Monophasic demyelination reduces brain growth in children

Novel Genetic Variants Distinguishing Myelin Oligodendrocyte Glycoprotein-IgG-Positive From Myelin Oligodendrocyte Glycoprotein-IgG-Negative Pediatric Acute Disseminated Encephalomyelitis in Northern China

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a common phenotype in children with myelin oligodendrocyte glycoprotein IgG (MOG-IgG)-associated disease. We aimed to identify novel genetic variants that distinguish children with MOG-IgG-positive ADEM (MOG-IgG+ ADEM) from children with MOG-IgG-negative ADEM (MOG-IgG- ADEM) using whole exome sequencing (WES) analysis.

METHODS

We conducted a two-stage study design. First, we performed WES on five patients with MOG-IgG+ ADEM and five patients with MOG-IgG- ADEM. Following bioinformatics analysis, the candidate variant list was constructed. Second, 29 children with MOG-IgG+ ADEM and 27 children with MOG-IgG- ADEM, together with discovery cohort, were genotyped to identify the novel variants.

RESULTS

WES resulted in 33,999 variants, and 5388 nonsynonymous variants were selected for downstream analysis. In total, 118 protein-affecting variants that were significantly different between the two groups were identified. Together with the five variants extracted from the literature, 49 variants were selected as the candidate variant list for genotyping in the replication cohort. Finally, we identified three variants: rs11171951 in NACα, rs231775 in CTLA4, and rs11171951 in GOLGA5, which were significantly different between MOG-IgG+ ADEM and MOG-IgG- ADEM. Only rs12440118 in NACα remained significant after Bonferroni correction for multiple testing (Padj < 0.001).

CONCLUSIONS

We identified strong associations between NACα, CTLA4, and GOLGA5 variants and MOG-IgG+ ADEM in a Han Chinese population of Northern China, which may present novel genetic risk factor distinguishing patients with MOG-IgG+ ADEM from those with MOG-IgG- ADEM.

Impact of adult-onset multiple sclerosis on MRI-based intracranial volume: A study in clinically discordant monozygotic twins

OBJECTIVE

Intracranial volume (ICV) represents the maximal brain volume for an individual, attained prior to late adolescence and remaining constant throughout life after. Thus, ICV serves as a surrogate marker for brain growth integrity. To assess the potential impact of adult-onset multiple sclerosis (MS) and its preceding prodromal subclinical changes on ICV in a large cohort of monozygotic twins clinically discordant for MS.

METHODS

FSL software was used to derive ICV estimates from 3D-T1-weighted-3 T-MRI images by using an atlas scaling factor method. ICV were compared between clinically affected and healthy co-twins. All twins were compared to a large healthy reference cohort using standardized ICV z-scores. Mixed models assessed the impact of age at MS diagnosis on ICV.

RESULTS

54 twin-pairs (108 individuals/80female/42.45 ± 11.98 years), 731 individuals (375 non-twins, 109/69 monozygotic/dizygotic twin-pairs; 398female/29.18 ± 0.13 years) and 35 healthy local individuals (20male/31.34 ± 1.53 years). In 45/54 (83 %) twin-pairs, both clinically affected and healthy co-twins showed negative ICV z-scores, i.e., ICVs lower than the average of the healthy reference cohort (M = -1.53 ± 0.11, P<10-5). Younger age at MS diagnosis was strongly associated with lower ICVs (t = 3.76, P = 0.0003). Stratification of twin-pairs by age at MS diagnosis of the affected co-twin (≤30 versus > 30 years) yielded lower ICVs in those twin pairs with younger age at diagnosis (P = 0.01). Comparison within individual twin-pairs identified lower ICVs in the MS-affected co-twins with younger age at diagnosis compared to their corresponding healthy co-twins (P = 0.003).

CONCLUSION

We offer for the first-time evidence for strong associations between adult-onset MS and lower ICV, which is more pronounced with younger age at diagnosis. This suggests pre-clinical alterations in early neurodevelopment associated with susceptibility to MS both in individuals with and without clinical manifestation of the disease.

The Impact of Neuroimmunologic Disease and Developing Nervous System

Over the last two decades, neuroimmunologic disorders of childhood have been increasingly described, phenotyped, and treated. These disorders remain rare in the general population and while sharing common therapeutic interventions due to their immune pathophysiology, are heterogeneous with regard to presentation and risk of recurrence. As such, the impact of these disorders on the developing brain has come into the forefront of emerging research in pediatric neuroimmunology. Investigations into the singular impact of monophasic disease on long-term development and the impact of early and aggressive disease-modifying therapy in relapsing conditions are quickly becoming areas of ripe investigation as the field's most optimal way to treat and monitor these conditions over time. Although critically important in evaluating the developing brain, research has been heterogeneous among these diseases and limited by small cohort size. This narrative review details the role of common neuroimmunologic disorders in long-term neurological and cognitive outcomes in children as they develop.

Patient Pathway to Diagnosis of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD): Findings from a Multinational Survey of 204 Patients

INTRODUCTION

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a rare demyelinating disorder of the central nervous system. Despite increased recognition of MOGAD as a distinct disease and the availability of sensitive methods of MOG antibody testing, diagnostic challenges remain. We conducted a survey to explore the patient experience from the start of symptoms to final MOGAD diagnosis.

METHODS

A 23-question online survey (including multiple-choice and free-text responses) covering symptom history, healthcare interactions and impact of diagnosis was emailed to people living with MOGAD by The MOG Project patient advocacy group. People living with MOGAD could share the survey with their caregivers. Anonymised responses were analysed.

RESULTS

In total, 204 people living with MOGAD or their caregivers from 21 countries completed the survey; most respondents were from North America. Age of symptom onset ranged from 1 to 66 (median 28) years. Symptoms that prompted patients to seek medical care included blurred vision/loss of vision (58.2%), eye pain (35.8%) and difficulty walking (25.4%). Patients most frequently presented to emergency care physicians (38.7%) and primary care doctors (26.0%), with the MOGAD diagnosis most often made by general neurologists (40.4%) or neuro-immunologists (30.0%). Patients saw a median of four doctors before diagnosis, with 26.5% of patients seeing at least six doctors. Although 60.6% of patients received a MOGAD diagnosis within 6 months of experiencing initial health problems, 17.7% experienced a ≥ 5-year delay. More than half of patients (55.4%) received an alternative primary diagnosis before final MOGAD diagnosis. Most respondents (60.6%) reported receiving insufficient information/resources at the time of MOGAD diagnosis. Diagnostic delay was associated with long-term negative consequences for physical health.

CONCLUSION

This survey provides unique insights from people living with MOGAD and their caregivers that could help address the challenges faced in the pathway to final MOGAD diagnosis.

Deviation From Normative Whole Brain and Deep Gray Matter Growth in Children With MOGAD, MS, and Monophasic Seronegative Demyelination

BACKGROUND AND OBJECTIVES

Pediatric-acquired demyelination of the CNS associated with antibodies directed against myelin oligodendrocyte glycoprotein (MOG; MOG antibody-associated disease [MOGAD]) occurs as a monophasic or relapsing disease and with variable but often extensive T2 lesions in the brain. The impact of MOGAD on brain growth during maturation is unknown. We quantified the effect of pediatric MOGAD on brain growth trajectories and compared this with the growth trajectories of age-matched and sex-matched healthy children and children with multiple sclerosis (MS, a chronic relapsing disease known to lead to failure of normal brain growth and to loss of brain volume) and monophasic seronegative demyelination.

METHODS

We included children enrolled at incident attack in the prospective longitudinal Canadian Pediatric Demyelinating Disease Study who were recruited at the 3 largest enrollment sites, underwent research brain MRI scans, and were tested for serum MOG-IgG. Children seropositive for MOG-IgG were diagnosed with MOGAD. MS was diagnosed per the 2017 McDonald criteria. Monophasic seronegative demyelination was confirmed in children with no clinical or MRI evidence of recurrent demyelination and negative results for MOG-IgG and aquaporin-4-IgG. Whole and regional brain volumes were computed through symmetric nonlinear registration to templates. We computed age-normalized and sex-normalized z scores for brain volume using a normative dataset of 813 brain MRI scans obtained from typically developing children and used mixed-effect models to assess potential deviation from brain growth trajectories.

RESULTS

We assessed brain volumes of 46 children with MOGAD, 26 with MS, and 51 with monophasic seronegative demyelinating syndrome. Children with MOGAD exhibited delayed (p < 0.001) age-expected and sex-expected growth of thalamus, caudate, and globus pallidus, normalized for the whole brain volume. Divergence from expected growth was particularly pronounced in the first year postonset and was detected even in children with monophasic MOGAD. Thalamic volume abnormalities were less pronounced in children with MOGAD compared with those in children with MS.

DISCUSSION

The onset of MOGAD during childhood adversely affects the expected trajectory of growth of deep gray matter structures, with accelerated changes in the months after an acute attack. Further studies are required to better determine the relative impact of monophasic vs relapsing MOGAD and whether relapsing MOGAD with attacks isolated to the optic nerves or spinal cord affects brain volume over time.

Impaired Brain Growth in Myelin Oligodendrocyte Glycoprotein Antibody-Associated Acute Disseminated Encephalomyelitis

BACKGROUND AND OBJECTIVES

Acute disseminated encephalomyelitis (ADEM) is the most common phenotype in pediatric myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease. A previous study demonstrated impaired brain growth in ADEM. However, the effect of MOG antibodies on brain growth remains unknown. Here, we performed brain volume analyses in MOG-positive and MOG-negative ADEM at onset and over time.

METHODS

In this observational cohort study, we included a total of 62 MRI scans from 24 patients with ADEM (54.2% female; median age 5 years), of which 16 (66.7%) were MOG positive. Patients were compared with healthy controls from the NIH pediatric MRI data repository and a matched local cohort. Mixed-effect models were applied to assess group differences and other relevant factors, including relapses.

RESULTS

At baseline and before any steroid treatment, patients with ADEM, irrespective of MOG antibody status, showed reduced brain volume compared with matched controls (median [interquartile range] 1,741.9 cm3 [1,645.1-1,805.2] vs 1,810.4 cm³ [1,786.5-1,836.2]). Longitudinal analysis revealed reduced brain growth for both MOG-positive and MOG-negative patients with ADEM. However, MOG-negative patients showed a stronger reduction (-138.3 cm³ [95% CI -193.6 to -82.9]) than MOG-positive patients (-50.0 cm³ [-126.5 to -5.2]), independent of age, sex, and treatment. Relapsing patients (all MOG positive) showed additional brain volume loss (-15.8 cm³ [-68.9 to 37.3]).

DISCUSSION

Patients with ADEM exhibit brain volume loss and failure of age-expected brain growth. Importantly, MOG-negative status was associated with a more pronounced brain volume loss compared with MOG-positive patients.

Narrative review based on fingolimod therapy in pediatric MS

The course of pediatric-onset multiple sclerosis and adult multiple sclerosis shows some clinical differences. The rate of having a second attack after the first clinical event is 80% in children and around 45% in adults but the time to the second event is similar in all age groups. The pediatric group usually has a more aggressive onset than adults. On the other hand, a higher rate of complete recovery is observed in pediatric-onset multiple sclerosis after the first clinical event compared to the adult group. Despite a highly active initial disease course, pediatric-onset multiple sclerosis patients show a slower increase in disability than patients with adult-onset disease. This is thought to be due to greater remyelination capacity and plasticity of the developing brain. The management of pediatric-onset multiple sclerosis includes safety issues as well as effective disease control. In the pediatric-onset multiple sclerosis group, similar to adult multiple sclerosis, injectable treatments have been used for many years with reasonable efficacy and safety. Since 2011, oral treatments and then infusion treatments have been approved and used effectively in adult multiple sclerosis and have gradually entered clinical use in the pediatric-onset multiple sclerosis group. However, clinical trials are fewer, smaller, and include shorter follow-up due to the much lower prevalence of pediatric-onset multiple sclerosis than adult multiple sclerosis. This is particularly important in the era of recent disease-modifying treatments. This review of the literature presents existing data on the safety and efficacy of fingolimod, pointing to a relatively favorable profile.

Progressive retinal changes in pediatric multiple sclerosis

Objectives To determine to what extent acute demyelinating episodes versus chronic degenerative phenomena drive retinal neuroaxonal damage in pediatric acquired demyelinating syndromes (ADS). Methods We acquired optical coherence tomography (OCT) data (follow-up range: 2 weeks - 5 years, at variable intervals from presentation) in pediatric participants who had multiple sclerosis (MS), monophasic ADS, or were healthy. Multivariable mixed effects models were used to assess the association of the number of demyelinating episodes (either optic neuritis [ON], or non-ON relapses) with changes in retinal nerve fiber layer (RNFL) or ganglion cell layer-inner plexiform layer (GCIPL) thickness. Results 64 OCT sans from 23 MS, and 33 scans from 12 monophasic ADS participants were compared with 68 scans from 62 healthy participants. The first ON episode had the biggest impact on RNFL or GCIPL thickness in monophasic ADS (RNFL: -7.9 µm, CI=5.5, p = 0.0056; GCIPL: -8.4 µm, CI=4.4, p = 0.0002) and MS (RNFL: -16 µm, CI = 3.7, p < 10^-6; GCIPL: -15 µm, CI = 2.6, p < 10^-6). Non-ON relapses were also associated with small but significant retinal thickness reductions in MS (RNFL: -2.6 µm/relapse, CI = 1.4, p = 0.0003; GCIPL: -2.8 µm/relapse, CI = 0.89, p < 10^-6). MS participants showed progressive GCIPL thinning independent of acute demyelinating episodes (-2.7 µm/year, CI = 1.9, p = 0.0058). Conclusions We showed a prominent impact of early ON episodes on OCT measures of neuroaxonal structure in patients with ADS. We also demonstrated negative effects of non-ON relapses, and the presence of chronic retinal neurodegenerative changes, in youth with MS.

Serum neurofilament light-chain levels in children with monophasic myelin oligodendrocyte glycoprotein-associated disease, multiple sclerosis, and other acquired demyelinating syndrome

Objective:

To assess the diagnostic and prognostic potential of serum neurofilament light chain (sNfL) in children with first acquired demyelinating syndrome (ADS).

Methods:

We selected 129 children with first ADS including 19 children with myelin oligodendrocyte glycoprotein (MOG)-antibody associated disease (MOGAD), 36 MOG/AQP4-seronegative ADS, and 74 with multiple sclerosis (MS) from the BIOMARKER study cohort. All children had a complete set of clinical, radiological, laboratory data and serum for NfL measurement using a highly sensitive digital ELISA (SIMOA). A control group of 35 children with non-inflammatory neurological diseases was included. sNfL levels were compared across patient groups according to clinical, laboratory, neuroradiological features and outcome after 2 years.

Results:

sNfL levels were significantly increased in MOGAD, seronegative ADS and MS compared to controls ( p-value < 0.001), in particular in children with an acute disseminated encephalomyelitis (ADEM)-like magnetic resonance imaging (MRI) pattern ( p < 0.001) or longitudinally extensive myelitis ( p < 0.01). In pediatric MS, elevated sNfL levels were significantly associated with higher numbers of cerebral ( p < 0.001) and presence of spinal ( p < 0.05) MRI lesions at baseline and predicted a higher number of relapses ( p < 0.05).

Conclusion:

sNfL levels are significantly elevated in all three studied pediatric ADS subtypes indicating neuroaxonal injury. In pediatric MS high levels of sNfL are associated with risk factors for disease progression.

Disrupted cognitive development following pediatric acquired demyelinating syndromes: a longitudinal study

Long-term cognitive deficits have been observed in some children who experience an acquired demyelinating syndrome (ADS). We examined changes in cognitive functioning over the first two years following incident ADS andtested whether normalized brain and thalamic volume accounted for decline over time. Twenty-five youth (mean age 12.8 years) with ADS, 9 of whom were diagnosed with multiple sclerosis (MS) and 16 of whom experienced monophasic ADS (monoADS), underwent two neuropsychological evaluationsand MRI scans at approximately6- and 24-months post ADS-onset. We examined changes in cognitive outcomes over time and between patient groups. Generalized linear mixed-effect regression models were used to examine the association of normalized brain and thalamic volumesbetween the two timepointswith cognitive z-scores. Cognitive performance was within the age-expected range for both groups and remained stable over time on 15 measures. In the combined sample of monoADS and MS patients, declines (p < .05) were noted on the Symbol Digit Modalities Test (SDMT), the Auditory Working Memory (AWM), and the WJ-III Visual Matching (VisMat)tests, but did not survive FDR correction. Clinically significant declines, as measured by the Reliable Change Index, were observed on the SDMT,AWM, and VisMattests by 19, 42, and 32%, respectively. Lower normalized brain volume at 6-months predicted a negative change in SDMT (B = 0.45, 95%CI: 0.07,0.83) and AWM (B = 0.30, 95%CI: 0.13, 0.47). Chronicity of demyelination is not required for cognitive decline nor for reduced brain volume, suggesting that even a single demyelinating event may negatively impact cognitive potential in children.

Long-term trajectory of acquired demyelinating syndrome and multiple sclerosis in children

AIM

We assessed the frequency, characteristics, and future trajectory of monophasic acquired demyelinating syndromes (ADS) associated with conversion to paediatric multiple sclerosis.

METHOD

This was a retrospective observational study of Sardinian children (<18y of age) with onset of ADS between 2001 and 2018.

RESULTS

We identified 44 children with ADS (21 males, 23 females; median age at onset 16y, range 4mo-18y), 21 of whom were already presenting with criteria for paediatric multiple sclerosis. The mean crude prevalence of ADS in Sardinian children was 59.2 per 100 000, while incidence was 3.1 per 100 000 per year (1.3 in children aged ≤10y and 11.9 in those aged 10-17y). After a mean (SD) follow-up of 8 years 5 months (5y 4mo), the most common (n=32) trajectory was conversion to paediatric multiple sclerosis. At onset, the total prevalence and mean annual incidence of paediatric multiple sclerosis were 35.6 per 100 000 and 2.3 per 100 000 respectively (0.5 in individuals aged ≤10y, 10.0 in the older group).

INTERPRETATION

Sardinia is a very high risk area for ADS in children. Nearly half of this population can already be diagnosed with paediatric multiple sclerosis at onset. Overall, 72% of those with ADS will have paediatric multiple sclerosis after a mean of 8 years. What this paper adds Sardinia is a very high risk area for paediatric acquired demyelinating syndromes (ADS). A high proportion of those with paediatric multiple sclerosis are diagnosed at onset of ADS. After an average 8 years from onset of paediatric ADS, three-quarters of patients are diagnosed with paediatric multiple sclerosis.

Inflammatory Diseases of the Central Nervous System

Pediatric neuroinflammatory conditions are a complex group of disorders with a wide range of clinical presentations. Patients can present with a combination of focal neurologic deficits, encephalopathy, seizures, movement disorders, or psychiatric manifestations. There are several ways that pediatric neuroinflammatory conditions can be classified, including clinical presentation, pathophysiologic mechanism, and imaging and laboratory findings. In this article, we group these conditions into acquired demyelinating diseases, immune-mediated epilepsies/encephalopathies, primary rheumatologic conditions with central nervous system (CNS) manifestations, CNS vasculitis, and neurodegenerative/genetic conditions with immune-mediated pathophysiology and discuss epidemiology, pathophysiology, clinical presentation, treatment, and prognosis of each disorder.

Management of pediatric post-infectious neurological syndromes

BACKGROUND

Post-Infectious Neurological Syndromes (PINS) are heterogeneous neurological disorders with post or para-infectious onset. PINS diagnosis is complex, mainly related to the absence of any recognized guidelines and a univocal definition.

AIM OF THE STUDY

To elaborate a diagnostic guide for PINS.

MATERIALS AND METHODS

We retrospectively analysed patients younger than 14 years old admitted to Bambino Gesù Children's Hospital in Rome for PINS from December 2005 to March 2018. Scientific literature using PubMed as research platform was analysed: the key words "Post-Infectious Neurological Syndromes" were used.

RESULTS

A polysymptomatic presentation occurred in a percentage of 88% of the children. Motor signs and visual disturbances the most observed symptoms/signs were the most detached, followed by fever, speech disturbances, sleepiness, headache and bradipsychism. Blood investigations are compatible with inflammation, as a prodromal illnesses was documented in most cases. Normal cerebral spinal fluid (CSF) characteristics has been found in the majority of the study population. Magnetic resonance imaging (MRI) was positive for demyelinating lesions. Antibiotics, acyclovir and steroids have been given as treatment.

DISCUSSION

We suggest diagnostic criteria for diagnosis of PINS, considering the following parameters: neurological symptoms, timing of disease onset, blood and CSF laboratory tests, MRI imaging.

CONCLUSIONS

We propose criteria to guide clinician to diagnose PINS as definitive, probable or possible. Further studies are required to validate diagnostic criteria.

Acute Disseminated Encephalomyelitis: Current Perspectives

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated central nervous system (CNS) disorder, characterized by polyfocal symptoms, encephalopathy and typical magnetic resonance imaging (MRI) findings, that especially affects young children. Advances in understanding CNS neuroimmune disorders as well as the association of myelin oligodendrocyte glycoprotein antibody (MOG-Ab) with both monophasic and recurrent forms of ADEM have led to new insights into its definition, management and outcome. In this review, we aim to provide an update based on current epidemiologic, clinical, radiological and immunopathological aspects and clinical outcome of ADEM.

E.U. paediatric MOG consortium consensus: Part 2 - Neuroimaging features of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders

Imaging plays a crucial role in differentiating the spectrum of paediatric acquired demyelinating syndromes (ADS), which apart from myelin oligodendrocyte glycoprotein antibody associated disorders (MOGAD) includes paediatric multiple sclerosis (MS), aquaporin-4 antibody neuromyelitis optica spectrum disorders (NMOSD) and unclassified patients with both monophasic and relapsing ADS. In contrast to the imaging characteristics of children with MS, children with MOGAD present with diverse imaging patterns which correlate with the main demyelinating phenotypes as well as age at presentation. In this review we describe the common neuroradiological features of children with MOGAD such as acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, AQP4 negative NMOSD. In addition, we report newly recognized presentations also associated with MOG-ab such as the 'leukodystophy-like' phenotype and autoimmune encephalitis with predominant involvement of cortical and deep grey matter structures. We further delineate the features, which may help to distinguish MOGAD from other ADS and discuss the future role of MR-imaging in regards to treatment decisions and prognosis in children with MOGAD. Finally, we propose an MRI protocol for routine examination and discuss new imaging techniques, which may help to better understand the neurobiology of MOGAD.

Risk factors for academic difficulties in children with myelin oligodendrocyte glycoprotein antibody-associated acute demyelinating syndromes

AIM

To describe cognitive abilities through the evaluation of academic difficulties in children with acute demyelinating syndromes (ADS) and myelin oligodendrocyte glycoprotein (MOG) antibodies.

METHOD

This was an observational, retrospective study of a French paediatric cohort that included children aged 18 years and younger. Clinical, biological, and imaging data were collected and academic outcome was measured.

RESULTS

Seventy-six children were included in the study with a mean (SD) follow-up of 4 years 7 months (6y 4mo). Median age at disease onset was 9 years 1 months (interquartile range=4y 7mo-13y 11mo; 36 females, 40 males). Thirty-six children relapsed and 20 had academic difficulties at the last follow-up. Academic difficulties, as well as deep grey matter and putaminal lesions (p=0.047 and p=0.006 respectively), were significantly more prevalent in children aged 10 years and younger (p=0.02). Using univariate binary regression analysis, we found that age at disease onset of 10 years and younger (odds ratio [OR] 3.72 [95% confidence interval {CI} 1.19-11.64]; p=0.024), acute disseminated encephalomyelitis at disease onset (OR 52.5 [95% CI 5.97-461.4]; p<0.001), and deep grey matter lesions (OR 17.33 [95% CI 3.87-77.72]; p<0.001) were associated with academic difficulties.

INTERPRETATION

MOG antibody-associated ADS have distinct clinical and radiological patterns that are age-dependent. Indirect cognitive evaluation through academic difficulties was prevalent in younger children and is associated with specific clinical and magnetic resonance imaging factors that need to be considered earlier on when assessing this patient population.

Acute disseminated encephalomyelitis in children and adults: A focused review emphasizing new developments

Acute disseminated encephalomyelitis (ADEM) was originally described in the medical literature more than 200 years ago. However, consensus clinical diagnostic criteria are less than 15 years old. Accurate diagnostic testing for myelin oligodendrocyte glycoprotein (MOG) autoantibodies has only become clinically available in the last 3-5 years and has facilitated a rapidly evolving understanding of patients with recurrent demyelination following ADEM. The field is working to optimize treatment for these patients with hopes of prospective treatment studies in the not too distant future. New imaging data suggest that even monophasic demyelination may have long-term impacts that were previously unrecognized. Recent developments in the literature are described in order to guide practice for providers who treat both adults and children with monophasic and recurrent forms of ADEM with and without MOG antibodies.

Clinical and Magnetic Resonance Imaging Outcome Predictors in Pediatric Anti-N-Methyl-D-Aspartate Receptor Encephalitis

OBJECTIVE

To evaluate disease symptoms, and clinical and magnetic resonance imaging (MRI) findings and to perform longitudinal volumetric MRI analyses in a European multicenter cohort of pediatric anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) patients.

METHODS

We studied 38 children with NMDARE (median age = 12.9 years, range =1-18) and a total of 82 MRI scans for volumetric MRI analyses compared to matched healthy controls. Mixed-effect models and brain volume z scores were applied to estimate longitudinal brain volume development. Ordinal logistic regression and ordinal mixed models were used to predict disease outcome and severity.

RESULTS

Initial MRI scans showed abnormal findings in 15 of 38 (39.5%) patients, mostly white matter T2/fluid-attenuated inversion recovery hyperintensities. Volumetric MRI analyses revealed reductions of whole brain and gray matter as well as hippocampal and basal ganglia volumes in NMDARE children. Longitudinal mixed-effect models and z score transformation showed failure of age-expected brain growth in patients. Importantly, patients with abnormal MRI findings at onset were more likely to have poor outcome (Pediatric Cerebral Performance Category score > 1, incidence rate ratio = 3.50, 95% confidence interval [CI] = 1.31-9.31, p = 0.012) compared to patients with normal MRI. Ordinal logistic regression models corrected for time from onset confirmed abnormal MRI at onset (odds ratio [OR] = 9.90, 95% CI = 2.51-17.28, p = 0.009), a presentation with sensorimotor deficits (OR = 13.71, 95% CI = 2.68-24.73, p = 0.015), and a treatment delay > 4 weeks (OR = 5.15, 95% CI = 0.47-9.82, p = 0.031) as independent predictors of poor clinical outcome.

INTERPRETATION

Children with NMDARE exhibit significant brain volume loss and failure of age-expected brain growth. Abnormal MRI findings, a clinical presentation with sensorimotor deficits, and a treatment delay > 4 weeks are associated with worse clinical outcome. These characteristics represent promising prognostic biomarkers in pediatric NMDARE. ANN NEUROL 2020 ANN NEUROL 2020;88:148-159.

Acute Disseminated Encephalomyelitis in Children: An Updated Review Based on Current Diagnostic Criteria

Acute disseminated encephalomyelitis is an inflammatory disorder of the central nervous system. Uniform diagnostic criteria for acute disseminated encephalomyelitis did not exist until publication of expert-defined consensus definitions by the International Pediatric Multiple Sclerosis Society Group in 2007, with updates in 2013. In the expanding field of pediatric neuroimmunology, consistent diagnostic criteria are essential to correctly categorize patients as increasing information regarding prognosis and management becomes available. Scientific literature is relatively lacking in review articles on International Pediatric Multiple Sclerosis Society Group-defined acute disseminated encephalomyelitis. This review focuses primarily on references applying the International Pediatric Multiple Sclerosis Society Group criteria for acute disseminated encephalomyelitis presenting specific, up-to-date, and translatable information regarding the epidemiology, pathophysiology, clinical features, diagnosis, management, and prognosis of acute disseminated encephalomyelitis in the pediatric population.

Diagnostic Considerations in Acute Disseminated Encephalomyelitis and the Interface with MOG Antibody

Acute disseminated encephalomyelitis (ADEM) is a common yet clinically heterogenous syndrome characterized by encephalopathy, focal neurologic findings, and abnormal neuroimaging. Differentiating ADEM from other demyelinating disorders of childhood can be difficult and appropriate interpretation of the historical, clinical, and neurodiagnostic components of a patient's presentation is critical. Myelin oligodendrocyte glycoprotein (MOG) antibody-associated diseases are a recently recognized set of disorders, which include ADEM presentations, among other phenotypes. This review article discusses the clinical diagnosis, differential diagnosis, interpretation of data, and treatment/prognosis of this unique syndrome with distinctive review of the spectrum of MOG antibodies.

Paediatric multiple sclerosis: a new era in diagnosis and treatment

Multiple sclerosis is a chronic immune-mediated demyelinating disease of the central nervous system. The diagnosis of multiple sclerosis in children, as in adults, requires evidence of dissemination of inflammatory activity in more than one location in the central nervous system (dissemination in space) and recurrent disease over time (dissemination in time). The identification of myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) and aquaporin-A antibodies (AQP4-Ab), and the subsequent discovery of their pathogenic mechanisms, have led to a shift in the classification of relapsing demyelinating syndromes. This is reflected in the 2017 revised criteria for the diagnosis of multiple sclerosis, which emphasizes the exclusion of multiple sclerosis mimics and aims to enable earlier diagnosis and thus treatment initiation. The long-term efficacy of individual therapies initiated in children with multiple sclerosis is hard to evaluate, owing to the small numbers of patients who have the disease, the relatively high number of patients who switch therapy, and the need for long follow-up studies. Nevertheless, an improvement in prognosis with a globally reduced annual relapse rate in children with multiple sclerosis is now observed compared with the pretreatment era, indicating a possible long-term effect of therapies. Given the higher relapse rate in children compared with adults, and the impact multiple sclerosis has on cognition in the developing brain, there is a question whether rapid escalation or potent agents should be used in children, while the short- and long-term safety profiles of these drugs are being established. With the results of the first randomized controlled trial of fingolimod versus interferon-β1a in paediatric multiple sclerosis published in 2018 and several clinical trials underway, there is hope for further progress in the field of paediatric multiple sclerosis. WHAT THIS PAPER ADDS: Early and accurate diagnosis of multiple sclerosis is crucial. The discovery of antibody-mediated demyelination has changed the diagnosis and management of relapsing demyelination syndromes. Traditional escalation therapy is being challenged by induction therapy.

Serum neurofilament light chain in pediatric MS and other acquired demyelinating syndromes

Objective

To explore the correlation between serum and CSF neurofilament light chain (NfL) and the association of NfL levels and future disease activity in pediatric patients with a first attack of acquired demyelinating syndromes (ADS).

Methods

In total, 102 children <18 years with a first attack of CNS demyelination and 23 age-matched controls were included. Clinically definite multiple sclerosis (CDMS) was set as an endpoint for analysis. CSF NfL was tested by the commercially available ELISA (UmanDiagnostics); serum NfL (sNfL) was tested with a Simoa assay. Hazard ratios (HR) were calculated with Cox regression analysis.

Results

Of the 102 patients, 47 (46%) were tested for CSF NfL. CSF and serum NfL correlated significantly in the total group (ρ 0.532, p < 0.001) and even more significantly in the subgroup of patients with future CDMS diagnosis (ρ 0.773, p < 0.001). sNfL was higher in patients than in controls (geometric mean 6.1 pg/mL, p < 0.001), and was highest in ADS presenting with encephalopathy (acute disseminated encephalomyelitis, n = 28, 100.4 pg/mL), followed by patients without encephalopathy (ADS−) with future CDMS diagnosis (n = 40, 32.5 pg/mL), and ADS− who remained monophasic (n = 34, 17.6 pg/mL). sNfL levels higher than a median of 26.7 pg/mL at baseline are associated with a shorter time to CDMS diagnosis in ADS− (p = 0.045). HR for CDMS diagnosis was 1.09 for each 10 pg/mL increase of sNfL, after correction for age, oligoclonal bands, and MRI measures (p = 0.012).

Conclusion

The significant correlation between CSF and serum NfL strengthens its reliability as a peripheral marker of neuroaxonal damage. Higher sNfL levels at baseline were associated with higher probability of future CDMS diagnosis in ADS−.

Pediatric acquired demyelinating syndrome (ADS) in inpatient hospital settings: The hospitalization rate, costs, and outcomes in the US

BACKGROUND

Although relatively rare among pediatric patients, acquired demyelinating syndromes of the central nervous system (ADS) is a potentially disabling condition that warrants hospitalization and long-term follow-up. As such, a better understanding of the epidemiology and hospital utilization for this condition could provide critical information for health care planning and resource allocation.

OBJECTIVE

To evaluate the trends of hospital utilization and resource use associated with pediatric ADS in the US.

METHOD

We conducted a serial cross-sectional trend analysis with complex sampling and weighting using nationally representative hospital discharge records, from the Kids´ Inpatient Database (KID), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality coded with International Classification of Diseases (Healthcare Cost and Utilization Project (HCUP) 2018), Ninth Revision (ICD-9-CM) for the years 2003, 2006, 2009, and 2012. We also conducted a cross-sectional study for the KID2016 dataset coded with ICD10-CM to estimate the pediatric ADS-related hospital utilization for the year. EXCLUDING TRANSFERRING DISCHARGES: we evaluated the discharge records for those aged 0 to 19 years diagnosed with any of ADS of central nervous systems including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), acute disseminated encephalomyelitis (ADEM), optic neuritis (ON), transverse myelitis (TM) and demyelinating disease not specified (DDNS). For the trend analysis, we used variance-weighted regression and Poisson regression for the annual hospitalization rate, total hospital charges and hospital days associated with the ADS hospitalizations for the year 2003 to 2012.

RESULTS

We estimated a total of 1,292 ADS-related hospitalizations (95%CI: 1127-1,458) in 2003, 2104 hospitalizations (95%CI: 1823-2385) in 2006, 2851 hospitalizations (95%CI: 2499-3203) in 2009, and 3501 hospitalizations (95%CI: 3058-3945) in 2012 among those aged 19 years or younger with diagnoses of ADS. There was an increase in the proportion of the inpatient hospital cost attributed to ADS from 0.06% in 2003 to 0.20% in 2012. The annual hospitalization rates relative to pediatric ADS were 1.59/100,000 (95%CI: 1.51-1.68) in 2003 and 4.21/100,000 (95%CI: 4.07-4.35) in 2012. In the cross-sectional analysis for the year 2016 coded by ICD10-CM, the number of pediatric ADS related hospitalizations were 4,568, constituting 0.30% of the total pediatric hospitalization cost. The annual hospitalization rate for the year 2016 was estimated to be 5.51/100,000.

CONCLUSION

Hospital utilization by pediatric patients with ADS increased during the period 2003 through 2012. The cross-sectional analysis for the year 2016 indicated that the trend could be ongoing, although the direct comparison was not feasible due to the changes in the coding system of the dataset from ICD9-CM to ICD10-CM. Although relatively rare, pediatric ADS warrant long-term follow-ups and hospitalizations, impacting the developmental trajectory of the affected children and the lives of their family members. Th potentially increasing trend of pediatric ADS hospital utilization should be acknowledged when allocating and planning future resources and supporting programs.

White matter plasticity and maturation in human cognition

White matter plasticity likely plays a critical role in supporting cognitive development. However, few studies have used the imaging methods specific to white matter tissue structure or experimental designs sensitive to change in white matter necessary to elucidate these relations. Here we briefly review novel imaging approaches that provide more specific information regarding white matter microstructure. Furthermore, we highlight recent studies that provide greater clarity regarding the relations between changes in white matter and cognition maturation in both healthy children and adolescents and those with white matter insult. Finally, we examine the hypothesis that white matter is linked to cognitive function via its impact on neural synchronization. We test this hypothesis in a population of children and adolescents with recurrent demyelinating syndromes. Specifically, we evaluate group differences in white matter microstructure within the optic radiation; and neural phase synchrony in visual cortex during a visual task between 25 patients and 28 typically developing age-matched controls. Children and adolescents with demyelinating syndromes show evidence of myelin and axonal compromise and this compromise predicts reduced phase synchrony during a visual task compared to typically developing controls. We investigate one plausible mechanism at play in this relationship using a computational model of gamma generation in early visual cortical areas. Overall, our findings show a fundamental connection between white matter microstructure and neural synchronization that may be critical for cognitive processing. In the future, longitudinal or interventional studies can build upon our knowledge of these exciting relations between white matter, neural communication, and cognition.

Childhood multiple sclerosis is associated with reduced brain volumes at first clinical presentation and brain growth failure

Background:

Paediatric multiple sclerosis (pedMS) patients at a single site were shown to have reduced brain volumes and failure of age-expected brain growth compared to healthy controls. However, the precise time of onset of brain volume loss remains unclear.

Objective:

To longitudinally study brain volumes in a multi-centre European cohort at first presentation and after 2 years.

Methods:

Brain volumes of high-resolution magnetic resonance imaging (MRI) data from 37 pedMS patients at first presentation prior to steroid therapy and at 2-year follow-up ( n = 21) were compared to matched longitudinal MRI data from the NIH Paediatric MRI Data Repository.

Results:

Patients showed significantly reduced whole brain, grey and white matter and increased ventricular volumes at initial presentation and at follow-up compared to controls. Over 2 years, patients exhibited significant reduction of whole brain and white matter volumes, accompanied by increased ventricular volume. Brain volume loss at follow-up correlated with a higher number of infratentorial lesions, relapses and an increased Expanded Disability Status Scale (EDSS) score.

Conclusions:

In pedMS patients, brain volume loss is present already at first clinical presentation and accelerated over 2 years. Increased disease activity is associated with more severe brain volume loss. MRI brain volume change might serve as an outcome parameter in future prospective pedMS studies.

Dynamic gray matter volume changes in pediatric multiple sclerosis

Objectives

To assess, using MRI, the spatial patterns of gray matter (GM) atrophy in pediatric patients with multiple sclerosis (MS), their dynamic changes over time, and their clinical relevance.

Methods

Sixty-eight pediatric patients with MS (30 with a clinical and MRI follow-up after 3.5 years) and 26 healthy controls (HC) underwent clinical and MRI evaluation. To overcome difficulties in obtaining longitudinal scans in pediatric HC, a group of 317 pediatric HC from an NIH-funded MRI Study of Normal Brain Development was used to estimate GM developmental trajectories. In pediatric patients with MS, deviations from normative GM volume values at the voxel level were assessed at baseline and during the follow-up, using linear mixed-effects models. Correlations between GM volume deviations and disability, IQ, and white matter (WM) lesion volumes (LV) were estimated.

Results

Pediatric patients with MS showed failures in GM development in several cortical and subcortical regions, as well as GM atrophy progression in most of these regions, which were only partially related to focal WM LV. Significant correlations were found between regional GM atrophy (particularly of deep GM regions) and disability, whereas higher IQ was associated with reduced deviations from age-expected GM volumes of specific GM regions at baseline and during the follow-up.

Conclusions

Impaired GM maturation occurs in pediatric patients with MS, which is only partially driven by WM inflammation, suggesting that early neurodegenerative phenomena contribute to disability. High IQ, a measure of reserve, may offer protection by promoting remodeling of GM pruning in this young age.

Physical activity and dentate gyrus volume in pediatric acquired demyelinating syndromes

Objective

To assess the association between daily moderate-to-vigorous physical activity (MVPA) and dentate gyrus volume (DGv) in pediatric patients with acquired demyelinating syndromes (ADSs) of the CNS.

Methods

Cross-sectional analysis of accelerometry (7 days) and research protocol MRI data from 12 pediatric MS and 18 children with monophasic ADS (monoADS). Total brain and DGv were quantified using standardized methods. The association of daily minutes of MVPA with normalized DGv (nDGv) was assessed using multivariable generalized linear models.

Results

Median (interquartile range) MVPA was lower in MS patients [9.5 (14)] and exhibited less variation than in monoADS patients [24.5 (47)]. nDGv did not differ significantly between groups [mean nDGv (SD) [cm³]: MS 0.34 (0.1); monoADS 0.4 (0.1); p = 0.100]. In the monoADS group, every 1-minute increase in MVPA was associated with a 2.4-mm³ increase in nDGv (p = 0.0017), an association that was independent of age at incident demyelination, time from incident demyelination, sex, and brain white matter T2 lesion volume. No significant association was found between MVPA and nDGv (−2.6 mm³/min, p = 0.16) in the MS group.

Conclusions

Higher MVPA associates with greater nDGv in children who have recovered from monophasic demyelination. Larger studies are required to determine whether MVPA can promote regional brain development, or limit tissue damage, in youth with MS.

Radiologically isolated syndrome in children: Current knowledge and future directions

As the use of magnetic resonance imaging (MRI) grows in clinical practice, clinicians are increasingly faced with the difficult task of interpreting the significance of incidental findings on brain MRI. Among individuals found to have incidental brain MRI findings, a small number have white matter abnormalities on MRI that resemble the demyelinating lesions of multiple sclerosis (MS) in the absence of a history of relevant clinical symptoms. This has been termed radiologically isolated syndrome (RIS). Recent years have seen growing interest in RIS, with observational studies that have specifically focused on answering questions regarding the subsequent risk of future clinical events and diagnosis of MS in adults and children with these findings. Given the high rate of subsequent clinical events seen in adult studies, knowledge related to RIS in children is paramount, particularly given the higher disease activity and burden in children with MS. This review examines this question, providing an overview of RIS with a focus on its significance in children including current definitions, its association with MS, and knowledge related to therapeutic interventions for RIS. We conclude with suggestions for an approach to assessment of and subsequent surveillance in children fulfilling criteria for RIS and directions for future study.

Incidence and outcome of acquired demyelinating syndromes in Dutch children: update of a nationwide and prospective study

INTRODUCTION

Acquired demyelinating syndromes (ADS) are immune-mediated demyelinating disorders of the central nervous system in children. A nationwide, multicentre and prospective cohort study was initiated in the Netherlands in 2006, with a reported ADS incidence of 0.66/100,000 per year and MS incidence of 0.15/100,000 per year in the period between 2007 and 2010. In this study, we provide an update on the incidence and the long-term follow-up of ADS in the Netherlands.

METHODS

Children < 18 years with a first attack of demyelination were included consecutively from January 2006 to December 2016. Diagnoses were based on the International Paediatric MS study group consensus criteria. Outcome data were collected by neurological and neuropsychological assessments, and telephone call assessments.

RESULTS

Between 2011 and 2016, 55/165 of the ADS patients were diagnosed with MS (33%). This resulted in an increased ADS and MS incidence of 0.80/100,000 per year and 0.26/100,000 per year, respectively. Since 2006 a total of 243 ADS patients have been included. During follow-up (median 55 months, IQR 28-84), 137 patients were diagnosed with monophasic disease (56%), 89 with MS (37%) and 17 with multiphasic disease other than MS (7%). At least one form of residual deficit including cognitive impairment was observed in 69% of all ADS patients, even in monophasic ADS. An Expanded Disability Status Scale score of ≥ 5.5 was reached in 3/89 MS patients (3%).

CONCLUSION

The reported incidence of ADS in Dutch children has increased since 2010. Residual deficits are common in this group, even in monophasic patients. Therefore, long-term follow-up in ADS patients is warranted.

High neurofilament levels are associated with clinically definite multiple sclerosis in children and adults with clinically isolated syndrome

Background:

A promising biomarker for axonal damage early in the disease course of multiple sclerosis (MS) is neurofilament light chain (NfL). It is unknown whether NfL has the same predictive value for MS diagnosis in children as in adults.

Objective:

To explore the predictive value of NfL levels in cerebrospinal fluid (CSF) for MS diagnosis in paediatric and adult clinically isolated syndrome (CIS) patients.

Methods:

A total of 88 adult and 65 paediatric patients with a first attack of demyelination were included and followed (mean follow up-time in adults: 62.8 months (standard deviation (SD) ±38.7 months) and 43.8 months (SD ±27.1 months) in children). Thirty control patients were also included. Lumbar puncture was done within 6 months after onset of symptoms. NfL was determined in CSF using enzyme-linked immunosorbent assay (ELISA). COX regression analyses were used to calculate hazard ratios (HR) for clinically definite multiple sclerosis (CDMS) diagnosis.

Results:

After adjustments for age, oligoclonal bands (OCB), and asymptomatic T2 lesions on baseline magnetic resonance imaging (MRI), increased NfL levels in both paediatric and adult CIS patients were associated with a shorter time to CDMS diagnosis (children HR = 3.7; p = 0.007, adults HR = 2.1; p = 0.032). For CIS patients with a future CDMS diagnosis, children showed higher NfL levels than adults (geometric mean 4888 vs 2156 pg/mL; p = 0.007).

Conclusion:

CSF NfL levels are associated with CDMS diagnosis in children and adults with CIS. This makes NfL a promising predictive marker for disease course with potential value in clinical practice.

Paediatric multiple sclerosis and other acute demyelinating diseases

PURPOSE OF REVIEW

Neuroimmunological diseases encompass a wide spectrum of diseases in children. Apart from the discovery of autoantibodies affecting primarily grey matter structures and the improved clinical characterization of rare entities such as N-methyl D-aspartate receptor-R- encephalitis, important strides have also been made in autoimmune-mediated white matter diseases, including paediatric multiple sclerosis (pedMS) and other acute demyelinating syndromes (ADS) often associated with antibodies (abs) against myelin-oligodendrocyte-glycoprotein (MOG). This review will cover findings of recent studies in pedMS, in the emerging field of non-MS acute demyelinating episodes associated with MOG abs and lastly from new imaging techniques such as diffusion tensor imaging (DTI) revealing new insights in the pathogenesis of ADS in children.

RECENT FINDINGS

The first prospective randomized clinical pedMS trial assessing the clinical and radiological efficacy of fingolimod versus a standard disease-modifying agent has shown clear superiority of fingolimod. The clinical spectrum of MOG-associated diseases has been characterized in more detail revealing clinical subtypes distinct from pedMS. A recent large European study further showed that MOG-associated diseases do not respond to first-line disease-modifying treatment (DMT) in MS but fare better with B-cell modulating therapies including regular intravenous immunoglobulin (IVIG).

SUMMARY

Recent findings strongly indicate that in particular in highly active pedMS characterized by new relapses or accrual of new MRI lesions despite first-line DMT treatment should be escalated. Secondly, several studies have shown that MOG-spectrum diseases include children with monophasic and recurrent subtypes other than MS with different clinical, radiological characteristics and treatment challenges.

'Leukodystrophy-like' phenotype in children with myelin oligodendrocyte glycoprotein antibody-associated disease

AIM

To review the demographics and clinical and paraclinical parameters of children with myelin oligodendrocyte glycoprotein (MOG) antibody-associated relapsing disease.

METHOD

In this UK-based, multicentre study, 31 children with MOG antibody-associated relapsing disease were studied retrospectively.

RESULTS

Of the 31 children studied, 14 presented with acute disseminated encephalomyelitis (ADEM); they were younger (mean 4.1y) than the remainder (mean 8.5y) who presented with optic neuritis and/or transverse myelitis (p<0.001). Similarly, children who had an abnormal brain magnetic resonance imaging (MRI) at onset (n=20) were younger than patients with normal MRI at onset (p=0.001) or at follow-up (p<0.001). 'Leukodystrophy-like' MRI patterns of confluent largely symmetrical lesions was seen during the course of the disease in 7 out of 14 children with a diagnosis of ADEM, and was only seen in children younger than 7 years of age. Their disability after a 3-year follow-up was mild to moderate, and most patients continued to relapse, despite disease-modifying treatments.

INTERPRETATION

MOG antibody should be tested in children presenting with relapsing neurological disorders associated with confluent, bilateral white matter changes, and distinct enhancement pattern. Children with MOG antibody-associated disease present with age-related differences in phenotypes, with a severe leukoencephalopathy phenotype in the very young and normal intracranial MRI in the older children. This finding suggests a susceptibility of the very young and myelinating brain to MOG antibody-mediated mechanisms of damage.

WHAT THIS PAPER ADDS

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination manifest with an age-related phenotype. Children with MOG antibody and 'leukodystrophy-like' imaging patterns tend to have poor response to second-line immunotherapy.