Nationwide Incidence of Acquired Central Nervous System Demyelination in Icelandic Children

Incidence and prevalence of paediatric-onset multiple sclerosis in two Canadian provinces: a population-based study representing over half of Canada's population

BACKGROUND

Population-based studies estimating the epidemiology of paediatric-onset multiple sclerosis (PoMS) are scarce.

METHODS

We accessed population-based health administrative data from two provinces in Canada, Ontario and British Columbia (BC). Individuals with PoMS were identified via a validated case definition. The index date ('MS onset') was the first demyelinating or MS specific claim recorded ≤18 years of age. We estimated the age-standardised annual incidence and prevalence of PoMS, and 95% CIs between 2003 and 2019. We used negative binomial regression models to assess the temporal changes in the annual crude incidence and prevalence of PoMS, and the ratios comparing sex groups.

RESULTS

From 2003 to 2019, a total of 148 incident PoMS cases were identified in BC, and 672 in Ontario. The age-standardised annual incidence of PoMS was stable in both provinces, averaging 0.95 (95% CI 0.79 to 1.13) in BC and 0.98 (95%CI 0.84 to 1.12) in Ontario per 100 000 person-years. The incidence ratio by sex (female vs male) was also stable over the study period, averaging 1.5:1 (95% CI 1.06 to 2.08, BC) and 2.0:1 (95% CI 1.61 to 2.59, Ontario). The age-standardised prevalence per 100 000 people rose from 4.75 (2003) to 5.52 (2019) in BC and from 2.93 (2003) to 4.07 (2019) in Ontario, and the increase was statistically significant in Ontario (p=0.002). There were more female prevalent PoMS cases than males in both provinces.

CONCLUSIONS

Canada has one of the highest rates of PoMS globally, and the prevalence, but not incidence, has increased over time. Allocation of resources to support the growing youth population with MS should be a priority.

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.

[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.

Evaluation of inflammatory acquired demyelinating syndromes in children: a single-center experience

To evaluate the clinical and neuroimaging features of pediatric acquired demyelinating syndromes (ADS) in a tertiary pediatric neurology clinic in Turkey. All children diagnosed with any subset of ADS between 2013 and 2018 were included in this retrospective cohort study. Forty-two patients (21 female) with a median follow-up period of 30 months were included. The median age of the patients at disease onset was 11 years (range 1.5-17 years). The most common pediatric ADS categories according to the International pediatric Multiple Sclerosis Study Group consensus classification criteria were acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS), each of which seen in 15 patients, followed by clinically isolated syndrome (CIS) (n = 11) and Neuromyelitis Optica Spectrum Disorder (NMOSD) (n = 1). At the first clinical event, children with ADEM significantly differed from the children affected by MS and CIS in terms of the following parameters: median age at onset (7 vs. 13.5 and 14.5 years; p < 0.001), encephalopathy (93.3 vs 0% and 0%; p < 0.001), and basal ganglia/thalamus lesions (73.3 vs 9.1% and 9.1%; p < 0.001). The frequency of seizure and pleocytosis were higher in ADEM group than MS group (p < 0.05), whereas oligoclonal bands (p < 0.001) and periventricular white matter lesions (p < 0.01) were more frequently observed in MS patients. Rituximab was used with great success in the prevention of relapses in 3 patients: NMOSD (n = 1), MS (n = 1) and ADEM followed by recurrent optic neuritis (n = 1). Our results define the longitudinal disease course of various ADS categories in a single referral center. In addition, this study compares various clinical, laboratory and neuroimaging features between these ADS categories.

Worldwide Incidence and Prevalence of Neuromyelitis Optica: A Systematic Review

Objective

Since the last epidemiologic review of neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD), 22 additional studies have been conducted. We systematically review the worldwide prevalence, incidence, and basic demographic characteristics of NMOSD and provide a critical overview of studies.

Methods

PubMed, Ovid MEDLINE, and Embase using Medical Subject Headings and keyword search terms and reference lists of retrieved articles were searched from 1999 until August 2019. We collected data on the country; region; methods of case assessment and aquaporin-4 antibody (AQP4-Ab) test; study period; limitations; incidence (per 100,000 person-years); prevalence (per 100,000 persons); and age-, sex-, and ethnic group–specific incidence or prevalence.

Results

We identified 33 relevant articles. The results indicated the highest estimates of incidence and prevalence of NMOSD in Afro-Caribbean region (0.73/100 000 person-years [95% CI: 0.45–1.01] and 10/100 000 persons [95% CI: 6.8–13.2]). The lowest incidence and prevalence of NMOSD were found in Australia and New Zealand (0.037/100 000 person-years [95% CI: 0.036–0.038] and 0.7/100,000 persons [95% CI: 0.66–0.74]). There was prominent female predominance in adults and the AQP4-Ab–seropositive subpopulation. The incidence and prevalence peaked in middle-aged adults. African ethnicity had the highest incidence and prevalence of NMOSD, whereas White ethnicity had the lowest. No remarkable trend of incidence was described over time.

Conclusion

NMOSD is a rare disease worldwide. Variations in prevalence and incidence have been described among different geographic areas and ethnicities. These are only partially explained by different study methods and NMO/NMOSD definitions, highlighting the need for specifically designed epidemiologic studies to identify genetic effects and etiologic factors.

Acute Disseminated Encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an autoimmune demyelinating disease of central nervous system (CNS). ADEM is most commonly seen in children, although adults can also be affected. The disease typically starts with an abrupt onset within day to weeks after a viral infection or immunization. Presenting features include an acute encephalopathy with multifocal neurologic signs and fever. ADEM generally has a monophasic course, although recurrent ADEM has also been described and is defined as multiphasic ADEM. MRI shows widespread lesions located in both brain and spinal cord. An involvement of basal ganglia and thalami has also been described. Analysis of cerebrospinal fluid (CSF) may reveal mild lymphocytic pleocytosis and increased proteins, whereas oligoclonal bands are usually negative. In the absence of specific biologic markers, ADEM remains a diagnosis of exclusion and it is still based on clinical manifestations, imaging, and laboratory features. Therapy is based on steroid administration and the prognosis is usually favorable.

Epidemiology of pediatric multiple sclerosis, neuromyelitis optica, and optic neuritis in Taiwan

BACKGROUND AND OBJECTIVE

The epidemiology of pediatric acquired demyelinating disorders remains to be clarified in many parts of Asia. We carry out this study to depict the epidemiology of pediatric multiple sclerosis (MS), neuromyelitis optica (NMO), and optic neuritis (ON) in Taiwan.

METHODS

We conducted a retrospective nationwide population-based study using data from Taiwan's National Health Insurance Research Database. Prevalent cases of pediatric MS and NMO during 2001-2015, and incident cases of pediatric MS, NMO, and ON during 2003-2015 were identified. The demographic features and comorbidities were investigated.

RESULTS

We identified 403 MS, 42 NMO, and 1496 ON incident cases under the age of 20 during 2003-2015. The majority of pediatric MS (86.1%) and NMO (90.5%) patients were 10 years old or above. The incidence of MS and ON was relatively steady, while that of NMO increased prominently later during the study period. The average incidence of pediatric MS and NMO during 2011-2015 was 0.52 and 0.11 per 100,000 person-years, respectively. The female preponderance was evident for pediatric MS and NMO, and less so for pediatric ON. The most common autoimmune comorbidities for pediatric MS were thyrotoxicosis (1.0%) and systemic lupus erythematosus (0.7%).

CONCLUSION

The epidemiology of pediatric MS was largely stationary in Taiwan during 2001-2015, while the prevalence of pediatric NMO rose steeply during this period, probably reflecting better recognition of this clinical entity. Autoimmune comorbidities were uncommon for pediatric MS and NMO in Taiwan.

Epidemiology of Pediatric-Onset Multiple Sclerosis: A Systematic Review of the Literature

Multiple sclerosis onset in youth is increasingly recognized. A systematic review was conducted to assess incidence and prevalence of pediatric-onset multiple sclerosis, focusing on occurrence by age subgroups and disease course. A literature search for the period 1965-2018 was carried out, selecting population-based studies of multiple sclerosis in individuals aged 19 years and younger. Nineteen studies met inclusion criteria. One pediatric neurologist extracted the data. Overall incidence ranged from 0.05 (95% confidence interval 0.03-0.08) to 2.85 (95% confidence interval 2.83-2.86) per 100 000 children and overall prevalence from 0.69 (95% confidence interval 0.58-0.80) to 26.92 (95% confidence interval 26.61-27.23) per 100 000 children. Incidence increased with age. The female-male ratio increased from 1.2:1 in children <12 years old to 2.8:1 in children ≥12 years old. Ten studies (n=521 children) reported disease course. Seven studies found only relapsing-remitting disease and 3 studies found primary-progressive disease in 3.0% to 6.7%. Two secondary-progressive disease cases were identified. Epidemiologic data aid in understanding the magnitude of multiple sclerosis and its clinical phenotypes, for planning for new disease-modifying therapies in the pediatric population.

Population-based Incidence of Pediatric and Adult Optic Neuritis and the Risk of Multiple Sclerosis

PURPOSE

To determine the age- and sex-specific prevalence and incidence of demyelinating optic neuritis and the risk of multiple sclerosis (MS) in pediatric and adult populations in South Korea.

DESIGN

A nationwide, population-based, retrospective study using data from the Korean National Health Claims database from 2010 to 2016.

PARTICIPANTS

The entire South Korean population aged 65 years of age or younger (n = 44 700 564). All patients with optic neuritis from the entire Korean population were included.

METHODS

Patients aged 14 years of age or younger were classified as pediatric patients, and those aged 15 to 65 years were classified as adults. Each group was analyzed separately. Patients with optic neuritis had a subsequent diagnosis, including idiopathic, MS, neuromyelitis optica (NMO), and acute disseminated encephalomyelitis. Prevalence and incidence, conversion rate to MS, and treatment modalities (steroids, plasmapheresis, interferon-β, and immunosuppressants) were estimated.

MAIN OUTCOME MEASURES

Prevalence and incidence of optic neuritis, and conversion rate to MS.

RESULTS

Among 44 700 564 individuals, 531 pediatric patients (50.7% female) and 7183 adults (53.3% female) were identified as having optic neuritis. Annual incidence was 1.04 (95% confidence interval [CI], 1.01-1.07) per 100 000 pediatric individuals and 3.29 (95% CI, 3.28-3.30) per 100 000 adults. Peak incidence was observed at 10 to 14 years in the pediatric population and at 30 to 34 years and 50 to 54 years in the adult population. Conversion rate to MS was 13.8% in the pediatric population and 11.4% in the adult population. Fourteen percent of all patients were treated with chronic immunosuppressants, 38% of patients with NMO underwent plasmapheresis, and 50% of patients with MS were treated with interferon-β.

CONCLUSIONS

This is a nationwide epidemiologic study of optic neuritis in individuals of all ages in South Korea. The incidence of optic neuritis and subsequent risk of MS in the pediatric population are comparable to those reported in western countries but are lower in the adult population than in western countries. The incidence rate in adults was 3.2-fold higher than in the pediatric population, and the overall MS conversion rate in the entire Korean population was estimated to be 10.6%.

Vaccination-associated acute disseminated encephalomyelitis

While the basic definition of vaccination-associated acute disseminated encephalomyelitis (ADEM) is relatively clear and easily understandable, it is often difficult to diagnose ADEM based on clinical findings alone. ADEM is actually a heterogeneous clinical syndrome that can be approximately characterized by encephalomyelitis with multiple inflammatory demyelination, autoimmune causes, and relationship with a preceding infection or vaccination. The differential diagnosis of ADEM should exclude the possibility of infectious or other autoimmune encephalitis. The occurrence of vaccination-associated ADEM is influenced by several factors including the health and ethnic status of the vaccinated individual, vaccine components, and environment. Cases suspected of vaccination-associated ADEM should be analyzed cautiously from multi-disciplinary perspectives.

Incidence and prevalence of MS in children

Objective

To validate a case definition of multiple sclerosis (MS) in the pediatric population using administrative (health claims) data, and to estimate the incidence and prevalence of MS in the pediatric population for Ontario, Canada.

Methods

We used population-based administrative data to identify persons aged ≤18 years with MS. We assessed the performance of multiple administrative case definitions using a clinical reference cohort including children with MS, children with monophasic demyelinating syndromes, and healthy children; we report sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). We applied 2 preferred case definitions to estimate the incidence and prevalence of MS from 2003 to 2014.

Results

The Canadian Chronic Disease Surveillance System definition of ≥1 hospitalization or ≥5 physician claims for MS within 2 years had a sensitivity of 81.1%, specificity of 100%, PPV of 100%, and NPV of 86%. The Marrie definition of ≥3 hospital or physician claims for MS ever had a sensitivity of 89.2%, specificity of 100%, PPV of 100%, and NPV of 91.5%. Depending on the administrative case definition used, in 2014, the annual age-standardized annual incidence of MS in the pediatric population ranged from 0.99 to 1.24 per 100,000 population, and the age-standardized prevalence ranged from 4.03 to 6.8 per 100,000 population. The prevalence of MS rose over time.

Conclusion

Administrative data provide a feasible, valid means of estimating the incidence and prevalence of MS in the pediatric population. MS prevalence in the Ontario pediatric population is among the highest reported in pediatric populations worldwide.

Paediatric Multiple Sclerosis: Update on Diagnostic Criteria, Imaging, Histopathology and Treatment Choices

Paediatric multiple sclerosis (MS) represents less than 5 % of the MS population, but patients with paediatric-onset disease reach permanent disability at a younger age than adult-onset patients. Accurate diagnosis at presentation and optimal long-term treatment are vital to mitigate ongoing neuroinflammation and irreversible neurodegeneration. However, it may be difficult to early differentiate paediatric MS from acute disseminated encephalomyelitis (ADEM) and neuromyelitis optica spectrum disorders (NMOSD), as they often have atypical presentation that differs from that of adult-onset MS. The purpose of this review is to summarize the updated views on diagnostic criteria, imaging, histopathology and treatment choices.

Pediatric-onset multiple sclerosis and other acquired demyelinating syndromes of the central nervous system in Denmark during 1977-2015: A nationwide population-based incidence study

BACKGROUND

The incidence of acquired demyelinating syndromes (ADS) including multiple sclerosis (MS) has never been investigated in a Danish pediatric population.

OBJECTIVES

We estimated the nationwide age- and sex-specific incidence of pediatric ADS including MS.

METHODS

Data were sourced from the Danish Multiple Sclerosis Registry, providing cases of pediatric MS for 1977-2015, and the National Patient Register, providing cases of ADS during 2008-2015. All medical records were reviewed to validate the register-based diagnoses.

RESULTS

We identified 364 cases of pediatric MS occurring during 1977-2015 (incidence rate = 0.79 per 100,000 person-years). MS was exceptionally rare before puberty, but the incidence rose considerably from 9 years in girls and 11 years in boys. The female-to-male ratio was 2.5; the median age at onset was 16 years (range = 7-17 years). The MS incidence rate was relatively stable through the study period. During 2008-2015, we identified 219 ADS cases. The incidence was 2.29 per 100,000 person-years with considerable differences in the age peaks for the separate ADS.

CONCLUSION

The incidence rates of MS and other ADS in Denmark were higher than those reported for some other European countries. Referral bias and classification differences may account for this disparity, in particular the age-intervals and the definition of onset.