Spondyloarthritis in a pediatric population: risk factors for sacroiliitis

Clinical features of juvenile onset ankylosing spondylitis in Japanese patients

OBJECTIVES

This retrospective study aimed to examine the clinical features of juvenile onset ankylosing spondylitis (JoAS) in Japanese patients.

METHODS

We examined clinical symptoms (including initial symptoms) and the progression to diagnosis of AS in 17 Japanese JoAS patients at our institute between January 2004 and May 2023. Initial symptoms were considered pain at axial joints and/or extra-axial joints.

RESULTS

Mean ages (± standard deviation) at onset and diagnosis of AS were 12.9 (± 2.0) years and 19.6 (± 9.6) years, respectively. The back was the most common site of initial symptoms (seven patients; 41.2%), followed by the hip (five patients; 29.4%) and knees (five patients; 29.4%). Initial symptoms were limited to extra-axial joints and axial joints in nine (52.9%) and seven (41.2%) patients, respectively. Nine patients (52.9%) were recognised as a musculoskeletal disease other than AS, such as oligoarticular juvenile idiopathic arthritis.

CONCLUSIONS

Sites of initial symptoms were frequently the back, hip, and knees, with 52.9% of patients having initial symptoms limited to extra-axial joints. More than half of the patients were recognised musculoskeletal diseases other than AS.

Effective diagnosis of sacroiliitis in children: evaluating magnetic resonance imaging with the Canadian scoring system

OBJECTIVES

To reveal the differences by comparing the magnetic resonance imaging (MRI) findings of patients with clinically symptomatic sacroiliitis with those undergoing sacroiliac imaging for other reasons using the Canadian Spondyloarthritis Research Consortium-Sacroiliac Inflammatory Scoring System (SPARCC-SIS).

METHODS

In this retrospective single-center study, sacroiliac MRIs performed between 2017 and 2023 were evaluated from the database. The SPARCC-SIS scoring system is used to evaluate and grade the inflammation of the sacroiliac joints. Mild inflammation is indicated by a score below 24, moderate by a score of 24-48, and severe by a score above 49. Additionally, structural defects of the sacroiliac joint, such as erosion, sclerosis, and ankylosis, were observed. After MRI evaluation, clinically symptomatic (group 1) and non-symptomatic (group 2) patients were divided into two groups. The clinical and laboratory findings of the patients and MRI findings were compared. The patient's age, gender, clinical information from hospital records, acute phase reactants (APRs), and the presence of the Human Leukocyte Antigen (HLA-B27) gene (if applicable) were thoroughly recorded.

RESULTS

One hundred thirty-six children who performed sacroiliac MRI for any indication were included in the study. The APRs positivity, presence of HLA-B27, and SPARCC scoring system were significantly higher in 24 patients with clinical sacroiliitis (group 1) than in 112 patients without sacroiliitis (group 2). In our study, the most common MRI findings in children were bone marrow edema, capsulitis, synovitis, and erosion, while chronic structural changes such as sclerosis and ankylosing were rare.

CONCLUSION

In this study, the SPARCC scoring method, which shows the severity of sacroiliac joint inflammation, correlates with the clinical diagnosis of sacroiliitis. In cases with suspected sacroiliitis, except for extraordinary reasons, it can be evaluated with MRI without contrast material and can be graded to guide the clinician in treatment and approach.

Does sacroiliitis is a mandatory criterion for enthesitis-related arthritis diagnosis?

INTRODUCTION AND OBJECTIVES

Magnetic resonance imaging (MRI) sensitivity and specificity seem to be less studied in enthesitis-related arthritis (ERA). We aimed to determine the ability of sacroiliac MRI to diagnose ERA patients.

MATERIALS AND METHODS

We conducted a retrospective study including 44 patients with juvenile idiopathic arthritis (JIA). Each patient had a sacroiliac joint MRI. We divided patients into two groups: G1 patients with ERA and G2 patients with non-ERA subtype.

RESULTS

ERA was noted in 61% of the cases. Sacroiliac joints were painful in 15 patients (34%). MRI was normal in 25 patients (57%) (G1:11 versus G2:14) and showed bone marrow edema in the sacroiliac joints in 19 patients (34%) (G1=16 versus G2=3, p=0.005). Sacroiliac joints MRI's sensitivity and specificity in the ERA diagnosis were 61.54% and 82.35%, respectively. Positive and negative predictive values were 84.21% and 58.33%, respectively. Furthermore, sacroiliac joint pain in the clinical examination was able to predict sacroiliac bone edema in MRI with an odds ratio of 6.8 (95% CI 1.68-28.09; p=0.006).

CONCLUSION

Our study showed that sacroiliac joint MRI has good specificity and positive predictive value in the diagnosis of ERA patients among JIA patients. This underlines the usefulness of sacroiliac joint MRI in the early diagnosis of ERA patients.

Childhood-Onset Sacroiliitis: Causes and Correlation Between Clinical Findings and Magnetic Resonance Imaging

OBJECTIVE

The aims of this study were to describe disease associations of magnetic resonance imaging (MRI)-confirmed and clinically symptomatic sacroiliitis in pediatric patients with rheumatic diseases and to examine the relationship between patient characteristics and MRI findings of the sacroiliac joint (SIJ).

METHODS

Demographic and clinical data were extracted from the electronic medical records of the patients with sacroiliitis followed in the last 5 years. Active inflammatory and structural damage lesions of the SIJ-MRI were examined by the modified Spondyloarthritis Research Consortium of Canada scoring system, and correlation analysis of these results with clinical characteristics was evaluated.

RESULTS

A total of 46 symptomatic patients were found to have MRI-proven sacroiliitis of 3 different etiologies: juvenile idiopathic arthritis (JIA) (n = 17), familial Mediterranean fever (FMF) (n = 14), and chronic nonbacterial osteomyelitis (CNO) (n = 8). Seven patients, FMF and JIA (n = 6) and FMF and CNO (n = 1), had a co-diagnosis that might cause sacroiliitis. Although inflammation scores and structural damage lesions did not statistically differ between the groups, capsulitis and enthesitis on the MRI were more frequently detected in the CNO group. There was a negative correlation between symptom onset and inflammation scores of bone marrow edema. Disease composite scores and acute phase reactants were correlated with MRI inflammation scores.

CONCLUSIONS

We demonstrated that JIA, FMF, and CNO were the major rheumatic causes of sacroiliitis in children originating from the Mediterranean region. Quantitative MRI scoring tools can be used to assess the inflammation and damage of the SIJ in rheumatic diseases, show discrepancies between them, and have an important correlation with various clinical and laboratory features.

Imaging in pediatric spondyloarthritis

PURPOSE OF REVIEW

Imaging is used in the diagnosis of peripheral and axial disease in juvenile spondyloarthritis (JSpA). Imaging of the joints and entheses in children and adolescents can be challenging for those unfamiliar with the appearance of the maturing skeleton. These differences are key for rheumatologists and radiologists to be aware of.

RECENT FINDINGS

In youth, skeletal variation during maturation makes the identification of arthritis, enthesitis, and sacroiliitis difficult. A great effort has been put forward to define imaging characteristics seen in healthy children in order to more accurately identify disease. Additionally, there are novel imaging modalities on the horizon that are promising to further differentiate normal physiologic changes versus disease.

SUMMARY

This review describes the current state of imaging, limitations, and future imaging modalities in youth, with key attention to differences in imaging interpretation of the peripheral joints, entheses, and sacroiliac joint in youth and adults.

Axial involvement in enthesitis-related arthritis: results from a single-center cohort

BACKGROUND

Axial involvement in children with enthesitis-related arthritis (ERA) has characteristics that differ from those of peripheral involvement. This study characterized their clinical characteristics and treatment.

METHODS

Patients with ERA at the Children's Hospital of Nanjing Medical University between January 2018 and December 2020 were included. The ERA cohort was divided into two based on the presence or absence of axial joint involvement. Demographic characteristics, clinical features, and treatments were described and compared.

RESULTS

In total, 105 children with ERA were enrolled (axial ERA, n = 57; peripheral ERA, n = 48). The age at disease onset of the axial group tended to be higher (11.93 ± 1.72 vs. 11.09 ± 1.91 years) and the diagnosis delay was bigger in patients with axial ERA (10.26 ± 11.66 months vs. 5.13 ± 7.92 months). The inflammatory marker levels were significantly higher in patients with axial. There were no differences in HLA-B27 positivity between the groups (34 [59.65%] vs. 28 [58.33%], P > 0.05). Hip involvement was more frequent in the axial group (52.63% vs 27.08%; X² = 7.033). A total of 38 (66.67%) and 10 (20.83%) patients with axial and peripheral ERA, respectively, were treated with biological disease-modifying anti-rheumatic drugs (DMARDs) at diagnosis. The administration of biologics increased gradually in the axial ERA group, peaking at 18 months and decreasing thereafter, whereas that in the peripheral ERA group peaked at 6 months and began to decline thereafter.

CONCLUSIONS

Axial ERA is a persistent active disease and requires a more aggressive treatment. Classification and early recognition of axial involvement may help with timely diagnosis and appropriate management.

Chronic Recurrent Multifocal Osteomyelitis (CRMO) and Juvenile Spondyloarthritis (JSpA): To What Extent Are They Related?

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disease occurring mainly in the pediatric age group (before 16 years) and generally presents as a separate entity. Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome combines osteoarticular and cutaneous involvement, similar to CRMO, and falls into the spectrum of spondyloarthritis (SpA). The fact that a patient can progress from one disease to another raises the question of whether CRMO, like SAPHO, could fall within the spectrum of SpA, ranging from a predominantly osteoarticular form to an enthesitic form with more or less marked skin involvement. In this review, we set out to discuss this hypothesis by highlighting the differences and similarities between CRMO and juvenile SpA in clinical, radiological and pathophysiological aspects. A common hypothesis could potentially consider intestinal dysbiosis as the origin of these different inflammatory diseases. Interindividual factors such as gender, environment, genetics and/or epigenetic background could act as combined disease modifiers. This is why we suggest that pathophysiology, rather than clinical phenotype, be used to reclassify these diseases.

Sacroiliitis at diagnosis as a protective predictor against disease flare after stopping medication: outcomes of a Southeast Asian enthesitis-related arthritis (ERA) longitudinal cohort

OBJECTIVES

To assess short- and long-term outcomes of ERA in a large monocentric cohort in Singapore.

METHODS

Children diagnosed with ERA according to ILAR criteria from 2002 to 2021 were recruited. Nonparametric statistics were used to describe the data. Outcomes were defined according to modified Wallace criteria, and probabilities and predictors were determined using Kaplan-Meier survival and logistic regression analyses.

RESULTS

One hundred fifty-one ERA patients (male 86%; Chinese 81%) were included. The median age at onset was 11.9 years (IQR: 9.4-13.9), and disease duration was 5.3 years (IQR: 2.9-8.4). At diagnosis, 39% of the patients had sacroiliitis. HLA-B27 was positive in 83%, and biologics were used in 72% of the patients. Clinical inactive disease (CID) was achieved in 92% of the patients, of which 27% achieved within 6 months. Sacroiliitis at diagnosis is an unfavorable predictor of early CID at 6 months. Medication was discontinued in one-third of the patients. Favorable predictor of medication withdrawal includes male gender, while unfavorable predictors include positive HLA-B27 and ANA. Two-thirds of the patients with CID had at least one disease flare. Sacroiliitis at diagnosis is a protective predictor of flare after stopping medication.

CONCLUSION

Despite a high proportion of ERA patients achieving CID, only one-third could stop medication with high rates of disease flare. Unfavorable predictors include older age at onset, HLA-B27, and ANA positivity. While sacroiliitis at diagnosis is a negative predictor of CID at 6 months, it is associated with less disease flare after discontinuing medication.

Whole body magnetic resonance imaging in healthy children and adolescents. Bone marrow appearances of the axial skeleton

OBJECTIVE

To describe the findings of focal high signal on T2 weighted (T2W) images of the bone marrow in the axial skeleton as assessed by whole-body MRI in healthy and asymptomatic children and adolescents.

MATERIAL AND METHODS

We assessed the bone marrow of the mandible, shoulder girdle, thorax, spine, and pelvis on water-only Dixon T2W sequences as part of a whole-body MRI protocol in 196 healthy and asymptomatic children aged 5-19 years. Intensity (0-2 scale) and extension (1-4 scale) of focal high signal areas in the bone marrow were scored and divided into minor or major findings, based on intensity and extension to identify the potentially conspicuous lesions in a clinical setting.

RESULTS

We registered 415 areas of increased signal in the axial skeleton whereof 75 (38.3%) were major findings. Fifty-eight (29.6%) individuals had at least one major finding, mainly located in the pelvis (54, 72%). We found no differences according to gender. The number of minor findings increased with age (p = 0.020), but there were no significant differences in the number of major findings. The most conspicuous findings were in the pelvis, spine and sternum.

CONCLUSION

Non-specific bone marrow T2W hyperintensities in the axial skeleton are frequently detected on whole-body MRI in healthy, asymptomatic children. Awareness of this is important as some findings may resemble clinically silent lesions in children with suspected multifocal skeletal disease.

[Spondyloarthritis in childhood and adulthood]

Axial spondylarthritis in adulthood (SpAA) is frequently initially manifested as a sacroiliitis, whereas this not true for enthesitis-related arthritis (EAA), which begins in childhood and adolescence. Classically, EAA begins with peripheral arthritis and only a part transitions into a juvenile SpA (jSpA) or SpAA. The criteria used for classification of SpAA and EAA are currently being validated and revised. For the first time imaging is included for EAA. For both diseases nonsteroidal anti-inflammatory drugs (NSAID) are initially used therapeutically, followed by biologicals or synthetic targeted disease-modifying drugs in refractory courses. Steroids should be avoided in long-term treatment. For optimal transition and further care in adulthood, a close cooperation between internistic and pediatric rheumatologists is necessary.

Changes over time in inflammatory and structural lesions at the sacroiliac joint in children with spondyloarthritis exposed and unexposed to tumor necrosis factor inhibitor

BACKGROUND

The objective of this work was to describe magnetic resonance imaging (MRI) changes over time in inflammatory and structural lesions at the sacroiliac joint (SIJ) in children with spondyloarthritis (SpA) exposed and unexposed to tumor necrosis factor inhibitor (TNFi).

METHODS

This was a retrospective, multicenter study of SpA patients with suspected or confirmed sacroiliitis who underwent at ≥2 pelvic MRI scans. Images were reviewed independently by 3 radiologists and scored for inflammatory and structural changes using the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ inflammation score (SIS) and structural score (SSS). Longitudinal, quantitative changes in patient MRI scans were measured using descriptive statistics and stratified by TNFi exposure. We used an average treatment effects (ATE) regression model to explore the average effect of TNFi exposure over time on inflammatory and structural lesions, adjusting for baseline lesion scores.

RESULTS

Forty-six subjects were evaluated using the SIS (n = 45) and SSS (n = 18). Median age at baseline imaging was 13.6 years, 63% were male and 71% were white. Twenty-three subjects (50%) were TNFi exposed between MRI studies. The median change in SIS in TNFi exposed and unexposed subjects with a baseline SIS ≥0 was - 20.7 and - 14.3, respectively (p = 0.09). Eleven (85%) TNFi exposed and 8 (89%) unexposed subjects with a baseline SIS ≥0 met the SIS minimal clinically important difference (MCID; ≥2.5). Using the ATE model adjusted for baseline SIS, the average effect of TNFi on SIS in patients with a baseline SIS ≥2 was - 14.5 (p < 0.01). Unadjusted erosion change score was significantly worse in TNFi unexposed versus exposed subjects (p = 0.03) but in the ATE model the effect of TNFi was not significant.

CONCLUSION

This study quantitatively describes how lesions in the SIJs on MRI change over time in patients exposed to TNFi versus unexposed. Follow-up imaging in TNFi exposed patients showed greater improvement than the unexposed group by most metrics, some of which reached statistical significance. Surprisingly, a majority of TNFi unexposed children with a baseline SIS≥2 met the SIS MCID. Additional studies assessing the short and long-term effects of TNFi on inflammatory and structural changes in juvenile SpA are needed.

Update on Juvenile Spondyloarthritis

Spondyloarthritis (SpA) is a blanket term encompassing entities such as enthesitis-related arthritis, nonradiographic axial SpA, and ankylosing spondylitis. These diseases share many clinical features, including a predilection for inflammation of the entheses and the sacroiliac joints. The nomenclature is based on the evolution of the classification of the disease and the age of the patient. SpA has a prevalence of approximately 1% of the population of the United States, with 10% to 20% of patients experiencing the onset during childhood. Children with onset of arthritis before age 16 years are classified as having juvenile idiopathic arthritis. Children with enthesitis and/or sacroiliitis are further classified as belonging to the enthesitis-related arthritis subtype of juvenile idiopathic arthritis. The initial manifestations can be subtle and will usually include a peripheral pattern of arthritis and enthesitis. It may take several years for axial disease to develop in children. Except for an association with the human leukocyte antigen (HLA-B27) serotype, there are no laboratory markers for the disease, and the radiographic findings are often negative. A careful clinical evaluation for evidence of inflammation in the entheses and the joints and a search for comorbidities are required. Magnetic resonance imaging facilitates the early detection of sacroiliitis, an important feature that may be clinically silent. Because recent studies indicate that earlier introduction of therapy can help achieve better outcomes, rapid identification and treatment of children with SpA is essential.

Precision medicine in juvenile idiopathic arthritis-has the time arrived?

The introduction of disease-modifying anti-rheumatic drug therapies for treating children and adolescents with chronic arthritis (ie, juvenile idiopathic arthritis [JIA]) has revolutionised care and outcomes. The biologic revolution continues to expand, with ever-changing immunological targets coming to market after basic research and clinical trials. The first class of biologics that was beneficial for children with JIA was tumour necrosis factor (TNF) inhibitors. If used early and aggressively, TNF inhibitors are capable of inducing disease remission for most of the seven subtypes of JIA, with the exception of systemic JIA (which more frequently responds to interleukin [IL]-1 or IL-6 inhibition). Nevertheless, there are still subsets of patients with JIA with disease that is difficult to treat or who develop extra-articular features that require a different therapeutic approach. Although finding an effective biological therapy for individual children with JIA can be trial and error, ongoing research and clinical trials are providing insight into a more personalised approach to care. In addition, redefining the JIA classification, in part based on shared similarities with various adult arthritides, could allow for extrapolation of knowledge from studies in adults with chronic arthritis.

Determinants of Tumor Necrosis Factor Inhibitor Use in Juvenile Spondyloarthropathy and Impact on Clinical Disease Outcomes

Objective

The objectives of this study were to characterize the reasons for tumor necrosis factor inhibitor (TNFi) initiation in patients with juvenile spondyloarthropathy (JSpA) and identify clinical correlates and to assess the effect of TNFi therapy on JSpA disease activity.

Methods

We conducted a retrospective cohort study of 86 patients with JSpA with first‐time use of a TNFi over a 7‐year period at Stanford Children's Health. We assessed the physician's reason for TNFi initiation, disease activity at 6 months, and clinical disease status at 12 months following TNFi start. Changes in active joint count, enthesitis count, and pain were measured. Demographics, physician reasons for TNFi initiation, and clinical characteristics were summarized.

Results

The mean age at JSpA diagnosis was 12.4 years (SD 4.0 years), and the mean time from diagnosis to TNFi initiation was 1.6 years (SD 2.3 years). The most common reason for initiating a TNFi was active disease on physical examination (61%). At 6 months post TNFi initiation, patients on average had three fewer active joints and one fewer active enthesitis point. Patient‐reported pain improved from moderate/severe to mild. After 12 months, 54% of patients had active disease.

Conclusion

The physician's decision to initiate a TNFi relied mostly on physical examination findings. Despite improvement in arthritis, enthesitis, and patient‐reported pain at 6 months post TNFi initiation, the majority of the patients still had active disease after 1 year of therapy.

Recent Updates in Juvenile Spondyloarthritis

Spondyloarthritis represents a group of disorders characterized by enthesitis and axial skeletal involvement. Juvenile spondyloarthritis begins before age 16. Joint involvement is usually asymmetric. Bone marrow edema on noncontrast MRI of the sacroiliac joints can facilitate diagnosis. The most significant risk factor for axial disease is HLA-B27. Most patients have active disease into adulthood. Enthesitis and sacroiliitis correlate with greater pain intensity and poor quality-of-life measures. Tumor necrosis factor inhibitors are the mainstay of biologic therapy. Although other biologics such as IL-17 blockers have shown benefit in adult spondyloarthritis, none are approved by the US Food and Drug Administration.

Inflammatory Foot Involvement in Spondyloarthritis: From Tarsitis to Ankylosing Tarsitis

Spondyloarthritis (SpA) is a group that includes a wide spectrum of clinically similar diseases manifested by oligoarticular arthritis and axial or peripheral ankylosis. Although axial SpA is predominant in Caucasians and adult-onset patients, juvenile-onset and Latin American patients are characterized by severe peripheral arthritis and particularly foot involvement. The peripheral involvement of SpA can vary from tarsal arthritis to the most severe form named ankylosing tarsitis (AT). Although the cause and etiopathogenesis of axSpA are often studied, the specific characteristics of pSpA are unknown. Several animal models of SpA develop initial tarsitis and foot ankylosis as the main signs, emphasizing the role of foot inflammation in the overall SpA spectrum. In this review, we attempt to highlight the clinical characteristics of foot involvement in SpA and update the knowledge regarding its pathogenesis, focusing on animal models and the role of mechanical forces in inflammation.

Advances in Juvenile Spondyloarthritis

PURPOSE

To provide an overview of recent studies on pathogenesis, diagnosis, and management of juvenile spondyloarthritis (JSpA).

RECENT FINDINGS

Recent studies show differences in gut microbiome in patients with JSpA in comparison to healthy controls. There is increased recognition of the impact of the innate immune system on disease pathology. Normative reference on MRI of sacroiliac (SI) joints in children is now available. However, there is significant variability in interpretation of MRI of SI joints in children and a need for standardization. NSAIDs, physical therapy, and Tumor Necrosis Factor Inhibitors (TNFi) remain the mainstay of management for patients with JIA who have polyarthritis, sacroiliitis, and/or enthesitis as per recent ACR guidelines. Newer therapeutic options beyond TNFi are needed to manage patients who fail TNFi. This review highlights some of the recent advances in our knowledge of JSpA pathophysiology, diagnosis, and treatment. It also identifies areas in need of further research and standardization to improve our understanding and outcomes in JSpA.

Outcomes in Juvenile-Onset Spondyloarthritis

Some studies have suggested children with juvenile onset spondyloarthritis (JoSpA) have a relatively poor outcome compared to other juvenile idiopathic arthritis (JIA) categories, in regards to functional status and failure to attain remission. Thus, in the interest of earlier recognition and risk stratification, awareness of the unique characteristics of this group is critical. Herein, we review the clinical burden of disease, prognostic indicators and outcomes in JoSpA. Of note, although children exhibit less axial disease at onset compared to adults with spondyloarthritis (SpA), 34–62% have magnetic resonance imaging (MRI) evidence for active inflammation in the absence of reported back pain. Furthermore, some studies have reported that more than half of children with “enthesitis related arthritis” (ERA) develop axial disease within 5 years of diagnosis. Axial disease, and more specifically sacroiliitis, portends continued active disease. The advent of TNF inhibitors has promised to be a “game changer,” given their relatively high efficacy for enthesitis and axial disease. However, the real world experience in various cohorts since the introduction of more widespread TNF inhibitor usage, in which greater than a third still have persistently active disease, suggests there is still work to be done in developing new therapies and improving the outlook for JoSpA.

Do geography and ethnicity play a role in juvenile Spondyloarthritis? A multi-center binational retrospective study

BACKGROUND

Observations among Israeli pediatric rheumatologists reveal that pediatric Juvenile Spondyloarthritis (JSpA) may present differently compared to patients from the United States (US). This study is aimed to compare the demographic and clinical variables of Israeli and US JSpA patients upon presentation.

METHODS

We performed a retrospective, cross-sectional, multicenter comparison of JSpA patients among 3 large Israeli pediatric rheumatology centers and a large US pediatric rheumatology center. Patients with diagnosis of Juvenile Ankylosing Spondylitis (JAS) and/or Enthesitis-related Arthritis (ERA) were included. The demographic, clinical and radiologic features were compared.

RESULTS

Overall 87 patients were included (39 Israeli, 48 US patients). Upon presentation, inflammatory back pain, sacroiliac joint tenderness and abnormal modified Schober test, were significantly more prevalent among Israeli patients (59% vs. 35.4, 48.7% vs. 16.7, and 41.2% vs. 21.5%, respectively, all p < 0.05), whereas peripheral arthritis and enthesitis were significantly more prevalent among US patients (43.6% vs. 91.7 and 7.7% vs. 39.6% in Israeli patients vs. US patients, p < 0.05). In addition, 96.7% of the Israeli patients versus 29.7% of the US patients demonstrated sacroiliitis on MRI (p < 0.001, N = 67). Less than one-third of the Israeli patients (32%) were HLA-B27 positive vs. 66.7% of US patients (p = 0.007).

CONCLUSION

Israeli children with JSpA presented almost exclusively with axial disease compared to US patients who were more likely to present with peripheral symptoms. HLA B27 prevalence was significantly lower in the Israeli cohort compared to the US cohort. Further studies are needed to unravel the genetic and possibly environmental factors associated with these findings.

Back Pain in Children and Adolescents

Back pain has long been considered an uncommon complaint in the pediatric population. When present, teaching had been that pediatric back pain almost always has a diagnosable cause, many of which are progressive and potentially debilitating. Recent evidence has suggested that pediatric back pain is not only more common than once thought but also, within certain populations, benign and idiopathic. This, in turn, places an increasing amount of pressure on pediatricians to accurately assess and manage their patients presenting with complaints of back pain. The aim of this article is to serve as a review of the current literature on pediatric back pain. The article reviews the epidemiology, basic anatomy, and important elements of a history and examination, which should be considered when a child presents complaining of back pain. Last, a common differential diagnosis with evaluation and management is also given to help guide pediatricians through their medical decision making.

Juvenile idiopathic arthritis in Southeast Asia: the Singapore experience over two decades

OBJECTIVES

To examine the clinical characteristics, treatment and outcomes of juvenile idiopathic arthritis (JIA) patients evaluated in Singapore and compare those with reports elsewhere.

METHODS

Patients with JIA were recruited from our Singapore pediatric rheumatology registry from January 1997 to December 2015. Demographic, clinical, treatment, and outcome data were retrospectively collected. Nonparametric statistics were used to describe the data. Chi-squared, Mann-Whitney U, or Kruskal-Wallis tests were applied to compare differences between groups where appropriate. Multivariate logistic regression analyses were used to identify predictors for clinical parameters.

RESULTS

Two hundred eighty-seven JIA patients with 60.6% males of predominantly Chinese descent were included in the study. The median onset age was 9 years (IQR 5.3-12.6), and the median follow-up duration was 30.1 months (IQR 9.1-61.7). Enthesitis-related arthritis (ERA, 32.8%) followed by persistent oligoarthritis (31.0%) was the most common. Elbow or ankle involvement predicted oligoarthritis extension (OR 15.8 (95% CI: 2.3-108.3, p = 0.005), 8.1 (95% CI: 1.5-45.3, p = 0.017)). JIA-associated uveitis was rare (2.8%) which paralleled the less common positive-ANA rate. Majority of our ERA patients had HLA-B27 (79.8%), together with older age predicted sacroiliitis (OR 4.7 (95% CI: 2.0-11.1, p < 0.05), OR 1.2 (95% CI: 1.1-1.3, p = 0.002)). TMJ involvement was under-reported. Methotrexate remained the most common DMARD used, but 36% of patients required biologics for which ERA and polyarthritis were the majority. Joint damage was rare.

CONCLUSION

This study highlights geographical and ethnic differences in JIA epidemiology. Compared with reports elsewhere, our JIA population had many unique findings and good functional outcomes requiring regional study validation. Key points • ERA is the most prominent JIA subtype in Singapore with high prevalence of HLA-B27. • JIA-associated uveitis is rare in SEA and is not associated with ANA or JIA-subtypes. • Elbow and/or ankle involvement at presentation is associated with oligoarthritis extension in our JIA cohort.

Juvenile-Versus Adult-Onset Spondyloarthritis: Similar, but Different

This article provides an overview of juvenile spondyloarthritis and important differences in the classification criteria, clinical presentation, outcomes, and pathology in juvenile versus adult-onset disease. Key differences in classification criteria between children and adults with spondyloarthritis are important to understand, as they can make transition from pediatric to adult care challenging. MRI and ultrasonography are increasingly relied on for the assessment of adult-onset disease activity and change over time in the pediatric population. The unique features of the maturing axial and peripheral skeleton are described for each modality, as they are key to understand for accurate interpretation of pathology in the pediatric population.

Psoriatic arthritis in childhood: A commentary on the controversy

Approximately 5% of children with juvenile idiopathic arthritis (JIA) are diagnosed with the psoriatic form of the disease. In recent years, there has been substantial scholarship demonstrating both heterogeneity within the disease as well as similarities with other forms of JIA, culminating in a recent proposal for the categorization of JIA that excluded the psoriatic form altogether. The purpose of the review is to summarize the clinical, epidemiologic, and genetic features of psoriatic JIA (PsJIA), comparing it with other categories of JIA including spondyloarthritis. We conclude that there are sufficient unique clinical and genetic features within PsJIA as well as similarities with its adult counterpart that warrant including it within the JIA paradigm.

Evaluation of factors affecting the duration of disease-modifying anti-rheumatic drugs application in patients with enthesitis-related arthritis

OBJECTIVE

Treatments for enthesitis-related arthritis (ERA) consist of a mono- or combination therapy with non-steroidal anti-inflammatory drugs, disease-modifying anti-rheumatic drugs (DMARDs), and biological agents, and they are primarily based on adult studies and studies on other forms of juvenile idiopathic arthritis, depending on whether there is axial or peripheral involvement. We use DMARDs frequently in our daily practice, even in patients with axial involvement. The main reason for this is that the health insurance system in Turkey does not allow the use of Tumor Negrosis Factor (TNF) blockers as the first line of treatment. The aim of this study is to evaluate the factors affecting the duration of DMARDs application in patients with ERA.

METHODS

Fifty-two patients with ERA were accepted in this retrospective cohort study. These patients did not have an inflammatory bowel disease, reactive arthritis or undifferentiated arthritis, psoriasis, and familial Mediterranean fever. Demographic characteristics, medical history, the initial and follow-up physical examination, initial Juvenile Spondyloarthritis Disease Activity Index (JSpADA), initial laboratory tests, radiographic tests, Juvenile Arthritis Damage Index-articulary (JADI-A) and extra-articulary (JADI-E) on the last admission, and data on medical treatments were recorded from the registered data. The univariate Cox proportional hazards regression analyses was used to determine factors affecting the non-response time of ERA patients to DMARDs before the biological treatment was started.

RESULTS

Twenty-seven patients (52%) achieved remission with DMARDs, while 25 (48%) patients did not. The age at diagnosis (HR=1.12; p=0.247); gender (HR=2.53; p=0.210); family history of ankylosing spondylitis (HR=1.17; p=0.730); inflammatory back pain (HR=0.57; p=0.175); the shoulder (HR=0.75 p=0.706), hip (HR=0.45; p=0.129), and small-joint involvement (HR=1.53; p=0.439); sacroiliitis with physical examination (HR=0.90; p=0.814) and magnetic resonance imaging (MRI) (HR=2.84; p=0.110); enthesitis (HR=0.83; p=0.670); presence of uveitis (HR=2.04; p=0.342); presence of HLA-B27 (HR=1.39; p=0.524); initial high acute phase reactants levels(HR=1.89; p=0.183); initial JSpADA score (HR=0.98; p=0.944); and last JADI-A (HR=1.41; p=0.060) score did not affect the duration of DMARDs treatment before switching to biological treatments.

CONCLUSION

In our study, the absence of factors affecting the duration of DMARDs application in patients with ERA showed that DMARDs may still be applied as the first line of treatment.

Spondyloarthritis Research Consortium of Canada Scoring System for Sacroiliitis in Juvenile Spondyloarthritis/Enthesitis-related Arthritis: A Reliability, Validity, and Responsiveness Study

OBJECTIVE

Intra- and interreader reliability, construct validity, and responsiveness of the Spondyloarthritis Research Consortium of Canada (SPARCC) magnetic resonance imaging (MRI) scoring system were investigated for scoring sacroiliitis in patients with juvenile spondyloarthritis (JSpA)/enthesitis-related arthritis (ERA) who have received biologic and/or nonbiologic treatment.

METHODS

Ninety whole-body MRI examinations with dedicated oblique coronal planes of the sacroiliac joints in 46 patients were independently reviewed and scored by 2 pediatric musculoskeletal radiologists, blinded to clinical details, using the SPARCC system. Intra- and interreader reliability was assessed by intraclass correlation coefficients (ICC). Construct validity testing was done by (1) correlating the SPARCC MRI scores of sacroiliitis with clinical disease activity indicators (cross-sectional validity), and (2) correlating the change in the MRI score with the change in clinical indicators before and after treatment (longitudinal validity). Responsiveness of the MRI and clinical indicators was also evaluated, grouped by biologic and nonbiologic treatment.

RESULTS

When applied in children with JSpA/ERA, the SPARCC showed almost perfect intra- and interreader reliability (ICC 0.79-1.00). There was poor cross-sectional and longitudinal correlation between clinical assessment indicators and MRI scoring. SPARCC scores showed higher responsiveness to treatment-related change than most clinical outcome measures. Three clinical outcome measures correlated longitudinally with SPARCC score in nonbiologic treatment: active joint count (r = 0.72, p < 0.001), FABER (Flexion, Abduction, External Rotation) test (r = 0.58, p = 0.012), and physician's global assessment (r = 0.61, p = 0.034).

CONCLUSION

The SPARCC MRI scoring system is a reliable tool with relatively higher responsiveness than clinical indicators and is suitable for objective quantification of sacroiliitis when applied to pediatric patients with JSpA/ERA.

Enthesitis-related arthritis: current perspectives

In this narrative review, we overview the recent literature on enthesitis-related arthritis (ERA). For the purpose of our review, we searched Scopus for recent articles on this subject from 2013 onward, including some classic older articles for perspective. ERA is a juvenile idiopathic arthritis (JIA) subtype more common in males, associated in a majority with human leucocyte antigen B27. Such children generally present with asymmetric oligoarthritis or polyarthritis, predominantly of lower limb joints, associated with enthesitis or sacroiliitis. While diagnosis remains clinical, ultrasound is being increasingly used to detect subclinical enthesitis and for guiding entheseal site injections. Spine MRI can help detect sacroiliitis, inflammatory spinal changes, and pelvic sites of enthesitis in such patients. The recent juvenile spondyloarthropathy disease activity index recognizes the key clinical features of ERA, viz enthesitis and inflammatory back pain, which other disease activity indices used in JIA did not include. Management includes NSAIDs with physical therapy. Conventional disease-modifying agents like sulfasalazine and methotrexate may be used to minimize duration of NSAID use and in those with high inflammatory burden. In patients refractory to these drugs, biologics such as antitumor necrosis factor alpha agents have proven useful, based on evidences from randomized controlled trials and retrospective registry analyses. Factors predicting a poorer outcome in such children include hip or ankle involvement or restricted spinal mobility. Considering that children with ERA have overall poorer long-term outcomes than other subtypes of JIA, there is a need to further optimize therapeutic strategies for such patients.

Juvenile Spondyloarthritis: A Distinct Form of Juvenile Arthritis

Juvenile spondyloarthritis (SpA) is a distinct form of juvenile arthritis characterized by male predominance and adolescent onset. Clinical manifestations include lower extremity and sacroiliac joint arthritis, enthesitis, and subclinical gastrointestinal inflammation. Juvenile SpA is an immune-mediated inflammatory disease long recognized as associated with HLA-B27, which may be related to the microbial environment as suggested by its coexistence with reactive arthritis and psoriasis. Treatment of peripheral arthritis includes nonsteroidal anti-inflammatory drugs, joint injections, and disease-modifying agents, whereas treatment of axial disease may necessitate a tumor necrosis factor inhibitor biologic agent. Fewer than half of children achieve remission off medication 5 years after diagnosis.

Feasibility and Reliability of the Spondyloarthritis Research Consortium of Canada Sacroiliac Joint Structural Score in Children

OBJECTIVE

There is a critical need for measures to evaluate structural progression in the pediatric sacroiliac joint (SIJ). We aimed to evaluate the construct validity and reliability of the Spondyloarthritis Research Consortium of Canada SIJ Structural Score (SSS) in children with suspected or confirmed juvenile spondyloarthritis.

METHODS

The SSS assesses structural lesions of the SIJ on magnetic resonance imaging (MRI) through the cartilaginous part of the joint. We conducted 3 sequential reading exercises with 6 readers (1 adult and 3 pediatric radiologists, 1 adult and 1 pediatric rheumatologist). Each exercise was preceded by a calibration module. Interobserver reliability was assessed using intraclass correlation coefficients (ICC). Prespecified acceptable reliability thresholds were ICC > 0.5 for erosion, backfill, and sclerosis, and ICC > 0.7 for ankylosis and fat metaplasia.

RESULTS

The SSS had face validity and was feasible to score in pediatric cases for all 3 reading exercises. Of the cases used in the 3 exercises, 58% were male and the median age was 14 years (range 6.8-18.7 yrs). After calibration, median ICC across all readers for each SSS component were the following: erosion 0.67 (interquartile range 0.54-0.80), backfill 0.33 (0.19-0.52), fat metaplasia 0.74 (0.62-0.85), sclerosis 0.63 (0.48-0.77), and ankylosis 0.44 (0.28-0.62). Prespecified reliability thresholds were achieved in the third exercise for erosion, sclerosis, and fat metaplasia but not for backfill or ankylosis.

CONCLUSION

The SSS was feasible to score and had acceptable reliability for pediatric SIJ MRI evaluation. The ICC improved with additional calibration and reading exercises, even for readers with limited experience.

Clinical features of children with enthesitis-related juvenile idiopathic arthritis / juvenile spondyloarthritis followed in a French tertiary care pediatric rheumatology centre

BACKGROUND

Childhood-onset spondyloarthropathies usually start with enthesitis and peripheral arthritis. However, axial disease may develop afterward. Patients are most often classified, following revised (Edmonton 2011) ILAR criteria, as enthesitis-related arthritis, psoriatic arthritis, or unclassified juvenile idiopathic arthritis, particularly in cases of psoriasis in the patient or a first-degree relative. In adults, peripheral spondyloarthritis is classified by ASAS criteria.

METHODS

We retrospectively studied patients with childhood-onset spondyloarthropathies followed for more than one year in our referral centre. We did not exclude patients with a personal or familial history of psoriasis.

RESULTS

We included 114 patients followed between January 2008 and December 2015 for a median of 2.5 years (IQR = 2.3). Sixty-nine per-cent of patients fulfilled the revised ILAR classification criteria for enthesitis-related arthritis, and 92% the ASAS criteria for peripheral spondyolarthritis (p <  0.001). Axial disease and sacroiliitis were rare at disease onset. However, they appeared during follow-up in 63% and 47% of cases respectively, after a median disease duration of 2.6 (IC 95% [2.2-4.4]) and 5.3 years (IC 95% [4.1-7.7]), respectively. Multivariable analysis showed that familial history of spondyloarthritis was associated with the presence of sacroiliitis and active disease at the latest follow-up (OR = 3.61 [1.5-8.7], p <  0.01 and 2.98 [1.2-7.3], p = 0.02, respectively).

CONCLUSION

Axial involvement developed in most patients within five years. Revised Edmonton criteria were less sensitive than ASAS criteria to classify patients as having childhood-onset spondyloarthropathies. The main risk factor for both sacroiliitis and persistent active disease was a familial history of spondyloarthritis.

Conventional radiography in juvenile idiopathic arthritis: Joint recommendations from the French societies for rheumatology, radiology and paediatric rheumatology

BACKGROUND

Juvenile idiopathic arthritis (JIA) can cause structural damage. However, data on conventional radiography (CR) in JIA are scant.

OBJECTIVE

To provide pragmatic guidelines on CR in each non-systemic JIA subtype.

METHODS

A multidisciplinary task force of 16 French experts (rheumatologists, paediatricians, radiologists and one patient representative) formulated research questions on CR assessments in each non-systemic JIA subtype. A systematic literature review was conducted to identify studies providing detailed information on structural joint damage. Recommendations, based on the evidence found, were evaluated using two Delphi rounds and a review by an independent committee.

RESULTS

74 original articles were included. The task force developed four principles and 31 recommendations with grades ranging from B to D. The experts felt strongly that patients should be selected for CR based on the risk of structural damage, with routine CR of the hands and feet in rheumatoid factor-positive polyarticular JIA but not in oligoarticular non-extensive JIA.

CONCLUSION

These first pragmatic recommendations on CR in JIA rely chiefly on expert opinion, given the dearth of scientific evidence. CR deserves to be viewed as a valuable tool in many situations in patients with JIA.

KEY POINTS

• CR is a valuable imaging technique in selected indications. • CR is routinely recommended for peripheral joints, when damage risk is high. • CR is recommended according to the damage risk, depending on JIA subtype. • CR is not the first-line technique for imaging of the axial skeleton.

Feasibility and reliability of the Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation score in children

BACKGROUND

Published methods for quantification of magnetic resonance imaging (MRI) evidence of inflammation in the sacroiliac joint lack validation in pediatric populations. We evaluated the reliability and construct validity of the Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint inflammation score (SIS) in children with suspected or confirmed juvenile spondyloarthritis (JSpA).

METHODS

The SPARCC SIS measures the presence, depth, and intensity of bone marrow inflammation on MRI through the cartilaginous part of the joint. Six readers blinded to clinical details except age, participated in two reading exercises, each preceded by a calibration exercise. Inter-observer reliability was assessed using intraclass correlation coefficients (ICCs) and for pre-specified acceptable reliability the inraclass correlation coefficient (ICC) was > 0.8.

RESULTS

The SPARCC SIS had face validity and was feasible to score in pediatric cases in both reading exercises. Cases were mostly male (64%) and the median age at the time of imaging was 14.9 years. After calibration, the median ICC across all readers for the SIS total score was 0.81 (IQR 0.71-0.89). SPARCC SIS had weak correlation with disease activity (DA) as measured by the JSpADA (r = - 0.12) but discriminated significantly between those with and without elevated C-reactive protein (p = 0.03).

CONCLUSION

The SPARCC SIS was feasible to score and had acceptable reliability in children. The ICC improved with additional calibration and reading exercises, for both experienced and inexperienced readers.

Imaging in Juvenile Spondyloarthritis

PURPOSE OF REVIEW

This review aims to provide an update on the use of imaging in the assessment of juvenile spondyloarthritis (JSpA) disease manifestations.

RECENT FINDINGS

Recent studies have demonstrated superior reliability and specificity of MRI for assessment of sacroiliac joint inflammation compared with radiography. The use of gadolinium contrast may not add incremental value to the assessment of inflammatory sacroiliitis. Sacroiliitis is common at diagnosis of spondyloarthritis. Inflammatory changes of the lumbar spine are not uncommon, and changes over time in the sacroiliac and apophyseal joints may not be concordant. Ultrasonography (US) in turn has been recognized as an excellent imaging technique to visualize the peripheral manifestations of JSpA. US does not only add important information to the clinical assessment but also helps to understand the complexity of the enthesis. Recognition of specific aspects in children is important though. The standardization of image acquisition as well as the establishment of the evidence base are underway. MRI and ultrasonography are recognized as increasingly important tools in the diagnosis and management of juvenile spondyloarthritis.

Update on enthesitis-related arthritis

PURPOSE OF REVIEW

This review provides a detailed update regarding the genetics, pathogenesis, disease phenotype evaluation, therapies and expected outcomes for children with enthesitis-related arthritis (ERA).

RECENT FINDINGS

Recent studies evaluated human leukocyte antigen (HLA)-B27 subtypes and non-major histocompatibility complex genes including toll like receptor 4, NLRP3, CXCR4 and PTPN12 in children with ERA. The microbiome and γδ-T cells have also been an area of active investigation. Several studies focus on the imaging phenotype of children with ERA, including the use of ultrasonography and MRI. MRI techniques studied in this population include dedicated MRI, whole-body MRI and diffusion-weighted imaging. Conventional and biologic disease-modifying agents continue to be the mainstay of therapy, though the past 2 years have witnessed several greatly needed randomized controlled trials to study the efficacy of these medications in ERA. Finally, long-term effectiveness studies of biologics in children with ERA have helped inform provider and patient expectations of disease response and prognosis.

SUMMARY

Further evaluation of the role of the microbiome and the interleukin 17/interleukin 23 axis, techniques to optimize evaluation of disease features, and efficacy and effectiveness of newer medications are greatly needed in this understudied population of children.

Multicenter inception cohort of enthesitis-related arthritis: variation in disease characteristics and treatment approaches

Background

Enthesitis-related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA) defined according to the International League of Associations for Rheumatology (ILAR) criteria. We aimed to characterize the clinical features and treatment regimens in an inception cohort of children with ERA.

Methods

We performed a retrospective, cross-sectional, multicenter cohort study including subjects diagnosed with ERA between 1989 and 2012. Patients all fulfilled the ILAR criteria for ERA within 3 months of initial presentation to the rheumatology clinic. Differences in the prevalence of clinical criteria across study sites and by human leukocyte antigen (HLA)-B27 status were assessed using the Wilcoxon rank-sum or chi-square test, as appropriate.

Results

Two hundred thirty-four children met the inclusion criteria. Their median age at diagnosis was 11.6 years, and 59% were HLA-B27-positive. Sixty-nine percent had enthesitis and arthritis at the time of diagnosis. Seventy-eight percent had a pauciarticular onset. The prevalence of all ILAR criteria at diagnosis, except arthritis and acute anterior uveitis, differed significantly across sites (all p < 0.01). Medication use varied significantly across sites for children with peripheral arthritis (p < 0.001), but not for sacroiliitis or enthesitis only. Nonsteroidal anti-inflammatory drugs and disease-modifying antirheumatic drugs were the most commonly prescribed treatments, with anti-TNF agents primarily being initiation for sacroiliitis. HLA-B27 positivity was associated with male sex, higher active joint count, sacroiliitis, and higher disease activity at disease onset.

Conclusions

The majority of children had a pauciarticular onset, and several statistically significant clinical differences based on HLA-B27 status were identified. The observed heterogeneity in clinical presentation across sites reflects either true differences in patient populations or differences in how the ILAR criteria are being applied.

Psoriasis and associated variables in classification and outcome of juvenile idiopathic arthritis - an eight-year follow-up study

BACKGROUND

To study the impact of psoriasis and features associated with psoriasis on classification and outcome in a population-based follow-up cohort of children with juvenile idiopathic arthritis (JIA).

METHODS

In all, 440 children with JIA were followed for a median of 8 years in a prospective Nordic population-based cohort study. Data for remission was available for 427 of these children. The presence of psoriasis, psoriasis-like rash, dactylitis, nail pitting, enthesitis, tenosynovitis and heredity was assessed in relation to ILAR classification and remission.

RESULTS

Clinical findings associated with psoriasis developed consecutively during the 8-year period. Six of 14 children with psoriasis were not classified as juvenile psoriatic arthritis according to the ILAR criteria at 8 year follow-up. Dactylitis was more common in children with early onset of JIA. After 8 years we found a cumulative median number of eleven arthritic joints in children with psoriasis or psoriasis-like rash compared with six in the rest of the cohort (p = 0.02). Also, the chance for not being in remission after 8 years increased significantly in patients with psoriasis, psoriasis-like rash or at least two of: 1) first-degree heredity for psoriasis or psoriatic arthritis, 2) dactylitis or 3) nail pitting, compared with the rest of the group (OR 3.32, p = 0.010).

CONCLUSIONS

Our results indicate a more severe disease over time in psoriasis-associated JIA, as features of psoriasis develop during the disease course. This group is a major challenge to encompass in a future JIA classification in order to facilitate early tailored treatment.

Discordant inflammatory changes in the apophyseal and sacroiliac joints: serial observations in enthesitis-related arthritis

OBJECTIVE

To determine the extent to which inflammation of the sacroiliac joints (SIJs) and apophyseal joints (AJs) changes concordantly after treatment in enthesitis-related arthritis (ERA).

METHODS

A retrospective study was performed with institutional review board approval. 31 young patients with ERA who had been scanned between March 2009 and November 2014 were included. All patients had post-contrast imaging of the SIJs and lumbar spine and short tau inversion-recovery (STIR) images of the SIJs. The severity of sacroiliitis was scored using a modification of an established technique, and inflammation of the AJs was evaluated using a recently described grading system. The changes in SIJ and AJ scores after treatment were classified as either concordant or discordant, and the proportion of scan pairs in these groups was recorded. In addition, the correlation between change in SIJ STIR score (Δnfla) and change in AJ score (ΔAJ) was assessed using Spearman's correlation coefficient.

RESULTS

Of a total of 43 scan pairs, the changes in inflammation were concordant in 16 scan pairs and discordant in 27 scan pairs. There was no significant correlation between Δnfla and ΔAJ (R = 0.14, p = 0.37).

CONCLUSION

Inflammatory changes in the SIJs and AJs are often discordant. This may be a reason why patients experience ongoing back pain despite apparent improvement in one or the other site.

ADVANCES IN KNOWLEDGE

Inflammation may behave differently at different anatomical sites. The SIJs and AJs should both be imaged in patients with ERA with back pain.

Assessment of Sacroiliitis at Diagnosis of Juvenile Spondyloarthritis by Radiography, Magnetic Resonance Imaging, and Clinical Examination

OBJECTIVE

To evaluate the prevalence of sacroiliitis at diagnosis of juvenile spondyloarthritis (SpA) and the accuracy of physical examination and back pain to detect sacroiliitis, using imaging as the reference standard.

METHODS

We performed a prospective cross-sectional study of 40 children with newly diagnosed juvenile SpA and 14 healthy controls. Subjects were assessed using physical examination, anteroposterior pelvic radiograph, and pelvic magnetic resonance imaging (MRI). Differences in clinical features between those children with and without sacroiliitis were assessed by Fisher's exact test for categorical variables and Wilcoxon's rank sum test for continuous variables. Accuracy of physical examination and back pain for detection of sacroiliitis was determined using MRI as the reference standard. Predicted probability of sacroiliitis was determined using exact multivariate logistic regression.

RESULTS

Eight children (20%) with juvenile SpA had active sacroiliitis. Of those subjects with active changes on MRI, 7 of 8 (88%) also had evidence of erosions or sclerosis. Five children (13%) with juvenile SpA and 1 control (7%) had nonperiarticular bone marrow edema. Of the subjects with active sacroiliitis, only 3 (38%) reported a history of back pain or tenderness on palpation of the sacroiliac joints. The positive and negative predictive values of clinical examination features and back pain for detection of sacroiliitis were low. The estimated probability of having sacroiliitis was 0.84 (95% confidence interval 0.40-1.00) in HLA-B27-positive patients with an elevated C-reactive protein (CRP) level.

CONCLUSION

Active sacroiliitis by MRI is common at diagnosis in juvenile SpA and is frequently asymptomatic. Children who are HLA-B27-positive and have elevated CRP levels have the highest probability of sacroiliitis.

Juvenile spondyloarthritis

PURPOSE OF REVIEW

This article provides a comprehensive update of the pathogenesis, diagnostic imaging, treatments, and disease activity measurements of juvenile spondyloarthritis (JSpA).

RECENT FINDINGS

Genetic and microbiome studies have provided new information regarding possible pathogenesis of JSpA. Recent work suggests that children with JSpA have decreased thresholds for pain in comparison to healthy children. In addition, pain on physical examination and abnormalities on ultrasound of the entheses are not well correlated. Treatment guidelines for juvenile arthritis, including JSpA, were published by the American College of Rheumatology and are based on active joint count and presence of sacroiliitis. Recent studies have established the efficacy of tumor necrosis factor inhibitors in the symptomatic treatment of axial disease, although their efficacy for halting progression of structural damage is less clear. Newly developed disease activity measures for JSpA include the Juvenile Arthritis Disease Activity Score and the JSpA disease activity index. In comparison to other categories of juvenile arthritis, children with JSpA are less likely to attain and sustain inactive disease.

SUMMARY

Further microbiome and genetic research may help elucidate JSpA pathogenesis. More randomized therapeutic trials are needed and the advent of new composite disease activity measurement tools will hopefully allow the design of these greatly needed trials.

Enthesitis-related arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthritis of childhood. Currently, it is characterized by seven categories. The enthesitis-related arthritis (ERA) category usually affects boys older than 6 years and presents with lower limb asymmetrical arthritis associated with enthesitis. Later, these children can develop inflammatory lumbosacral pain (IBP). These children are at risk of developing acute anterior uveitis. A recently devised disease activity index, Juvenile Spondyloarthropathy Disease Activity Index (JSpADA), has been validated in retrospective cohorts. The corner stone of treatment is NSAIDs, local corticosteroid injections, and exercise. Methotrexate and sulfasalazine can be used for peripheral arthritis while anti-tumor necrosis factor (TNF) agents are sometimes used to treat refractory enthesitis and sacroiliitis. Almost two third of patients with ERA have persistent disease and often have impairments in their quality of life. The presence of hip or ankle arthritis and a family history of spondyloarthropathy or polyarticular joint involvement at onset are associated with poorer prognosis.

Enthesitis-related arthritis: time to re-define?

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood. Enthesitis-related arthritis (ERA) is one of the seven JIA subtypes classified by the International League of Associations for Rheumatology (ILAR). Due to inclusion and exclusion criteria, a pitfall of the ERA category is that it does not include all subsets of juvenile spondyloarthropathy, with many children ending up in the undifferentiated category. The ERA nomenclature also does not have a method for distinguishing between axial and peripheral disease, two phenotypes which vary in presentation and treatment requirements. This distinction is very important given the overall poor prognosis seen in ERA patients, specifically in those with axial involvement. Since axial involvement is more common and presents earlier than previously thought in ERA, the pediatric rheumatology community should develop more accurate and sensitive classification criteria based on disease course to assist in improving timely diagnosis and appropriate management.

Gut microbes, immunity, and spondyloarthritis

The last decade has witnessed an explosion of studies evaluating the impact of the human microbiota on a variety of disease states. The microbiota can impact diseases in multiple ways, including through abnormalities in the diversity and contents of the microbiota, as well as by acting as targets of immunologic dysregulation. Herein, evidence that the microbiota in spondyloarthritis is both altered and abnormally targeted by the immune system will be presented.

[Epidemiologic profile of juvenile-onset compared to adult-onset spondyloarthritis in a large Brazilian cohort]

OBJECTIVE

To analyze the clinical and epidemiologic characteristics of juvenile-onset spondyloarthritis (SpA) (< 16 years) and compare them with a group of adult-onset (≥ 16 years) SpA patients.

PATIENTS AND METHODS

Prospective, observational and multicentric cohort with 1,424 patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group (ESSG) submitted to a common protocol of investigation and recruited in 29 reference centers participants of the Brazilian Registry of Spondyloarthritis (RBE - Registro Brasileiro de Espondiloartrites). Patients were divided in two groups: age at onset<16 years (JOSpA group) and age at onset ≥ 16 years (AOSpA group).

RESULTS

Among the 1,424 patients, 235 presented disease onset before 16 years (16.5%). The clinical and epidemiologic variables associated with JOSpA were male gender (p<0.001), lower limb arthritis (p=0.001), enthesitis (p=0.008), anterior uveitis (p=0.041) and positive HLA-B27 (p=0.017), associated with lower scores of disease activity (Bath Ankylosing Spondylitis Disease Activity Index - BASDAI; p=0.007) and functionality (Bath Ankylosing Spondylitis Functional Index - BASFI; p=0.036). Cutaneous psoriasis (p<0.001), inflammatory bowel disease (p=0.023), dactylitis (p=0.024) and nail involvement (p=0.004) were more frequent in patients with adult-onset SpA.

CONCLUSIONS

Patients with JOSpA in this large Brazilian cohort were characterized predominantly by male gender, peripheral involvement (arthritis and enthesitis), positive HLA-B27 and lower disease scores.