Background/Purpose: Although both systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) may lead to the joint deformity, different characteristics such as the absence or the presence of bone destruction have been recognized as well: lupus arthritis is typically non-erosive and often accompanied by Jaccoud’s deformity. Therefore, we examined characteristics of joint and tendon lesions in SLE patients as compared with RA patients by using ultrasonography.

Methods: Thirteen SLE and 32 RA patients were selected from the treatment-naïve patients with joint symptoms, visiting Toho University Ohashi Medical Center between January 2011 and March 2014. Enrolled patients had at least one swollen or tender joint. The wrist, metacarpophalangeal and proximal interphalangeal joints and related extensor/flexor tendons were ultrasonographically examined from both palmar and dorsal sides. Their joints and tendons including tendon sheaths were evaluated using a gray-scale (GS) for synovial thickening and synovial fluid retention, and power Doppler (PD) for blood flow according to a semiquantitative method based on a scale of grades 0 to 3, and patients graded with GS ≥ 2 or PD ≥ 1 were judged as having joint synovitis and or tendinitis/tenosynovitis.

Results: Joint synovitis and tendinitis/tenosynovitis were observed in 11 (79%) and 12 (86%) of 13 SLE patients, respectively, and in 31 (91%) and 18 (53%) of 32 RA patients, respectively. Thus, SLE patients had tendinitis/tenosynovitis more frequently (p=0.034) as compared with RA, and particularly in the wrist joints (p=0.008, Table 1). Moreover, the concordance of joint synovitis and tendinitis/tenosynovitis in the same region was less in SLE patients (κ=0.18) as compared with RA (κ=0.44).

Conclusion: Joint synovitis was similarly observed ultrasonographically in both SLE and RA patients, while tendinitis/tenosynovitis was more frequently observed in SLE patients than in RA patients. In addition, tenosynovitis in SLE patients may develop rather independently from synovitis.