SONOGRAPHIC EVALUATION OF WRIST AND HAND JOINTS AND TENDON INVOLVEMENT IN SYSTEMIC LUPUS ERYTHEMATOSUS

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple clinical manifestations, including arthropathy (mostly involving wrists, hands and knees). Articular involvement ranges from arthralgia to erosive arthropathy with functional disability. Objectives: To investigate the prevalence of wrist and hand joints involvement in SLE patients by musculoskeletal ultrasound (US). Methods: Eighty consecutive patients affected by SLE (according to the ACR criteria), referring to four different Rheumatology Units in Italy, were enrolled in the study. In each unit, US examinations were performed by a rheumatologistexperienced in musculoskeletal US, using a Logiq 9 machine (General Electrics Medical Systems, Milwaukee, WI) with a linear probe operating at 14 MHz. A multiplanar scanning technique was used to perform bilateral examination of radiocarpal (RC), intercarpal (IC), metacarpo-phalangeal (MCP) and proximal interphalangeal (PIP) joints, extensor ulnaris carpi tendon at the wris and, flexor tendons of the 2nd and 3rd fingers. Moreover, cartilage of the 2nd metacarpal head (with the MCP joint in maximal flexion) was imaged and ulna and the 2nd metacarpal bone head were evaluated for bone erosions. A semi-quantitative grading method (0 to 3) for scoring joint effusion, synovial proliferation and intra-articular power Doppler (PD) signal was used.Laboratory data (rheumatoid factor, anti-CCP antibodies, ESR, CRP, C3, C4, serum creatinine and proteinuria), as well as the presence of pericardial or pleural effusion and therapies were recorded. Results: History of actual or previous arthritis/arthralgia at wrist and/or hand at the examination time were present in 36 (45) patients. Rheumatoid factor and anti-CCP antibodies were present in 7 and 1 patient respectively. Both ESR and CRP were elevated in 25 of patients. Serum C3 and/or C4 were abnormally low in 44 of patients. Proteinuria was >1.0 g/24h in 14 patients. Pericardial and pleural effusion were observed in 15 and 10 patients, respectively. Forty five patients were on therapy with steroids, 36 with hydroxycloroquine, 14 with azatioprine, 19 with mycophenolate mofetil, 6 with cyclosporine, 6 with methotrexate, 1 with leflunomide and 1 more with cyclophosphamide. Synovitis was observed in 39 (49) patients at the wrist (at RC and IC joints in 30 and 24 patients respectively), in 35 (44) patients at the hand (31 at MCP joint and 15 at PIP joints). Tenosynovitis was visualised in 18 (22) patients (only at the wrist in 3 patients, only at the hand in 8). Structural damages were present in 13 (16) patients (erosions in 4, exclusively thinner cartilage layer in 9). We did not observe any statistically significant correlation between joint or tendon involvement and disease activity parameters, systemic involvement or disease duration. Conclusions: We detected mild signs of joint as well as tendon inflammation, the commonest joint involved being the wrist. The results of our study confirm that musculoskeletal involvement is common in SLE but usually mild with only minimal structural damages. Finally, the absence of correlation between systemic disease activity parameters and US joint findings, reinforces the importance of include musculoskeletal US examination in SLE patients.