Subclinical synovitis in primary Sjögren's syndrome: an ultrasonographic study

To evaluate, by musculoskeletal ultrasound (MSUS), articular involvement in primary SS (pSS) patients by analysing hand and wrist changes, and to correlate them with clinical evaluation and laboratory tests.

Thirty-two pSS patients underwent clinical and laboratory examinations, including the SS Disease Damage Index (SSDDI) and the SS Disease Activity Index (SSDAI). MSUS was performed in all patients in both hands and wrists, evaluating the presence of inflammation within joints and periarticular tissues, and the existence of permanent joint damage. For synovial hypertrophy, joint effusion and Doppler signal findings, a semi-quantitative score (0-3) was used indicating the degree of involvement (0 = normal; 1 = mild change; 2 = moderate change; and 3 = severe change). For tenosynovitis and bone erosions, a dichotomous score (0 = absent and 1 = present) was applied.

Sonographic signs of synovitis of the radio-ulno-carpal joint were found in 17 (26.5%) out of 64 wrists. Wrist synovitis was found in 12 (37.5%) out of 32 patients. Ultrasonographic examination of the hand did not show significant changes. A statistically significant correlation was found between SSDDI score and the degree of sonographic signs of synovial proliferation in the wrist (P = 0.04). The correlation between the incidence of clinical involvement and the presence of pathological ultrasonographic findings was not significant. Patients with synovitis had a higher median age and higher median SSDDI (P = 0.004).

In pSS patients, MSUS may be considered a useful tool for detecting synovitis since articular involvement can often be silent but correlated with SSDDI.