Plasma exchange in pediatric anti-NMDAR encephalitis: A systematic review

Review of the Longitudinal Management of Autoimmune Encephalitis, Potential Biomarkers, and Novel Therapeutics

Purpose of Review

Increasing awareness and earlier diagnosis of autoimmune encephalitis (AE) have led to a greater number of patients being cared for longitudinally by neurologists. Although many neurologists are now familiar with the general approach to diagnosis and acute immunosuppression, this review aims to provide neurologists with guidance related to management beyond the acute phase of disease, including long-term immunosuppression, monitoring, potential biomarkers of disease activity, outcome measures, and symptom management.

Recent Findings

Observational studies in AE have demonstrated that early diagnosis and treatment is associated with improved neurologic outcomes, particularly in AE with antibodies targeting neuronal cell surface/synaptic proteins. The literature regarding long-term management is evolving. In addition to traditional immunosuppressive approaches, there is emerging use of novel immunosuppressive therapies (ISTs) in case series, and several randomized controlled trials are planned. Novel biomarkers of disease activity and methods to measure outcomes and response to treatment are being explored. Furthermore, it is increasingly recognized that many individuals have chronic symptoms affecting quality of life including seizures, cognitive impairment, fatigue, sleep disorders, and mood disorders, and there are emerging data supporting the use of patient centered outcome measures and multidisciplinary symptom-based care.

Summary

This review aims to summarize recent literature and offer a practical approach to long-term management of adult patients with AE through a multidisciplinary approach. We summarize current knowledge on ISTs, potential biomarkers of disease activity, outcome measures, and long-term sequelae. Further research is needed to answer questions regarding optimal IST, biomarker validity, and sequelae of disease.

Patterns of Neuropsychiatric Manifestations of Ovarian Teratomas: A Systematic Review of Case Reports

Ovarian teratomas are germ cell tumors composed of multiple cell types. Ovarian teratomas may express antigens found in the nervous system or neuroendocrine proteins. These neural antigens and neuroendocrine proteins may lead to an autoimmune response with associated encephalitis. There are a growing number of case reports of autoimmune encephalitis in patients with ovarian teratomas. However, the patterns of neuropsychiatric manifestations of ovarian teratomas associated with encephalitis have not been established. The aim of this article is to conduct a systematic review to determine the patterns of neuropsychiatric manifestations of ovarian teratoma-associated encephalitis, focusing on their frequency and clinical course. Thirty-three case reports were collected and analyzed for a systematic review. The studies were full-text, peer-reviewed journal publications from April 2014 to April 2024. Fifty-eight patients were included in our study. The age group of 22-35 years old was the most reported, with 25 (43.1%) patients. The most commonly reported symptoms were memory impairment in 29 (50%) patients, hallucinations in 25 (43.1%) patients, and aggressive behavior in 23 (39.7%) patients. Neuropsychiatric symptoms had a prodromal phase of flu-like symptoms in 31 (53.4%) patients. The neuropsychiatric symptoms preceded the diagnosis of ovarian teratoma in 57 (98.3%) patients. In 53 (91.4%) patients, patients did not respond to psychiatric medications. Autoimmune antibodies to neural antigens were found in 45 (77.6%) patients, with 25 (43.1%) patients having neural tissue present in the teratoma. Treatment of the underlying teratoma and encephalitis led to full recovery in 37 (63.8%) patients. However, long-term outcomes such as relapse and mortality were discussed in only 11 (19.0%) patients. Findings suggest that neuropsychiatric symptoms correlate with teratoma-associated encephalitis and often precede tumor detection. The treatment of the teratoma led to full recovery of the neuropsychiatric manifestations; however, the long-term outcomes of the patients need to be further studied. Future research is needed on the prognosis of patients with neuropsychiatric manifestations of ovarian teratoma.

Surgical procedures and plasma exchange for ovarian teratoma-associated anti-N-methyl D-aspartate receptor encephalitis: a case report and review of literature

We reported a case of ovarian teratoma-associated Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis with recurrent epileptic seizures and disturbance of consciousness. Although surgical excision of the tumor remains the established standard of care, unlike other reported cases, the patient exhibited limited response to early oophorocystectomy, as well as IVIG and steroid therapy; however, a favorable response was observed with Plasma exchange (PE) initiated on postoperative day 12. Literature review revealed no definite recommended surgical extent for ovarian teratomas, and outstanding improvement in patients with anti-NMDAR encephalitis following PE. Our case raises the question regarding the optimal surgical extent for tumor resection, necessitating careful consideration when deciding between oophorectomy and adnexectomy as the preferred surgical procedure for anti-NMDAR encephalitis in female teens and adults. Furthermore, for refractory patients who fail to respond following tumor resection, PE can be performed early instead of immediately initiating second-line therapy.

Analysis of the relation between cerebrospinal fluid antibody titers and clinical characteristics in pediatric patients with anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

This retrospective study aimed to investigate the relationship between cerebrospinal fluid (CSF) antibody titers of N-methyl-d-aspartate receptor (NMDAR), and clinical characteristics in pediatric patients with anti-NMDAR encephalitis.

METHODS

The clinical and laboratory characteristics of hospitalized patients with anti-NMDAR encephalitis, stratified by antibody titers in CSF and disease severity, were retrospectively studied. The demographics, clinical characteristics, main accessory examinations, immunotherapy, and prognosis of patients were recorded, and each observed indicator was statistically analyzed.

RESULTS

A total of 103 pediatric anti-NMDAR encephalitis patients were enrolled in the study, including 41 males (39.8%) and 62 females (60.2%) with a mean age of 8.0 ± 4.0 years. The proportion of patients with cognitive dysfunction and the positive pathogen was higher in the high-titer group than in the low-titer group (p = 0.023, p = 0.042). Consciousness disturbance that occurred as an initial symptom or during the course in the severe group was higher than in the non-severe group (p = 0.002, p < 0.001). More patients in the high-titer group received plasma exchange (PE) than in the low-titer group (p = 0.022). The cure rate of patients was higher with PE (65.2%) than with Corticosteroids and (or) intravenous immunoglobulin (58.1%).

CONCLUSIONS

Patients with symptoms of disturbance of consciousness may be severer. The severity in pediatric anti-NMDAR encephalitis patients was not correlated with anti-NMDAR antibody titers. Patients with high CSF antibody titers had a better prognosis after early PE therapy.

Therapeutic plasma exchange in anti-N-methyl-D-aspartate receptor encephalitis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is the most commonly identified cause of autoimmune encephalitis. Therapeutic plasma exchange has been increasingly employed to treat this disease. This expansion is a consequence of improved techniques and apheresis instruments, as well as the recognition of its applicability in neurological diseases. However, several aspects of treatment remain incompletely clarified, and treatment strategies are still heterogeneous, especially with regard to therapeutic plasma exchange in anti-NMDAR encephalitis. This review provides an overview of the use of therapeutic plasma exchange including the principle and mechanisms, the evidence, initial time, efficiency and complications in anti-NMDAR encephalitis.

Anti-NMDA Receptor Autoimmune Encephalitis: Diagnosis and Management Strategies

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most recognized form of autoimmune encephalitis. It is characterized by a constellation of neurologic and psychiatric features along with positive NMDAR antibody, which is more sensitive and specific in CSF than serum. All patients should be screened at least once for neoplasm, with ovarian teratoma being found in most tumor-related cases. In the acute phase, first-line immunotherapy, often a combination of high-dose steroids, immunoglobulins, and/or plasma exchange, is strongly recommended. When first-line therapy fails, escalation to second-line immunotherapy, particularly rituximab, can further improve outcomes and prevent relapses. In refractory cases, additional complementary immunotherapies, such as cyclophosphamide, bortezomib and/or tocilizumab may be considered. Relapses occur in 10-30% of cases, mostly within the first two years from onset. Individuals should be followed up to determine if chronic maintenance therapy is required.

Diagnosis and Management of Suspected Pediatric Autoimmune Encephalitis: A Comprehensive, Multidisciplinary Approach and Review of Literature

Autoimmune encephalitis is an increasingly recognized entity in children. When treated promptly, favorable outcomes are seen in a majority of pediatric patients. However, recognition of autoimmune encephalitis in young patients is challenging. Once autoimmune encephalitis is suspected, additional difficulties exist regarding timing of treatment initiation and duration of treatment, as evidence to guide management of these patients is emerging. Here, we review available literature regarding pediatric autoimmune encephalitis and present our institution's comprehensive approach to the evaluation and management of the disease. These guidelines were developed through an iterative process involving both pediatric neurologists and rheumatologists.

Immunotherapy-responsive Non-paraneoplastic Encephalitis with Antibodies against GAD, LGI1, and GABAA Receptor

A 62-year-old man showed abnormal behavior. Brain magnetic resonance imaging revealed multifocal lesions on T2-weighted images. Initial screening revealed that he was seropositive for antibodies against glutamate decarboxylase, which usually indicates treatment resistance to autoimmune encephalitis (AE). Intensive immunosuppressive therapies, however, improved the neurological symptoms. In line with this, we also detected seropositivity for antibodies against leucine-rich glioma-inactivated 1 and gamma-aminobutyric acid A receptor (GABA_AR). Brain imaging and treatment responsiveness suggested that antibodies against GABA_AR were the main cause of symptoms. Furthermore, the patient showed the presence of triple anti-neural antibodies in the absence of malignancy and had a favorable clinical course.

Immunomodulation in the acute phase of autoimmune encephalitis

Autoimmune encephalitides constitute an emerging group of diseases for which the diagnosis and management may be challenging, and are usually associated with antibodies against neuroglial antigens used as biomarkers. In this review, we aimed to clarify the diagnostic approach to patients with encephalitis of suspected autoimmune origin in order to initiate early immunotherapy, and to summarize the evidence of current immunotherapies and alternative options assessed for refractory cases. Currently, the general therapeutic approach consists of steroids, IVIG, and/or plasma exchange as first-line medications, which should be prescribed once a diagnosis of possible autoimmune encephalitis is established. For patients not responding to these treatments, rituximab and cyclophosphamide are used as second-line immunotherapy. Additionally, alternative therapies, chiefly tocilizumab and bortezomib, have been reported to be useful in particularly refractory cases. Although the aforementioned approach with first and second-line immunotherapy is widely accepted, the best therapeutic strategy is still unclear since most available evidence is gathered from retrospective non-controlled studies. Moreover, several predictors of good long-term prognosis have been proposed such as response to first-line therapies, modified Rankin score lesser than 4 at the worst neurologic status, no need for admission in intensive care unit, and early escalation to second-line immunotherapy. Thus, the lack of solid evidence underlines the necessity of future well-conducted trials addressing both the best therapeutic regimen and the outcome predictors, but since autoimmune encephalitides have a relatively low incidence, international collaborations seem imperative to reach a reasonable study population size.

Anti-NMDAR encephalitis presenting after immature teratoma resection

This is a case of a young woman who developed neurological and psychiatric symptoms 3 days after resection of an immature teratoma. She was diagnosed with anti-NMDA receptor encephalitis via positive serum antibody titres, which was later confirmed with cerebrospinal fluid antibody titres. Given her cancer diagnosis, she underwent treatment with bleomycin, etoposide and cisplatin chemotherapy in addition to 5 days of high-dose steroids (1 g of intravenous methylprednisolone) for the encephalitis. This treatment regimen led to significant clinical improvement 3 weeks after completion of one cycle of chemotherapy.

Use and Safety of Immunotherapeutic Management of N-Methyl-d-Aspartate Receptor Antibody Encephalitis: A Meta-analysis

Question

What are the most effective treatments for N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis?

Findings

In this meta-analysis of individual patient data including 1550 cases, treatment factors at first event that were significantly associated with good functional outcome 12 months from disease onset included first-line treatment with therapeutic apheresis alone, corticosteroids in combination with intravenous immunoglobulin (IVIG), or corticosteroids in combination with IVIG and therapeutic apheresis, while lack of immunotherapy within 30 days of disease onset was significantly associated with poor outcome. Rituximab and long-term IVIG use were significantly associated with nonrelapsing disease course.

Meaning

Separate treatment factors are associated with functional outcomes and relapsing disease biology in those with NMDAR antibody encephalitis.

Importance

Overall, immunotherapy has been shown to improve outcomes and reduce relapses in individuals with N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis (NMDARE); however, the superiority of specific treatments and combinations remains unclear.

Objective

To map the use and safety of immunotherapies in individuals with NMDARE, identify early predictors of poor functional outcome and relapse, evaluate changes in immunotherapy use and disease outcome over the 14 years since first reports of NMDARE, and assess the Anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score.

Data Sources

Systematic search in PubMed from inception to January 1, 2019.

Study Selection

Published articles including patients with NMDARE with positive NMDAR antibodies and available individual immunotherapy data.

Data Extraction and Synthesis

Individual patient data on immunotherapies, clinical characteristics at presentation, disease course, and final functional outcome (modified Rankin Scale [mRS] score) were entered into multivariable logistic regression models.

Main Outcomes and Measures

The planned study outcomes were functional outcome at 12 months from disease onset (good, mRS score of 0 to 2; poor, mRS score greater than 2) and monophasic course (absence of relapse at 24 months or later from onset).

Results

Data from 1550 patients from 652 articles were evaluated. Of these, 1105 of 1508 (73.3%) were female and 707 of 1526 (46.3%) were 18 years or younger at disease onset. Factors at first event that were significantly associated with good functional outcome included adolescent age and first-line treatment with therapeutic apheresis, corticosteroids plus intravenous immunoglobulin (IVIG), or corticosteroids plus IVIG plus therapeutic apheresis. Factors significantly associated with poor functional outcome were age younger than 2 years or age of 65 years or older at onset, intensive care unit admission, extreme delta brush pattern on electroencephalography, lack of immunotherapy within the first 30 days of onset, and maintenance IVIG use for 6 months or more. Factors significantly associated with nonrelapsing disease were rituximab use or maintenance IVIG use for 6 months or more. Adolescent age at onset was significantly associated with relapsing disease. Rituximab use increased from 13.5% (52 of 384; 2007 to 2013) to 28.3% (311 of 1100; 2013 to 2019) (P < .001), concurrent with a falling relapse rate over the same period (22% [12 of 55] in 2008 and earlier; 10.9% [35 of 322] in 2017 and later; P = .006). Modified NEOS score (including 4 of 5 original NEOS items) was associated with probability of poor functional status at 1 year (20.1% [40 of 199] for a score of 0 to 1 points; 43.8% [77 of 176] for a score of 3 to 4 points; P = .05).

Conclusions and Relevance

Factors influencing functional outcomes and relapse are different and need to be considered independently in development of evidence-based optimal management guidelines of patients with NMDARE.

Anti-N-methyl-D-aspartate Receptor Encephalitis as a Paraneoplastic Presentation of Mature Ovarian Teratoma

Patient: Female, 26-year-old

Final Diagnosis: Anti NMDA receptor encephalitis • familial adenomatous polyposis

Symptoms: Autonomic instability • catatonia • ovarian cyst • psychosis

Medication: —

Clinical Procedure: Ovariectomy

Specialty: General and Internal Medicine

The Role of Plasma Exchange in the Treatment of Refractory Autoimmune Neurological Diseases: a Narrative Review

Autoimmune neurological disorders are commonly treated with immunosuppressive therapy. In patients with refractory conditions, standard immunosuppression is often insufficient for complete recovery or to prevent relapses. These patients rely on other treatments to manage their disease. While treatment of refractory cases differs between diseases, intravenous immunoglobulin, plasma exchange (PLEX), and immune-modulating treatments are commonly used. In this review, we focus on five autoimmune neurological disorders that were the themes of the 2018 Midlands Neurological Society meeting on PLEX in refractory neurology: Autoimmune Encephalitis (AE), Multiple Sclerosis (MS), Neuromyelitis Optica Spectrum disorders (NMOSD), Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Myasthenia Gravis (MG). The diagnosis of inflammatory neuropathies is often challenging, and while PLEX can be very effective in refractory autoimmune diseases, its ineffectiveness can be confounded by misdiagnosis. One example is POEMS syndrome (characterized by Polyneuropathy Organomegaly, Endocrinopathy, Myeloma protein, Skin changes), which is often wrongly diagnosed as CIDP; and while CIDP responds well to PLEX, POEMS does not. Accurate diagnosis is therefore essential. Success rates can also differ within 'one' disease: e.g. response rates to PLEX are considerably higher in refractory relapsing remitting MS compared to primary or secondary progressive MS. When sufficient efforts are made to correctly pinpoint the diagnosis along with the type and subtype of refractory autoimmune disease, PLEX and other immunotherapies can play a valuable role in the patient management.

Successful treatment with immunoadsorption therapy in four patients with severe and refractory anti-N-methyl-D-aspartate receptor encephalitis

There is still no optimal treatment for patients with severe anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis refractory to first-line therapy (including intravenous methylprednisolone [IVMP] and intravenous immunoglobulin [IVIG]). A small study has shown that immunoadsorption (IA) is effective in treating anti-NMDAR encephalitis. However, the effectiveness and safety of IA in the treatment of patients with refractory and severe anti-NMDAR encephalitis is not fully known. Four patients with severe anti-NMDAR encephalitis are reported, which were refractory to the first-line immunotherapy including IVMP and IVIG. Immunoadsorption is performed during the fulminant stage of disease, and the effectiveness and safety of IA are assessed. The modified Rankin Scale (mRS) is used to assess neurological conditions before and after IA. Four patients with the most severe form of anti-NMDAR encephalitis (two with teratoma and two with unknown origin) did not respond to one or more rounds of IVMP plus IVIG. They all required intensive care unit (ICU) support including long-term mechanical ventilation, and thus developed ICU-related complications. Gradual and steady improvement was observed after IA treatment. Except for mild hypotension in patient 1, no other adverse events were observed during IA. Two patients had good early overall recovery on discharge. The other two patients had a good outcome with mRS of 2 at the 12-month follow-up. This small case series suggests that IA may be an effective treatment option to accelerate the recovery of patients with severe and refractory anti-NMDAR encephalitis.

Anti-NMDAR Encephalitis After Neonatal HSV-1 Infection in a Child With Low TLR-3 Function

Neonatal herpes simplex virus encephalitis (HSVE) often results in long-lasting neuro-disability in affected children. In addition to primary HSVE and HSVE relapses, children with herpes simplex virus are at increased risk of developing anti-N-methyl-d-aspartate receptor encephalitis (NMDARe), an autoimmune encephalitis. In this study, we describe a patient with neonatal disseminated herpes infection, who developed HSVE after discontinuation of 2 years of acyclovir suppressive therapy. After resolution of HSVE, the patient rapidly deteriorated with significant behavioral and neurologic changes including emotional outbursts, fearfulness, involuntary movements, and focal seizures. The patient was diagnosed with anti-NMDARe and was later found to have low toll-like receptor-3 function. In this study, we review published pediatric cases of anti-NMDARe after HSVE as well as previous literature and primary data examining the presentation, predisposing risk factors, predictive outcomes, future directions, and the role of immunodeficiency in HSVE-mediated anti-NMDARe. The neonatal immune system and developing brain are disproportionately vulnerable to early viral exposure; therefore, it is important to recognize the value of early immunodeficiency screening in patients with neonatal herpes simplex virus. By understanding the immune landscape within this patient population, we can mitigate long-term neurologic disability and improve the quality of life of affected children.

Centrifugal Therapeutic Plasma Exchange in Pediatric Patients

OBJECTIVE

To assess the safety of centrifugal therapeutic plasma exchange (TPE) in pediatric patients.

METHODS

The authors did a retrospective analysis of all TPE procedures performed in pediatric patients over a period of 19 y (2001-2019). Procedures were done on different apheretic devices, daily or on alternate days depending on the clinical condition of the patient. Adverse events during the procedure were noted and analyzed.

RESULTS

A total of 672 TPE (with mean of 6.77 ± 4.85) procedures were performed for 99 pediatric patients with different indications like hematological (n = 68), renal (n = 12), neurology (n = 18) and hepatology (n = 1). The mean age was 7.00 ± 3.11 y and weight was 20.72 ± 9.17 kg. Adverse events (AEs) were observed during 34 (5%) procedures, most common were allergic reactions to replacement fluid (2.24%) followed by hypotension (1.04%), symptomatic hypocalcemia (1.04%), line occlusion (0.59%), and febrile non hemolytic transfusion reaction (0.41%). A significant correlation of AEs was observed with weight (p = 0.045), total blood volume of the patient (p = 0.04), increasing number of procedures (p = 0.000) and replacement fluid [Fresh frozen plasma (FFP)] (p = 0.04). All AEs were managed as per departmental standard operating procedures (SOPs) completing procedures successfully except one which was abandoned. No mortality was observed during the procedures.

CONCLUSION

TPE is a safe therapeutic modality in pediatric patients when performed under expert technical supervision with proper SOPs in place.

International Consensus Recommendations for the Treatment of Pediatric NMDAR Antibody Encephalitis

Objective

To create an international consensus treatment recommendation for pediatric NMDA receptor antibody encephalitis (NMDARE).

Methods

After selection of a panel of 27 experts with representation from all continents, a 2-step Delphi method was adopted to develop consensus on relevant treatment regimens and statements, along with key definitions in pediatric NMDARE (disease severity, failure to improve, and relapse). Finally, an online face-to-face meeting was held to reach consensus (defined as ≥75% agreement).

Results

Corticosteroids are recommended in all children with NMDARE (pulsed IV preferred), with additional IV immunoglobulin or plasma exchange in severe patients. Prolonged first-line immunotherapy can be offered for up to 3–12 months (oral corticosteroids or monthly IV corticosteroids/immunoglobulin), dependent on disease severity. Second-line treatments are recommended for cases refractory to first-line therapies (rituximab preferred over cyclophosphamide) and should be considered about 2 weeks after first-line initiation. Further immunotherapies for refractory disease 1-3 months after second-line initiation include another second-line treatment (such as cyclophosphamide) and escalation to tocilizumab. Maintenance immune suppression beyond 6 months (such as rituximab redosing or mycophenolate mofetil) is generally not required, except for patients with a more severe course or prolonged impairments and hospitalization. For patients with relapsing disease, second-line and prolonged maintenance therapy should be considered. The treatment of NMDARE following herpes simplex encephalitis should be similar to idiopathic NMDARE. Broad guidance is provided for the total treatment duration (first line, second line, and maintenance), which is dictated by the severity and clinical course (i.e., median 3, 9 and 18 months in the best, average, and worst responders, respectively). Recommendations on the timing of oncologic searches are provided.

Conclusion

These international consensus recommendations for the management of pediatric NMDARE aim to standardize the treatment and provide practical guidance for clinicians, rather than absolute rules. A similar recommendation could be applicable to adult patients.

Therapeutic plasma exchange in clinical pediatric neurology practice: Experience from a tertiary referral hospital

OBJECTIVE

This study aims to retrospectively evaluate the long-term efficacy, tolerability, and safety of therapeutic plasma exchange (TPE) in children with various neuroimmunological disorders.

METHODS

This analysis was a single-center, retrospective cohort study of pediatric patients with neuroimmunological events undergoing TPE procedures in a tertiary referral center.

RESULTS

There were 23 patients, 14 boys (60.9%), aged at diagnosis onset 8 months to 16.8 years. The main indications of TPE were Guillain-Barré syndrome (GBS, n = 8), autoimmune encephalitis (n = 5), febrile infection-related epilepsy syndrome (FIRES, n = 4), and acute disseminated encephalomyelitis (ADEM, n = 3). There was no life-threatening complication due to the TPE procedures. Eight (34.8%) of 23 patients experienced 13 (7%) complications in 186 TPE procedures, mostly electrolyte disturbances (n = 5). None of patients discontinued TPE due to complications. Two (8.7%) of 23 patients had marked improvement, 6 (26.1%) had moderate and 11 (47.8%) had mild improvement after TPE. The last follow-up visit revealed neurological sequelae in 12 (52.2%) patients. Therapeutic plasma exchange was found to be more effective on GBS, autoimmune encephalitis and myasthenia gravis, less effective on ADEM and FIRES. There was no correlation between improvement with TPE and clinical parameters, including age, sex, diagnosis, disease duration before TPE, presence of intubation, and length of stay in the intensive care unit and hospital.

CONCLUSION

Therapeutic plasma exchange was found to be effective and well-tolerated in children with various types of neuroimmunological disorder, with at least mild improvement in approximately 80% of the patients and no life-threatening complications.

Therapeutic plasma exchange in critically ill children: experience of the pediatric intensive care unit of two centers in Chile

INTRODUCTION

Therapeutic plasma exchange (TPE) is an extracorporeal blood purification technique used in a wide spectrum of diseases. We aim to review the indications, complications, and outcomes of critically ill children who received TPE and to compare a membrane versus centrifugal method in this cohort.

METHODS

A retrospective observational study in two pediatric intensive care units in Chile during eight years (2011-2019) Results: A total of 36 patients underwent 167 TPE sessions (20 centrifugation and 16 membrane-based). The more frequent indications for TPE were autoimmune neurological diseases in 14 cases, renal diseases (9), and rheumatological disorders (5). 58 % of children received other immunomodulatory therapy. According to ASFA, 45 % of cases were I-II category, 50 % to III, and 5% not classified. Response to treatment was complete in 64 % (23/36) and partial in 33 % (12/36). Complications occurred in 17.4 % of sessions, and the most frequent was transient hypotension during the procedure. Overall survival at discharge from the PICU was 92 %. Patients who received TPE as a single therapy (n = 26) survived 96 %. The clinical outcomes between the two apheresis methods were similar. Survivors had a significantly lower PELOD score on admission (14.5 vs. 6.5, p = 0.004).

CONCLUSIONS

TPE is mainly indicated as a rescue treatment in neurological autoimmune diseases refractory to conventional immunomodulatory treatment. Complications in critically ill children are mild and low. The outcome in children requiring TPE as a single therapy is good, and no differences were observed with centrifugation or membrane method.

Clinical Features, Treatment Strategies, and Outcomes in Hospitalized Children With Immune-Mediated Encephalopathies

BACKGROUND

Autoimmune encephalitis (AE) and acute disseminated encephalomyelitis (ADEM) are immune-mediated brain conditions that can cause substantial neurological sequalae. Data describing the clinical characteristics, treatments, and neurological outcomes for these conditions are needed.

METHODS

This is a single-center retrospective review of children diagnosed with AE or ADEM over a nine-year period with discharge outcomes measured by the Modified Rankin Score.

RESULTS

Seventy-five patients (23 with ADEM and 52 with AE) were identified. Patients with ADEM had a higher percentage of abnormal magnetic resonance imaging findings (100% vs 60.8%; P < 0.001) and a shorter time from symptom onset to diagnosis (6 vs 14 days; P = 0.024). Oligoclonal bands and serum and cerebrospinal fluid inflammatory indices were higher in patients with AE. Nearly all patients received corticosteroids followed by plasmapheresis or intravenous immunoglobulin, and treatment strategies did not differ significantly between groups. Second-line immune therapies were commonly used in patients with AE. Finally, patients with AE had trends toward longer hospital lengths of stay (21 vs 13 days) and a higher percentage of neurological disability at hospital discharge (59.6% vs 34.8%).

CONCLUSIONS

Although patients with ADEM and AE may have similar presenting symptoms, we found significant differences in the frequency of imaging findings, symptom duration, and laboratory and cerebrospinal fluid profiles, which can assist in distinguishing between the diagnoses. Patients in both groups were treated with a combination of immunomodulating therapies, and neurological disability was common at hospital discharge.

Autoimmune Encephalitis in Children: From Suspicion to Diagnosis

There are several well-described and studied autoimmune diseases that affect different organ systems, and a limited number of these affect the central nervous system. Autoimmune encephalitis represents a disease with a wide spectrum of clinical manifestations and different levels of severity, from mild cognitive impairment to complex encephalopathy. Immune-mediated encephalitis refers to a diverse and rare group of conditions in children associated with nonspecific symptomatology, altered mental state, and recalcitrant seizures. Infectious etiology must be excluded. Immune-mediated encephalitis syndromes could be associated with paraneoplastic or primarily autoimmune mechanisms. The newest scientific advantages have concluded that autoimmune encephalitis may be further divided into different groups of diseases depending on the immune response; examples are antibodies to cell surface proteins, antibodies to intracellular synaptic proteins, T-cell response with antibodies to intracellular antigens, among others. Treatment consists of supportive therapy, ranging from supplemental oxygen, fluid restriction to mechanical circulatory support. Specific treatment includes immunoglobulin infusion, plasmapheresis, and pulse steroid treatment. Prognosis is poor if specific treatment is not timely instituted. The diagnosis of autoimmune encephalitis could be challenging to clinicians due to its diverse clinical features, which can mimic a variety of other pathologic processes. Screening for cancer and proper management that includes immune therapy are fundamental, although some patients will need immune suppression for weeks or months as autoimmune encephalitis may relapse; therefore, follow-up is always necessary.

Encephalitis in Previously Healthy Children

Encephalitis is defined as altered mental status for more than 24 hours accompanied by 2 or more findings concerning for inflammation of the brain parenchyma: fever, seizures or other focal neurologic disorders, cerebrospinal fluid pleocytosis, and abnormal neuroimaging and electroencephalographic findings. Herpes simplex virus causes the most severe form of virus-induced encephalitis; the early administration of acyclovir can improve the prognosis of this disease. The rising interest in autoimmune causes of encephalitis, most notably anti-N-methyl-d-aspartate receptor, should prompt the clinician to consider immunomodulatory treatments, which may improve outcomes. A broad testing panel may be necessary to detect the etiologic agent; a few published pediatric cases suggest that infectious and autoimmune causes may occur concurrently in the same patient with encephalitis. More than 40% of children diagnosed as having encephalitis will not return to their previous level of neurologic function after resolution of their disease, although outcomes are highly variable depending on the etiologic agent.

Risk Factor and Long-Term Outcome Analyses for Acute Limbic Encephalitis and Calcineurin Inhibitor-Induced Encephalopathy in Adults following Allogeneic Hematopoietic Cell Transplantation

Post-transplantation acute limbic encephalitis (PALE) is a rare, severe inflammatory disorder in the bilateral limbic system, including the hippocampus. To date, only a few studies have reported details, including risk factors for PALE; however, further clinical evidence of PALE, especially in cerebrospinal fluid human herpesvirus 6-negative cases, is warranted. In addition, data are sparse regarding the risk factors for calcineurin inhibitor (CNI)-induced encephalopathy (CNIE) following allogeneic hematopoietic cell transplantation (allo-HCT) in adults. Therefore, we examined the risk factors for and clinical details of PALE and CNIE. We retrospectively analyzed consecutive patients who underwent allo-HCT between January 2005 and November 2017. A total of 485 patients age 46 years (median) were eligible. In total, 14 PALE cases and 11 CNIE cases were identified. Multivariable analyses identified older age, use of an HLA-mismatched unrelated donor (URD), graft-versus-host disease (GVHD) prophylaxis with CNI and mycophenolate mofetil, and grade II-IV acute GVHD as significantly associated with an increased risk of PALE. In 13 patients who received high-dose methylprednisolone (mPSL) therapy, 6 (46%) responded to mPSL therapy, and 3 (23%) achieved complete remission at day 90 after mPSL administration. Furthermore, myelodysplastic syndrome (MDS), HLA-mismatched URD, and grade II-IV acute GVHD were significantly associated with an increased risk of CNIE. The 5-year nonrelapse mortality rate was 50% in PALE and 63% in CNIE, suggesting a very poor prognosis. In conclusion, this study provides evidence that HLA-mismatched URD and acute GVHD may independently contribute to the development of PALE, possibly in part through HLA-mismatch-derived alloimmune responses. Other than acute GVHD, we have identified MDS and HLA-mismatched URD as novel predictors of CNIE after allo-HCT.

Psychiatric autoimmune conditions in children and adolescents: Is catatonia a severity marker?

OBJECTIVES

Patients with autoimmune encephalitis (AE) are likely to exhibit an acute onset of severe psychiatric features, including psychosis and/or catatonia. Based on the high prevalence of catatonia in AE and our clinical experience, we hypothesized that catatonia might be a marker of severity requiring more aggressive treatment approaches.

METHODS

To reach a sufficient number of cases with brain-autoimmune conditions, we pooled two samples (N = 58): the first from the French National Network of Rare Psychiatric diseases and the second from the largest Italian neuro-pediatrics center for encephalopathies. Autoimmune conditions were diagnosed using a multidisciplinary approach and numerous paraclinical investigations. We retrospectively compared patients with and without catatonia for psychiatric and non-psychiatric clinical features, biological and imaging assessments, type of immunotherapy used and outcomes.

RESULTS

The sample included 25 patients (43%) with catatonia and 33 (57%) without catatonia. Forty-two patients (72.4%) had a definite AE (including 27 anti-NMDA receptor encephalitis) and 16 (27.6%) suspected autoimmune encephalitis. Patients with catatonia showed significantly more psychotic features [18 (72%) vs 9 (27.3%), p < 0.001)] and more movement disorders [25 (100%) vs 20 (60.6%), p < 0.001] than patients without catatonia. First line (corticoids, immunoglobulin and plasma exchanges) and second line (e.g., rituximab) therapies were more effective in patients with catatonia, with 24 (96%) vs 22 (66.7%) (p = 0.006) and 17 (68%) vs 9 (27.3%) (p = 0.002), respectively. However, those with catatonia received more combinations of first and second line treatments and had more relapses during outcomes.

CONCLUSION

Despite its exploratory design, the study supports the idea that autoimmune catatonia may be a marker of severity and morbidity in terms of initial presentation and relapses, requiring the need for early and aggressive treatment.

Therapeutic Plasma Exchange in the Critically Ill Patient: Technology and Indications

Therapeutic plasma exchange (TPE) is frequently the most common Apheresis Medicine technique used for extracorporeal therapy of a wide variety of renal, neurological, hematological, and other clinical indications. Many of these clinical indications require intensive care during critical illness. Conventional TPE uses one of two main technical methods to achieve the goal of removing known disease mediators from the plasma: using centrifugal forces to separate and remove components of blood, or a membrane filtration method that separates plasma from the cellular components of blood. The following review discusses the basic principles of TPE, the technological aspects, and relevant clinical scenarios encountered in the intensive care unit, including relevant guidelines and recommendations from the American Society for Apheresis.

A narrative review of pharmacologic approaches to symptom management of pediatric patients diagnosed with anti-NMDA receptor encephalitis

Anti-N-Methyl-D-Aspartate Receptor Encephalitis (ANMDARE) is one of the most common autoimmune encephalitis in the pediatric population. Patients with ANMDARE initially present with a prodrome of neuropsychiatric symptoms followed by progressively worsening seizures, agitation, and movement disorders. Complications can include problems such as aggression, insomnia, catatonia, and autonomic instability. Due to the complexity of this disease process, symptom management can be complex and may lead to significant polypharmacy. The goal of this review is to educate clinicians about the challenges of managing this disorder and providing guidance in symptom management.

Use of therapeutic plasma exchange for pediatric neurological diseases

Therapeutic plasma exchange is used to treat neurological diseases in the pediatric population. Since its first use in pediatric patients with hepatic coma in the form of manual whole blood exchange, therapeutic plasma exchange has been increasingly used to treat these disorders of the nervous system. This expansion is a result of improved techniques and apheresis instruments suitable for small children, as well as the recognition of its applicability to many diseases in the pediatric population. This review provides a historical overview of the use of therapeutic apheresis in children and highlights the most common applications for therapeutic plasma exchange to treat neurological disorders in children.

Pharmacologic Treatment and Early Rehabilitation Outcomes in Pediatric Patients With Anti-NMDA Receptor Encephalitis

OBJECTIVES

To describe the immunotherapy and pharmacologic treatments administered to pediatric patients with N-methyl-D-aspartate receptor encephalitis (NMDARE) during inpatient rehabilitation as well as to examine clinical and demographic variables associated with early functional outcomes.

DESIGN

Retrospective chart review and post hoc analysis.

SETTING

Pediatric inpatient rehabilitation unit.

PARTICIPANTS

Pediatric patients (N=26; mean age, 10.79±5.17y) admitted to an inpatient rehabilitation unit with a confirmed diagnosis of NMDARE.

INTERVENTIONS

Inpatient rehabilitation; pharmacologic treatments.

MAIN OUTCOME MEASURE

FIM for Children (WeeFIM) Developmental Functional Quotient (DFQ).

RESULTS

All patients received first-line immunotherapies to treat NMDARE, and 69% also received second-line immunotherapies. Patients were prescribed an average of 8 medications for symptom management (range, 3-15 per patient), most often for the treatment of agitation (100%), psychiatric symptoms (92%), and seizures (65%). Sixty-five percent of patients demonstrated an improvement in Total WeeFIM DFQ over the course of inpatient rehabilitation, with 35% demonstrating limited to no change in Total WeeFIM DFQ ("unfavorable early outcome"). Those with unfavorable early outcome were significantly younger than those showing more favorable outcome. Pharmacologic treatment for seizures, movement disorders, and decreased arousal or level of consciousness were each associated with unfavorable early outcome independent of age differences.

CONCLUSION

Findings highlight the symptomatic heterogeneity and polypharmacy involved in the care and treatment of patients with NMDARE, with patients receiving a variety of immunotherapies and medications for symptom management. The presence of (and treatment for) seizures, movement disorders, and deteriorated neurologic status may each be associated with poor early outcomes in this population. Further investigation is needed to better classify presentations and treatments for this disease and to determine how differences are associated with long-term outcomes.

Autoimmune encephalitis and epilepsy: evolving definition and clinical spectrum

Advances in autoimmune encephalitis studies in the past 10 years have led to the identification of new syndromes and biomarkers that have transformed the diagnostic approach to the disorder. The disorder or syndrome has been linked to a wide variety of pathologic processes associated with the neuron-specific autoantibodies targeting intracellular and plasma membrane antigens. However, current criteria for autoimmune encephalitis are quite dependent on antibody testing and responses to immunotherapy, which might delay the diagnosis. This form of encephalitis can involve the multifaceted presentation of seizures and unexpected behavioral changes. The spectrum of neuropsychiatric symptoms in children is less definitive than that in adults, and the incorporation of clinical, immunological, electrophysiological, and neuroradiological results is critical to the diagnostic approach. In this review, we document the clinical and immunologic characteristics of autoimmune encephalitis known to date, with the goal of helping clinicians in differential diagnosis and to provide prompt and effective treatment.

Response to immunotherapy in anti-IgLON5 disease: A systematic review

The aim of this study was to evaluate the frequency of response to immunotherapy in patients with anti-IgLON5 disease through a systematic review of the literature. MEDLINE and Embase databases were searched for studies that included patients with anti-IgLON5 disease who received immunotherapy (IT). Review inclusion criteria were met by 18 studies. The main study variable was response to IT, defined as the frequency of patients with an improvement greater than mild in at least one of the main symptoms defined by the clinical phenotype. Data were also gathered on the rate of response to last follow-up, the line(s) of IT received, the administration of monotherapy or combination therapy, and clinical and analytical characteristics. Selected studies included a total of 46 patients. A response to IT was observed in 20 (43.4%) and the presence of response to last follow-up in 15 (32.6%). Response was achieved more frequently with combination therapy vs monotherapy (14/21 [66.6%] vs 7/22 [31.8%]) and second-line therapy vs first-line therapy (7/13 [53.8%] vs 15/46 [32.6%]). The response rate by drug was 34.2% (12/35) for steroids, 42.8% (9/21) for IVIg, 46% (7/15) for PLEX, 100% (5/5) for AZA and 75% (3/4) for MMF. Factors associated with a response to IT included the cognitive impairment and non-classical phenotypes, presence of HLA-DQB1*05:01 without HLA-DRB1*10:01 and cerebral spinal fluid inflammation. Patients with anti-IgLON5 disease respond to IT, and this response is associated with certain clinical and analytical characteristics of the patients. Also rate of response seems higher with second-line and combination treatment. However, the quality of available studies is inadequate to allow definitive conclusions to be drawn.

Anti-N-methyl-D-aspartate receptor encephalitis: A review of pathogenic mechanisms, treatment, prognosis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune disorder characterized by prominent neuropsychiatric symptoms that predominantly affects children and young adults. In this review, we discuss the pathogenic mechanisms and immunologic triggers of anti-NMDAR encephalitis, and provide an overview of treatment and prognosis of this disorder, with specific focus on the management of common symptoms, complications, and patients during pregnancy. Most patients respond well to first-line treatment and surgical resection of tumors. When first-line immunotherapy fails, second-line immunotherapy can often improve outcomes. In addition, treatment with immunomodulators and tumor resection are effective treatment strategies for pregnant patients. Benzodiazepines are the preferred treatment for patients with catatonia, and electroconvulsive therapy (ECT) may be considered when pharmacological treatment is ineffective. Age, antibody titer, cerebellar atrophy, levels of biomarkers such as C-X-C motif chemokine 13 (CXCL13), cell-free mitochondrial (mt)DNA in cerebral serum fluid (CSF), and timing from symptom onset to treatment are the main prognostic factors. Patients without tumors or those who receive insufficient immunotherapy during the first episode are more likely to relapse.

Little Children, Bigger Problems: Anti-N-Methyl D-Aspartate Receptor Encephalitis!

Anti N-methyl D-aspartate receptor (NMDAR) antibody positive autoimmune encephalitis is a well-described entity both in adults as well as in children. The authors report an 18-mo-old boy who presented with seizures, movement disorder, cognitive impairment, and behavioral disturbances. Anti-NMDAR encephalitis was confirmed by detection of NMDAR antibodies in the cerebrospinal fluid. The patient was administered pulse corticosteroids and intravenous immunoglobulin followed by further immunomodulatory therapy. No tumor was detected on screening. The child remained unresponsive to treatment. The authors wish to highlight the occurrence of anti-NMDAR encephalitis in young toddlers and the poor response to therapy often seen in very young children.

Relapse risk factors in anti-N-methyl-D-aspartate receptor encephalitis

AIM

To identify factors that may predict and affect the risk of relapse in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.

METHOD

This was a retrospective study of an Italian cohort of patients with paediatric (≤18y) onset anti-NMDAR encephalitis.

RESULTS

Of the 62 children included (39 females; median age at onset 9y 10mo, range 1y 2mo-18y; onset between 2005 and 2018), 21 per cent relapsed (median two total events per relapsing patient, range 2-4). Time to first relapse was median 31.5 months (range 7-89mo). Severity at first relapse was lower than onset (median modified Rankin Scale [mRS] 3, range 2-4, vs median mRS 5, range 3-5; admission to intensive care unit: 0/10 vs 3/10). At the survival analysis, the risk of relapsing was significantly lower in patients who received three or more different immune therapies at first disease event (hazard ratio 0.208, 95% confidence interval 0.046-0.941; p=0.042). Neurological outcome at follow-up did not differ significantly between patients with relapsing and monophasic disease (mRS 0-1 in 39/49 vs 12/13; p=0.431), although follow-up duration was significantly longer in relapsing (median 84mo, range 14-137mo) than in monophasic patients (median 32mo, range 4-108mo; p=0.002).

INTERPRETATION

Relapses may occur in about one-fifth of children with anti-NMDAR encephalitis, are generally milder than at onset, and may span over a long period, although they do not seem to be associated with severity in the acute phase or with outcome at follow-up. Aggressive immune therapy at onset may reduce risk of relapse.

WHAT THIS PAPER ADDS

Relapses of anti-N-methyl-D-aspartate receptor encephalitis may span over a long period. Relapses were not associated with severity in the acute phase or outcome at follow-up. Aggressive immune therapy at onset appears to decrease risk of relapse.

Plasma exchange in neurological disease

Plasma exchange is a highly efficient technique to remove circulating autoantibodies and other humoral factors rapidly from the vascular compartment. It was the first effective acute treatment for peripheral disorders such as Guillain-Barré syndrome and myasthenia gravis before intravenous immunoglobulin became available. The recent recognition of rapidly progressive severe antibody-mediated central nervous system disorders, such as neuromyelitis optica spectrum disorders and anti-N-methyl-D-aspartate-receptor encephalitis, has renewed interest in using plasma exchange for their acute treatment also. In this review we explain the principles and technical aspects of plasma exchange, review its current indications, and discuss the implications for its provision in the UK.

Efficacy of Therapeutic Plasma Exchange in Patients with Severe Refractory Anti-NMDA Receptor Encephalitis

The objective of the present study was to assess the efficacy of therapeutic plasma exchange (TPE) in patients with severe refractory anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis. Patients with severe anti-NMDA receptor encephalitis who showed no improvement after steroids and/or intravenous immunoglobulin treatment for at least 10 days were enrolled. All patients received immunotherapy and were divided into a TPE group and a non-TPE group according to treatment received. Each patient in the TPE group received at least 1 TPE course. NMDA receptor antibody titers in the cerebrospinal fluid (CSF) and plasma were evaluated within 1 week after the last TPE procedure. The clinical efficacy of treatment was evaluated after 1 month, 2 months, 3 months, 6 months, and 12 months. Forty patients were enrolled: 19 in the TPE group and 21 in the non-TPE group. Nineteen patients received TPE for a total of 118 procedures. NMDA receptor antibody titers in the CSF and/or plasma decreased or were negative after the last TPE procedure in 18 patients (94.7%). Compared with the non-TPE group, the TPE group exhibited greater clinical improvement after 1 month and 2 months following treatment (P < 0.05). After 3 months, 6 months, and 12 months, there were no significant differences in the outcomes between the TPE group and non-TPE group. The results suggest that TPE might rapidly improve the clinical manifestations in patients with severe refractory anti-NMDA receptor encephalitis, and we believe that TPE should be considered as a first-line treatment.

Management of antibody-mediated autoimmune encephalitis in adults and children: literature review and consensus-based practical recommendations

Autoimmune encephalitis associated with antibodies against neuronal surface targets (NSAE) are rare but still underrecognized conditions that affect adult and pediatric patients. Clinical guidelines have recently been published with the aim of providing diagnostic clues regardless of antibody status. These syndromes are potentially treatable but the choice of treatment and its timing, as well as differential diagnoses, long-term management, and clinical and paraclinical follow-up, remain major challenges. In the absence of evidence-based guidelines, management of these conditions is commonly based on single-center expertise.Taking into account different published expert recommendations in addition to the multicenter experience of the Italian Working Group on Autoimmune Encephalitis, both widely accepted and critical aspects of diagnosis, management and particularly of immunotherapy for NSAE have been reviewed and are discussed.Finally, we provide consensus-based practical advice for managing hospitalization and follow-up of patients with NSAE.

Utility and safety of plasma exchange in paediatric neuroimmune disorders

AIM

Our aim was to ascertain the indications, side effects, and outcomes in children receiving therapeutic plasma exchange (TPE) for neurological disorders.

METHOD

Medical records were retrospectively reviewed for 58 consecutive children (age ≤16y) undergoing 67 courses of TPE across four tertiary centres. Patient characteristics, treatment schedules, complications, and outcomes were analysed.

RESULTS

Median age at initiation of TPE was 9 years (range 1-15y). Indications included peripheral nervous system (PNS; n=18) and central nervous system (CNS; n=40) disorders. Courses comprised a median six exchanges (range 2-179) over 8 days (range 3-466). Forty-two out of 58 (73%) children were severely disabled (bedridden) at initiation and 24 out of 58 (41%) were admitted to intensive care units. Treating clinicians' impression of response was positive in 16 out of 18 of those with PNS disorders versus 22 out of 40 with CNS disorders (p=0.016). Improvements in disability (modified Rankin Scale) occurred in 13 out of 58 (22%) children by completion of TPE (p=0.003). Complications occurred in 40 out of 67 (60%) courses, of which 16 out of 67 (24%) were line related. Potentially life-threatening complications occurred in 2 out of 67 (3%) courses.

INTERPRETATION

This cohort study provides safety and efficacy information for clinicians and families and a basis for future prospective studies.

WHAT THIS PAPER ADDS

Disability scores for severe neuroimmune disorders remained stable or improved during therapeutic plasma exchange treatment. Complications occurred frequently but were typically mild and correctable.

The role of plasma exchange in the management of autoimmune disorders

Therapeutic plasma exchange (TPE) has been mainly used in the treatment of autoimmune diseases. The main mechanisms of action of TPE include the removal of circulating autoantibodies, immune complexes, complement components, cytokines and adhesion molecules, along with sensitization of antibody-producing cells to immunosuppressant agents. TPE is useful in autoimmune haematological, renal, rheumatic and neurological diseases, and is recommended for acute disorders, together with relapsed or worsened chronic diseases that are often unresponsive to conventional treatments. The American Society for Apheresis and the British Society of Haematology have published guidelines on the clinical use of apheresis procedures, indicating the different levels of efficacy of TPE. Based on the evidence from current literature and our personal experience, this review discusses the indications and the suggested regimens for TPE in autoimmune haematological and non-haematological disorders.

Atypical Autoimmune Encephalitis With Neuropil Antibodies Against a Yet Unknown Epitope

Autoimmune encephalitis often causes acute psychiatric symptoms and epileptic seizures. However, it is becoming increasingly clear that depending on the target antigen both symptoms and disease severity may vary. Furthermore, the identification and characterization of antibody subtypes are highly relevant for personalizing the treatment and to prevent relapses. Here we present an atypical case of encephalitis with cerebellar and temporal dysfunction but without seizures associated with high levels of cerebrospinal fluid neuropil antibodies against a yet unknown epitope on the neuronal surface in the cerebellum, hippocampus, thalamus, and the olfactory bulb. We treated the patient successfully with corticosteroids, plasmapheresis, and rituximab.

Application of Plasma Exchange in Steroid-Responsive Encephalopathy

Plasma exchange has been widely used in autoimmune neurological diseases and is the standard treatment for myasthenia gravis crisis and Guillain-Barre syndrome. A growing body of research suggests that, in the clinical application of steroid-responsive encephalopathy, such as for Hashimoto's encephalopathy, limbic encephalitis, systemic lupus erythematosus encephalopathy, ANCA-associated vasculitis encephalopathy, and acute disseminated encephalomyelitis, plasma exchange is a safe, and effective option when steroids or other immunosuppressive therapies are ineffective in the short term or when contraindications are present. Additionally, plasma exchange can also be used alone or in combination with steroids, immunoglobulins, or other immunosuppressive agents to treat steroid-responsive encephalopathy. This paper reviews the clinical application of plasma exchange in steroid-responsive encephalopathy, including its indications, onset time, course, curative effects, and side effects.

Mycophenolate mofetil, azathioprine and methotrexate usage in paediatric anti-NMDAR encephalitis: A systematic literature review

BACKGROUND

Available data on mycophenolate mofetil (MMF), azathioprine (AZA) and methotrexate (MTX) for paediatric-onset anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE) is limited.

METHODS

Systematic literature review on patients treated with MMF/AZA/MTX for paediatric-onset anti-NMDARE, with focus on modes of use, efficacy and safety.

RESULTS

87 patients were included (age at onset median 11 years, range 0.8-18 years; 69% females). 46% had a relapsing course. 52% received MMF, 27% AZA, 15% MTX, and 6% a combination of MMF/AZA/MTX (7 patients received intrathecal MTX). Before MMF/AZA/MTX, 100% patients received steroids, 83% intravenous immunoglobulin and 45% plasma exchange, and 50% received second-line treatments (rituximab/cyclophosphamide). MMF/AZA/MTX were administered >6 months from onset in 51%, and only after relapse in 40%. Worst mRS before MMF/AZA/MTX was median 4.5 (range 3-5). At last follow-up (median 2 years, range 0.2-8.6), median mRS was 1 (range 0-6). Median annualised relapse rate was 0.4 (range 0-6.7) pre-MMF/AZA/MTX (excluding first events), and 0 on MMF/AZA/MTX (mean 0.03, range 0-0.8). 7% patients relapsed on MMF/AZA/MTX. These relapsing patients had low rate of second-line treatments before MMF/AZA/MTX (25%), long median time between onset and MMF/AZA/MTX usage (18 months), and frequently they were started on MMF/AZA/MTX only after relapse (75%). Relapse rate was lower among patients who received first immune therapy ≤30 days (25%) than later (64%), who received second-line treatments at first event (14%) rather than not (64%), who were started on MMF/AZA/MTX after the first (12%) rather than subsequent events (17%), and who were started on MMF/AZA/MTX ≤3 months from onset (33%) rather than later (53%). Adverse reactions to MMF/AZA/MTX occurred in 2 cases (cytomegalovirus colitis and respiratory infection), of grade 3 Common Terminology Criteria for Adverse Events v4.0.

DISCUSSION

Our literature review disclosed heterogeneity in the use of MMF/AZA/MTX in paediatric-onset anti-NMDARE. MMF/AZA/MTX usage is mostly restricted to retrospective cohort descriptions. These agents may reduce risk of relapse, and have a reasonable safety profile, however data on larger cohorts are required to definitively determine effect.

A causality algorithm to guide diagnosis and treatment of catatonia due to autoimmune conditions in children and adolescents

OBJECTIVES

Pediatric catatonia is a rare and life-threatening syndrome. Around 20% of juvenile catatonia is associated with organic condition (Consoli et al., 2012). Autoimmune conditions represent a diagnostic and therapeutic challenge since specific antibodies can be missed. To facilitate decision making, we recently formulated a causality assessment score (CAUS) using a stepwise approach and an immunosuppressive therapeutic challenge (Ferrafiat et al., 2016). Our objectives were to validate retrospectively CAUS and to define its threshold for an accurate distinction between organic catatonia and non-organic catatonia, and specifically between autoimmune catatonia and non-organic catatonia.

METHOD

To obtain a sufficient number of cases with organic catatonia, we pooled two samples (N=104) - one from a child psychiatry center, the other from neuro-pediatrics center - expert in catatonia and autoimmune conditions. Organic conditions were diagnosed using a multidisciplinary approach and numerous paraclinical investigations. Given the binary classification needs, we used receiver operating characteristic (ROC) analysis (Peacock and Peacock, 2010) to calculate the best classification threshold.

RESULTS

The cohort included 67 cases of non-organic catatonia and 37 cases of organic catatonia. ROC analysis showed that the CAUS performance in discriminating both organic catatonia vs. non-organic catatonia, and autoimmune catatonia vs. non-organic catatonia was excellent (Area Under the Curve=0.99). In both analyses, for a CAUS threshold≥5, accuracy equaled to 0.96.

CONCLUSION

Regarding juvenile catatonia, the use of the CAUS score algorithm combining a therapeutic challenge and a threshold≥5 may help to diagnose and treat autoimmune conditions even without formal identification of auto-antibodies.

Therapeutic plasma exchange in paediatric neurology: a critical review and proposed treatment algorithm

Therapeutic plasma exchange (TPE) has been a key immunotherapeutic strategy in numerous neurological syndromes, predominantly during the acute phase of illness. This paper reviews the indications, strength of evidence, and safety of TPE in children with neurological conditions. The rarity of these immune conditions in children, alongside an often incomplete understanding of their pathobiology, has limited the development of a robust scientific rationale for TPE therapy and the feasibility of conducting larger controlled trials. TPE continues to be used, but is a costly therapy with common adverse effects. Uncertainty remains over how to compare the different TPE methods, the optimal dosage of therapy, and monitoring and integration of TPE with other immunotherapies. Further studies are also required to define the indications and benefits of TPE and assess evolving technologies such as immunoadsorption.

WHAT THIS PAPER ADDS

Studies investigating therapeutic plasma exchange (TPE) are small and mainly uncontrolled. They provide evidence for the efficacy of TPE in childhood neuro-inflammatory conditions. TPE is generally well tolerated provided key adverse effects are anticipated and avoided. Systematic dosing and objective assessment of treatment effect should be priorities for future research.

Anti-NMDA receptor encephalitis in a toddler: A diagnostic challenge

Anti N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder and is considered to be one of the most common causes of encephalitis in children. Despite the fact that around half of all reported cases are of children, the number of studies that report infants and toddlers is very small. Furthermore, reports on children from the Middle East particularly are extremely rare.

We report a 21-month-old Jordanian female toddler with NMDAR encephalitis, who initially presented with behavioral changes and some autistic features. She presented a diagnostic challenge due to a concurrent urinary tract infection and gastroenteritis. Multiple investigations were conducted and she was treated with methylprednisolone and intravenous immunoglobulin (IVIg) empirically as well as plasma exchange and rituximab once the diagnosis was confirmed. Her condition improved gradually. We discuss her clinical picture and the diagnostic challenges within this age group; we also review the current related literature.

Principles and approaches to the treatment of immune-mediated movement disorders

Immune mediated movement disorders include movement disorders in the context of autoimmune encephalitis such as anti-NMDAR encephalitis, post-infectious autoimmune movement disorders such as Sydenham chorea, paraneoplastic autoimmune movement disorders such as opsoclonus myoclonus ataxia syndrome, and infection triggered conditions such as paediatric acute neuropsychiatric syndrome. This review focuses on the approach to treatment of immune mediated movement disorders, which requires an understanding of the immunopathogenesis, whether the disease is destructive or 'altering', and the natural history of disease. Factors that can influence outcome include the severity of disease, the delay before starting therapy, use of multimodal therapy and whether the course is monophasic or relapsing. Although the four main conditions listed above have different pathophysiological processes, there are general themes that broadly apply including: early diagnosis and treatment is better, minimise the severity of disease, escalate treatment if the patient is not responding to initial treatments, and minimise relapse.