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Objective: To evaluate the prevalence and rate of a missed diagnosis of sacroiliitis on abdominal computed tomography (CT) in patients with inflammatory bowel disease (IBD). Factors associated with sacroiliitis were also assessed., Method: This retrospective study included 210 patients with IBD (mean age 31.1 years) who underwent abdominal CT. Based on a validated abdominal CT scoring tool, bilateral sacroiliac (SI) joints on abdominal CT in the whole study population were retrospectively reviewed. Subsequently, patients were classified into the 'patients with sacroiliitis' group and the 'patients without sacroiliitis' group. Univariate and multivariate regression analyses were used to clarify the factors associated with sacroiliitis., Results: Sacroiliitis was identified in 26 out of 210 patients (12.4%). However, sacroiliitis was recognized on the primary reading in only five of these 26 patients (19.2%) and was missed on the initial report in the remaining 21 patients (80.8%). Among the 21 patients, 20 (95.2%) were finally diagnosed with axial spondyloarthritis (axSpA). There was a higher prevalence of female sex (p = 0.04), upper gastrointestinal involvement (p = 0.04), and back pain (p < 0.01) in patients with sacroiliitis than in those without sacroiliitis. However, on multivariate analysis, back pain was the only factor associated with sacroiliitis (p = 0.01)., Conclusion: Physicians should carefully evaluate SI joints on abdominal CT in patients with IBD to enable early detection of sacroiliitis, potentially leading to an early diagnosis of axSpA. In addition, if patients with IBD present with back pain, the possibility of sacroiliitis should be considered.

Objective: To compare the demographic, clinical, and radiological features of patients with axial spondyloarthritis (axSpA) accompanying familial Mediterranean fever (FMF) to patients with each condition alone., Method: Hacettepe University Hospital database was screened regarding ICD-10 codes for FMF (E85.0) and axSpA (M45). The diagnosis of FMF was confirmed by Tel-Hashomer criteria, and axSpA by the presence of sacroiliitis according to the modified New York criteria or active sacroiliitis on magnetic resonance imaging. As control groups, 136 gender-matched, consequent FMF patients without axSpA and 102 consequent axSpA patients without FMF previously treated with any biological agents were included in the analysis., Results: In patients with FMF + axSpA compared to the axSpA group, age at axSpA symptom onset and age at diagnosis were lower [median with interquartile range (IQR): 21 (17-30) vs 27 (21-37), p < 0.001; 23 (21-38) vs 32 (24-43) years, p = 0.001], moderate to severe hip disease and total hip replacement were more prevalent (23.4% vs 4.7%, p < 0.001; 11.2% vs 2.8%, p = 0.016). In patients with FMF + axSpA compared to the FMF group, age at FMF symptom onset and age at diagnosis were higher [13 (6-30) vs 11 (5-18), p = 0.057; 23 (13-33) vs 18 (10-31) years, p = 0.033] and amyloidosis was more prevalent (6.6% vs 2.2%, p = 0.076). Although the M694V variant (in one or two alleles) was more prevalent in the FMF + axSpA group, the difference was not statistically significant., Conclusion: In patients with FMF + axSpA, the age of onset of axSpA was significantly earlier, moderate to severe hip involvement and amyloidosis were more common than in patients with each condition alone.

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., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Epidemiological studies have demonstrated a wide, unexplained disparity in the prevalence of juvenile idiopathic arthritis (JIA) subtypes depending on geographical location, ethnicity and other factors. Enthesitis-related arthritis (ERA) is more prevalent in Southeast Asia. Axial involvement in ERA patients is increasingly recognised to occur early in the disease course. Inflammation in the sacroiliac joint (SIJ) observed on MRI seems highly predictive of subsequent structural radiographic progression. The resulting structural damage can have significant impacts on both functional status and spinal mobility. This study aimed to evaluate the clinical characteristics of ERA in a tertiary centre in Hong Kong. The primary objective of the study was to provide a comprehensive description of the clinical course and radiological findings of the SIJ among ERA patients., Method: Paediatric patients diagnosed with JIA attending the paediatric rheumatology clinic from January 1990 to December 2020 were recruited from our registry based at the Prince of Wales Hospital., Results: In our cohort, 101 children were included. The median age of diagnosis was 11 years, interquartile range (IQR) 8-15 years. The median follow-up duration was 7 years (IQR 2-11.5 years). ERA was the most prevalent subtype (40%), followed by oligoarticular JIA (17%). Axial involvement was frequently reported in our cohort of ERA patients. 78% demonstrated radiological evidence of sacroiliitis. Among those, 81% had bilateral involvement. The median duration from disease onset to confirmation of radiological sacroiliitis was 17 months (IQR 4-62 months). Among the ERA patients, 73% had structural changes of the SIJ. Alarmingly, 70% of these patients had already developed radiological structural changes when sacroiliitis was first detected on imaging (IQR 0-12 months). Erosion was the most common finding (73%), followed by sclerosis (63%), joint space narrowing (23%), ankylosis (7%) and fatty change (3%). The duration from symptom onset to diagnosis was significantly longer in ERA patients with SIJ structural changes (9 vs 2 months, p = 0.009), comparing with those without., Conclusion: We found that a high proportion of ERA patients had sacroiliitis and a significant number of them had radiological structural changes during early disease. Our findings illustrate the importance of prompt diagnosis and early treatment in these children., (© 2023. The Author(s).)

Objective: The study aims to investigate the prevalence and neglected rate of sacroiliitis on lumbar spine computed tomography (CT) in patients with low back pain., Materials and Methods: From January 2016 to December 2020, a total of 4827 patients (mean age: 35.4 ± 9.5 years) who underwent lumbar spine CT examinations were included in this retrospective study. The CT degree of sacroiliitis in all study population were retrospectively reviewed by two radiologists. The independent sample t-test was used to compare the continuous values and chi-squared or Fisher's exact test was used to compare the categorized values., Results: Sacroiliitis was identified in 514 of 4827 patients (10.6%). Patients with sacroiliitis were significantly younger than those without sacroiliitis (32.1 ± 8.9 vs. 35.8 ± 9.5 years, p < 0.001). Moreover, significantly more patients with sacroiliitis had HLA-B27 (p < 0.001) positivity and inflammatory back pain syndrome (p = 0.003) than those without sacroiliitis. Among the 514 patients, sacroiliitis was recognized on primary reading in 386 patients (75.1%) but was neglected in the remaining 128 patients (24.9%). Of the 386 patients, 371 patients were followed up, and finally, 295 patients of them (79.5%) were diagnosed with axSpA., Conclusion: Radiologists should pay careful and more attention to sacroiliac joint on lumbar spine CT for early diagnosis of sacroiliitis in young patients with low back pain, which could result in early diagnosis and treatment of axSpA., (© 2022. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Purpose: To determine the prevalence of incidental findings on sacroiliac joint MRI and to determine the added value of MRI-based synthetic CT in the detection and evaluation of these incidental findings., Method: In this retrospective study 210 patients clinically suspected of spondyloarthritis who underwent MRI of the sacroiliac joint with synthetic CT sequence were included. The images were reviewed by two radiologists in consensus for the prevalence of sacroiliitis, incidental findings, and the ability of synthetic CT and the conventional MRI to detect and diagnose these findings., Results: In 44.7% of patients sacroiliitis was present. In 89.0% of patients MRI showed at least one incidental finding other than sacroiliitis. Degeneration of the sacroiliac joint was the most prevalent finding (140 patients, 66.6%). The most frequent incidental findings outside the sacroiliac joint were facet joint degeneration (29.0%), disc degeneration (25.2%), enostosis (19.5%) and lumbosacral transitional vertebrae (14.3%). A total of 788 lesions was recorded and synthetic CT was found to be problem solving or necessary for diagnosis in 543 (68.9%) of these lesions. 42.1% of lesions were not visible on conventional MRI (T1 TSE and STIR), most often degenerative osteophytes in the sacroiliac joint or lower lumbar spine., Conclusion: Incidental findings are seen more frequently on sacroiliac joint MRI than sacroiliitis, which is relevant as some will have clinical significance or require treatment. Nearly half of these incidental lesions were only visible on synthetic CT, which additionally has been shown to be problem solving for diagnosis in many other cases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Familial Mediterranean fever (FMF) and spondyloarthritis (SpA) may show several common signs. This study aimed to evaluate the frequency of SpA and its manifestations in FMF, the impact of SpA on FMF, and the associations of non-episodic findings (heel enthesitis, protracted arthritis, and sacroiliitis) with the FMF features. Demographic, clinical, imaging, and genetic data were retrieved from medical records of the patients with adult FMF. To identify patients who met the classification criteria for SpA, data including rheumatologic inquiry were recorded. Patients with SpA and those who did not meet the criteria were compared in terms of FMF features. Regression analyses were performed to determine the factors that were most associated with sacroiliitis, enthesitis, and protracted arthritis. Of the 283 patients with FMF, 74 (26.1%) met the SpA criteria (64 axial, 10 peripheral); and 65 (22.9%) patients had sacroiliitis, 27 (9.5%) protracted arthritis, and 61 (21.6%) heel enthesitis. Patients with SpA were older and had more FMF severity, and heel pain rate than those without; however, genetic features, CRP, resistance to colchicine, and heel enthesitis did not differ. A meaningful number of patients without SpA had also displayed heel enthesitis, protracted arthritis, inflammatory back pain, heel pain, family history of SpA, and elevated CRP. Age was found to be the main predictor of heel enthesitis and protracted arthritis was linked with FMF severity. A significant number of patients with FMF meet the peripheral SpA classification criteria as well as axial SpA. SpA and its shared manifestations with FMF may have an impact on FMF., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Isotretinoin has been reported to induce inflammatory back pain (IBP) and sacroiliitis in the patients with acne vulgaris. The aim of this study is to investigate the incidence of IBP and sacroiliitis in patients receiving isotretinoin treatment compared with oral antibiotics for acne vulgaris., Materials and Methods: A total of 201 patients with moderate-to-severe acne vulgaris who received isotretinoin (n = 100) or oral antibiotics (n = 101) were included in the study. All patients were monthly questioned for IBP symptoms during their treatment. Patients described IBP were also evaluated for sacroiliitis by c-reactive protein, sedimentation rate, HLAB27, and sacroiliac magnetic resonance imaging (MRI). Isotretinoin was discontinued in all patients diagnosed as sacroiliitis, and these patients were reevaluated after 3 months., Results: IBP was observed in 21 (10.4%), and sacroiliitis was detected in 11 (11%) patients on isotretinoin treatment; in oral antibiotic group, we did not observe IBP or sacroiliitis. The incidence of IBP and sacroiliitis differed significantly between the isotretinoin and oral antibiotic groups (p < 0.0001, p = 0.02). Complete regression was observed in the great majority of patients following cessation of isotretinoin., Conclusions: Our study is the largest prospective controlled study that investigated the incidence of sacroiliitis in patients receiving isotretinoin and compared with patients using oral antibiotics., (© 2022 Wiley Periodicals LLC.)

Objectives: Patients with Crohn's disease (CD) usually undergo magnetic resonance enterography (MRE) for evaluating small bowel involvement. Musculoskeletal symptoms are the most frequent extraintestinal manifestation in inflammatory bowel diseases, especially in CD, with sacroiliitis at imaging occurring in about 6-46% of patients and possibly correlating with axial spondyloarthritis. The primary study aim was to assess the prevalence of sacroiliitis in adult and pediatric patients with CD performing an MRE. We also evaluated the inter-rater agreement for MRE sacroiliitis and the association between sacroiliitis and patients' clinical data., Method: We retrospectively identified 100 adult and 30 pediatric patients diagnosed with CD who performed an MRE between December 2012 and May 2020 in three inflammatory bowel disease centers. Two radiologists assessed the prevalence of sacroiliitis at MRE. We evaluated the inter-rater agreement for sacroiliitis with Cohen's kappa and intraclass correlation coefficient statistics and assessed the correlation between sacroiliitis and demographic, clinical, and endoscopic data (Chi-square and Fisher's tests)., Results: The prevalence of sacroiliitis at MRE was 20% in adults and 6.7% in pediatric patients. The inter-rater agreement for sacroiliitis was substantial (k = 0.62, p < 0.001) in the adults and moderate (k = 0.46, p = 0.011) in the pediatric cohort. Age ≥ 50 years and the time between CD diagnosis and MRE (≥ 86.5 months) were significantly associated with sacroiliitis in adult patients (p = 0.049 and p = 0.038, respectively)., Conclusions: Sacroiliitis is a frequent and reliable abnormality at MRE in adult patients with CD, associated with the age of the patients ≥ 50 years and CD duration., (© 2022. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Objective: Factors predicting axial spondyloarthritis (axSpA) among first-degree relatives (FDRs) of ankylosing spondylitis (AS) patients need to be defined. We investigated the predictive value of the probands' HLA-B27 and radiographic sacroiliitis status on disease occurrence among their FDR. We also assessed the predictive value of features of the clinical history, including chronic inflammatory back pain (CIBP) and acute anterior uveitis (AAU), among the FDR and how they can be used to improve classification and diagnosis of axSpA., Methods: In 1985, we studied 363 AS probands and 806 FDR who underwent rheumatologic examination, completed questionnaires, provided blood samples for HLA-typing and underwent radiography of sacroiliac joints. At follow-up in 2018-2019, 125 patients and 360 FDR were available for study, and completed a postal questionnaire about axSpA features. FDRs were asked to report whether after 1985 they had been diagnosed by Swiss rheumatologists as having axSpA., Results: Among HLA-B27(+) FDR, axSpA occurred in 25.4%-26.3%, independent of the radiographic sacroiliitis status of the proband. AAU occurred in 13/34 (38.2%) FDR with axSpA vs 29/251 (11.6%) FDR without axSpA (p = 0.00004, OR=4.74 95% CI 2.15 to 10.47). The presence of CIBP at baseline did not predict later occurrence of axSpA but combining CIBP and pain/discomfort at the thoracic spine and at anterior (ventral) chest wall ever, assessed at follow-up in 2018-2019, provided 83.1% sensitivity and 87.2% specificity for current axSpA., Conclusion: Occurrence of AAU among FDR of axSpA probands should prompt screening for axSpA. Moreover, co-occurrence of CIBP and pain/discomfort in the thoracic spine and at anterior chest wall as a three-question tool may further enhance clinical suspicion of axSpA among these FDR., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To determine the prevalence of sacroiliitis among patients who have been referred for MR arthrography., Materials and Methods: A retrospective search identified 130 consecutive MR arthrograms of the hip performed on a 1.5T Siemens Avanto at our institution from August 2013 to August 2014. Four studies were excluded due to the absence of a coronal short tau inversion recovery sequence of the pelvis, leaving 126 studies for analysis. A musculoskeletal radiology fellow and three attending musculoskeletal radiologists reviewed the images for the presence of bone marrow edema affecting the sacroiliac joints. Only cases of bone marrow edema meeting the Assessment of SpondyloArthritis international Society definition were considered positive. The two-tailed Fisher's exact test was used to compare the prevalence of positive MRI findings among age and gender groups. GraphPad InStat (GraphPad Software) was used for statistical calculations., Results: Patients less than 40 years of age demonstrated a statistically higher prevalence of positive MRI findings of sacroiliitis when compared to patients older than 40 (p = 0.0082). No difference in prevalence was found between genders. Overall prevalence of MRI signal alteration suggestive of sacroiliitis as defined by the Assessment of SpondyloArthritis international Society was 4.8%. Among the six patients with positive findings, two were subsequently diagnosed with spondyloarthritis., Conclusion: Hip pain may be a presenting symptom of spondyloarthritis and attention should be paid to the sacroiliac joints during screening examinations, particularly in patients less than 40 years of age., (© 2021. ISS.)

Background: Takayasu arteritis (TA), a systemic large-vessel vasculitis, was reported to have high incidence of spondyloarthropathy., Purpose: To evaluate the prevalence of inflammatory sacroiliitis in patients with TA that underwent abdominal/pelvic magnetic resonance imaging (MRI) examinations as part of their vasculitis work-up., Material and Methods: Consecutive abdominal/pelvic MRI examinations of 34 patients with TA fulfilling the 1990 ACR criteria and 34 age- and gender-matched controls performed between 2008 and 2020 were retrospectively reviewed for the presence sacroiliitis. The presence of active and structural lesions was scored twice (with a one-month interval between reads) by one reader. Structural lesions were also evaluated on computed tomography, when available, and correlated to MRI findings. Clinical data were extracted from the patients' clinical files. MRI scores were compared between the study and control groups and correlated with the clinical data., Results: Sacroiliitis was evident in 11.7% of the TA group examinations compared to 0.3% in the control group ( P  = 0.6). Participants with TA had significantly more erosions and fat deposition compared to the control group (Study: 0.01/0.03, Control: 0/0, P  = 0.03/0.003, respectively). However, mean sacroiliitis score was not significantly different (Study: 1.06, Control: 0.78, P  = 0.015). Of the four patients with TA and sacroiliitis, 3 (75%) had a diagnosis of inflammatory bowel disease (IBD)., Conclusion: Sacroiliitis was detected in 11.7% of abdominal MRI examinations of patients with TA, 75% of which had associated IBD, suggesting that both IBD and sacroiliitis should be routinely screened in the TA population as their presence may influence treatment decisions.

Objectives: Osteitis condensans ilii (OCI) is a benign condition characterised by triangular sclerosis of the iliac bone which may mimic radiographic sacroiliitis. Prevalence is estimated between 0.9 and 2.5%, with female predominance, but the most recent article reporting original epidemiological data in the general population was published in 1971. The aim of our study is to contribute updated figures about prevalence of OCI in Italy., Method: A retrospective review of pelvic radiographs was conducted. Consecutive patients visiting the emergency department of our Institution between 1st January and 31st December 2020 were enrolled. Individuals with a past diagnosis of axial spondyloarthritis were excluded. Presence of OCI was evaluated by two musculoskeletal radiologists. Clinical and radiologic features such as osteoarthritis and insertional enthesopathy were also assessed., Results: We included 1047 individuals (61% female) with a median age of 74 years. OCI was present in 10 cases, accounting for a prevalence in the general population of 1.0% (95% CI 0.5-1.7). All patients with OCI were women and, in the female sample, prevalence was 1.6% (95% CI 0.7-2.8). Clinical characteristics and associated radiographic features were not different between patients with OCI and women without OCI., Conclusions: The prevalence of OCI observed in our study is consistent with previous literature, and we confirm that it is more frequently retrieved in women. Longitudinal research is warranted to elucidate the evolution, while knowledge about the disorder is needed to raise the awareness of rheumatologists and radiologists and to properly identify and report the condition. Key Points • OCI may mimic sacroiliitis and is a major differential diagnosis of radiographic axial spondyloarthritis. • Prevalence of OCI in our sample is 1.0%, in line with previous literature. • OCI predominantly affects women, and our study suggests that the disorder can be incidentally identified even after childbearing age. • Increased awareness of the characteristics of OCI can facilitate identification and reporting of the disorder., (© 2021. International League of Associations for Rheumatology (ILAR).)

Objective: To describe the prevalence of inflammatory and structural lesions using whole spine MRI in patients with psoriatic disease, and to assess their correlation with clinical features and with axial spondyloarthritis (axSpA) classification criteria., Methods: This retrospective analysis included patients with whole spine and sacroiliac joints (SIJ) MRI, selected from 2 populations: (1) active psoriatic arthritis (PsA), irrespective of axial symptoms; (2) psoriasis with confirmed or suspected PsA and axSpA symptoms. MRI spondylitis and/or sacroiliitis (MRI-SpA) was defined according to Assessment of Spondyloarthritis International Society (ASAS) consensus and by radiologist impression. Agreement between MRI-SpA and different inflammatory back pain (IBP) definitions (Berlin/ASAS/rheumatologist criteria) and the axSpA classification criteria were calculated considering MRI as gold standard. Logistic regression determined MRI-SpA-associated factors., Results: 93 patients were analysed (69.9% PsA; 30.1% psoriasis). Back pain was present in 81.7%, defined as IBP in 36.6%-57%. MRI-SpA was found in 9.7% of patients by ASAS definition and in 12.9% by radiologist impression, of which 25% had isolated spondylitis.Low agreement was found between the three IBP definitions and MRI-SpA. Rheumatologist criteria was the most sensitive (50%-55.6%) while ASAS and Berlin criteria were the most specific (61.9%-63%). axSpA criteria had poor sensitivity for MRI-SpA (22.2%-25%). Late onset of back pain or asymptomatic patients accounted for most cases with MRI-SpA not meeting axSpA or IBP criteria. Male sex was associated with MRI-SpA (OR 6.91; 95% CI 1.42 to 33.59) in multivariable regression analysis., Conclusion: Prevalence of MRI-defined axSpA was low and showed poor agreement with IBP and axSpA criteria., Competing Interests: Competing interests: LE received research grants/research support from AbbVie, Eli Lily, Janssen, Novartis, Pfizer, UCB; consultation fee from Novartis, Eli Lily, Janssen, AbbVie, Pfizer. PD, JF and IE declared no conflicts., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

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., Competing Interests: AUTHOR DISCLOSUREDrs Aeder and Onel have disclosed no financial relationships relevant to this article. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device., (© American Academy of Pediatrics, 2021. All rights reserved.)

Aim: To evaluate clinical characteristics and natural history of non-radiographic axial spondyloarthritis (nr-axSpA) using KOrean Nonradiographic Axial SPondyloArthritis (KONASPA) data., Methods: Data were collected from 11 centers in South Korea. A total of 278 patients with nr-axSpA from January 2018 to July 2020 were included. Demographic data, clinical features, comorbidities, disease activity, medications, and laboratory results were collected., Results: Mean age at symptom onset was 28.2 ± 14.2 years. Of 278 patients, 152 (54.7%) were male. Mean Bath Ankylosing Spondylitis Disease Activity Index at diagnosis was 3.5 ± 2.1. Dyslipidemia was the most common comorbidity (8.4%), followed by hypertension (6.1%). Mean age at diagnosis of nr-axSpA was older in female patients than in male patients (31.8 ± 15.8 years vs 24.9 ± 12.0 years, P < 0.001). Enthesitis and uveitis were more frequently found in female patients than in male patients. Thirty-one (11.1%) participants with nr-axSpA progressed to ankylosing spondylitis. The median follow-up duration was 48 months. In multivariable Cox regression analysis, age at symptom onset (hazard ratio [HR] 0.93, 95% confidence interval (CI) 0.88-0.97, P = 0.006), body mass index (BMI) (HR 1.24, 95% CI 1.06-1.44, P = 0.005) and sacroiliitis grade (HR 1.86, 95% CI 1.19-2.92, P = 0.006) were associated with progression to ankylosing spondylitis., Conclusions: Results of nationwide data revealed that women with nr-axSpA showed a late disease onset and more extra-articular manifestations than men. Young age at symptom onset, high BMI, and presence of radiographic sacroiliitis at diagnosis were risk factors for progression to AS., (© 2021 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Objectives: After traumatic Sacroiliac (SI) joint injury, follow up radiographic imaging can demonstrate subchondral bone resorption resembling inflammatory sacroiliitis. No studies have described the incidence of marginal SI post-traumatic osteitis, the probable temporal relationship to the initial traumatic injury, or the possible effect of unilateral hardware fixation on the contralateral SI joint., Methods: A Level 1 trauma center imaging database was queried to identify patients with pelvic bony trauma between 2005 and 2017 with CT baseline preserved SI cortication and unilateral/bilateral traumatic SI diastasis. Serial radiographs were retrospectively evaluated by 2 musculoskeletal-trained radiologists at initial, 6 weeks, 3 months and 6 months following trauma, with documentation of diastasis, subchondral resorption, and operative fixation., Results: 206 SI joints in 106 total patients met inclusion criteria. There was a statistically significant association between injury and presence of resorption at 6 weeks post-trauma for the right SI joint only. There was no other statistically significant relationship between injury and presence of resorption at any other post-trauma evaluation. There was no statistical relationship between resorption and surgical fixation. There was a statistically significant increased incidence of resorption in the post-traumatic population when compared to an atraumatic population undergoing CT pelvis study for non-SI related indications as well as compared to the incidence of inflammatory sacroiliitis in a general population., Conclusions: This study confirms an incidence of sub-acute subchondral bone resorption following traumatic joint injury above that expected for a general, non-traumatic population. Accurate interpretation of this traumatic finding minimizes inappropriate consultation and intervention for inflammatory sacroiliitis., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective : Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent, self-limited attacks of fever with serositis. Acute recurrent arthritis is the most common form of musculoskeletal involvement in FMF; however, ≤5% of FMF patients can develop chronic arthritis, including sacroiliitis. It is difficult to determine if sacroiliitis is a musculoskeletal finding of FMF or if they are concomitant diseases-FMF and juvenile spondyloarthropathy (JSpA). The present study aimed to compare clinical and laboratory findings in FMF patients with concomitant sacroiliitis and JSpA patients with concomitant sacroiliitis. Materials and Methods : The medical files of patients diagnosed with FMF and JSpA with concomitant sacroiliitis were retrospectively evaluated. All patients had MRI findings consistent with sacroiliitis. Patient demographic data, clinical features, and laboratory findings were compared between the patients with FMF and concomitant sacroiliitis, and those with JSpA and concomitant sacroiliitis. Results : The study included 18 patients with FMF and sacroiliitis, and 38 patients with JSpA and sacroiliitis. The median (range) age at diagnosis of FMF accompanied by sacroiliitis and JSpA accompanied by sacroiliitis was 12.0 years (3.5-18 years) and 13 years (4-18 years), respectively. There weren't any significant differences in HLA-B27 positivity, family history of ankylosing spondylitis, presenting complaints, arthritis, enthesitis, or treatment between the 2 patient groups. Conclusion : The present findings show that pediatric patients with FMF and sacroiliitis, and those with JSpA and sacroiliitis have the same clinical and laboratory findings.

Background/aims: Sacroiliitis is a frequent extraintestinal manifestation of inflammatory bowel diseases (IBDs). This study aimed to assess the prevalence of sacroiliitis using a validated screening tool based on abdominopelvic computed tomography (APCT) in Korean patients with Crohn's disease (CD) and examine potential associations between clinical characteristics and sacroiliitis., Methods: One hundred five patients with CD undergoing APCT for any indication at an IBD clinic were matched 1:1 for age and sex with 105 controls without underlying chronic illnesses. Using a validated APCT screening tool that defines sacroiliitis as either ankylosis or a total erosion score (TES) ≥ 3, all computed tomography scans were assessed by two independent, blinded radiologists. We compared the prevalence of sacroiliitis between CD patients and controls and clinical characteristics between CD patients with and without sacroiliitis., Results: The prevalence of sacroiliitis was significantly higher in CD patients than in controls (13.3% vs. 4.8%, p = 0.030). All subjects with sacroiliitis had a TES ≥ 3, but no ankylosis. The assessment of sacroiliitis in APCT showed excellent interreader reliability (Cohen's kappa = 0.933 for presence of sacroiliitis). Sacroiliitis in CD patients was bilateral and asymptomatic. There were no significant associations between sacroiliitis and any demographic data or clinical characteristics in these patients., Conclusion: The prevalence of APCT-detected sacroiliitis in CD patients was higher than that in controls, but the condition was asymptomatic. The clinical significance of asymptomatic sacroiliitis in Korean CD patients remains unclear.

Objective: To establish the prevalence of nonradiographic sacroiliitis within a real-life sample of patients with psoriatic arthritis (PsA), using pelvic radiographs and magnetic resonance imaging (MRI) of sacroiliac joints (SIJs)., Methods: This cross-sectional study included 107 consecutive adults with PsA (Classification Criteria for Psoriatic Arthritis criteria). Participants completed clinical and laboratory evaluation, pelvic radiographs scored for radiographic sacroiliitis according to the modified New York (mNY) criteria, and noncontrast MRI of SIJs, scored by the Berlin score and categorized into active sacroiliitis using the 2016 Assessment of Spondyloarthritis international Society (ASAS) criteria and the presence of structural sacroiliitis., Results: Radiographic sacroiliitis/mNY criteria were detected in 28.7% (n = 29), confirmed by MRI-detected structural lesions in 72.4% (n = 21). Active sacroiliitis was detected by MRI in 26% (n = 28) of patients, with 11% (n = 11) qualifying for nonradiographic sacroiliitis. Patients with radiographic and nonradiographic sacroiliitis had similar clinical characteristics, except for a longer duration of psoriasis (PsO) and PsA in the radiographic subgroup (PsO: 23.8 ± 12.5 vs 14.1 ± 11.7 yrs, P = 0.03; PsA: 12.3 ± 9.8 vs 4.7 ± 4.5 yrs, P = 0.02, respectively). Inflammatory back pain (IBP) was reported in 46.4% (n = 13) with active sacroiliitis and 27% (n = 3) with nonradiographic sacroiliitis. The sensitivity of IBP for detection of nonradiographic sacroiliitis was low (27%) and moderate for radiographic sacroiliitis (52%), whereas specificity ranged from 72% to 79% for radiographic and nonradiographic sacroiliitis, respectively., Conclusion: The prevalence of active sacroiliitis among a real-life population of patients with PsA was 26%. However, the prevalence of nonradiographic sacroiliitis was low (11%) compared to the radiographic sacroiliitis (28.7%) seen in patients with longer disease duration. IBP was not a sensitive indicator for the presence of early-stage sacroiliitis that was commonly asymptomatic., (Copyright © 2021 by the Journal of Rheumatology.)

Objective: To describe characteristics of children with enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (PsA) who were enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry., Methods: All children with ERA and those with juvenile PsA were identified. Demographic characteristics, clinical characteristics, and treatments were described. The children with sacroiliitis and those without sacroiliitis were compared. In the children with sacroiliitis, the first visit with clinically active sacroiliitis (which came first in 72% of cases) was compared to the first visit without clinically active sacroiliitis., Results: A total of 902 children with ERA or juvenile PsA were identified. Children with ERA were older at diagnosis (ages 10.8 years versus 8.2 years; P < 0.01) and were more likely to be male (56% versus 38%; P < 0.01). Polyarticular involvement was reported in 57% of children with ERA and in 72% of those with juvenile PsA. Of the children tested, HLA-B27 was positive in 38% of those in the ERA group and in 12% of those in the juvenile PsA group. At least 1 biologic was taken by 72% of those with ERA and 64% of those with juvenile PsA. Sacroiliitis (diagnosed clinically and/or by imaging) was reported in 28% of the children (40% of those with ERA and 12% of those with juvenile PsA). Of these, 54% of the children were female, 36% were HLA-B27 positive, and 81% took at least 1 biologic. In children with sacroiliitis, scores according to the physician global assessment of disease activity, parent/patient global assessment of well-being, and clinical Juvenile Arthritis Disease Activity Score 10 were all significantly worse at the first visit with clinically active sacroiliitis versus the first visit without active sacroiliitis., Conclusion: In this registry, there are more than 900 children with ERA or juvenile PsA. There was high biologic use in this population, especially in those with sacroiliitis. Further, there was equal sex representation in those children with sacroiliitis., (© 2020, American College of Rheumatology.)

Objective: Although musculoskeletal system involvement is a well-known manifestation in systemic lupus erythematosus (SLE), the probability of sacroiliac joint involvement and its effect on patients might be ignored. The aim of the study was to investigate the association between SLE and sacroiliitis and to evaluate the relationship between clinical parameters and sacroiliitis in SLE., Methods: The study was designed as a case-control study. A total of 63 patients with SLE and 31 age- and sex-matched healthy controls were included in the study. The clinical and demographic variables of the study population were documented. The sacroiliac joints of patients and controls were evaluated with sacroiliac magnetic resonance imaging. Human leukocyte antigen (HLA) B27 was assessed using flow cytometry (Beckman Coulter Navios-model 3, Beckman Coulter Inc., Brea, CA, USA). Multinomial logistic regression analysis was used to determine the clinical risk factors related to sacroiliitis., Results: Among the 63 patients, acute sacroiliitis was found in 25 patients (39.7%) and chronic sacroiliitis was found in 21 patients (33.3%). Sacroiliitis was higher in patients than in controls (p = 0.001). Acute sacroiliitis was more frequently observed in patients when compared with the control group (p = 0.001). Higher C‑reactive protein (CRP) concentrations (odds ratio = 1.75, 95% confidence interval: 1.30-2.35; p < 0.001) were found to be a risk factor for acute sacroiliitis., Conclusion: The ratio of sacroiliitis was higher in patients with SLE than in controls. Increased CRP concentrations were determined as a risk factor for acute sacroiliitis. Thus, one should keep in mind that patients with SLE and higher CRP concentrations may have sacroiliitis.

Background: Sacroiliitis is an inflammatory arthritis of the sacroiliac joints and is associated with inflammatory bowel disease (IBD). Yet, sacroiliitis often goes undiagnosed in IBD, and the clinical association between IBD disease activity and sacroiliitis is not well established. Patients with Crohn's disease (CD) often receive magnetic resonance enterography (MRE) to assess disease activity, affording clinicians the opportunity to evaluate for the presence of sacroiliitis. We aimed to identify the prevalence and disease characteristics associated with sacroiliitis in CD patients undergoing MRE., Methods: All CD patients undergoing MRE for any indication between 2014 and 2018 at an IBD referral center were identified. The MREs were reviewed for the presence of sacroiliitis based on bone marrow edema (BME) and structural lesions. We analyzed demographics, IBD characteristics, clinical and endoscopic disease activity, and management between CD patients with and without sacroiliitis., Results: Two hundred fifty-eight patients with CD underwent MRE during the study period. Overall, 17% of patients had MR evidence of sacroiliitis, of whom 73% demonstrated bone marrow edema. Female gender, back pain, and later age of CD diagnosis were associated with sacroiliitis (P = 0.05, P < 0.001, P = 0.04, respectively). Disease location and CD therapy were not associated with sacroiliitis on MRE. Clinical, endoscopic, and radiographic disease activity were not associated with sacroiliitis on MRE., Conclusion: Sacroiliitis is a common comorbid condition in CD. With limited clinical clues and disease characteristics to suggest sacroiliitis, physicians may utilize MRE to identify sacroiliitis, especially in CD patients with back pain., (© 2020 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Prevalence of sacroiliitis in Crohn's disease (CD) is variable depending on defining criteria. This study utilized standardized sacroiliac joint (SIJ) magnetic resonance imaging (MRI) to identify sacroiliitis in CD patients and its association with clinical and serological markers., Methods: Consecutive adult subjects with CD prospectively enrolled from an inflammatory bowel disease clinic underwent SIJ MRI. Data collected included CD duration, history of joint/back pain, human leukocyte antigen-B27 status, Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Disease Activity Index, Harvey Bradshaw Index (HBI) for activity of CD, Ankylosing Spondylitis Disease Activity Score, and various serologic markers of inflammation. Three blinded readers reviewed MRIs for active and structural lesions according to the Spondyloarthritis Research Consortium of Canada modules., Results: Thirty-three CD patients were enrolled: 76% female, 80% White, median age 36.4 years (interquartile range 27.2-49.0), moderate CD activity (mean HBI 8.8 ± SD 4.5). Nineteen subjects (58%) reported any back pain, 13 of whom had inflammatory back pain. Four subjects (12%) showed sacroiliitis using global approach and 6 (18%) met Assessment of SpondyloArthritis international Society MRI criteria of sacroiliitis. Older age (mean 51.2 ± SD 12.5 vs. 37.2 ± 14; P = .04), history of dactylitis (50.0% vs. 3.4%, P = .03) and worse BASMI (4.1 ± 0.7 vs. 2.4 ± 0.8, P ≤ .001) were associated with MRI sacroiliitis; no serologic measure was associated., Conclusion: There were 12%-18% of CD patients who had MRI evidence of sacroiliitis, which was not associated with back pain, CD activity or serologic measures. This data suggests that MRI is a useful modality to identify subclinical sacroiliitis in CD patients., (© 2021 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Objective: To evaluate whether the presence of psoriasis influences the clinical expression, disease activity and disease burden in both axial and peripheral phenotypes of spondyloarthritis (SpA)., Methods: Patients from the Spanish REGISPONSER registry classified as having SpA according to the ESSG criteria were included. Patients were classified as psoriatic or non-psoriatic depending on the presence of cutaneous or nail psoriasis; thereafter, they were classified as having either axial [presence of radiographic sacroiliitis OR inflammatory back pain (IBP)] or peripheral phenotype (absence of radiographic sacroiliitis AND absence of IBP AND presence of peripheral involvement). Pair-wise univariate and multivariate analyses among the four groups (psoriatic/non-psoriatic axial phenotypes and psoriatic/non-psoriatic peripheral phenotypes) were performed with adjustment for treatment intake., Results: A total of 2296 patients were included in the analysis. Among patients with axial phenotype, psoriasis was independently associated (P < 0.05) with HLA-B27+ [odds ratio (OR) 0.27], uveitis (OR 0.46), synovitis (ever) (OR 2.59), dactylitis (OR 2.78) and the use of conventional synthetic DMARDs (csDMARDs) (OR 1.47) in comparison with non-psoriatic patients. Among patients with peripheral phenotype and adjusting for csDMARD intake, psoriasis was independently associated with higher age at disease onset (OR 1.05), HLA-B27+ (OR 0.14) and heel enthesitis (OR 0.22). Higher scores for patient-reported outcomes and greater use of treatment at the time of the study visit were observed in psoriatic patients with either axial or peripheral phenotype., Conclusion: These findings suggest that, among all patients with SpA, psoriasis is associated with differences in clinical expression of SpA, a greater disease burden and increased use of drugs., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

A significant proportion of patients with spondyloarthritis (SpA) have peripheral enthesitis. Data suggest that psoriatic arthritis (PsA) patients with enthesitis have a higher disease burden than those without enthesitis. Over the past decade, there has been a proliferation of treatment options for spondyloarthropathy. These medications target multiple signaling pathways, including tumor necrosis factor (TNF), interleukin (IL)-17A, IL-12/23, IL-23, thymus (T)-cell co-stimulation, intracellular Janus kinases, and phosphodiesterase enzymes. As a key domain in SpA, enthesitis outcomes are included in pivotal trials of these agents and are reported as secondary outcome measures. One significant limitation is that the clinical evaluation of enthesitis relies on eliciting tenderness on palpation and is insensitive when compared with imaging. Furthermore, direct comparisons between studies are not available due to the use of different outcome measures, lack of consistent and comprehensive reporting outcomes, and subgroup analyses with a lower number of patients with enthesitis. This systematic review describes the epidemiology, pathophysiology, and available targeted therapies against enthesitis, as well as a detailed report of their efficacy. One major trend identified during this review is incomplete reporting of outcome measures, as many studies reported proportions of enthesitis prevalence. Factors that affected responsiveness in clinical trials included the entheseal instrument used, the number of subjects available for comparison, as well as the therapeutic agent. In general, anti-TNF and anti-IL-17 agents, as well as Janus kinase inhibitors, show moderate responsiveness for enthesitis. The data for IL-23 targeting is contradictory.

The sacroiliac joint (SIJ) is a possible source of persistent or new onset pain after lumbar or lumbosacral fusion. The aim of this paper is to systematically review and analyze the available literature related to the incidence, diagnosis and management of sacroiliitis after spinal arthrodesis. The authors independently screened the titles and abstracts of all articles identified concerning sacroiliac joint pain after lumbar or lumbosacral fusion, to assess their suitability to the research focus. The average incidence of sacroiliitis after lumbar or lumbosacral arthrodesis was found to be 37 ± 28.48 (range 6-75), increasing directly to the number of fused segments involved, especially when the sacrum is included. The most accurate evaluation is the image-guided injection of anesthetic solutions in the joint. Surgery treatment may be considered when conservative therapy fails, with open surgery or with minimally invasive SIJ fusion. Although the risk of developing SIJ degeneration is unclear, the results indicate that pain and degeneration of SIJ develop more often in patients undergoing lumbosacral fusion regardless of the number of melting segments. The treatment of sacroiliitis appears to be independent of his etiology, with or without previous instrumentation on several levels.

Objectives: Bone marrow oedema (BMO) on MRI of sacroiliac joints (SIJs) represents a hallmark of axial spondyloarthritis (SpA), yet such lesions may also occur under augmented mechanical stress in healthy subjects. We therefore sought to delineate the relationship between pregnancy/delivery and pelvic stress through a prospective study with repeated MRI. Results were matched with maternal, child and birth characteristics., Methods: Thirty-five women underwent a baseline MRI-SIJ within the first 10 days after giving birth. MRI was repeated after 6 months and, if positive for sacroiliitis according to the Assessment of SpondyloArthritis International Society (ASAS) definition, after 12 months. BMO and structural lesions were scored by three trained readers using the Spondyloarthritis Research Consortium of Canada (SPARCC) method., Results: Seventy-seven per cent of the subjects (27/35) displayed sacroiliac BMO immediately postpartum, 60% fulfilled the ASAS definition of a positive MRI. After 6 months, 46% of the subjects (15/33) still showed BMO, representing 15% (5/33) with a positive MRI. After 12 months, MRI was still positive in 12% of the subjects (4/33). Few structural lesions were detected. Intriguingly, in this study, the presence of BMO was related to a shorter duration of labour and lack of epidural anaesthesia., Conclusion: A surprisingly high prevalence of sacroiliac BMO occurs in women immediately postpartum. Our data reveal a need for a waiting period of at least 6 months to perform an MRI-SIJ in postpartum women with back pain. This study also underscores the importance of interpreting MRI-SIJ findings in the appropriate clinical context., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Sacroiliitis is commonly seen in enthesitis-related arthritis (ERA), a subtype of juvenile idiopathic arthritis (JIA). Sacroiliitis is characterized by the inflammation of the sacroiliac (SI) joints (+/- adjacent tissues). The treatment options include systemic therapy with or without corticosteroid SI joint injections. Image guided SI joint injections are frequently requested in pediatric patients with sacroiliitis. The purpose of this study was to evaluate the feasibility and efficacy of SI joint injections in children with sacroiliitis., Methods: A retrospective study of patients referred to Interventional Radiology (IR) for SI joint corticosteroid injections (2000-2018). Clinical information was collected from Electronic Patient Charts and procedural details from PACS. Efficacy was determined clinically, by MRI, or both when available., Results: 50 patients (13.8 years; M:F = 35:15) underwent image-guided SI joint corticosteroid injections. Most common indications were JIA (84%) and inflammatory bowel disease (14%). 80% had bilateral injections. 80% were performed under general anesthesia and 20% under sedation. The corticosteroid of choice was triamcinolone hexacetonide in 98% of patients. Needle guidance and confirmation was performed using CT and fluoroscopy (54%), Cone Beam CT (CBCT, 46%), with initial ultrasound assistance in 34%. All procedures were technically successful without any complications. 32/50 patients had long-term follow-up (2 years); 21/32 (66%) had clinical improvement within 3-months. Of 15 patients who had both pre- and post-procedure MRIs, 93% showed short-term improvement. At 2 years, 6% of patients were in remission, 44% continued the same treatment and 47% escalated treatment., Conclusion: Image-guided SI joint injections are safe and technically feasible in children. Imaging modalities for guidance have evolved, with CBCT being the current first choice. Most patients showed short-term clinical and imaging improvement, requiring long-term maintenance or escalation of medical treatment.

Introduction: Oral isotretinoin is commonly prescribed for acne vulgaris. Several case reports and observational studies have reported serious musculoskeletal side effects; however, the incidence, imaging findings, and longitudinal follow-up data are limited for patients who develop inflammatory back pain (IBP)., Objective: To assess the incidence of isotretinoin-triggered axial spondyloarthropathy (SpA) in acne vulgaris patients based on clinical features and MRI findings and to examine clinical and radiological outcomes following drug withdrawal., Methods: Five hundred thirteen acne patients receiving isotretinoin were screened for IBP; IBP patients were assessed for CRP, plain radiographs, and MRI of the sacroiliac joint. MRI-proven sacroiliitis was scored semi-quantitatively. Patients were followed longitudinally to assess SpA clinical course and longitudinal MRI sacroiliac joints, and CRP levels were reassessed 3 weeks after patients were symptom-free, following isotretinoin discontinuation., Results: Of the 513 patients, 23.98% developed IBP. MRI-proven sacroiliitis was detected in 42.3% of the symptomatic patients or 10.1% of the cohort. Among MRI-proven sacroiliitis cases, 51.9% fulfilled the Assessment of Spondyloarthritis International Society criteria for axial SpA. Mean CRP level was 32.05 ± 17.23 mg/L at pain onset and 3.4 ± 2.7 mg/L after symptom resolution. MRI findings completely resolved within 9 months (mean 6.27 ± 1.7) after isotretinoin discontinuation. MRI scores positively correlated with baseline CRP levels and global acne grading system score, pain, and the Ankylosing Spondylitis Disease Activity Score., Conclusion: Isotretinoin-induced axial SpA is a prevalent side effect in acne vulgaris patients. Early detection and follow-up of isotretinoin-induced sacroiliitis can be facilitated by MRI. Cessation of isotretinoin resulted in complete resolution in all affected patients.Key Points• Detection of underdiagnosed isotretinoin side effects which are common but not always correctly diagnosed and managed.• Incidence, diagnosis, and management of these side effects in a real-world setting.• This is the first large prospective longitudinal cohort study to report on axial manifestations in patients treated with isotretinoin as well as the effect of drug cessation upon the clinical, laboratory, and radiological findings.

The sacroiliac (SI) joint can be directly jeopardized by malignancy and indirectly by ergonomic changes of pelvic obliquity that introduces uneven weight distribution. Cancer treatment can exacerbate preexisting arthritis and cause diffuse arthropathies, but these are unlikely to be isolated to the SI joint. The cancer population is exposed to unique stressors that might facilitate development of SI joint pain that includes cancer itself and therapy-related complications. Like the general population, cancer patients are subject to aging and BMI and musculoskeletal structural changes that affect symmetric body functioning and posturing. No frank association between sacroiliitis and cancer has been identified. Therefore, we believe there is a need to characterize any relationship between cancer and SI joint dysfunction and pain.

The prevalence of axial spondyloarthritis (axSpA) in the published data varies significantly. Two types of axSpA can be distinguished depending upon the presence of abnormalities consistent with sacroiliitis on plain radiography: ankylosing spondylitis (AS) and nonradiographic axial SpA (nr-axSpA). The aim of this study is to perform a retrospective analysis of axSpA prevalence in Poland in the years 2008-2017. The National Health Fund (NHF) database for the period 2008-2017 was analysed. Data of all patients with the ICD-10 codes M46 (M46.1, M46.8, M46.9) or M45 (further named other inflammatory spondylopathies-OIS and AS, respectively) as the main or co-existing diagnosis were extracted and analysed. The AS prevalence was stable during the period under examination amounting to approximately 0.083%, while the OIS prevalence increased from 0.036 to 0.059%. For both men and women, the AS prevalence increased with age, reaching a maximum around the age of 70; however, in men, a marked increase in prevalence was observed earlier as compared to women (20-24 vs. 40-44 years, respectively). The OIS prevalence also increased with age; however, the maximum was reached earlier as in case of AS. Moreover, a sharp increase in OIS prevalence occurred earlier than in AS (15-19 years) with no difference between sexes. In Poland, approximately 0.1% of the population suffers from AS-the prevalence remained stable over the last decade. The prevalence of OIS increased markedly over the studied period which presumably reflects an increasing prevalence of nr-axSpA as the effect of the introduction of ASAS classification criteria for axSpA.

Background: Juvenile idiopathic arthritis (JIA) has been categorized into seven different categories according to the International League of Associations for Rheumatology (ILAR) criteria. Enthesitis-related arthritis (ERA) was found to represent the largest category in a Taiwanese cohort study. The aim in this study was to compare the clinical characteristics, treatments, and outcomes of ERA in a single tertiary center in Taiwan, as compared to those of other categories of JIA. Furthermore, we determined patients' characteristics and risk factors that can help assess the outcomes in ERA., Methods: A retrospective chart review of all patients with JIA referred to a pediatric rheumatology clinic in the National Taiwan University Hospital between 1993 and 2018 were identified according to ILAR criteria. Outcomes were assessed based on the Wallace criteria to categorize patients into active and non-active, including inactive, remission on medication, and remission off medication, groups. A subset of samples was further tested by DNA sequencing to identify HLA-B27 subtypes., Results: One-hundred and eighty-three patients were included in the study, with a mean of 8 years' follow-up. ERA was the single largest category of JIA (39.9%); psoriasis and undifferentiated JIA were both the least common type (0.5%). ERA was male predominant (86%), had a late age of onset (11.0 ± 3.2 years), and the majority of ERA patients was HLA-B27-positive (97%). Of 25 HLA-B27-positive ERA patients checked by HLA-B27 sequencing, 23 were B*27:04 and 2 were B*27:05. ERA patients were significantly less likely to achieve non-active status compared to patients with persistent oligoarthritis (P = 0.036). In terms of treatment response to TNF-α inhibitors in methotrexate-refractory ERA, 26 patients remained active and only 11 patients (30%) achieved a non-active status. Sacroiliitis was a risk factor contributing to poorer treatment response in ERA (P = 0.006)., Conclusion: ERA represented the most common category of JIA in Taiwan. Those ERA patients with sacroiliitis were likely to have persistent active disease and may require a more aggressive treatment strategy to improve their outcomes.

Objective: To explore potential subclinical involvement of the axial skeleton by magnetic resonance imaging (MRI) of the sacroiliac (SI) joints and the entire spine in patients with skin psoriasis without clinical evidence of peripheral or axial inflammation., Methods: Twenty patients with skin psoriasis but no clinical evidence of peripheral or axial inflammation and 22 healthy controls underwent standardized dermatologic and rheumatologic clinical examination and unenhanced 1.5T MRI of the SI joint and the entire spine. Two blinded readers globally assessed the presence or absence of SI joint inflammation simultaneously on T1-weighted and short tau inversion recovery MRI sequences with a confidence estimate. Bone marrow edema, fat metaplasia, erosion, and ankylosis of the SI joint, and vertebral corner inflammatory lesions and fat lesions were recorded using standardized modules. The prevalence of each lesion type was calculated in both groups, averaged across 2 readers. The number of subjects with lesions in the SI joint and spine (≥1, 2, 3, 4, or 5 lesions) as concordantly assessed by both readers was recorded., Results: The median duration of skin psoriasis was 23.0 years, the median age of patients was 48.5 years, and 25.0% of patients and 9.1% of healthy controls were concordantly classified by both readers as having SI joint inflammation (P = 0.23). The prevalence of bone marrow edema and structural lesions was comparable across patients and controls, both on SI joint and spine MRI., Conclusion: In this controlled study, patients with skin psoriasis but no clinical arthritis or spondylitis showed limited evidence of concomitant subclinical axial involvement by SI joint and spine MRI. These findings do not support routine screening for subclinical axial inflammation in patients with longstanding skin psoriasis., (© 2018, American College of Rheumatology.)

Objectives: We aimed to describe the prevalence and characteristics of peripheral enthesitis in recent onset axial spondyloarthritis, estimate the incidence of peripheral enthesitis over time, and determine the factors associated with the presence of peripheral enthesitis., Methods: 708 patients with recent onset axial spondyloarthritis were enrolled in the DESIR cohort ( prospective multi-centre, longitudinal). Data regarding the patients and spondyloarthritis characteristics at baseline with a specific focus on enthesitis and occurrence of peripheral enthesitis were collected during the five years of follow-up., Results: At inclusion, 395 patients (55.8%) reported peripheral enthesitis. The locations were mainly the plantar fascia (53.7%) and the Achilles tendon (38.5%). During the 5-year follow-up period, 109 additional patients developed peripheral enthesitis resulting in an estimated (Kaplan-Meier method) percentage of 71% (95% CI: 68-75). Variables associated with peripheral enthesitis in the univariate analysis were: older age, male gender, absence of HLA B27, MRI sacroiliitis and fulfilled Modified NY criteria, presence of anterior chest wall pain, peripheral arthritis, dactylitis, psoriasis, high BASDAI, BASFI, mean score ASAS-and the use of NSAIDs. Only the history of anterior chest wall pain and of peripheral arthritis were retained in the multivariate analysis (odds ratio (OR)=1.6 [95% confidence interval [1.1-2.3], and OR=2.1 [1.4-3.0], respectively)., Conclusions: This study highlights the high prevalence of peripheral enthesitis in recent onset axial spondyloarthritis, and suggests that in combination with peripheral arthritis, enthesitis might have an impact on the burden of the disease.

Background: Pediatric sacroiliitis (SI) is an uncommon entity of infectious or inflammatory etiology. Recent data regarding pediatric SI are scarce. The study objective was to describe and compare the clinical features of pediatric infectious and noninfectious SI., Methods: We reviewed files of children ≤18 years of age, admitted with SI in 2004-2017. Patients were grouped by etiology, infectious versus noninfectious. Clinical and laboratory indices, imaging, treatment protocols and outcome were compared., Results: Study population included 40 patients with infectious SI (range: 3-192 months, median age: 15 months, 45% female) and 13 patients with noninfectious SI (range: 30-216 months, median age: 168 months, 62% females). Duration of symptoms before admission averaged 5.9 ± 7.5 days in the infectious group and 54.2 ± 96 days in the noninfectious group (P = 0.003). Symptoms observed solely in the infectious group included refusal to stand (n = 27, 77%); walk or crawl (n = 24, 65%); irritability (n = 20, 50%) and recent constipation event (n = 8, 20%). No significant differences in laboratory results were found. Infectious SI patients had uneventful medical history, rapid response to antibiotics and a higher rate of complete resolution of symptoms without recurrences., Conclusions: An acute unilateral presentation in young patients ≤2 years of age, without chronic medical conditions, suggests an infectious etiology of SI anticipated to completely resolve with antibiotic treatment, not necessitating further workup for noninfectious etiologies.

Objectives: To document the current training, implementation and role of modern musculoskeletal imaging techniques: ultrasound, magnetic resonance imaging, computed tomography and positron emission tomography, among rheumatologists in the member countries of the EULAR., Methods: English-language questionnaires for each imaging modality developed by a EULAR task force were sent out to national and international scientific societies as well as imaging experts in the given modalities involved in research and/or training. The surveys were distributed via an online survey tool (SurveyMonkey). Simple descriptive and summary statistics were calculated from the responses., Results: More than 90% of ultrasound (US) experts reported the availability of a US unit in their department. Suspicion of rheumatoid arthritis and spondyloarthritides were the main clinical indications for performing US for diagnostic purposes. Suspicion of sacroiliitis and degenerative spine disease were the most common indications to perform magnetic resonance imaging (MRI) or computed tomography (CT) for diagnostic purposes, while positron emission tomography was mainly performed to diagnose large vessel vasculitis and to investigate fever of unknown origin. The reported percentage of rheumatologists performing US was highly variable, ranging from more than 80% in 6% of countries to less than 10% in 15% of countries. The majority of experts (77%) reported that their national rheumatology societies organise musculoskeletal US courses, while courses in MRI or CT organised by the national rheumatology societies were less commonly reported (29% and 8%, respectively)., Conclusions: Rheumatologists in Europe utilise modern imaging techniques; however, access to the techniques and training offered is varied., Competing Interests: Competing interests: None declared.

Objective: To develop treatment recommendations for children with juvenile idiopathic arthritis manifesting as non-systemic polyarthritis, sacroiliitis, or enthesitis., Methods: The Patient/Population, Intervention, Comparison, and Outcomes (PICO) questions were developed and refined by members of the guideline development teams. A systematic review was conducted to compile evidence for the benefits and harms associated with treatments for these conditions. GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to rate the quality of evidence. A group consensus process was conducted among the Voting Panel to generate the final recommendations and grade their strength. A Parent and Patient Panel used a similar consensus approach to provide patient/caregiver preferences for key questions., Results: Thirty-nine recommendations were developed (8 strong and 31 conditional). The quality of supporting evidence was very low or low for 90% of the recommendations. Recommendations are provided for the use of nonsteroidal antiinflammatory drugs, disease-modifying antirheumatic drugs, biologics, and intraarticular and oral glucocorticoids. Recommendations for the use of physical and occupational therapy are also provided. Specific recommendations for polyarthritis address general medication use, initial and subsequent treatment, and adjunctive therapies. Good disease control, with therapeutic escalation to achieve low disease activity, was recommended. The sacroiliitis and enthesitis recommendations primarily address initial therapy and adjunctive therapies., Conclusion: This guideline provides direction for clinicians, caregivers, and patients making treatment decisions. Clinicians, caregivers, and patients should use a shared decision-making process that accounts for patients' values, preferences, and comorbidities. These recommendations should not be used to limit or deny access to therapies., (© 2019, American College of Rheumatology.)

Background: Sacroiliitis, an inflammatory arthropathy associated with ankylosing spondylitis (AS), is found in patients with inflammatory bowel disease (IBD) but may go undiagnosed. The aims of this study were to assess prevalence of sacroiliitis in IBD and to determine association between clinical characteristics of IBD and sacroiliitis., Methods: Inflammatory bowel disease patients undergoing abdomino-pelvic computed tomography (CT) for any indication (2006-2015) were identified. Using standardized CT scoring, sacroiliitis was confirmed. Two blinded readers used a standardised model where presence of ankylosis or erosion score >3 indicated sacroiliitis. Inflammatory bowel disease scoring was blinded to the presence of sacroiliitis. Demographics, IBD characteristics, clinical activity (Harvey Bradshaw Index >4, Mayo >2, as denoted by attending physician), endoscopic activity (Simple Endoscopic Score for Crohn's Disease >4/Mayo subscore >1), and arthritis/extraintestinal manifestations (EIMS) were recorded. Comparisons were made between those with/without sacroiliitis., Results: Three hundred sixteen patients were included (50% male; 74% Crohn's disease [CD]). Computed tomography scoring identified 49 (16%) with sacroiliitis. Radiologists had reported sacroiliitis in 33% of these. Five patients had been to a spondylitis clinic. Thirty-three of 49 had abdominal x-rays; 64% of these fulfilled the imaging component of Modified New York criteria for AS. More than 5 sacroiliac erosions were associated with radiologist-reported sacroiliitis (P < 0.0001). There was no difference in prevalence between CD and ulcerative colitis. Sacroiliitis was associated with male sex (63.3% vs 47.9%; odds ratio [OR], 1.8; P = 0.04), known arthritis (41% vs 12%; OR, 4.7; P < 0.0001), pain as an IBD symptom (77.7% vs 56.9%; P = 0.03), and CD inflammatory phenotype (P = 0.01). Endoscopic activity, location, and extent were not associated., Conclusions: Sacroiliitis is underdiagnosed in IBD and is associated with male sex, arthritis, and inflammatory CD. Data support targeted screening in at-risk patients., (© 2018 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background/objective: Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent, self-limited attacks of fever with serositis. Various diseases were reported to be associated with FMF. The aim of this study was to investigate the frequency and characteristics of sacroiliitis in children with FMF., Methods: Files of FMF patients who had been seen in 2 reference hospitals in Ankara were retrospectively evaluated. Patients with FMF and concomitant sacroiliitis were included to the study. All patients had magnetic resonance imaging evidence of sacroiliitis., Results: Among 650 FMF patients, 17 (11 females, 6 males; mean age, 13.32 ± 4.24 years) (2.6%) of them were found to have sacroiliitis. Familial Mediterranean fever diagnosis was done prior to sacroiliitis diagnosis in 11 patients (65%) and concurrently or afterward in 6 patients (35%). Ten patients had isolated sacroiliitis, and 7 had associated diseases (5 enthesitis-related arthritis, 1 psoriatic arthritis, and 1 ulcerative colitis). Arthritis (59%), arthralgia (77%), leg pain (71%), heel pain (41%), and enthesitis (29%) were common complaints. Sacroiliac tenderness was detected in 77%, and M694V mutation in almost 90% of the patients. All patients received colchicine therapy. Additionally, 14 of them were treated with nonsteroidal anti-inflammatory drugs, 10 were on sulfasalazine treatment, and 7 of them were on biological agents., Conclusions: Sacroiliitis can be seen in patients with FMF during childhood, and M694V mutation seems to be a susceptibility factor for its development. Inflammatory low-back pain and leg and heel pain could suggest sacroiliitis.

Introduction: The prevalence of Sjögren's syndrome (SS) in patients with the diagnosis of SpA has been reported to be higher than normal population. Yet, the vice-versa is unclear. In this study, we aimed to investigate the prevalence of IBP, radiologic sacroiliitis and SpA in patients with primary SS., Methods: 85 patients followed at the rheumatology clinics of the Marmara and Kocaeli Universities with the diagnosis of primary SS between November 2011 and August 2012 were included in this study. The control group consisted of 100 age-and gender-matched patients. Inflammatory back pain and axial SpA were diagnosed according to the assessment of spondylo arthritis International Society (ASAS) criteria., Results: 83 patients were (97%) female and 2 (3%) were male. Mean age of the patients was 49.1 (±11) years. Mean disease duration was 7.3 (±4) years. The patient and control groups were comparable in terms of age and gender (p > 0.05). Inflammatory back pain was observed in 21 (24.7%) of 85 primary SS patients and in 4 (4%) of 100 control subjects (p < 0.001), radiographic sacroiliitis was demonstrated in 9 (10.5%) of primary SS patients and 2 (2%) of the control subjects (p = 0.025). Remaining SpA findings were not encountered in either group., Conclusion: inflammatory back pain and radiologic sacroiliitis is increased in patients with primary SS. Whether IBP, SI joint inflammation and radiologic sacroiliitis is due to the co-existence of SpA and primary SS or IBP is an underdiagnosed clinical feature of SS deserves further studies of large patient numbers.

Objective: There is an increasing emphasis on the early identification and treatment of ankylosing spondylitis (AS) of which the hallmark is sacroiliitis. Patients with inflammatory bowel disease (IBD) are at increased risk of AS and often receive computed tomography (CT) scans of their abdomen, affording clinicians the opportunity to determine the presence of sacroiliitis. Previous studies using CT have relied only on the radiologist's gestalt or a nonvalidated adaptation of the modified New York criteria. Our aim is to assess the prevalence of sacroiliitis in IBD using a validated screening tool and to determine how frequently these patients are referred for rheumatologic evaluation., Methods: Patients with IBD were recruited from an IBD clinic. Control patients were recruited from a urology clinic and were confirmed to be without back pain, spondylitis, psoriasis, colitis, or uveitis by chart review. CT scans were read by 2 blinded readers and sacroiliitis was defined by the presence of ankylosis or a total erosion score of ≥3., Results: CT scans were available in 233 Crohn's disease (CD) patients, 83 ulcerative colitis (UC) patients, and 108 control patients, and sacroiliitis was seen in 15%, 16.9%, and 5.6% of patients, respectively. The prevalence was higher in patients with IBD than in controls (P = 0.007), with no significant difference between CD and UC patients. Of the 49 IBD patients found to have sacroiliitis by CT scan, only 5 had been referred to a rheumatologist., Conclusion: There is a 3-fold higher prevalence of sacroiliitis in IBD compared with controls. Despite a growing awareness of this increased prevalence, many patients are not referred to a rheumatologist., (© 2017, American College of Rheumatology.)

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.

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.

Objectives: To determine the predictors of sacroiliitis detected by magnetic resonance imaging (MRI) in children with enthesitis-related arthritis., Methods: In this retrospective, longitudinal study, we retrieved clinical and laboratory data from the charts of patients with confirmed enthesitis related arthritis and evaluated their association with magnetic sacroiliitis detected at first MRI after disease onset. The MRI images of sacroiliac joints were read by 2 independent radiologists and validated against those from 25 age- and sex-matched subjects with known non-rheumatologic conditions., Results: We reviewed the clinical records of 20 patients with enthesitis-related arthritis for whom MRI images of sacroiliac joints were available. Five had bilateral MRI sacroiliitis, 3 unilateral sacroiliitis while 12 had no sacroiliitis. All MRI images of sacroiliiitis showed bone-marrow oedema but no erosions, sclerosis or sacroiliac enthesitis. Personal history of buttock pain or abnormal physical examination of sacroiliac joints predicted MRI sacroiliitis with a positive predictive value of 0.75 (95% confidence interval 0.35-0.95). In the absence of these clinical elements, MRI sacroiliitis was unlikely to be found (negative predictive value 0.83; 95% confidence interval 0.50-0.97)., Conclusion: In children with enthesitis-related arthritis the presence of buttock pain or of abnormal sacroiliac joint examination is a strong predictor of magnetic sacroiliitis., (Copyright © 2017 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.)

Background: Magnetic resonance imaging (MRI) is the most sensitive imaging modality for the detection of sacroiliitis. Diagnosing sacroiliitis on MRI is not always straightforward and can be challenging in some cases., Objectives: To evaluate the prevalence of alternative diagnoses suggested by MRI and characterize the MR appearance of the most common ones., Methods: Consecutive MRI examinations of the sacroiliac joints (SIJ) performed between 2005 and 2012 were retrospectively evaluated for the presence of structural and active sacroiliitis findings according to the Assessment of SpondyloArthritis International Society guidelines. Alternative diagnoses, including degenerative changes, diffuse idiopathic skeletal hyperostosis (DISH), Osteitis condensans ilii (OCI), septic sacroiliitis/discitis, stress reaction as well as anatomic variants, were registered., Results: We evaluated 281 MRI examinations, 116 males, 165 females, average age 44 ± 15 years. Sacroiliitis was found in 71 examinations (25%) and alternative diagnoses were suggested in 87 (31%) (OCI 8.9%, anatomic variants 5.3%, septic sacroiliitis 5.3%, degenerative findings 4.3%, diffuse idiopathic skeletal hyperostosis [DISH] 1.5%, stress reaction 0.7%, tumor 0.3%). A normal examination was found in the remaining 123 examinations. Patients with alternative diagnoses were older than those with sacroiliitis (62 vs. 47 years of age, respectively, P > 0.05). Alternative pathologies in the SIJ were significantly more common in females (66) than males (21), P < 0.05., Conclusions: A substantial proportion of patients with suspected sacroiliitis had normal SIJ while the rest were more commonly diagnosed with other pathologies. A referral by an experienced rheumatologist may improve the sensitivity and specificity of this important examination.

Background: The aim of this study was to improve knowledge of pediatric pyogenic sacroiliitis (PSI) in the pediatric population based on a consecutive case series., Method: We conducted a single-center cross-sectional study on 16 patients admitted to the emergency department of our Hospital between January 1990 and December 2015 with a confirmed diagnosis of PSI. The patients were divided into 2 groups by age: infants (6 months to 4 years) and children-adolescents (4-16 years). The features of PSI, clinical signs and symptoms, laboratory tests, bacteriologic investigations, radiologic examinations and outcome were compared among the 2 groups., Results: Patients in the children-adolescent group usually presented with a history of limping and buttock or lower back pain, and methicillin-susceptible Staphylococcus aureus was the most frequent pathogen. We observed a second peak of incidence of PSI in infants with consistent difference in clinical and microbiologic presentation. Infants were more likely to have an ambiguous onset with the refusal to bear weight as the only consistent clinical manifestations, and biologic investigations demonstrated higher erythrocyte sedimentation rate and platelet counts. However, all blood and joint fluid cultures were sterile in the infant group., Conclusion: PSI in infants and adolescents may represent 2 different conditions. Although PSI is mainly caused by S. aureus in the children-adolescent group, clinical manifestations and biologic characteristics of PSI in infants suggest Kingella kingae as the etiology osteoarticular infection. Thus, oropharyngeal swab polymerase chain reaction assay for K. kingae and magnetic resonance imaging should be considered for early diagnosis and treatment of this condition in the younger age group.

Purpose of Review: The Assessment of Spondyloarthritis International Society (ASAS) axial spondyloarthritis (axSpA) classification criteria marked a major step forward in SpA research, distinguishing axial from peripheral disease, and allowing earlier identification through MRI. This facilitated all aspects of research including epidemiology, therapeutics and patient outcomes., Recent Findings: The ASAS axSpA classification criteria have been applied broadly in research, and were validated in a recent meta-analysis of international studies. Concerns arose because of clinical differences between the clinical and imaging arms, which imply different risk for radiographic progression, and perform differently in validation studies. Low specificity of the MRI finding of sacroiliac joint bone marrow edema may lead to misclassification in populations with low axSpA prevalence. We suggest methodology to improve upon the criteria, including rigorous assessment of potential candidate criteria sets, discrete choice experiments to allow consideration of feature weights, and validation. Separately, assessment of structural and inflammatory MRI abnormalities should be performed to refine the MRI definition of sacroiliitis., Summary: The debate regarding the validation and modification of the ASAS axSpA classification criteria should lead to international efforts to build upon the gains made by these criteria, to further refine the axSpA population definitions for research and ultimately improve patient outcomes.

Background/objective: Acne vulgaris is a chronic inflammatory disease affecting the pilosebaceous unit in the skin. Isotretinoin is a synthetic vitamin A derivative regarded as the most effective agent in the treatment of acne. There have recently been increasing reports of adverse effects of isotretinoin on the skeletal system. Our aim in this study was to evaluate the rheumatic side-effects triggered by this drug, and particularly the prevalence of sacroiliitis., Materials and Methods: A total of 73 patients receiving isotretinoin due to moderate or severe acne vulgaris were included. All patients were questioned about inflammatory low back pain and musculoskeletal pains during the treatment process. Inflammatory low back pain was evaluated using Assessment of Spondyloarthritis International Society (ASAS) criteria. Patients meeting ASAS criteria were evaluated with radiography and when necessary with sacroiliac magnetic resonance., Results: The dose range for isotretinoin was between 0.4 and 0.8 mg/kg/day (mean 0.53 mg/kg/day). Treatment lasted for 6-8 months (mean 6.8 months). Lethargy was determined in 37 (50.7%) patients, myalgia in 31 (42.5%) and low back pain in 36 (49.3%). Mechanical low back pain symptoms were present in 20 of the patients describing low back pain and inflammatory low back pain in 16. Acute sacroiliitis was determined in six patients (8.2%) following a sacroiliac magnetic resonance imaging (MRI). Five (83.3%) of the patients with sacroiliitis were female and one (16.7%) was male. No statistically significant difference was determined between male and female patients in terms of prevalence of sacroiliitis (p = 0.392)., Conclusion: The incidence of sacroiliitis in patients using isotretinoin is quite high. Patients using isotretinoin must be questioned about sacroiliitis findings and must be subjected to advanced assessment when necessary. Further studies regarding the development of sacroiliitis under isotretinoin therapy are now needed.