To investigate the types and distribution of musculoskeletal ultrasonographic changes of the symptomatic joints, their correlations with clinical manifestations in systemic lupus erythematosus (SLE) patients, as well as the differences of ultrasonographic changes from Rhupus syndrome [SLE overlapping with rheumatoid arthritis (RA)] patients.
In the study, 114 SLE patients who complained of arthralgia or arthritis from May 2014 to August 2017 and 15 Rhupus syndrome patients were recruited for ultrasound evaluation. Ultrasound scans of the symptomatic joint areas were completed. The correlation between ultrasonographic changes and clinical characteristics was analyzed. Additionally, ultrasound changes of bilateral wrists and hands of the SLE patients were compared with those of the Rhupus syndrome patients.
In a total of the 114 SLE patients with 1 866 joints scanned, synovial hyperplasia, tenosynovitis, erosion, and osteophytes were all observed. Synovial hyperplasia was more often observed in wrists in 33.3% (23/69) patients, knees in 28.6% (12/42) patients, and ankles in 25.0% (7/28) patients. Tenosynovitis and erosion were most commonly found in shoulders in 35.0% (7/20) and 65.0% (13/20) patients. Osteophytes were more common in proximal interphalangeal (PIP) joints, elbows and knees. Among 69 patients with 22 joints (bilateral wrists and hands) scanned, 57 (82.6%) of them had ultrasonographic changes. Synovial hyperplasia was observed in 36.2% of the patients and erosion in 14.5% of the patients. The agreement between synovial hyperplasia and swollen joints in PIP was fair (κ=0.633, P<0.01), however poor in wrists between synovial hyperplasia and swollen/tender joints (κ=0.089, P=0.584). 18.4% patients with synovial hyperplasia had no tenderness or swollen clinically, while 15.8% patients with tenderness or swollen had no synovial hyperplasia on ultrasound. No correlation was found between ultrasonographic changes with the SLE disease activity index. Both synovial hyperplasia and erosion were more common in the Rhupus syndrome patients (73.3% vs. 36.2%, P=0.08; 66.7% vs. 14.5%, P=0.03) with significantly higher grey scale scores (7.4±6.4 vs. 1.6±4.1, P=0.04) than in the SLE patients.
Variety of changes could be observed by ultrasound in different joint areas of SLE patients. The ultrasonographic changes and clinical manifestations did not always correspond to each other. Synovial hyperplasia and erosion was more common in Rhupus syndrome patients.