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

Aim

The study aims to analyze the incidence, clinical features, investigation findings and treatment outcomes of anti-N-methyl-d-aspartate receptor encephalitis in children from Hong Kong.

Autoimmune encephalitis: Recent updates and emerging challenges

The knowledge of immune dysregulation and autoimmunity in neurological disorders has expanded considerably in recent times. Recognition of clinical syndromes, reliable methods of diagnosis, and early targeted immunotherapy can lead to a favourable outcome in acute and subacute neurological disorders that may be associated with significant morbidity and mortality if left untreated. This review focuses on the rapidly expanding field of autoimmune encephalitis. We describe the differences between limbic encephalitis associated with antibodies targeting intracellular antigens, and neuronal surface antibody syndromes (NSAS) where the antigens are primarily receptors or synaptic proteins located on the neuronal cell surface. We chronologically highlight important developments in NSAS by focusing on voltage gated potassium channel complex-associated antibody mediated encephalitis, anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis, and anti-dopamine 2 receptor antibody-associated basal ganglia encephalitis. Contentious issues such as the complexities of using serum antibodies as biomarkers, the initiation of central nervous system autoimmunity, and possible pathogenic mechanisms of these antibodies will be reviewed. The therapeutic challenges that clinicians face such as the timing of therapy and the role of second-line therapy will be discussed, with crucial concepts highlighted in the form of clinical vignettes. Future directions will involve the identification of novel antigens and methods to establish their pathogenicity, as well as evaluation of the most efficacious therapeutic strategies in patients with established NSAS.     

Anti-N-methyl-D-aspartate receptor encephalitis associated with hepatic neuroendocrine carcinoma: A case report

Anti-N-methyl-D-aspartate receptor (Anti-NMDAR) encephalitis can present with and without tumor. Tumor associations are less common in older patients. We report a 65-year-old gentleman who presented with one week history of cough, chills, rigor and altered behavior, followed by florid visual and auditory hallucinations. Mini mental status examination score was 16/30. Both cerebrospinal fluid and plasma anti-NMDA receptor antibodies were detected. A course of intravenous methylprednisolone was given with partial symptom improvement. A hepatic neuroendocrine carcinoma was detected and confirmed on biopsy. Unfortunately, he developed several medical complications: non-ST elevation myocardial infarction, infected foot gangrene and peripheral vascular disease, which made him unsuitable for both surgery and chemotherapy. He passed away 6 months later due to the progression of the malignancy. This case illustrated that NMDAR encephalitis may be associated with an uncommon hepatic neuroendocrine carcinoma in an older person, which is responsive to early treatment.     

Characterisation of a syndrome of autoimmune adult onset focal epilepsy and encephalitis

We report a series of patients with a clinical syndrome characterised by the explosive onset in adulthood of recurrent focal seizures of frontotemporal onset and features suggestive of autoimmune encephalitis. We propose that this presentation of “autoimmune adult onset focal epilepsy and encephalitis” is a recognisable clinical syndrome, and provide evidence it may be associated with heterogeneous immunological targets. Between 2008 and 2011 we encountered six patients with new-onset epilepsy in whom we suspected an autoimmune aetiology. We first characterised the clinical, electroencephalographic, cerebrospinal fluid (CSF), imaging, and pathological findings of this syndrome. We subsequently tested them for antibodies against both intracellular and neuronal cell surface antigens. All patients presented with recurrent seizures with focal frontotemporal onset, refractory to multiple anticonvulsants. Four had focal T2-weighted hyperintensities on MRI. CSF mononuclear cells were variably elevated with positive oligoclonal bands in four. Brain biopsy in one patient demonstrated perivascular lymphocytic infiltration. Two were treated with immunosuppression and went on to achieve complete seizure control and return to baseline cognition. Three of four patients who received only pulsed steroids or no treatment had ongoing frequent seizures, with two dying of sudden unexpected death in epilepsy. Subsequently, three had antibodies identified against neuronal cell surface antigens including N-methyl-d-aspartate receptor and leucine-rich glioma inactivated 1. We suggest that patients with such a presentation should be carefully evaluated for a suspected autoimmune aetiology targeting cell surface antigens and have a therapeutic trial of immunosuppression as this may improve their long-term outcome.     

Clinical analysis of psychiatric symptoms of Japanese encephalitis during the convalescent Period: A single center study in Chongqing,China

BackgroundThis study aimed to analyze clinical and imaging features of children with severe Japanese encephalitis (JE), and to analyze causes and solutions for psychiatric symptoms of JE during the convalescent period.MethodsWe analyzed clinical information for 78 children with severe JE at the Department of Neurology, Department of Infection, and Department of Rehabilitation in our hospital during 2014–2016. Seventy-eight cases of severe JE were divided into patients with psychiatric symptoms and no psychiatric symptoms groups. We focused on analysis of the patients with psychiatric symptoms group.ResultsThe incidence of psychiatric symptoms during the convalescent period was 46.15% (36/78). Antipsychotic drugs can effectively control psychiatric symptoms and shorten duration of symptoms. Seventy-one patients underwent reexamination with a head MRI. Of these, 8 cases (8/36 = 22.22%) in patients with psychiatric symptoms group showed new lesions in the basal ganglia, insula, and hippocampus. During the 12-month follow-up, two cases showed reappearance of psychiatric symptoms that had been relieved previously.ConclusionThis study found that severe JE cases revealed a considerable proportion with psychiatric symptoms during the convalescent period.     

成年和儿童日本脑炎患者的临床分析

目的研究成年和儿童日本脑炎患者的临床差异。方法回顾性分析2004-07~2006-09我院治疗的日本脑炎患者,分为成年组和儿童组(<14岁,不包括新生儿),评定其临床资料和3个月时的预后。结果72.9%的患者来自经济卫生条件差的农村,14名成年(60.9%)和22名儿童(88%)患者出现癫发作(χ2=4.70,P<0.05)。2组患者在神经功能缺失、影像学及脑脊液分析方面无明显差异。成年患者急性期病死率高,而3个月时成年生存患者的预后好(χ2=7.96,P<0.05)。结论成年患者急性期病死率高,3个月时的预后较好;癫发作少见于成年患者,2组脑电图也有不同表现。上述差异可能与免疫因素、神经元可塑性及分化相关。     

N-methyl D-aspartate receptor encephalitis: A new addition to the spectrum of autoimmune encephalitis

A large proportion of “encephalitis” is caused by unknown agents. Of late, a new category of disorders, “autoimmune encephalitis,” has been described, which present with features similar to viral encephalitides. A well-delineated and common entity among this group is the recently described anti-NMDAR encephalitis (NMDARE). Although this entity was initially described in young women harboring ovarian teratomas, it is now characterised as well in children and men. Approximately 60% of the patients have an underlying tumor, usually an ovarian teratoma. In 40% of the patients, no cause can be found (idiopathic NMDARE). NMDARE typically presents with psychiatric features followed by altered level of consciousness, severe dysautonomia, hyperkinetic movement disorders, seizures and central hypoventilation. Orofacial dyskinesias resulting in lip and tongue mutilation are quite common. Seizures, are common and may be difficult to treat. The disease can be confirmed by serum and cerebrospinal fluid anti-NMDAR antibodies. Titers of these antibodies can also guide response to treatment. Tumor removal is necessary if identified, followed by immunological treatment. Intravenous methylprednisolone and immunoglobulins aim to suppress/modulate immune response while plasma exchange attempts to remove antibodies and other inflammatory cytokines. Rituximab and cyclophosphamide aim to suppress antibody production. Recovery is slow and often with neurological deficits if treatment is delayed. With many distinctive clinical features, a specific antibody that aids diagnosis, and early effective treatment with commonly available drugs leading to good outcomes, NMDARE is a diagnosis that should be considered early in any case of “unexplained encephalitis.”     

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

ObjectiveAnti-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.MethodsBetween 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.ResultsWe 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).ConclusionsWe 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.     

Suppression of synaptic plasticity by cerebrospinal fluid from anti-NMDA receptor encephalitis patients

The functional effects of cerebrospinal fluid (CSF) from patients with anti-NMDA receptor (NMDAR) encephalitis on the NMDAR-mediated synaptic plasticity were evaluated by using mouse hippocampus slices. Anti-NMDAR antibody detection system was established by immunostaining recombinant NMDAR heteromers expressed in HEK cell culture as well as native NMDARs in cultured hippocampal neurons. Under a complete blind manner for the clinical information, CSF and sera collected from 36 pre-diagnosed patients were tested for anti-NMDAR antibodies. With this test, thirteen patients were diagnosed as anti-NMDAR encephalitis. CSF positive for anti-NMDAR antibodies suppressed induction of long-term potentiation (LTP) at Schaffer collateral-CA1 synapses in mouse hippocampal slices. LTP induction was not suppressed by CSF collected from herpes simplex virus (HSV) encephalitis or non-encephalitis control patients. Antibody absorption with NMDAR-expressing HEK cell culture reversed the suppression of LTP by anti-NMDAR encephalitis patients' CSF, confirming that anti-NMDAR antibodies suppressed LTP. The present experiments firmly support the proposal that the anti-NMDAR encephalitis autoantibody is responsible for cognitive disorders like amnesia accompanying this disease.     

Hyperammonemia in a case of herpes simplex and anti-N-methyl-d-aspartate receptor encephalitis

Herpes simplex encephalitis (HSE) is a widely accepted risk factor for anti N-methyl-d-aspartate receptor (NMDAR) encephalitis. Association of inherited metabolic disease has never been reported in a patient with HSE and anti-NMDAR encephalitis. Herein, we report a case of pediatric HSE complicated by development of anti-NMDAR encephalitis; this patient showed subsequent recurrent, unexplained episodes of encephalopathy associated with hyperammonemia. The patient was diagnosed with lysinuric protein intolerance (LPI), a rare inborn metabolic disorder. Although it would be difficult to make conclusions regarding the casual link of HSE and anti-NMDAR encephalitis with LPI from a single case, there have been many reports that autoimmune diseases and immunologic abnormalities are frequently associated with LPI. Thus, we speculate that LPI may contribute to the development of anti-NMDAR encephalitis following HSE.     

Japanese encephalitis in Western Europe

Japanese encephalitis is the leading cause of viral encephalitis in Asia. In Western Europe, however, Japanese encephalitis has not been reported so far.     

Movement disorders in Japanese encephalitis

Movement disorders in Japanese encephalitis (JE), although reported, have not been analyzed systematically. In this study, we report an analysis of movement disorders in 14 out of 17 JE patients, correlated with the radiological findings. All patients had at least a four fold rise of IgG antibodies against JE in a haemagglutination inhibition test. The patients’ ages ranged between 2 and 54 years and 4 of them were women. Extrapyramidal signs, such as hypokinesia, hypophonia and masking of the face, were present in all patients by the first month as the patients came out of the coma – except for 1 patient. Eight patients had axial and 3 tongue dyskinesia; rigidity was present in 6 and tremor in 2 patients. At 3 months, these symptoms improved considerably in 6 patients. Cranial CT scan revealed thalamic involvement in 10, which was bilateral in 9 patients. Two patients had brain stem and one had cerebellar involvement. Cranial MRI was carried out in 9 patients and revealed additional findings in lentiform nucleus, midbrain and pons in 3 each and cerebellum in 4 patients. Bilateral thalamic involvement on MRI was seen in all the patients, including two patients whose CT scans were normal. SPECT studies using ^99mTc-ECD revealed bilateral thalamic hypoperfusion in all (n = 7) and frontal hypoperfusion in 3 patients. In JE, movement disorders are common and may be due to thalamic involvement in isolation or in combination with basal ganglia or midbrain or both. Received: 19 August 1996 Received in revised form: 6 January 1997 Accepted: 13 January 1997     

Transient extreme spindles in a young child with anti-NMDAR encephalitis: A case report

Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is a type of immune-mediated encephalitis, which is a new category of treatment-responsive paraneoplastic encephalitis. In patients with this disease, electroencephalography (EEG) shows non-specific findings, but recently, a unique EEG pattern, named the extreme delta brush, was detected in 40% of adult patients and was suggested to be specific to this type of encephalitis. Here, we describe a two-year-old boy with anti-NMDAR encephalitis, who presented with speech arrest and disturbances of gait and cognition several weeks after developing febrile convulsions. In the early stages of the disease, EEG showed 14–16?Hz, continuous, fast waves characterized by a high amplitude (200–500?µV), very diffuse spreading, and a sharp morphology, during light sleep only, which was compatible with extreme spindles. As the patient’s symptoms worsened, this finding was replaced by rhythmic, diffuse, high-voltage, slow waves. Immediately after immunomodulatory therapies, including intravenous methylprednisolone and immunoglobulin, his clinical manifestations and EEG abnormalities appeared to improve. We propose that although the extreme spindle is a non-specific finding of this type of encephalitis, early EEG monitoring might be necessary to detect not only the extreme delta brush pattern, but also non-specific findings, including extreme spindles, which would aid early diagnosis and treatment.     

日本脑炎28例患者的预后分析

目的评估日本脑炎(JE)患者预后的影响因素。方法回顾性分析2004年7月～2008年9月我院治疗的28例JE患者,评定其临床资料及6个月时预后。结果 28例JE患者6个月时随访,9名患者死亡,8名患者预后差,生活不能自理。结论呼吸衰竭、癫、深昏迷(GCS<6)、颅内压显著增高(>240mmH2O)和脑电图异常及影像学病变范围广与结局差相关(P<0.05),而呼吸衰竭、频发癫(>2次)、颅内压显著增高和深昏迷与死亡密切相关(P<0.05)。积极控制成年JE患者出现的癫发作和高颅压可能是改善预后的关键措施。     

视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎1例

目的 探讨视神经脊髓炎合并抗N-甲基-D-天冬氨酸(NMDA)受体脑炎的临床特征。方法 报道本院收治的1例视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎的临床特点及诊治经过,并结合文献分析该病的特征。结果 患者为21岁女性,表现为腹泻后急性起病的下肢麻木无力、昏睡、视物模糊; MRI示双侧基底节、海马、桥臂、齿状回、延髓背侧多发异常信号,同时伴有颈髓多发条片状长T₂异常信号。脑脊液NMDA受体抗体阳性,血清和脑脊液水通道蛋白4(AQP4)抗体阳性,合并心动过缓并发症,筛查未发现肿瘤; 经激素冲击、丙种球蛋白及免疫抑制剂治疗后症状逐渐好转至痊愈。结论 视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎可以在感染后起病,症状和影像学主要表现为两种疾病的叠加,可出现心动过缓并发症,早期积极行免疫治疗效果较好。     

Altered perception might be a symptom of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis

ABSTRACT

Most patients with N-methyl-D-aspartate receptor (NMDAR) encephalitis initially present with psychiatric symptoms. Although a delayed diagnosis may lead to a poor outcome, psychiatric symptoms that could differentiate anti-NMDAR encephalitis from other psychoses have not been fully investigated. We evaluated two patients with anti-NMDAR encephalitis who were observed by psychiatrists from onset throughout the course of disease. Both patients exhibited disorientation, memory deficits, perceptual disturbances, hallucinations, and mood liability. Among those, altered perceptions were most prominent - in particular, altered time perceptions without disorganization syndrome. The information obtained for these patients may help clinicians differentiate anti-NMDAR encephalitis from other psychoses, e.g., schizophrenia.     

Characteristic residual neuropathological features of Japanese B encephalitis

Summary Characteristic residual (12–67 years) neuropathological features of 4 verified or suspected cases of Japanese B encephalitis (JBE) are reported. These features are summarized as: 1. unique distribution pattern of the main lesions, i.e. combination of lesions in the thalamus, substantia nigra and Ammon's horn. Lesions in the thalamus consistently involved, in a linear fashion, lamina medullaris medialis with nucleus intralaminalis and adjacent portions of the nucleus lateralis thalami. Lesions in the substantia nigra usually occupied the middle parts of zona compacta. These lesions were usually symmetrical, though unequal in extent. 2. Unique nature of the lesions, especially those in the thalamus and substantia nigra. Characteristic light circumscribed foci (LCF), which consisted of small rarefied areas, with few cellular and fibrous elements, surrounded by dense gliomesenchymal scarring, were observed there and occasionally in cerebral cortices. Lesions were thought to be vestiges of circumscribed necrotic foci reported in the CNS of acute stage of JBE. Additional characteristic features in the thalamic lesions were calcified and binucleated nerve cells. Alzheimer's neurofibrillary tangles were not found. Authors consider that the distribution and nature of the lesions are of diagnostic value.     

The efficacy of adrenocorticotropic hormone in a girl with anti-N-methyl-D-aspartate receptor encephalitis

Background

Immunomodulatory therapy has shown some therapeutic benefits in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. In this report, we describe the use of adrenocorticotropic hormone (ACTH) immunotherapy with good outcome in a patient with anti-NMDAR encephalitis.