Background Musculoskeletal involvement is one of the most common manifestations of SLE and, recently, different studies have demonstrated the role of MSUS in the evaluation of tendons and joints involvement in SLE patients (1). The enthesis is traditionally not included as a potential target of the inflammatory process of the disease, remaining a yet unexplored anatomical area in this cohort of patients.
Objectives To investigate the prevalence and distribution of entheseal abnormalities in SLE patients using MSUS.
Methods 30 consecutive SLE patients were enrolled in the present study. The scanned entheses were those included in the Glasgow Ultrasound Enthesitis Scoring System: the patellar insertion of the quadriceps tendon (QT), the patellar and distal insertion of the patellar tendon (PT), the calcaneal insertion of the Achilles tendon (AT) and the calcaneal insertion of the plantar fascia (PF). All patients underwent both clinical and ultrasound examination aimed at assessing the entheseal involvement. MSUS entheseal pathology was evaluated by detecting the presence of grey scale changes and power Doppler (PD) signal, as defined by the OMERACT Ultrasound Task Force (2). All the factors that may affect the MSUS findings at entheseal level (lipid profile, body mass index, history of trauma, sport activity and corticosteroid therapy) were carefully evaluated.
Results MSUS entheseal abnormalities were found in 20 out of the 30 patients (66.6%) and in 59 of the 300 entheses examined (19.6%). Patients were clinically asymptomatic in 71.4% of the cases. Among the entheses affected, the distal insertion of the PT was the most commonly involved area (37.2%), followed by the calcaneal insertion of the AT (22%) and the proximal insertion of the PT (16.9%). The patellar insertion of the QT and the calcaneal insertion of the PF were involved in the 13.5% and 10.4% of the cases respectively. With regard to the pathological changes PD signal, hypoechoic areas and entheseal thickening were the most frequently detected abnormalities (29.3%, 26.7% and 24.1%, respectively). Calcifications and bone erosions were found in 11.3% and 8.6% of the cases respectively.
Conclusions Although the inflammatory process in SLE patients is traditionally considered to be localized at synovial tissue level, this study shows that entheseal changes are not uncommon in SLE, especially at PT insertions, occurring frequently in asymptomatic patients. These preliminary results should lead to further investigations aimed at identifying the factors associated with entheseal involvement in SLE patients.
Gabba A et al. Joint and tendon involvement in systemic lupus erythematosus: an ultrasound study of hands and wrists in 108 patients. Rheumatology (Oxford). 2012 Dec; 51:2278–85.
Terslev L et al. Defining enthesitis in spondyloarthritis by ultrasound: result of a Delphi process and of a reliability reading exercise; Outcome Measures in Rheumatology Ultrasound Task Force. Arthritis Care Res 2014; 66:741–8.
Disclosure of Interest None declared