Reliability assessment of the definition of ultrasound enthesitis in SpA: results of a large, multicentre, international, web-based study.

OBJECTIVES: To investigate the reliability of the OMERACT US Task Force definition of US enthesitis in SpA. METHODS: In this web exercise, based on the evaluation of 101 images and 39 clips of the main entheses of the lower limbs, the elementary components included in the OMERACT definition of US enthesitis in SpA (hypoechoic areas, entheseal thickening, power Doppler signal at the enthesis, enthesophytes/calcifications, bone erosions) were assessed by 47 rheumatologists from 37 rheumatology centres in 15 countries. Inter- and intra-observer reliability of the US components of enthesitis was calculated using Light's kappa, Cohen's kappa, Prevalence And Bias Adjusted Kappa (PABAK) and their 95% CIs. RESULTS: Bone erosions and power Doppler signal at the enthesis showed the highest overall inter-reliability [Light's kappa: 0.77 (0.76-0.78), 0.72 (0.71-0.73), respectively; PABAK: 0.86 (0.86-0.87), 0.73 (0.73-0.74), respectively], followed by enthesophytes/calcifications [Light's kappa: 0.65 (0.64-0.65), PABAK: 0.67 (0.67-0.68)]. This was moderate for entheseal thickening [Light's kappa: 0.41 (0.41-0.42), PABAK: 0.41 (0.40-0.42)], and fair for hypoechoic areas [Light's kappa: 0.37 (0.36-0.38); PABAK: 0.37 (0.37-0.38)]. A similar trend was observed in the intra-reliability exercise, although this was characterized by an overall higher degree of reliability for all US elementary components compared with the inter-observer evaluation. CONCLUSIONS: The results of this multicentre, international, web-based study show a good reliability of the OMERACT US definition of bone erosions, power Doppler signal at the enthesis and enthesophytes/calcifications. The low reliability of entheseal thickening and hypoechoic areas raises questions about the opportunity to revise the definition of these two major components for the US diagnosis of enthesitis.

How normal is the enthesis by ultrasound in healthy subjects?

OBJECTIVES: To explore the prevalence of the ultrasound (US) findings of enthesitis in a group of healthy subjects. METHODS: US assessments of quadriceps, patellar and Achilles tendons, and plantar fascia entheses were performed by a rheumatologist on 82 healthy volunteers focusing on the US findings indicative of "active" inflammation according to the Outcome Measures in Rheumatology (OMERACT) definitions. RESULTS: Eight hundred and twenty entheses were evaluated in 82 healthy subjects. One or more US findings of "active" inflammation were found in at least one enthesis in 30 out of 82 subjects (34.1%), in 69 out of 820 entheses (8.4%). Entheseal thickening, hypoechogenicity and PD signal were respectively found in at least one enthesis in 23 (28.0%), 11 (13.4%) and 8 (9.8%) out of 82 subjects. Among the 69 entheses showing US features of "active" inflammation, entheseal thickening, hypoechogenicity and PD signal were found as isolated in 61 entheses and in combination in the remaining 8 (entheseal thickening and hypoechogenicity). CONCLUSIONS: Our results show a relatively high prevalence of US findings of "active" inflammation at the lower limb entheses in a group of healthy subjects, thus questioning the discriminant power of the OMERACT definitions for the diagnosis of "active" enthesitis. A combination of grey-scale and PD findings at a specific threshold to be defined could improve both the reliability and clinical usefulness of US.

Interobserver Reliability of Magnetic Resonance Imaging of Sacroiliac Joints in Axial Spondyloarthritis.

INTRODUCTION: Axial spondyloarthritis (axSpA) is characterized by damage to the axial skeleton and entheses, and is often associated with extra-articular manifestations, in the presence of the human leukocyte antigen (HLA) B27. The aim of our study is to assess the performance of rheumatologists in interpreting the inflammatory and structural damage to sacroiliac joints, in comparison to radiologists. MATERIAL AND METHODS: The present study included a total of 34 patients diagnosed with axSpA, according to the Assessment of SpondyloArthritis International Society (ASAS) criteria for axSpA, examined from January 2021 to November 2021 in the Departments of Rheumatology and Radiology and Medical Imaging of the University of Medicine and Pharmacy of Craiova. All patients underwent physical examination, laboratory tests, and magnetic resonance imaging (MRI) of the sacroiliac joints. The images were interpreted by a senior radiologist (SR), a junior radiologist (JR), a senior rheumatologist (SRh), and a junior rheumatologist (JRh), who were blinded to the clinical and paraclinical data. RESULTS: The overall κ was 0.7 for the JR (substantial agreement), 0.707 for the SRh (substantial agreement), and 0.601 for the JRh (moderate agreement), in comparison with the SR. Regarding the overall inflammatory changes, the SRh and JR were proven to have substantial agreement (κ = 0.708 and 0.742, respectively) with the SR, while the JRh was proven to have moderate agreement (κ = 0.607). The structural damage observed by the JR showed substantial agreement (κ = 0.676) with the SR, while the SRh and JRh had substantial and moderate agreement (κ = 0.705 and 0.596, respectively) with the SR. CONCLUSIONS: Our study showed substantial agreement between the senior radiologist, senior rheumatologist, and junior radiologist, and moderate agreement with the junior rheumatologist.

COVID-19-A Trigger Factor for Severe Immune-Mediated Thrombocytopenia in Active Rheumatoid Arthritis.

Thrombocytopenia is defined as a platelet count below 150,000/mm3 for adults. There is still controversy about whether individuals with platelet counts of 100,000/mm3 to 150,000/mm3 should be classified as having genuine thrombocytopenia or borderline thrombocytopenia. Thrombocytopenia is considered mild when the platelet count is between 70,000 and 150,000/mm3 and severe if the count is less than 20,000/mm3. Thrombocytopenia in rheumatoid arthritis is a rare complication, with an incidence estimated between 3 and 10%. The main etiological aspects include drug-induced thrombocytopenia and immune thrombocytopenic purpura. The most common hematological abnormalities in SARS-CoV-2 infection are lymphopenia and thrombocytopenia. It has been observed that the severity of thrombocytopenia correlates with the severity of the infection, being a poor prognosis indicator and a risk factor for mortality. COVID-19 can stimulate the immune system to destroy platelets by increasing the production of autoantibodies and immune complexes. Autoimmunity induced by viral infections can be related to molecular mimicry, cryptic antigen expression and also spreading of the epitope. During the COVID-19 pandemic, it is of great importance to include the SARS-CoV-2 infection in differential diagnoses, due to the increased variability in forms of presentation of this pathology. In this review, our aim is to present one of the most recently discovered causes of thrombocytopenia, which is the SARS-CoV-2 infection and the therapeutic challenges it poses in association with an autoimmune disease such as rheumatoid arthritis.

Reliability assessment of ultrasound muscle echogenicity in patients with rheumatic diseases: Results of a multicenter international web-based study.

Objectives: To investigate the inter/intra-reliability of ultrasound (US) muscle echogenicity in patients with rheumatic diseases. Methods: Forty-two rheumatologists and 2 radiologists from 13 countries were asked to assess US muscle echogenicity of quadriceps muscle in 80 static images and 20 clips from 64 patients with different rheumatic diseases and 8 healthy subjects. Two visual scales were evaluated, a visual semi-quantitative scale (0-3) and a continuous quantitative measurement ("VAS echogenicity," 0-100). The same assessment was repeated to calculate intra-observer reliability. US muscle echogenicity was also calculated by an independent research assistant using a software for the analysis of scientific images (ImageJ). Inter and intra reliabilities were assessed by means of prevalence-adjusted bias-adjusted Kappa (PABAK), intraclass correlation coefficient (ICC) and correlations through Kendall's Tau and Pearson's Rho coefficients. Results: The semi-quantitative scale showed a moderate inter-reliability [PABAK = 0.58 (0.57-0.59)] and a substantial intra-reliability [PABAK = 0.71 (0.68-0.73)]. The lowest inter and intra-reliability results were obtained for the intermediate grades (i.e., grade 1 and 2) of the semi-quantitative scale. "VAS echogenicity" showed a high reliability both in the inter-observer [ICC = 0.80 (0.75-0.85)] and intra-observer [ICC = 0.88 (0.88-0.89)] evaluations. A substantial association was found between the participants assessment of the semi-quantitative scale and "VAS echogenicity" [ICC = 0.52 (0.50-0.54)]. The correlation between these two visual scales and ImageJ analysis was high (tau = 0.76 and rho = 0.89, respectively). Conclusion: The results of this large, multicenter study highlighted the overall good inter and intra-reliability of the US assessment of muscle echogenicity in patients with different rheumatic diseases.

Ultrasound and clinical features of hip involvement in patients with gout.

OBJECTIVES: To investigate the prevalence of the ultrasound findings indicative of monosodium urate crystal deposits at the hip joint in patients with gout and to explore the association between the ultrasound findings and the clinical and serological features. METHODS: Bilateral ultrasound assessment of the hip joint was carried out in 40 consecutive patients with gout, diagnosed according to the latest Gout American College of Rheumatology/European League Against Rheumatism classification criteria, and 25 disease controls. Ultrasound evidence of crystal deposits was obtained using the Outcome Measures in Rheumatology definitions: hip intra-articular aggregates and/or tophi, and "double contour" sign over the hyaline cartilage of the femoral head. RESULTS: The ultrasound examination revealed crystal deposits in at least one hip in 17 out of 40 patients (42.5%) with gout, and in 2 out of 25 disease controls (8.0%) (P = 0.0029). Aggregates, tophi, and "double contour" sign were found in at least one hip in 13 (32.5%), 6 (15.0%) and 6 (15.0%) out of 40 patients with gout, respectively. A moderate association between disease duration (P = 0.004, Rpb = 0.442), number of gouty "attacks" in the previous year (P = 0.029, Rpb = 0.346), presence of subcutaneous tophi (P = 0.037, V = 0.330) and ultrasound crystal deposits was found. CONCLUSION: Our results indicate that detecting monosodium urate crystals by ultrasound is common at hip joint in patients with gout.

Hip Involvement in Patients With Calcium Pyrophosphate Deposition Disease: Potential and Limits of Musculoskeletal Ultrasound.

OBJECTIVE: To preliminarily explore the diagnostic potential of ultrasound (US) in detecting calcium pyrophosphate (CPP) crystal deposits at the hip joint in a cohort of patients with CPP deposition disease (CPPD) who were previously evaluated by conventional radiography (CR) and to assess the sensitivity and specificity as well as the agreement between US and CR in the evaluation of hip CPP crystal deposits. METHODS: Fifty consecutive patients with definite CPPD and 40 age/sex/body mass index-matched disease control subjects who had undergone hip CR within the previous 6 months were enrolled. Bilateral hip US examination was carried out to assess the presence of CCP crystal deposits at the acetabular labrum fibrocartilage and at the femoral head's hyaline cartilage. Two independent radiologists evaluated the presence of hip CPP crystal deposits on CR in both groups. RESULTS: US findings indicative of CPP crystal deposits were found in at least 1 hip in 45 of 50 patients with CPPD (90.0%) and in 73 of 100 hips (73.0%). CPP crystal deposits were more frequently found at the acetabular labrum fibrocartilage than at the femoral head's hyaline cartilage (72% and 17% of the hips in patients with CPPD, respectively). US and CR sensitivity was 90% and 86%, whereas US and CR specificity was 85% and 90%, respectively. Total agreement between the US and CR findings was 77.8%. CONCLUSION: Our results provide new evidence supporting US as a first-line, sensitive, safe, and reliable imaging technique in detecting CPP crystal deposits at the hip level.