Long-term follow-up of neuromyelitis optica with a pediatric onset

Sex ratio and age of onset in AQP4 antibody-associated NMOSD: a review and meta-analysis

BACKGROUND

Aquaporin-4 (AQP4) antibody-associated neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system. We have undertaken a systematic review and meta-analysis to ascertain the sex ratio and mean age of onset for AQP4 antibody associated NMOSD. We have also explored factors that impact on these demographic data.

METHODS

A systematic search of databases was conducted according to the PRISMA guidelines. Articles reporting sex distribution and age of onset for AQP4 antibody-associated NMSOD were reviewed. An initially inclusive approach involving exploration with regression meta-analysis was followed by an analysis of just AQP4 antibody positive cases.

RESULTS

A total of 528 articles were screened to yield 89 articles covering 19,415 individuals from 88 population samples. The female:male sex ratio was significantly influenced by the proportion of AQP4 antibody positive cases in the samples studied (p < 0.001). For AQP4 antibody-positive cases the overall estimate of the sex ratio was 8.89 (95% CI 7.78-10.15). For paediatric populations the estimate was 5.68 (95% CI 4.01-8.03) and for late-onset cases, it was 5.48 (95% CI 4.10-7.33). The mean age of onset was significantly associated with the mean life expectancy of the population sampled (p < 0.001). The mean age of onset for AQP4 antibody-positive cases in long-lived populations was 41.7 years versus 33.3 years in the remainder.

CONCLUSIONS

The female:male sex ratio and the mean age of onset of AQP4 antibody-associated NMOSD are significantly higher than MS. The sex ratio increases with the proportion of cases that are positive for AQP4 antibodies and the mean age of onset increases with population life expectancy.

Neuromyelitis optica spectrum disorder: Exploring the diverse clinical manifestations and the need for further exploration

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder characterized by inflammatory assaults on the central nervous system (CNS), particularly on the optic nerves and spinal cord. In recent years, a wider range of clinical manifestations of this complex disease have been observed, emphasizing the importance of gaining a more profound understanding beyond optic neuritis (ON) and transverse myelitis (TM).

CURRENT KNOWLEDGE

This study explores the many clinical symptoms of NMOSD, including common and uncommon presentations. Distinctive aspects of ON, TM, and diencephalic/brainstem syndromes are examined, highlighting their unique characteristics in contrast to conditions such as multiple sclerosis. We also discuss extra-CNS involvement, such as unusual signs, including muscle involvement, retinal injury, auditory impairment, and rhinological symptoms.

AIMS AND OBJECTIVES

Our study intends to highlight the wide range and complexity of NMOSD presentations, emphasizing the significance of identifying unusual symptoms for precise diagnosis and prompt management. The specific processes that contribute to the varied clinical presentation of NMOSD are not well understood despite existing information. This emphasizes the necessity for more study to clarify the mechanisms that cause different symptoms and discover new treatment targets for this complex autoimmune disorder.

CONCLUSION

It is essential to acknowledge the complex and varied clinical manifestations of NMOSD to enhance diagnosis, treatment, and patient results. By enhancing our comprehension of the fundamental processes and investigating innovative therapeutic approaches, we may aim to enhance the quality of life for persons impacted by this illness.

Neuromyelitis optica spectrum disorders: a review with a focus on children and adolescents

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and severe inflammatory disorder of the central nervous system (CNS). It is strongly associated with anti-aquaporin 4 antibodies (AQP4-IgG), and it mainly affects young women from non-white ethnicities. However, ∼ 5 to 10% of all cases have onset during childhood. Children and adolescents share the same clinical, radiologic, and laboratory presentation as adults. Thus, the same NMOSD diagnostic criteria are also applied to pediatric-onset patients, but data on NMOSD in this population is still scarce. In seronegative pediatric patients, there is a high frequency of the antibody against myelin oligodendrocyte glycoprotein (MOG-IgG) indicating another disease group, but the clinical distinction between these two diseases may be challenging. Three drugs (eculizumab, satralizumab, and inebilizumab) have been recently approved for the treatment of adult patients with AQP4-IgG-positive NMOSD. Only satralizumab has recruited adolescents in one of the two pivotal clinical trials. Additional clinical trials in pediatric NMOSD are urgently required to evaluate the safety and efficacy of these drugs in this population.

Vision Prognosis and Associated Factors of Optic Neuritis in Dependence of Glial Autoimmune Antibodies

PURPOSE

To assess the visual prognosis of optic neuritis (ON) in dependence of the glial autoimmune antibody status and associated factors.

DESIGN

Longitudinal observational cohort study.

METHODS

Patients with ON and measurements of serum concentrations of glial autoantibodies were consecutively and longitudinally examined with a minimal follow-up of 3 months. Patients with multiple sclerosis and double seronegative results were excluded.

RESULTS

The study included 529 patients (aquaporin-4 immunoglobulin [AQP4-IgG] seropositive, n = 291; myelin oligodendrocyte glycoprotein immunoglobulin [MOG-IgG] seropositive, n = 112; double-seronegative, n = 126) with 1022 ON episodes (AQP4-IgG seropositive, n = 550; MOG-IgG seropositive, n=254; double-seronegative, n = 218). Prevalence of severe vision loss (best-corrected visual acuity [BCVA] ≤20/200 at the end of follow-up) was higher (P < .001) in the AQP4-IgG group (236/550; 42.9%) than in the seronegative group (68/218; 31.2%) and in the MOG-IgG group (15/254; 5.9%). Prevalence of good vision recovery (BCVA≥20/40) was higher (P < .001) in the MOG-IgG group (229/254; 90.2%) than in the seronegative group (111/218; 50.9%) and in the AQP4-IgG group (236/550; 42.9%). In multivariable logistic analysis, higher prevalence of severe vision loss was associated with AQP4-IgG seropositivity (odds ratio [OR] 1.66; 95% CI 1.14, 2.43; P = .008), male sex (OR 1.97, 95% CI 1.33, 2.93; P < .001), age at ON onset >45 years (OR 1.93, 95% CI 1.35, 2.77; P < .001), nadir vision ≤20/200 (OR 14.11, 95% CI 6.54, 36.93; P < .001), and higher number of recurrences (OR 1.35, 95% CI 1.14, 1.61; P = .001). Higher prevalence of good vision outcome was associated with MOG-IgG seropositivity (OR 8.13, 95% CI 4.82, 14.2; P < .001), age at ON onset <18 years (OR 1.78, 95% CI 1.18, 2.71; P = .006), nadir visual acuity ≥20/40 (OR 4.03; 95% CI 1.45, 14.37; P = .015), and lower number of recurrences (OR 0.60; 95% CI 0.50, 0.72; P < .001).

CONCLUSION

Severe vision loss (prevalence in the AQP4-IgG group, MOG-IgG group, and seronegative group: 42.9%, 5.9%, and 31.2%, respectively) was associated with AQP4-IgG seropositivity, male gender, older age at onset, worse nadir vision, and higher number of recurrences.

Clinico-epidemiologic characteristics of optic neuritis in a tertiary eye centre in Eastern India based on the status of serum aquaporin-4 antibody

Purpose:

To elucidate the clinico-epidemiologic characteristics of optic neuritis based on the status of serum aquaporin-4 antibody (AQP4-Ab) in patients with optic neuritis (ON).

Methods:

Medical records of 106 patients with ON and a follow-up of 3 years were reviewed. For each patient, the following data were extracted: medical history, findings of the ocular examination, brain, orbital or spinal MRI, and serological tests for AQP4. The ON was classified as typical or atypical based on disc examination and improvement in vision after intravenous methylprednisolone (IVMP). The clinical findings (typical or atypical), disease course, and outcomes were analyzed according to the serostatus of the ON.

Results:

10 patients ((9.4%) were seropositive for AQP4-Ab; all had atypical ON. 96 patients (91%) were seronegative for AQP4-Ab: 36 atypical ON and 60 typical ON. Profound visual impairment at presentation was seen in all patients. However, at the end of the study period, seropositive and seronegative atypical ON had poor visual outcomes as compared to seronegative typical ON (P = 0.002). Five seropositive and four seronegative patients with atypical ON developed transverse myelitis. Bilateral disease with relapse was more in seropositive patients (80%); however, seronegative with atypical ON also had bilateral presentation and relapse in 42% and 41%, respectively.

Conclusion:

AQP4-Ab seropositive patients mostly present with atypical features such as bilateral recurrent ON, poor visual outcome, and increased incidence of transverse myelitis. However, atypical clinical features can also be seen in seronegative ON with a poor visual outcome and a recalcitrant course.

Pediatric neuromyelitis optica spectrum disorders in Portugal: A multicentre retrospective study

INTRODUCTION

Neuromyelitis optica spectrum disorders (NMOSD) are more prevalent in adulthood, with few cases reported in pediatric age (<18 years). In this group, anti-aquaporin 4 (AQP4) antibodies are less frequent, while antibodies against myelin oligodendrocyte glycoprotein (MOG) are more commonly detectable than in adults.

OBJECTIVE AND METHODS

Description of pediatric NMOSD cases identified in a national multicentric NMOSD Portuguese registry.

RESULTS

Twenty (11.1%) NMOSD cases were diagnosed in pediatric age. Twelve (60%) were female, with a median age of onset of 12.5 (6.8-16.5) years. The presenting feature was transverse myelitis in 10 (50%), 4 of which with simultaneous optic neuritis and 2 with concomitant brainstem syndrome. Nine patients (45%) had pleocytosis in the CSF. Six (30.0%) exhibited anti-AQP4 antibodies, 13 (65.0%) anti-MOG antibodies, and one was seronegative for both. Four anti-AQP4 antibodies-positive patients had ≥1 relapse. Most anti-MOG-positive cases were monophasic (53.8%). In the acute phase, all patients received IV methylprednisolone, nine received IVIg and four plasma exchange. One anti-AQP4-positive patient died. Ten patients (5 anti-AQP4-positive/5 anti-MOG-positive) were on maintenance immunosuppressive therapy at the time of data collection.

CONCLUSION

NMOSD may present in pediatric age. It is essential to establish the diagnosis and promptly start therapy to improve the prognosis.

Early predictors of disability of paediatric-onset AQP4-IgG-seropositive neuromyelitis optica spectrum disorders

OBJECTIVE

To describe onset clinical features predicting time to first relapse and time to long-term visual, motor and cognitive disabilities in paediatric-onset aquaporin-4 antibody (AQP4-IgG) neuromyelitis optica spectrum disorders (NMOSDs).

METHODS

In this retrospective UK multicentre cohort study, we recorded clinical data of paediatric-onset AQP4-IgG NMOSD. Univariate and exploratory multivariable Cox proportional hazard models were used to identify long-term predictors of permanent visual disability, Expanded Disability Status Scale (EDSS) score of 4 and cognitive impairment.

RESULTS

We included 49 paediatric-onset AQP4-IgG patients (38.8% white, 34.7% black, 20.4% Asians and 6.1% mixed), mean onset age of 12±4.1 years, and 87.7% were female. Multifocal onset presentation occurred in 26.5% of patients, and optic nerve (47%), area postrema/brainstem (48.9%) and encephalon (28.6%) were the most involved areas. Overall, 52.3% of children had their first relapse within 1 year from disease onset. Children with onset age <12 years were more likely to have an earlier first relapse (p=0.030), despite showing no difference in time to immunosuppression compared with those aged 12-18 years at onset. At the cohort median disease duration of 79 months, 34.3% had developed permanent visual disability, 20.7% EDSS score 4 and 25.8% cognitive impairment. Visual disability was associated with white race (p=0.032) and optic neuritis presentations (p=0.002). Cognitive impairment was predicted by cerebral syndrome presentations (p=0.048), particularly if resistant to steroids (p=0.034).

CONCLUSIONS

Age at onset, race, onset symptoms and resistance to acute therapy at onset attack predict first relapse and long-term disabilities. The recognition of these predictors may help to power future paediatric clinical trials and to direct early therapeutic decisions in AQP4-IgG NMOSD.

Reduced quality of life in a pediatric-onset Neuromyelitis optica spectrum disorders cohort

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is a severe condition associated with high disability and low quality of life (QoL) in adults. Since this evaluation had been rarely perfomed in children, this study aimed to describe QoL in pediatric-onset NMOSD with positive aquaporin4 antibody (AQP4-IgG) patients.

METHODS

This was a cross-section evaluation of patients and parents' proxy QoL from individuals enrolled in a longitudinal cohort of AQP4-IgG positive NMOSD with onset ≤ 18 years of age.

RESULTS

Eighteen patients were included, sixteen girls. The mean (SD) age at disease onset was 11.5 (3.6) years. Eleven of patients experienced disability during a mean (SD) of 8.3 (5.3) years of follow-up. NMOSD had impact in QoL in 10 patients, being associated with higher EDSS and poor academic performance at last follow-up. Results from the PedsQL inventory for 13 patients and 10 parents disclosed low QoL specially in emotional functioning.

CONCLUSION

This study indicates impaired quality of life, high disability and high impact of the disease in daily life of adolescents and young adults with pediatric onset NMOSD.

Relapsing neuromyelitis optica in an adolescent girl

Early differentiation of neuromyelitis optica spectrum disorder (NMO-SD) from multiple sclerosis (MS) is of paramount importance as NMO-SD (especially relapsing variant) has more severe morbidity than MS. We describe a case of an adolescent girl who presented with repeated episodes of optic neuritis over a period of 4 years with normal brain MRI scans. She was treated initially as relapsing remitting MS, before showing clinical evidence of transverse myelitis (TM), and eventually being diagnosed as NMO-SD. Pulse intravenous methyl prednisolone along with immunosuppressive therapy led to remission of her disease. However, delay in diagnosis as NMO-SD led to visual disability in the left eye. Therefore, in young patients with recurrent optic neuritis and normal brain MRI, it may be prudent to get spinal MRI done to look for TM, even when asymptomatic. In addition, we should keep a low threshold for requesting aquaporin-4 antibody testing in these patients.

[Epidemiology of neuromyelitis optica spectrum disorder]

Neuromyelitis optica spectrum disorder (NMOSD) is a group of rare and mostly severe autoimmune demyelinating central nervous system disorders which prevalence is 0.7-1 per 100.000 population and incidence is 0.037-0.73 per 100.000 person-years. NMOSD may present as a combination of uni- or bilateral optic neuritis, transverse myelitis or lesions of brain stem and other brain regions. The symptoms are mostly relapsing (up to 97.5%) and progressive. Occurrence of relapses is associated with seropositivity for aquaporin-4 (up to 80% of NMOSD patients) and bears a less favorable prognosis (mortality up to 32%). Women seropositive for aquaporin 4 constitute 90% of NMOSD patients. Compared to other demyelinating disorders, NMOSD is characterized by late onset (mean age is about 39 years) and association with other autoimmune disorders, including systemic lupus erythematosus, myasthenia gravis and Sjogren's syndrome. A genetic predisposition was found among Blacks and Asians, with HLA-DRB1*03:01 gene associated with higher risk of NMOSD in Asians. The course of the disease tends to be more severe in Blacks. There are clusters of an increased incidence of NMOSD in the Carribeans and in the Far East. Continued increase of prevalence and incidence of NMOSD worldwide compels continued epidemiological research in order to provide early diagnosis and treatment for this disorder.

Optic neuritis classification in 2021

Optic neuritis (ON) can be associated with inflammatory disease of the central nervous system or can be isolated, with or without relapse. It can also be associated with infectious or systemic disease. These multiple associations based on a variety of clinical, radiological, and biological criteria that have changed over time have led to overlapping phenotypes: a single ON case can be classified in several ways simultaneously or over time. As early, intensive treatment is often required, its diagnosis should be rapid and precise. In this review, we present the current state of knowledge about diagnostic criteria for ON aetiologies in adults and children, we discuss overlapping phenotypes, and we propose a homogeneous classification scheme. Even if distinctions between typical and atypical ON are relevant, their phenotypes are largely overlapping, and clinical criteria are neither sensitive enough, nor specific enough, to assure a diagnosis. For initial cases of ON, clinicians should perform contrast enhanced MRI of the brain and orbits, cerebral spinal fluid analysis, and biological analyses to exclude secondary infectious or inflammatory ON. Systematic screening for MOG-IgG and AQP4-IgG IgG is recommended in children but is still a matter of debate in adults. Early recognition of neuromyelitis optica spectrum disorder, MOG-IgG-associated disorder, and chronic relapsing idiopathic optic neuritis is required, as these diagnoses require therapies for relapse prevention that are different from those used to treat multiple sclerosis.

The current situation of diagnosis and treatment of neuromyelitis optica spectrum disorder: Experience with 461 cases from a single centre in South China

In this study, we included 461 NMOSD patients at our hospital from January 2016 to June 2019 and got some results. Eight (1.9%) originally AQP4-IgG-seronegative patients were retested as seropositive. 221 patients (47.9%) did not receive immunosuppressive treatment within 3 month. The adult/child distribution was significantly different (p = 0.001). Thirty-three patients (7.2%) had relapses after drug withdrawal, and fifteen of them had used drugs ≥3 years. The conclusion is that decision to treat with immunosuppression was made less often in children than in adults. Patients who took medication for a long time still need to be cautious of stopping using immunosuppression.

Early age of onset predicts severity of visual impairment in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Severe residual visual loss (SRVL) is frequent in neuromyelitis optica spectrum disorders (NMOSD). Identifying higher-risk patients at onset is important to prevent disability accumulation.

OBJECTIVE

To determine predictors of SRVL in a large NMOSD cohort.

METHODS

Patient characteristics at last visual acuity (VA) evaluation were retrospectively collected. VA was scored 0: better than 20/40, 1: 20/40-20/99, 2: 20/100-20/200, and 3: worse than 20/200. SRVL was defined as a combined score (VA worst + best eye) ⩾ 4. Descriptive statistics were used to compare groups and logistic regression to evaluate predictors of VA.

RESULTS

106 patients (mean age at disease onset (AO): 35.8 ± 16.5 years) were included. Patients with SRVL had earlier AO (mean: 26.7 vs 38.0 years) compared to non-SRVL group (p = 0.005). Patients with AO < 21 years were more likely to have SRVL, be blind, present with binocular optic neuritis, have recurrent optic neuritis, and receive oral therapy first-line than those with AO ⩾ 21. After adjusting for race, sex, and disease duration, the odds of SRVL were 4.68 times higher in patients < 21 at disease onset (95% CI: 1.53-14.34, p = 0.007).

CONCLUSION

Early AO predicts SRVL in NMOSD, independent of disease duration. High-efficacy therapies should be considered for first-line treatment in this group.

Clinical Characteristics of Chinese Male Patients with Aquaporin-4 Antibody-Positive Late-Onset Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVE

Limited studies are available for male patients with anti-aquaporin-4 antibody (AQP4-Ab)-positive late-onset neuromyelitis optica spectrum disease (LONMOSD). The aim of this study was to investigate the clinical characteristics of Chinese male patients with AQP4-Ab-positive LONMOSD.

METHODS

We retrospectively reviewed the medical records of 12 male patients with LONMOSD, 16 male patients with early-onset NMOSD (EONMOSD), and 64 female patients with LONMOSD. These enrolled patients were classified according to the age of onset: LONMOSD (≥50 years of age at onset) versus EONMOSD (<50 years of age at onset). Clinical characteristics and magnetic resonance imaging (MRI) findings were collected. All included patients were positive for AQP4 antibody.

RESULTS

Compared with female LONMOSD patients, male LONMOSD patients had less frequent transverse myelitis (TM) at onset (8.33 vs. 53.13%, p = 0.004) and lower Expanded Disability Status Scale (EDSS) scores (median 1 vs. 4, p = 0.036). Compared with male EONMOSD patients, male LONMOSD patients had a shorter time from onset to diagnosis (0.85 months vs. 6.00 months, p = 0.04).

CONCLUSION

Less common TM at onset, less disease severity, and shorter time from onset to diagnosis probably occur in male LONMOSD patients.

Treatment and outcome of aquaporin-4 antibody-positive NMOSD: A multinational pediatric study

Objective

To describe the clinical phenotypes, treatment response, and outcome of children with antibodies against aquaporin-4 (AQP4-Ab) neuromyelitis optica spectrum disorder (NMOSD).

Methods

Retrospective, multicenter, and multinational study of patients with AQP4-Ab NMOSD aged <18 years at disease onset from a center in Brazil and 13 European centers. Data on demographics, clinical findings, and laboratory results were analyzed; calculation of annualized relapse rates (ARRs) pre- and on-treatment with disease-modifying therapies (DMTs) and of ORs for predictors of poor outcome was performed.

Results

A total of 67 children were identified. At last follow-up (median 4 years, interquartile range 2–10 years), 37/67(57.8%) were found to have permanent disability. A more severe disease course was seen in the non-White ethnicity with both a shorter time to first relapse (p = 0.049) and a worse Expanded Disability Status Scale score at last follow-up (p = 0.008). The median ARR on treatment was 0.18 on azathioprine (n = 39, range 0–4), 0 on mycophenolate mofetil (n = 18, range 0–3), and 0 on rituximab (n = 29, range 0–2). No patient treated with rituximab as first-line therapy relapsed. Optic neuritis at onset was associated with a poor visual outcome below 20/200 (OR 8.669, 95% CI 1.764–42.616, p = 0.008), and a younger age at onset was associated with cognitive impairment (OR 0.786, 95% CI 0.644–0.959, p = 0.018).

Conclusions

AQP4-Ab NMOSD in children is an aggressive disease with permanent disabilities observed in over half the cohort. All DMTs were associated with a reduction of ARR. First-line rituximab prevented further clinical relapses. International consensus on treatment protocols for children is required to reduce heterogeneity of treatment regimens used worldwide.

Classification of evidence

This study provides Class IV evidence that for children with AQP4-Ab NMOSD, all DMTs, particularly first-line rituximab, reduced the ARR and prevented further clinical relapses.

Imaging in Pediatric Multiple Sclerosis : An Iconographic Review

Pediatric-onset multiple sclerosis (POMS) is defined by a first multiple sclerosis (MS) attack occurring before 18 years old and is diagnosed by demonstration of dissemination in time (DIT) and space (DIS). Although guidelines evolved over the years, they always recognized the importance of magnetic resonance imaging (MRI) for diagnosis. The 2017 McDonald criteria are increasingly used and have been validated in several cohorts. The use of MRI is the most important tool for the early diagnosis, monitoring, and assessment of treatment response of MS and standard protocols include precontrast and postcontrast T1, T2, fluid attenuation inversion recovery (FLAIR) and diffusion sequences. A distinctive MS lesion compromises white matter and it is well-demarcated and confluent, showing demyelination, inflammation, gliosis, and relative axonal preservation. Considering the growing recognition of pediatric MS as a differential diagnosis for children presenting with a clinical central nervous system event, we present a POMS lesions guide (periventricular, juxtacortical, infratentorial, spinal cord, cortical, tumefactive, black hole, contrast-enhanced). Owing to its rareness, POMS is a diagnosis by exclusion and MRI plays a fundamental role in distinguishing POMS from other demyelinating and non-demyelinating conditions. Three main groups of disorders can mimic POMS: inflammatory, metabolic and tumoral; however, imaging patterns earlier described lower the possibilities of alternative diagnoses and strongly suggest POMS when likely.

Imaging of Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica (NMO) is a rare and chronic disabling autoimmune astrocytopathy of the central nervous system. Current advances regarding aquaporin-4 antibody function facilitate the understanding of clinical manifestations and imaging findings beyond optic neuritis and transverse myelitis. The current definition of NMO spectrum disorder (NMOSD) includes both aquaporin-4-IgG seropositive and seronegative patients who present with characteristic findings. This review will briefly summarize the pathophysiology and the latest NMOSD diagnostic criteria and focus on the NMOSD imaging findings and its differential diagnosis.

Outcome prediction models in AQP4-IgG positive neuromyelitis optica spectrum disorders

Pathogenic antibodies targeting the aquaporin-4 water channel on astrocytes are associated with relapsing inflammatory neuromyelitis optica spectrum disorders. The clinical phenotype is characterized by recurrent episodes of optic neuritis, longitudinally extensive transverse myelitis, area postrema attacks and less common brainstem and cerebral events. Patients often develop major residual disability from these attacks, so early diagnosis and initiation of attackpreventing medications is important. Accurate prediction of relapse would assist physicians in counselling patients, planning treatment and designing clinical trials. We used a large multicentre dataset of 441 patients from the UK, USA, Japan and Martinique who collectively experienced 1976 attacks, and applied sophisticated mathematical modelling to predict likelihood of relapse and disability at different time points. We found that Japanese patients had a lower risk of subsequent attacks except for brainstem and cerebral events, with an overall relative relapse risk of 0.681 (P = 0.001) compared to Caucasians and African patients, who had a higher likelihood of cerebral attacks, with a relative relapse risk of 3.309 (P = 0.009) compared to Caucasians. Female patients had a higher chance of relapse than male patients (P = 0.009), and patients with younger age of onset were more likely to have optic neuritis relapses (P < 0.001). Immunosuppressant drugs reduced and multiple sclerosis disease-modifying agents increased the likelihood of relapse (P < 0.001). Patients with optic neuritis at onset were more likely to develop blindness (P < 0.001), and those with older age of onset were more likely to develop ambulatory disability. Only 25% of long-term disability was related to initial onset attack, indicating the importance of early attack prevention. With respect to selection of patients for clinical trial design, there would be no gain in power by selecting recent onset patients and only a small gain by selecting patients with recent high disease activity. We provide risk estimates of relapse and disability for patients diagnosed and treated with immunosuppressive treatments over the subsequent 2, 3, 5 and 10 years according to type of attack at onset or the first 2-year course, ethnicity, sex and onset age. This study supports significant effects of onset age, onset phenotype and ethnicity on neuromyelitis optica spectrum disorders outcomes. Our results suggest that powering clinical treatment trials based upon relapse activity in the preceding 2 years may offer little benefit in the way of attack risk yet severely hamper clinical trial success.

Update on Pediatric Optic Neuritis

PURPOSE OF REVIEW

The purpose of this review is to provide an update on advances in the understanding of pediatric demyelinating optic neuritis.

RECENT FINDINGS

In the past decade, the disease phenotypes for demyelinating syndromes in children have been more clearly defined. Pediatric optic neuritis may present as a clinically isolated syndrome or in the setting of underlying neurologic disease. In addition to optic neuritis associated with multiple sclerosis or neuromyelitis optica, recent work has identified antibodies to the myelin oligodendrocyte glycoprotein (MOG IgG) as a unique demyelinating cause with distinct features regarding treatment and prognosis. The disease phenotypes for demyelinating pediatric optic neuritis have expanded. Treatment strategies vary and are not universally effective for each cause of demyelinating disease. Accurately distinguishing among these unique clinical syndromes is therefore critical for initiation of appropriate treatment to prevent disability, to maximize visual outcomes, and to provide insight into long-term prognosis.

Neuromyelitis Optica Spectrum Disorder and Anti-Aquaporin 4 Channel Immunoglobulin in an Australian Pediatric Demyelination Cohort

Neuromyelitis optica spectrum disorder is uncommon in children, and often seronegative for aquaporin-4 immunoglobulin G (AQP4-IgG). We conducted a retrospective study of 67 children presenting to a single Australian center with acquired demyelinating syndromes over a 7-year period. All patients were tested for AQP4-IgG. Five children (7.5%) had neuromyelitis optica spectrum disorder. One child was seropositive for AQP4-IgG (1.5%) and had a relapsing disease course with mild residual deficits. She also had a concomitant motor axonal neuropathy that improved with immunosuppressive therapy. Of the remaining 4 children, 3 had a monophasic course and 1 a relapsing course. Two were tested for anti-myelin oligodendrocyte glycoprotein (anti-MOG) antibody and both were seropositive. This study confirms that neuromyelitis optica spectrum disorder is uncommon in children, and that AQP4-IgG seropositivity is rare. Anti-MOG antibodies should be tested in children with neuromyelitis optica spectrum disorder.

Pediatric NMOSD: A Review and Position Statement on Approach to Work-Up and Diagnosis

Neuromyelitis Optica Spectrum Disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) primarily affecting the optic nerves and spinal cord, but also involving other regions of the CNS including the area postrema, periaqueductal gray matter, and hypothalamus. Knowledge related to pediatric manifestations of NMOSD has grown in recent years, particularly in light of newer information regarding the importance of not only antibodies to aquaporin 4 (AQP4-IgG) but also myelin oligodendrocyte glycoprotein (MOG-IgG) in children manifesting clinically with this syndrome. In this review, we describe the current state of the knowledge related to clinical manifestations, diagnosis, and chronic therapies for children with NMOSD, with emphasis on literature that has been published in the last 5 years. Following the review, we propose recommendations for the assessment/follow up clinical care, and treatment of this population.

Differential Diagnosis of Pediatric Multiple Sclerosis

The differential diagnosis of pediatric multiple sclerosis (MS) can be broad and pose diagnostic challenges, particularly at initial presentation. Among demyelinating entities, neuromyelitis optica spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibodies (MOG-ab) associated disorders, and acute disseminated encephalomyelitis (ADEM) are now well-known as unique disease processes and yet continue to overlap with MS in regards to clinical presentation and imaging. In non-inflammatory entities, such as metabolic disorders and leukodystrophies, an erroneous diagnosis of MS can be made even while applying appropriate diagnostic criteria. Knowing the epidemiology, typical clinical presentation, diagnostic criteria, and ancillary test results in each disease, can aid in making the correct diagnosis by contrasting these features with those of pediatric MS. Determining the correct diagnosis early, allows for efficient and effective treatment as well as appropriate prognostication.

Brain MRI Findings in Pediatric-Onset Neuromyelitis Optica Spectrum Disorder: Challenges in Differentiation from Acute Disseminated Encephalomyelitis

BACKGROUND AND PURPOSE

Differentiating pediatric-onset neuromyelitis optica spectrum disorder from acute disseminated encephalomyelitis could be challenging, especially in cases presenting with only brain manifestations. Our purpose was to investigate brain MR imaging features that may help distinguish these 2 entities.

MATERIALS AND METHODS

We retrospectively examined initial brain MR imaging studies of 10 patients with pediatric-onset neuromyelitis optica spectrum disorder (female/male ratio, 7:3) and 10 patients with acute disseminated encephalomyelitis (female/male ratio, 2:8). The mean age of the patients was 10.3 ± 5.6 and 8.7 ± 5.3 years, respectively. Brain lesions were evaluated with respect to location, extent, expansion, T1 hypointensity, contrast enhancement/pattern, and diffusion characteristics. The χ² test (Yates or Fisher exact χ²tests) was used to compare differences between groups.

RESULTS

Cerebral subcortical ± juxtacortical and pons ± middle cerebellar peduncle were the most frequent locations involved in both neuromyelitis optica spectrum disorder (n = 5 and 4, respectively) and acute disseminated encephalomyelitis (n = 9 and 7, respectively). Thalamic lesions were more frequent in acute disseminated encephalomyelitis (P = .020) and were detected only in 1 patient with neuromyelitis optica spectrum disorder. None of the patients with neuromyelitis optica spectrum disorder had hypothalamic, internal capsule, or cortical lesions. The internal capsule involvement was found to be significantly different between groups (P = .033). There was no significant difference in terms of extent, expansion, T1 hypointensity, contrast enhancement/pattern, and diffusion characteristics.

CONCLUSIONS

Although there is a considerable overlap in brain MR imaging findings, thalamic and internal capsule involvement could be used to differentiate pediatric-onset neuromyelitis optica spectrum disorder from acute disseminated encephalomyelitis.

Anti-MOG Antibody Seropositive Neuromyelitis Optica: A Rare Pediatric Case

Neuromyelitis Optica spectrum disorder (NMO-SD) is a rare demyelinating disease detected in pediatric patients affecting the primary optic nerve and spinal cord. Clinical findings might overlap with other demyelinating diseases and compare to particularly multiple sclerosis the treatment regimens significantly differ. Therefore, to establish an immediate and definite diagnosis of NMO-SD is crucial. In the majority of patients, the aquaporin-4 antibody is detected in the serum as one of the supporting diagnostic criteria. The antibody against myelin oligodendrocyte glycoprotein (MOG) is recently reported to be associated with serum aquaporin-4 antibody seronegative NMO-SD. Although not included in the diagnostic criteria, we believe that anti-MOG antibody may facilitate the diagnosis of NMO-SD. We herein report a pediatric case of NMO-SD with the anti-MOG antibody seropositivity.

Clinical course, treatment responses and outcomes in Chinese paediatric neuromyelitis optica spectrum disorder

BACKGROUND

Few data exists on paediatric neuromyelitis optica spectrum disorder (NMOSD). Here, we investigated the clinical presentation, treatment responses and long-term prognoses in a large cohort of patients with NMOSD and compared between children and adults with aquaporin-4 antibody (AQP4-IgG).

METHODS

A retrospective chart review of patients followed in multiple centres identified 127 patients with NMOSD (31 children; 96 adults). Data were collected through medical records and structured questionnaire.

RESULTS

In the paediatric cohort, median age at onset was 14 (range 7-17) years; 87% were female. AQP4 and myelin oligodendrocyte glycoprotein antibodies were detected in 82% and 16%, respectively. During a median disease duration of 48 months, 23% developed visual acuity of <6/60 Snellen, 3% were wheelchair-dependent. The frequency of brain/brainstem phenotype (18% vs 9%, p = 0.018) was more common in AQP4-IgG-positive children, while AQP4-IgG-positive adults were more likely to present transverse myelitis (TM) (44% vs 29%, p = 0.005) of all 452 episodes. Multivariable analyses showed that sustained disability was independently associated with the presence of TM (p = 0.030), brain/brainstem symptoms (p = 0.010), annualized relapse rate (p < 0.001) and possibly age of onset (p = 0.069). The reduction of ARR after azathioprine was more prominent in adults (79%) than in children (48%). Mycophenolate mofetil and rituximab decreased the relapse frequency of children, with a reduction of 94% and 100%, respectively.

CONCLUSIONS

paediatric NMOSD is a severely disabling disorder characterized by repeated brain attacks and early disability accrual. Prompt therapy including mycophenolate mofetil and rituximab should be considered to improve paediatric care.

Neuromyelitis optica spectrum disorders: Features of aquaporin-4, myelin oligodendrocyte glycoprotein and double-seronegative-mediated subtypes

The new diagnostic classification of neuromyelitis optica spectrum disorder (NMOSD) in 2015 highlights the central role of biomarkers, such as antibodies against aquaporin-4 (AQP4-Ab), in diagnosis. Also, in approximately 20-25% of patients without AQP4-Ab (NMOSD^AQP4-) the presence of an antibody directed against myelin oligodendrocyte glycoprotein (MOG) characterizes a specific population of NMOSD patients (NMOSD^MOG+), according to their demographic and clinical data and prognoses. While double-seronegative cases (NMOSD^NEG) have not been fully described, they may correspond to the very first patients with opticospinal demyelination reported by Devic and Gault in 1894. The present report reviews the current knowledge of the pathophysiology and clinical features of NMOSD^AQP4+, NMOSD^MOG+ and NMOSD^NEG patients, and also discusses the relationship between the extended spectrum of MOG disease and NMOSD^MOG+. Finally, the current treatments for acute relapses and relapse prevention are described, with a focus on serological-based therapeutic responses and the promising new therapeutic targets.

Imaging of Childhood Inflammatory Brain Diseases

Brain has been considered as an immune-privileged site for centuries owing to the presence of blood-brain barrier, absent lymphatic drainage, and antigen-presenting cells. However, the present prevailing concept is of immune surveillance where brain is continuously surveyed by immune cells. However, the presence of immune cells in central nervous system (CNS) brings the risk of inflammation and autoimmunity involving both T and B cell mediated pathways. These mechanisms form the underlying pathology in a wide spectrum of pediatric CNS diseases manifesting as acquired neurological deficits. Overlapping, heterogenous, and ambiguous clinical features often delays the diagnosis. Although not always pathognomonic, magnetic resonance imaging can be an important biomarker leading to early diagnosis, prognostication, and systematic follow-up pf these diseases. This review describes the spectrum of different pediatric inflammatory disorders and their pertinent imaging features illustrated with clinical examples.

Clinical and radiological characteristics of neuromyelitis optica spectrum disorder in the North Egyptian Nile Delta

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disorder of the central nervous system that was previously thought to be a subtype of multiple sclerosis (MS). Epidemiology studies of NMOSD are rare in both Middle East and North African countries. To our knowledge, there are no such studies in Egypt. Herein, we describe a case series of NMOSD patients from North Egyptian Nile Delta region and compare them to NMOSD in other parts in the Middle East and the world.

METHODS

This is a case series study of NMOSD patients who were seen at the neuroimmunology clinic, Elhadara Hospital, University of Alexandria, Egypt, from January 2017 to January 2018. We describe their clinical, serological and radiological features.

RESULTS

Our study identified twenty Egyptian patients, all of who fulfilled the 2015 international NMOSD diagnostic criteria. Ten tested positive for AQP4 antibodies in the serum while the other ten were seronegative. The mean age at onset was 27.8 years with an average disease duration of 6.8 years. There was a strong female predominance with a ratio of 5.6:1. We identified clinical features of the cohort that differ from those reported in other worldwide studies.

INTERPRETATION

This is the first NMOSD case series in Egypt. Despite some limitation in testing and access to care, there are features of our NMOSD cases that appear to be different from other worldwide cohorts reported in the literature.

Neuromyelitis Optica Spectrum Disorders: Spectrum of MR Imaging Findings and Their Differential Diagnosis

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder for which the aquaporin-4 (AQP4) water channels are the major target antigens. Advances in the understanding of NMO have clarified several points of its pathogenesis, clinical manifestations, and imaging patterns. A major advance was the discovery of the AQP4 antibody, which is highly specific for this disorder. Descriptions of new clinical and radiologic features in seropositive patients have expanded the spectrum of NMO, and the term NMO spectrum disorder (NMOSD) has been adopted. NMOSD is now included in a widening list of differential diagnoses. Acknowledgment of NMOSD imaging patterns and their mimicry of disorders has been crucial in supporting early NMOSD diagnosis, especially for unusual clinical manifestations of this demyelinating disease. This pictorial review summarizes the wide imaging spectrum of NMOSD and its differential diagnosis, as well as its historical evolution, pathophysiology, and clinical manifestations. ^©RSNA, 2018.

Pediatric-onset multiple sclerosis in Brazilian patients: Clinical features, treatment response and comparison to pediatric neuromyelitis optica spectrum disorders

BACKGROUND

Multiple Sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are acquired demyelinating syndromes of the central nervous system more frequently in young adults and their beginning before 18 years of age is rare. They are autoimmune diseases with distinct pathophysiology, clinical presentation, treatment and prognoses. During childhood these conditions often present similar clinical features and differential diagnosis among pNMOSD, pMS and acute disseminated encephalomyelitis (ADEM) is still difficult at disease onset. The aim of this article is to describe the epidemiologic and clinical features, to evaluate the response to treatment and to compare the mains characteristics between the patients with MS and NMOSD who had the first event prior to 18 years of age followed at the Universidade Federal de São Paulo (UNIFESP).

METHODS

Retrospective analysis of patients with MS and NMOSD who started the disease before 18 years of age followed for at UNIFESP. All patients fulfilled the McDonald 2010 criteria for MS and the IPND 2015 criteria or 2006 diagnostic criteria for NMOSD. For treatment analysis, we select patients with a follow-up of more than 6 months.

RESULTS

Sixty-eight patients fulfilled the inclusion criteria for MS and were selected for analysis. Mean age of onset was 15 years, 73.5% were female and the mean follow-up was 6.7 years. Mean annualized relapse rate (aRR) observed was 0,82 relapse/year and mean progression index (PI) was 0.31 EDSS points/year. The multivariate analysis showed a significant association between the EDSS on first appointment and total number of relapses with neurological disabilities in long term in patients with MS. The treatment with interferon-beta (IFN-β) and glatiramer acetate (GA) was safe and patients treated with high dose IFN-β and GA had a statistically significant reduction in disability progression. Eleven patients fulfilled the inclusion criteria for NMOSD: mean age of onset was 14 years, 72.7% were female and the mean follow-up was 6.3 years. Mean aRR observed was 1.5 relapse/year and mean PI was 2.2 EDSS points/year. The treatment with azathioprine was safe and significant halts disability progression. Patients with NMOSD reached EDSS 6 prior than those with MS.

CONCLUSIONS

Pediatric demyelinating diseases in Brazil are similar to the diseases described abroad. In patients with pMS, the EDSS score at the first appointment and the total number of relapses were associated with poor prognosis. NMOSD is more severe than MS in pediatric patients. Treatment with DMD and azathioprine was well tolerated and effective in reducing relapse rate and disability.

Update on pediatric-onset multiple sclerosis

Pediatric-onset multiple sclerosis (POMS) has distinctive features compared with adult-onset multiple sclerosis (AOMS), and warrants caution despite being a rare form of MS. POMS diagnostic criteria are somewhat different from those used in AOMS, with acute disseminated encephalomyelitis being a key differential diagnosis of MS in children. Other differential diagnoses that have to be ruled out before diagnosing MS include demyelinating syndromes, autoimmune and systemic pathologies, and infectious, genetic, metabolic and neoplastic diseases. Compared with AOMS, POMS has several different clinical, biological and imaging findings. At onset, high-level inflammatory activity is mainly reported, and patients with POMS are also at high risk of developing early physical disabilities and early cognitive impairment. Yet, treating patients with POMS is challenging due to a lack of randomized controlled trials. Some of the disease-modifying drugs currently prescribed are analogous to therapies used in adults, and are associated with good tolerability in pediatric patients. However, a few clinical trials dedicated to POMS are now in progress, and the future outlook is to improve the long-term prognosis of POMS patients with early effective and safe treatments.

Pediatric Multiple Sclerosis: Distinguishing Clinical and MR Imaging Features

This article presents an overview of evolving diagnostic criteria of pediatric multiple sclerosis and related disorders, emphasizing distinguishing clinical and neuroimaging features that should be considered for differential diagnosis in childhood and adolescence. New data on the integrity of brain tissue in children with MS provided by advanced MR imaging techniques are addressed as well.

An update on multiple sclerosis in children: diagnosis, therapies, and prospects for the future

INTRODUCTION

Multiple sclerosis (MS), a chronic demyelinating disease of the central nervous system, is increasingly being recognized in children and adolescents. Pediatric MS follows a relapsing-remitting course at onset, with a risk for early cognitive impairment. Areas covered: In this review, we discuss the clinical features of acute demyelinating syndromes in children and risk factors that increase the likelihood of a diagnosis of MS. We also address the application of diagnostic criteria for MS in children, immunological features, therapeutic options and psychosocial considerations for children and adolescents with MS. Expert commentary: Collaborative multicenter clinical trials and research efforts are key to the advancement in understanding the pathophysiology and therapeutic strategies for multiple sclerosis across the lifespan.

Pediatric Optic Neuritis

Optic neuritis is rare in children in comparison to adults, but accounts for approximately 25% of pediatric acute demyelinating syndromes. Features of pediatric optic neuritis that differ from adults include a higher rate of bilaterality, poor visual acuity on presentation, and papillitis. Diagnostic work-up includes brain magnetic resonance imaging, lumbar puncture, and blood tests to exclude infectious and inflammatory disorders. Pediatric optic neuritis may occur following infection or vaccination, or in association with a systemic demyelinating process such as acute disseminated encephalomyelitis, neuromyelitis optica, or multiple sclerosis. Treatment is controversial, but most practitioners administer corticosteroids. Most children with optic neuritis experience full visual recovery. The recently launched Pediatric Optic Neuritis Prospective Data Collection Study (PON1) aims to provide estimates of visual acuity outcome and assess the potential to recruit for a future pediatric optic neuritis treatment trial.

Clinical characteristics of late-onset neuromyelitis optica spectrum disorder: A multicenter retrospective study in Korea

Background:

There are currently few studies regarding late-onset neuromyelitis optica spectrum disorder (LO-NMOSD).

Objective:

We aimed to describe the characteristic features of patients with LO-NMOSD in Korea.

Methods:

Anti-aquaporin-4 antibody-positive patients with neuromyelitis optica spectrum disorder (NMOSD) from nine tertiary hospitals were reviewed retrospectively. The patients were divided into two groups based on age of onset: LO-NMOSD (⩾50 years of age at onset) versus early-onset neuromyelitis optica spectrum disorder (EO-NMOSD) (<50 years of age at onset). Clinical, laboratory, and magnetic resonance imaging (MRI) parameters were investigated.

Results:

Among a total of 147 patients (125 female; age of onset, 39.4 ± 15.2 years), 45 patients (30.6%) had an age of onset of more than 50 years. Compared to patients with EO-NMOSD, patients with LO-NMOSD had more frequent isolated spinal cord involvement at onset (64.4% vs 37.2%, p = 0.002), less frequent involvement of the optic nerve (40.0% vs 67.7%, p = 0.002), and less frequent brain MRI lesions (31.1% vs 50.0%, p = 0.034). Furthermore, there was a significant positive correlation between age of onset and Expanded Disability Status Scale (EDSS) score at last follow-up ( r = 0.246, p = 0.003).

Conclusion:

Age of onset could be an important predictor of lesion location and clinical course of patients with NMOSD.

Distinctive characteristics of early-onset and late-onset neuromyelitis optica spectrum disorders

OBJECTIVES

Little is known about patients with neuromyelitis optica spectrum disorders (NMOSD) as defined by onset age. This study aimed to analyze the different demographic, clinical, laboratory, and magnetic resonance imaging (MRI) characteristics in early-onset (≤50 years) NMOSD (EONMOSD) and late-onset (>50 years) NMOSD (LONMOSD).

MATERIALS AND METHODS

We enrolled 142 patients with NMOSD from Tianjin Medical University General Hospital, Tianjin, China, and categorized them into two groups according to the age of onset: EONMOSD and LONMOSD. Demographic, clinical, laboratory, and MRI characteristics were collected and compared between the two groups. Serum aquaporin-4 (AQP4) antibody levels were determined by cell-based assay and fluorescence immunoprecipitation assays.

RESULTS

Among the patients studied, 83 had early onset (≤50 years) and 59 had late onset (>50 years) of NMOSD. As compared with LONMOSD, EONMOSD patients had more severe visual disability according to functional scores in clinical parameters, significantly lower C3 and C4 serum levels, more frequent cervical lesions, and more lesions around the fourth ventricle, but fewer lesions in hemispheric white matter. LONMOSD patients suffered more motor and sensory disability than EONMOSD patients.

CONCLUSIONS

In NMOSD, the clinical, laboratory, and MRI features differ according to age of onset, suggesting that differences in pathogenesis and treatment should be further investigated.

Clinical features of neuromyelitis optica in children: US Network of Pediatric MS Centers report

Objective:

To compare clinical features of pediatric neuromyelitis optica (NMO) to other pediatric demyelinating diseases.

Methods:

Review of a prospective multicenter database on children with demyelinating diseases. Case summaries documenting clinical and laboratory features were reviewed by an adjudication panel. Diagnoses were assigned in the following categories: multiple sclerosis (MS), acute disseminated encephalomyelitis, NMO, and recurrent demyelinating disease not otherwise specified.

Results:

Thirty-eight cases of NMO were identified by review panel, 97% of which met the revised International Panel on NMO Diagnosis NMO-SD 2014 criteria, but only 49% met 2006 Wingerchuk criteria. Serum or CSF NMO immunoglobulin G (IgG) was positive in 65% of NMO cases that were tested; however, some patients became seropositive more than 3 years after onset despite serial testing. No patient had positive CSF NMO IgG and negative serum NMO IgG in contemporaneous samples. Other than race (p = 0.02) and borderline findings for sex (p = 0.07), NMO IgG seropositive patients did not differ in demographic, clinical, or laboratory features from seronegatives. Visual, motor, and constitutional symptoms (including vomiting, fever, and seizures) were the most common presenting features of NMO. Initiation of disease-modifying treatment was delayed in NMO vs MS. Two years after onset, patients with NMO had higher attack rates, greater disability accrual measured by overall Expanded Disability Status Scale score, and visual scores than did patients with MS.

Conclusion:

The new criteria for NMO spectrum disorders apply well to the pediatric setting, and given significant delay in treatment of NMO compared to pediatric MS and worse short-term outcomes, it is imperative to apply these to improve access to treatment.

International consensus diagnostic criteria for neuromyelitis optica spectrum disorders

Neuromyelitis optica (NMO) is an inflammatory CNS syndrome distinct from multiple sclerosis (MS) that is associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Prior NMO diagnostic criteria required optic nerve and spinal cord involvement but more restricted or more extensive CNS involvement may occur. The International Panel for NMO Diagnosis (IPND) was convened to develop revised diagnostic criteria using systematic literature reviews and electronic surveys to facilitate consensus. The new nomenclature defines the unifying term NMO spectrum disorders (NMOSD), which is stratified further by serologic testing (NMOSD with or without AQP4-IgG). The core clinical characteristics required for patients with NMOSD with AQP4-IgG include clinical syndromes or MRI findings related to optic nerve, spinal cord, area postrema, other brainstem, diencephalic, or cerebral presentations. More stringent clinical criteria, with additional neuroimaging findings, are required for diagnosis of NMOSD without AQP4-IgG or when serologic testing is unavailable. The IPND also proposed validation strategies and achieved consensus on pediatric NMOSD diagnosis and the concepts of monophasic NMOSD and opticospinal MS.