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BackgroundThe interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes.ObjectiveTo establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management.MethodsA multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care.ResultsThe task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA.ConclusionThe 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

IntroductionProspective comparative effectiveness research in chronic nonbacterial osteomyelitis (CNO) is lacking.ObjectivesStudy objectives were to: 1) determine the use and safety of each consensus treatment plan (CTP) regimen for CNO, 2) the feasibility of usingchronic nonbacterialosteomyelitis international registry (CHOIR) data for comparative effectiveness research, and 3) develop and validate a CNO clinical disease activity score (CDAS) using CHOIR.MethodsConsenting children or young adults with CNO were enrolled into CHOIR. Demographic, clinical, and imaging data were prospectively collected. The CNO CDAS was developed through a Delphi survey and nominal group technique. External validation surveys were administered to CHOIR participants.Results140 (76%) CHOIR participants enrolled between August 2018 and September 2020 received at least one CTP regimen. Baseline characteristics from the three groups were well matched. Patient pain, patient global assessment, and clinical CNO lesion count were key variables included in the CNO CDAS. The CDAS showed a strong correlation with patient/parent report of difficulty using a limb, back, or jaw and patient/parent report of disease severity, but a weak correlation with patient/parent report of fatigue, sadness, and worry. The change in CDAS was significant in patients reporting disease worsening or improvement. The CDAS significantly decreased after initiating second-line treatments from median 12 (8-15.5) to 5 (3-12). While second-line treatments were well tolerated, psoriasis was the most common adverse event.ConclusionThe CNO CDAS was developed and validated for disease monitoring and assessment of treatment effectiveness. CHOIR provided a comprehensive framework for future comparative effectiveness research.Key messagesThechronic nonbacterialosteomyelitis international registry (CHOIR) provides comprehensive prospective data for comparison of treatment effectivenessThe clinical disease activity score (CDAS) has content and construct validity to assess CNO

Introduction Acro-osteolysis is a radiographic finding which refers to bone resorption of the distal phalanges. Acro-osteolysis is associated with various conditions and its presence should prompt the clinician to search for the underlying etiology. The aim of this review is to discuss disorders with which acro-osteolysis is associated and their distinguishing features, with a focus on the pediatric population. Methods A targeted literature review was performed using the term “acro-osteolysis” in combination with other key terms. The primary search results were supplemented using reference citations. Articles published prior to the year 2000 were included if they described additional associations not encountered in the more recent literature. Results Genetic disorders (particularly primary hypertrophic osteoarthropathy and skeletal dysplasias) and rheumatic diseases (particularly psoriatic arthritis and systemic sclerosis) are the most frequently encountered conditions associated with acro-osteolysis in children. Hyperparathyroidism, neuropathy, local trauma and thermal injury, and spinal dysraphism should also be included in the differential diagnosis. Conclusion Although acro-osteolysis is uncommon, its presence should prompt the clinician to consider a differential diagnosis based on clinical and radiographic features.

En coup de sabre form of morphea often affects the scalp with thickening, sclerosis, dyspigmentation, and scarring alopecia. Traditionally, it has been thought that the alopecia is not responsive to treatment and permanent. This report presents two cases with extensive, apparent scarring alopecia that improved with medical treatment.

The objective of this study was to describe the clinical course and outcomes in children with technology dependence (TD) hospitalized with SARS-CoV-2 infection.Seventeen pediatric hospitals (15 Canadian and one each in Iran and Costa Rica) included children up to 17 years of age admitted February 1, 2020, through May 31, 2021, with detection of SARS-CoV-2. For those with TD, data were collected on demographics, clinical course and outcome.Of 691 children entered in the database, 42 (6%) had TD of which 22 had feeding tube dependence only, 9 were on supplemental oxygen only, 3 had feeding tube dependence and were on supplemental oxygen, 2 had a tracheostomy but were not ventilated, 4 were on non-invasive ventilation, and 2 were on mechanical ventilation prior to admission. Three of 42 had incidental SARS-CoV-2 infection. Two with end-stage underlying conditions were transitioned to comfort care and died. Sixteen (43%) of the remaining 37 cases required increased respiratory support from baseline due to COVID-19 while 21 (57%) did not. All survivors were discharged home.Children with TD appear to have an increased risk of COVID-19 hospitalization. However, in the absence of end-stage chronic conditions, all survived to discharge.

BackgroundPaediatric inflammatory multisystem syndrome (PIMS) is a rare but serious condition temporally associated with SARS-CoV-2 infection. Using the Canadian Paediatric Surveillance Program (CPSP), a national surveillance system, we aimed to 1) study the impact of SARS-CoV-2 linkage on clinical and laboratory characteristics, and outcomes in hospitalized children with PIMS across Canada 2) identify risk factors for ICU admission, and 3) establish the minimum national incidence of hospitalizations due to PIMS and compare it to acute COVID-19.MethodsWeekly online case reporting was distributed to the CPSP network of more than 2800 pediatricians, from March 2020 to May 2021. Comparisons were made between cases with respect to SARS-CoV-2 linkage. Multivariable modified Poisson regression was used to identify risk factors for ICU admission and Minimum incidence proportions were calculated.FindingsIn total, 406 PIMS cases were analyzed, of whom 202 (49· 8%) had a positive SARS-CoV-2 linkage, 106 (26· 1%) had a negative linkage, and 98 (24· 1%) had an unknown linkage. The median age was 5· 4 years (IQR 2· 5–9· 8), 60% were male, and 83% had no identified comorbidities. Compared to cases with a negative SARS-CoV-2 linkage, children with a positive SARS-CoV-2 linkage were older (8· 1 years [IQR 4· 2–11· 9] vs. 4· 1 years [IQR 1· 7–7· 7]; pInterpretationWhile PIMS is rare, almost 1 in 3 hospitalized children required ICU admission and respiratory/hemodynamic support, particularly those ≥ 6 years and with a positive SARS-CoV-2 linkage.FundingFinancial support for the CPSP was received from the Public Health Agency of Canada.

Objective The aim of this study was to evaluate factors associated with extracutaneous involvement (ECI) in juvenile localized scleroderma (jLS). Methods A prospective, multicentre, 6-month observational study was performed. The data collected included disease features, global assessments, and subject symptoms. Bivariate and linear multilevel regression analyses were performed. Results A total of 86 jLS subjects (80% female, 80% Caucasian), median age of disease onset 7.7 years, were evaluated. Most had linear scleroderma or mixed morphea. Of the 86 subjects, 49 (57%) had 125 extracutaneous problems {median 2 [interquartile range (IQR) 1, 3] per subject} from nine organ systems. Most of these subjects had multiple musculoskeletal problems. ECI was associated with more extensive cutaneous involvement, higher number of symptoms, family history of autoimmunity, and ANA and RF positivity. Subjects with ECI had higher scores for physician global assessment of damage (PGA-D), and parental global assessment of disease impact, but not baseline physician global assessment of disease activity (PGA-A). Although subjects with ECI received more MTX and glucocorticoid treatment, they had a slower reduction in PGA-A scores and symptoms over time, suggesting a poorer response to treatment. In logistic regression modelling, female sex had the largest effect on parental impact scores. Conclusion ECI occurred in the majority of subjects with jLS, and was associated with more medication use, longer treatment duration, higher PGA-D scores, and higher parental assessment of disease impact. Our findings suggest that jLS subjects with ECI have greater overall disease burden, both cutaneous and extracutaneous, and poorer response to treatment. More study of the treatment needs of this population is warranted.

Background Biallelic loss-of-function variants in NCF1 lead to reactive oxygen species deficiency and chronic granulomatous disease (CGD). Heterozygosity for the p.Arg90His variant in NCF1 has been associated with susceptibility to systemic lupus erythematosus, rheumatoid arthritis, and Sjögren’s syndrome in adult patients. This study demonstrates the association of the homozygous p.Arg90His variant with interferonopathy with features of autoinflammation and autoimmunity in a pediatric patient. Case presentation A 5-year old female of Indian ancestry with early-onset recurrent fever and headache, and persistently elevated antinuclear, anti-Ro, and anti-La antibodies was found to carry the homozygous p.Arg90His variant in NCF1 through exome sequencing. Her unaffected parents and three other siblings were carriers for the mutant allele. Because the presence of two NCF1 pseudogenes, this variant was confirmed by independent genotyping methods. Her intracellular neutrophil oxidative burst and NCF1 expression levels were normal, and no clinical features of CGD were apparent. Gene expression analysis in peripheral blood detected an interferon gene expression signature, which was further supported by cytokine analyses of supernatants of cultured patient’s cells. These findings suggested that her inflammatory disease is at least in part mediated by type I interferons. While her fever episodes responded well to systemic steroids, treatment with the JAK inhibitor tofacitinib resulted in decreased serum ferritin levels and reduced frequency of fevers. Conclusion Homozygosity for p.Arg90His in NCF1 should be considered contributory in young patients with an atypical systemic inflammatory antecedent phenotype that may evolve into autoimmunity later in life. The complex genomic organization of NCF1 poses a difficulty for high-throughput genotyping techniques and variants in this gene should be carefully evaluated when using the next generation and Sanger sequencing technologies. The p.Arg90His variant is found at a variable allele frequency in different populations, and is higher in people of South East Asian ancestry. In complex genetic diseases such as SLE, other rare and common susceptibility alleles might be necessary for the full disease expressivity.

ObjectiveTreat to target (T2T) is a strategy of adjusting treatment until a target is reached. An international task force recommended T2T for juvenile idiopathic arthritis (JIA) treatment. Implementing T2T in a standard and reliable way in clinical practice requires agreement on critical elements of (1) target setting, (2) T2T strategy, (3) identifying barriers to implementation, and (4) patient eligibility. A consensus conference was held among Pediatric Rheumatology Care and Outcomes Improvement Network (PR-COIN) stakeholders to inform a statement of understanding regarding the PR-COIN approach to T2T.MethodsPR-COIN stakeholders including 16 healthcare providers and 4 parents were invited to form a voting panel. Using the nominal group technique, 2 rounds of voting were held to address the above 4 areas to select the top 10 responses by rank order.ResultsIncorporation of patient goals ranked most important when setting a treatment target. Shared decision making (SDM), tracking measurable outcomes, and adjusting treatment to achieve goals were voted as the top elements of a T2T strategy. Workflow considerations, and provider buy-in were identified as key barriers to T2T implementation. Patients with JIA who had poor prognostic factors and were at risk for high disease burden were leading candidates for a T2T approach.ConclusionThis consensus conference identified the importance of incorporating patient goals as part of target setting and of the influence of patient stakeholder involvement in drafting treatment recommendations. The network approach to T2T will be modified to address the above findings, including solicitation of patient goals, optimizing SDM, and better workflow integration.

The original version of this article unfortunately contained a mistake in Tables 1 and 2 entries.

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disease most prevalent in children. In this review, we seek to highlight the most recent advances in the understanding of the pathophysiology, treatment, and outcomes of CNO. Recent observations support a pathophysiologic framework involving imbalanced expression of pro-inflammatory versus anti-inflammatory cytokines, thereby inducing increased differentiation and activation of osteoclasts. Although no medication nor protocol is yet specifically indicated in the treatment of CNO, there exists an expanding body of evidence for agents exerting their effects via interference with these pro-inflammatory pathways (namely non-steroidal anti-inflammatory drugs, disease-modifying anti-rheumatic drugs, bisphosphonates, and biologics), highlighted herein. With an incidence rivaling that of bacterial osteomyelitis, childhood CNO represents an important and growing field of study. Once thought to be benign and self-limiting, CNO is now recognized to follow a relapsing and remitting course in the majority of children, and to carry substantial risk of irreversible growth and bone sequelae. Perhaps of greatest importance to the study of CNO treatment is the recent development of the Childhood Arthritis and Rheumatology Research Alliance (CARRA) consensus treatment plans, the implementation of which will allow for prospective comparative effectiveness studies and, ultimately, the development of standardized treatment protocols.

MLKL is the essential effector of necroptosis, a form of programmed lytic cell death. We have isolated a mouse strain with a single missense mutation, MlklD139V, that alters the two-helix ‘brace’ that connects the killer four-helix bundle and regulatory pseudokinase domains. This confers constitutive, RIPK3 independent killing activity to MLKL. Homozygous mutant mice develop lethal postnatal inflammation of the salivary glands and mediastinum. The normal embryonic development of MlklD139V homozygotes until birth, and the absence of any overt phenotype in heterozygotes provides important in vivo precedent for the capacity of cells to clear activated MLKL. These observations offer an important insight into the potential disease-modulating roles of three common human MLKL polymorphisms that encode amino acid substitutions within or adjacent to the brace region. Compound heterozygosity of these variants is found at up to 12-fold the expected frequency in patients that suffer from a pediatric autoinflammatory disease, chronic recurrent multifocal osteomyelitis (CRMO)., Necroptosis is a regulated form of inflammatory cell death driven by activated MLKL. Here, the authors identify a mutation in the brace region that confers constitutive activation, leading to lethal inflammation in homozygous mutant mice and providing insight into human mutations in this region.

Activation of RIPK1 controls TNF-mediated apoptosis, necroptosis and inflammatory pathways1. Cleavage of human and mouse RIPK1 after residues D324 and D325, respectively, by caspase-8 separates the RIPK1 kinase domain from the intermediate and death domains. The D325A mutation in mouse RIPK1 leads to embryonic lethality during mouse development2,3. However, the functional importance of blocking caspase-8-mediated cleavage of RIPK1 on RIPK1 activation in humans is unknown. Here we identify two families with variants in RIPK1 (D324V and D324H) that lead to distinct symptoms of recurrent fevers and lymphadenopathy in an autosomal-dominant manner. Impaired cleavage of RIPK1 D324 variants by caspase-8 sensitized patients' peripheral blood mononuclear cells to RIPK1 activation, apoptosis and necroptosis induced by TNF. The patients showed strong RIPK1-dependent activation of inflammatory signalling pathways and overproduction of inflammatory cytokines and chemokines compared with unaffected controls. Furthermore, we show that expression of the RIPK1 mutants D325V or D325H in mouse embryonic fibroblasts confers not only increased sensitivity to RIPK1 activation-mediated apoptosis and necroptosis, but also induction of pro-inflammatory cytokines such as IL-6 and TNF. By contrast, patient-derived fibroblasts showed reduced expression of RIPK1 and downregulated production of reactive oxygen species, resulting in resistance to necroptosis and ferroptosis. Together, these data suggest that human non-cleavable RIPK1 variants promote activation of RIPK1, and lead to an autoinflammatory disease characterized by hypersensitivity to apoptosis and necroptosis and increased inflammatory response in peripheral blood mononuclear cells, as well as a compensatory mechanism to protect against several pro-death stimuli in fibroblasts.

Objective.To perform a comparative effectiveness feasibility study in juvenile localized scleroderma (LS), using standardized treatment regimens (consensus treatment plans; CTP).Methods.A prospective, multicenter 1-year pilot observational cohort study was performed by Childhood Arthritis and Rheumatology Research Alliance (CARRA) LS workgroup members. Patients with active, moderate to severe juvenile LS were treated with one of 3 CTP: methotrexate alone, or in combination with intravenous (30 mg/kg/dose for 3 mos) or oral corticosteroids (2 mg/kg/day tapered by 48 weeks).Results.Fifty patients, with demographics typical for juvenile LS, were enrolled, and 44 (88%) completed the study. Most had extracutaneous involvement. Patients improved in all 3 CTP, with > 75% having a major or moderate level of improvement compared to baseline. Damage accrued in some patients. Major deviations from prescribed regimen resulted from medication intolerance (n = 6; 14%) or treatment failure (n = 11; 25%); failures occurred in all 3 CTP. Significant responses to treatment were demonstrated by LS skin scoring measures and overall physician assessments, with differences in response level identified in some patient subsets. Response differences were associated with baseline disease activity level, LS subtype, skin disease extent, and extracutaneous involvement.Conclusion.This study demonstrates the feasibility of conducting juvenile LS comparative effectiveness studies. The CTP were found to be safe, effective, and tolerable. Our assessments performed well. Because damage is common and may progress despite effective control of activity, we recommend initial treatment efficacy be evaluated primarily by activity measures. Potential confounders for response were identified that warrant further study.

Age is the most important determinant of COVID-19 severity. Infectious disease severity by age is typically J-shaped, with infants and the elderly carrying a high burden of disease. We report on the comparative disease severity between infants and older children in a multicenter retrospective cohort study of children 0 to 17 years old admitted for acute COVID-19 from February 2020 through May 2021 in 17 pediatric hospitals. We compare clinical and laboratory characteristics and estimate the association between age group and disease severity using ordinal logistic regression. We found that infants comprised one-third of cases, but were admitted for a shorter period (median 3 days IQR 2-5 versus 4 days IQR 2-7), had a lower likelihood to have an increased C-reactive protein, and had half the odds of older children of having severe or critical disease (OR 0.50 (95% confidence interval 0.32-0.78)). Conclusion: When compared to older children, there appeared to be a lower threshold to admit infants but their length of stay was shorter and they had lower odds than older children of progressing to severe or critical disease. What is Known: • A small proportion of children infected with SARS-CoV-2 require hospitalization for acute COVID-19 with a subgroup needing specialized intensive care to treat more severe disease. • For most infectious diseases including viral respiratory tract infections, disease severity by age is J-shaped, with infants having more severe disease compared to older children. What is New: • One-third of admitted children for acute COVID-19 during the first 14 months of the pandemic were infants. • Infants had half the odds of older children of having severe or critical disease.

ImportanceChildren are less likely than adults to have severe outcomes from SARS-CoV-2 infection and the corresponding risk factors are not well established.ObjectiveTo identify risk factors for severe disease in symptomatic children hospitalized for PCR-positive SARS-CoV-2 infection.DesignCohort study, enrollment from February 1, 2020 until May 31, 2021Setting15 children’s hospitals in Canada, Iran, and Costa RicaParticipantsPatients ExposuresVariables assessed for their association with disease severity included patient demographics, presence of comorbidities, clinical manifestations, laboratory parameters and chest imaging findings.Main Outcomes and MeasuresThe primary outcome was severe disease defined as a WHO COVID-19 clinical progression scale of ≥6, i.e., requirement of non-invasive ventilation, high flow nasal cannula, mechanical ventilation, vasopressors, or death. Multivariable logistic regression was used to evaluate factors associated with severe disease.ResultsWe identified 403 hospitalizations. Median age was 3.78 years (IQR 0.53-10.77). At least one comorbidity was present in 46.4% (187/403) and multiple comorbidities in 18.6% (75/403). Severe disease occurred in 33.8% (102/403). In multivariable analyses, presence of multiple comorbidities (adjusted odds ratio 2.24, 95% confidence interval 1.04-4.81), obesity (2.87, 1.19-6.93), neurological disorder (3.22, 1.37-7.56), anemia, and/or hemoglobinopathy (5.88, 1.30-26.46), shortness of breath (4.37, 2.08-9.16), bacterial and/or viral coinfections (2.26, 1.08-4.73), chest imaging compatible with COVID-19 (2.99, 1.51-5.92), neutrophilia (2.60, 1.35-5.02), and MIS-C diagnosis (3.86, 1.56-9.51) were independent risk factors for severity. Comorbidities, especially obesity (40.9% vs 3.9%, pConclusions and RelevancePediatric risk factors for severe SARS-CoV-2 infection vary according to age and can potentially guide vaccination programs and treatment approaches in children.Key pointsQuestionWhat are the risk factors for severe disease in children hospitalized for PCR-positive SARS-CoV-2 infection?FindingsIn this multinational cohort study of 403 children, multiple comorbidities, obesity, neurological disorder, anemia, and/or hemoglobinopathy, shortness of breath, bacterial and/or viral coinfections, chest imaging compatible with COVID-19, neutrophilia, and MIS-C diagnosis were independent risk factors for severity. The risk profile and presence of comorbidities differed between pediatric age groups, but age itself was not associated with severe outcomes.MeaningThese results can inform targeted treatment approaches and vaccine programs that focus on patient groups with the highest risk of severe outcomes.

ObjectiveTo examine the Canadian pediatric rheumatology workforce and care processes.MethodsPediatric rheumatologists and allied health professionals (AHPs) participated. A designee from each academic center provided workforce information including the number of providers, total and breakdown of full-time equivalents (FTEs), and triage processes. We calculated the clinical FTE (cFTE) available per 75,000 (recommended benchmark) and 300,000 (adjusted) children using 2019 census data. The national workforce deficit was calculated as the difference between current and expected cFTEs. Remaining respondents were asked about ambulatory practices.ResultsThe response rate of survey A (workforce information) and survey B (ambulatory practice information) was 100% and 54%, respectively. The majority of rheumatologists (91%) practiced in academic centers. The median number of rheumatologists per center was 3 (IQR 3) and median cFTE was 1.9 (IQR 1.5). The median cFTE per 75,000 was 0.2 (IQR 0.3), with a national deficit of 80 cFTEs. With the adjusted benchmark, there was no national deficit, but there was a regional maldistribution of rheumatologists. All centers engaged in multidisciplinary practices with a median of 4 different AHPs, although the median FTE for AHPs was ≤ 1. Most centers (87%) utilized a centralized triage process. Of 9 (60%) centers that used an electronic triage process, 6 were able to calculate wait times. Most clinicians integrated quality improvement practices, such as previsit planning (67%), postvisit planning (68%), and periodic health outcome monitoring (36–59%).ConclusionThis study confirms a national deficit at the current recommended benchmark. Most rheumatologists work in multidisciplinary teams, but AHP support may be inadequate.

Objective To provide clinical guidance to rheumatology providers who treat children with pediatric rheumatic disease (PRD) in the context of the coronavirus disease 2019 (COVID-19) pandemic. Methods The task force, consisting of 7 pediatric rheumatologists, 2 pediatric infectious disease physicians, 1 adult rheumatologist, and 1 pediatric nurse practitioner, was convened on May 21, 2020. Clinical questions and subsequent guidance statements were drafted based on a review of the queries posed by the patients as well as the families and healthcare providers of children with PRD. An evidence report was generated and disseminated to task force members to assist with 3 rounds of asynchronous, anonymous voting by email using a modified Delphi approach. Voting was completed using a 9-point numeric scoring system with predefined levels of agreement (categorized as disagreement, uncertainty, or agreement, with median scores of 1-3, 4-6, and 7-9, respectively) and consensus (categorized as low, moderate, or high). To be approved as a guidance statement, median vote ratings were required to fall into the highest tertile for agreement, with either moderate or high levels of consensus. Results To date, 39 guidance statements have been approved by the task force. Those with similar recommendations were combined to form a total of 33 final guidance statements, all of which received median vote ratings within the highest tertile of agreement and were associated with either moderate consensus (n = 5) or high consensus (n = 28). Conclusion These guidance statements have been generated based on review of the available literature, indicating that children with PRD do not appear to be at increased risk for susceptibility to SARS-CoV-2 infection. This guidance is presented as a "living document," recognizing that the literature on COVID-19 is rapidly evolving, with future updates anticipated.

BACKGROUNDSARS-CoV-2 infection can lead to multisystem inflammatory syndrome in children (MIS-C). We investigated risk factors for severe disease and explored changes in severity over time.METHODSChildren up to 17 years of age admitted March 1, 2020 through March 7th, 2021 to 15 hospitals in Canada, Iran and Costa Rica with confirmed or probable MIS-C were included. Descriptive analysis and comparison by diagnostic criteria, country, and admission date was performed. Adjusted absolute average risks (AR) and risk differences (RD) were estimated for characteristics associated with ICU admission or cardiac involvement.RESULTSOf 232 cases (106 confirmed) with median age 5.8 years, 56% were male, and 22% had comorbidities. ICU admission occurred in 73 (31%) but none died. Median length of stay was 6 days (inter-quartile range 4-9). Children 6 to 12 years old had the highest AR for ICU admission (44%; 95% confidence interval [CI] 34-53). Initial ferritin greater than 500 mcg/L was associated with ICU admission. When comparing cases admitted up to October 31, 2020 to those admitted later, the AR for ICU admission increased from 25% (CI 17-33) to 37% (CI 29-46) and for cardiac involvement from 44% (CI 35-53) to 75% (CI 66-84). Risk estimates for ICU admission in the Canadian cohort demonstrated a higher risk in December 2020-March 2021 compared to March-May 2020 (RD 25%; 95%CI 7-44).INTERPRETATIONMIS-C occurred primarily in previously well children. Illness severity appeared to increase over time. Despite a high ICU admission incidence, most children were discharged within one week.

Objective To identify discrete clusters comprising clinical features and inflammatory biomarkers in children with JIA and to determine cluster alignment with JIA categories. Methods A Canadian prospective inception cohort comprising 150 children with JIA was evaluated at baseline (visit 1) and after six months (visit 2). Data included clinical manifestations and inflammation-related biomarkers. Probabilistic principal component analysis identified sets of composite variables, or principal components, from 191 original variables. To discern new clinical-biomarker clusters (clusters), Gaussian mixture models were fit to the data. Newly-defined clusters and JIA categories were compared. Agreement between the two was assessed using Kruskal–Wallis analyses and contingency plots. Results Three principal components recovered 35% (three clusters) and 40% (five clusters) of the variance in patient profiles in visits 1 and 2, respectively. None of the clusters aligned precisely with any of the seven JIA categories but rather spanned multiple categories. Results demonstrated that the newly defined clinical-biomarker lustres are more homogeneous than JIA categories. Conclusion Applying unsupervised data mining to clinical and inflammatory biomarker data discerns discrete clusters that intersect multiple JIA categories. Results suggest that certain groups of patients within different JIA categories are more aligned pathobiologically than their separate clinical categorizations suggest. Applying data mining analyses to complex datasets can generate insights into JIA pathogenesis and could contribute to biologically based refinements in JIA classification.

Objectives Before a clinician decides whether treatment with TNF inhibition in children with JIA has failed, one should ensure adequate systemic exposure has been achieved. Therapeutic drug monitoring might allow for improved treatment outcome with lower treatment-associated costs. However, this requires understanding of the pharmacokinetic (PK) characteristics, and the pharmacokinetic/pharmacodynamic (PK/PD) relationship for children with JIA. We performed a scoping review to summarize the available literature and identify areas for future research. Methods A systematic search was conducted of the Medline, EMBASE, Web of Science and Cochrane databases as well as the clinicaltrials.gov registry. In total, 3959 records were screened and 130 publications were selected for full text assessment. Results Twenty publications were included and divided into three categories: PK (n = 9), PK/PD (n = 3) and anti-drug antibodies (n = 13). Industry involvement was significant in 14 publications. Although data are limited, systemic exposure to TNF inhibitors is generally lower in younger children but meta-analysis is not possible. The PK/PD relationship has had limited study but there is partial evidence for infliximab. Anti-drug antibodies are common, and are related to impaired clinical outcome with adalimumab and infliximab therapy. Conclusion The current knowledge about the PK and PK/PD of TNF inhibitors in the treatment of children with JIA is limited, which prevents the introduction of TDM. Re-analysis of available data from previous trials, incorporation of pharmacologic assessments into existing biorepository studies as well as new prospective PK and PK/PD trials are required to obtain this knowledge.

Autoinflammatory diseases have emerged as a group of disorders that have significant morbidity, and even mortality. Since their onset predominately occurs during childhood, it is important that paediatricians are aware of what these diseases are, how they present, when to include them in differential diagnoses, and when to refer to a specialist. This review will focus on the clinical indicators suggestive of autoinflammatory disease, how the presence of an autoinflammatory disease may influence routine care, indications for immediate referral, and both their acute and chronic complications.

We report the natural history, clinical manifestations, genetics, and immunohematological findings in 14 patients from 11 families with ARPC1B deficiency, delineating the spectrum of the disease that appears progressive and challenging to manage clinically.

Objective To review pediatric idiopathic intervertebral disc calcification (PIIVDC) within a single center and within the literature to outline the disease course, management, and outcome. Study design A retrospective chart review was performed spanning the period between January 2001 and February 2016 for diagnoses of PIIVDC. Patient age, sex, symptoms, and history and physical and neurologic findings were reviewed. Laboratory and imaging findings, management, follow-up, and outcome also were studied. Results Nine cases of PIIVDC were identified; they included 6 male and 3 female patients, with an age range of 23 months to 12 years. Two patients were asymptomatic, and PIIVDC was discovered incidentally. Of the remaining 7 patients, 5 presented with neck and/or back pain, 1 with painless torticollis, and 1 with painful torticollis. One patient reported neurologic symptoms of pain radiating along 1 dermatome. Disc spaces affected were 5 cervical, 4 thoracic, and 2 lumbar, with 2 patients having more than 1 space affected. All patients were managed conservatively. In 1 case, symptoms and lesions persisted after 5 years, but the remainder had complete symptom resolution, generally within 6 months. Conclusions The etiology of PIIVDC remains unknown but appears to occur spontaneously, without preceding trauma or underlying medical condition. A conservative approach to patients without severe neurologic deficit with outpatient follow-up is supported.

OBJECTIVE To compare the clinical features, efficacy and safety of treatment regimens, and outcomes of childhood- and adult-onset Takayasu arteritis (TAK). METHODS The study was designed as a retrospective cohort study comparing patients with childhood-onset TAK (from 1986 onward) to patients with adult-onset TAK (from 1988 onward) who were followed up until 2014 or 2015 at 4 centers in Ontario, Canada. Demographic, clinical, laboratory, and angiographic features, treatment regimens, and outcomes were recorded throughout the course of the disease. Disease activity and damage scores were completed retrospectively. RESULTS Twenty-nine children and 48 adults (median age at diagnosis 12.1 years and 31.2 years, respectively) were included. A lower predominance of females was observed among the childhood-onset TAK cohort (76% versus 100% of patients with adult-onset TAK; P < 0.01), and children had a shorter delay to diagnosis (median 6.0 months versus 12.2 months for adults; P = 0.03). The distribution of vascular involvement was also different, with children having significantly more aortic and renal artery involvement and a higher frequency of arterial hypertension. Relapses in the first year after diagnosis were common both in children (39%) and in adults (28%). Two children, but no adults, died. CONCLUSION Childhood-onset TAK has a lower female predominance and a higher frequency of aortic and renal involvement compared to adult-onset TAK. Relapses and disease burden were high in both groups, corroborating the need for careful monitoring of disease activity and aggressive therapeutic management.

Since first defined in 1998, paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) and its later, broader iteration, paediatric acute-onset neuropsychiatric syndrome (PANS), have garnered significant attention and controversy. The role of streptococcal infection in children with explosive onset obsessive-compulsive disorder and new onset tics, the natural history of this entity, and the role of symptomatic and disease-modifying therapies, including antibiotics, immunotherapy, and psychoactive drugs, are all issues that have yet to be definitively addressed. While definitive proof of the autoimmune hypothesis of PANDAS is lacking, given the heightened attention to this entity and apparent rise in use of this diagnostic category, addressing questions around diagnosis, treatment, and etiology is imperative. In this paper, we review current working definitions of PANDAS/PANS, discuss published evidence for interventions related to this entity, and propose a clinical approach to children presenting with acute symptoms satisfying criteria for PANDAS/PANS.