PNSs. However, we propose upgrading the classification of antibody-negative rapidly progressive cerebellar ataxia with neuroblastoma to definite diagnosis. This adjustment aims to further improve the diagnostic efficacy of this diagnostic criterion in childhood.

Evaluation, Treatment, and Outcomes of Viral and Autoimmune Encephalitis in Children

Viral encephalitis and autoimmune encephalitis are currently the most common causes of encephalitis. Determining the causative agent is helpful in initiating medical treatment that may help reduce long-term sequelae. Cerebrospinal fluid, neuroimaging, serologic, and electroencephalogram in combination with clinical manifestations play a role in determining the cause of the encephalitis. Although motor dysfunction tends to improve, there is a significant risk of long-term neurologic and cognitive sequelae. These persistent deficits that occur in childhood indicate the importance for ongoing rehabilitative services to maximize functional skills, improve cognitive deficits, and assist with community integration.

Emphasizing Pulmonary Function With Respiratory Therapy in an Infant With Congenital Adrenal Hyperplasia, Bronchopneumonia and Leptomeningitis

A set of hereditary diseases affecting the adrenal glands, a couple of walnut-sized structures above the kidneys, is known as congenital adrenal hyperplasia (CAH). The adrenal glands generate essential hormones like cortisol, mineralocorticoids, and androgens. It is usually diagnosed in the early neonatal period. The documentation of this case study is aimed to provide a case of an infant with CAH associated with bronchopneumonia and leptomeningitis. Brought with complaints of poor feeding, moderate fever associated with chills, and loose stools, was an 11-months-old patient with a known diagnosis of CAH. Symptoms have shown that the baby was in a possible adrenal crisis. He was intubated with an endotracheal tube after repeated episodes of seizures. Investigations revealed signs of bronchopneumonia and leptomeningitis. A thorough assessment, once completed, helped in analyzing relevant problems to be treated with respiratory therapy. Respiratory therapy, in this case, was aimed at improving the blood oxygen levels and assisting breathing by clearing out secretions and opening up the airways. Parent education was the foremost part of the treatment regime, followed by bronchodilator administration, conventional chest physiotherapy, postural drainage positions in the mother’s lap, lung squeezing technique, and perioral pressure. A holistic and multidisciplinary approach is beneficial in patients with CAH undergoing an adrenal crisis. It needs to be offered to the patients who would be benefited, considering the effect, which needs to be reassessed on specific outcomes with changes in the management with the improving condition.

External Assessment of the Anti-N-Methyl-D-Aspartate Receptor Encephalitis One-Year Functional Status Score in Chinese Pediatric Patients

Objective

to assess the performance of the Anti-N-Methyl-D-Aspartate Receptor encephalitis (NMDAR) One-Year Functional Status (NEOS) score in predicting one-year functional outcome in Chinese children with anti-NMDAR encephalitis.

Methods

children with anti-NMDAR encephalitis at the Children’s Hospital of Chongqing Medical University were retrospectively enrolled from January 2014 to December 2020. Patients were categorized into two groups based on the modified Rankin Scale (mRS) at one-year follow-up. Discrimination of the NEOS score was assessed by the area under curve (AUC) of the receiver operating characteristic curve. Calibration of the NEOS score was assessed by comparing predicted probabilities with observed probabilities using a calibration curve and the Hosmer-Lemeshow test. The clinical practicability of the NEOS score was evaluated by performing a decision curve analysis.

Results

one hundred seventy-five children (101 females and 74 males) with anti-NMDAR encephalitis and a median age of 7.7 years were enrolled. Of those, 149 (85.1%) had a good outcome at 1 year (mRS ≤ 2), and the remaining 26 (14.9%) had a poor outcome (mRS > 2). Patients with a higher NEOS score had a significantly higher mRS at one-year follow-up [Spearman r = 0.3878, 95% confidence interval (CI): 0.2500-0.5103, P < 0.001]. The AUC of the NEOS score was 0.870 (95% CI: 0.801-0.938, P < 0.001). The observed probability and predicted probability showed moderate consistency in the calibration curve and the Hosmer-Lemeshow test (P = 0.912). The decision curve analysis showed that using the NEOS score to predict one-year outcomes could provide additional net benefit during clinical practice.

Conclusions

the NEOS score is a potentially reliable model to predict the one-year functional outcome in Chinese children with anti-NMDAR encephalitis.

Arterial spin labeling perfusion imaging in an infant with anti-N-methyl-D-aspartate receptor encephalitis: A case report

BACKGROUND

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an autoimmune encephalitis characterized by complex neuropsychiatric syndromes and the presence of cerebrospinal fluid (CSF) antibodies against NMDAR. The characteristics of anti-NMDAR encephalitis in children, particularly infants, are unclear due to difficulties in neurologic assessment such as psychiatric symptoms. Additionally, subtle or non-specific findings of conventional magnetic resonance imaging (MRI) make early diagnosis even more difficult. Herein, we present the first case of infant anti-NMDAR encephalitis in which perfusion imaging demonstrated marked abnormalities and the absence of conventional MRI findings.

CASE PRESENTATION

The patient was an 11-month-old boy who was admitted because of seizure and prolonged fever. He presented with involuntary movements of the mouth and tongue. Brain MRI showed no morphological abnormalities, but three-dimensional arterial spin labeling (ASL) perfusion imaging showed reduced blood flow in the left temporal and frontal regions and the right cerebellum. After that, a positive anti-NMDAR antibody test result was received. Despite treatment with IVIG and methylprednisolone, the involuntary movements and autonomic dysfunction gradually became more prominent. After rituximab administration, the clinical symptoms improved slightly, and follow-up MRI revealed diffuse brain atrophy and improvement in the balance of brain perfusion.

CONCLUSIONS

To the best of our knowledge, this is the first case report of infantile anti-NMDAR encephalitis in which cerebral blood flow was evaluated using three-dimensional ASL perfusion imaging. Indeed, our case, which showed abnormalities only in ASL perfusion imaging, suggests that CBF assessment could aid in the early diagnosis of anti-NMDAR encephalitis in infants.

Clinical Characteristics of Children With Anti-N-Methyl-d-Aspartate Receptor Encephalitis After Japanese Encephalitis

BACKGROUND

Viral encephalitis is an important trigger for anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. We analyzed the clinical characteristics of anti-NMDAR encephalitis after Japanese encephalitis (JE) in children.

METHODS

Clinical data of 185 children with anti-NMDAR encephalitis were retrospectively reviewed. Patients with a history of viral encephalitis other than JE or who were identified with other autoantibodies were excluded.

RESULTS

Twenty children with anti-NMDAR encephalitis after JE were enrolled with a median age of 6 years and 10 months (interquartile range [IQR]: 3 years to 11 years and 5 months). The median time from JE to anti-NMDAR encephalitis was 29 (IQR: 25 to 32) days. At 12 months, most patients (17 of 18) recovered to at least their baseline modified Rankin scale (mRS) scores caused by JE. One hundred forty two children with classical anti-NMDAR encephalitis were enrolled. Compared with classical anti-NMDAR encephalitis, patients after JE had significantly more decreased level of consciousness (50% vs 18.3%, P = 0.003), more autonomic dysfunction (30.0% vs 9.9%, P = 0.021), fewer psychiatric or behavioral symptoms (70.0% vs 90.8%, P = 0.016), fewer seizures (25.0% vs 68.3%, P < 0.001), lesser improvement 4 weeks after immunotherapy (35.0% vs 73.2%, P = 0.001), and worse outcomes at 12 months (median mRS: 1 vs 0, P < 0.001).

CONCLUSIONS

Anti-NMDAR encephalitis after JE in children mainly occurred within two months. Their clinical manifestation may differ from classical anti-NMDAR encephalitis. The prognosis of children with anti-NMDAR encephalitis after JE probably depends on the neurological sequelae after JE.