Ultrasound evaluation of hand, wrist and foot joint synovitis in systemic lupus erythematosus.

OBJECTIVES

To assess the prevalence and severity of inflammatory abnormalities of the hand, wrist and foot joints in SLE patients by US and to correlate them with clinical, laboratory and disease activity score parameters.

METHODS

Sixty-two consecutive SLE patients were enrolled in the present study and underwent clinical evaluation, laboratory tests and bilateral high-resolution US of the hand, wrist and foot joints. Joint effusion (JE), synovial hypertrophy (SH) and local pathological vascularization [power Doppler (PD)] were evaluated according to both a dichotomous score and a semi-quantitative (0-3) grading system. In addition, a global US score was calculated by summing the values given to each elementary lesion for every single joint and every joint group. US findings were correlated with physical examination, serological parameters (CRP, ANA, anti-dsDNA, ENA, aPL, C3 and C4 serum levels) and disease activity indexes (SLEDAI-2K, ECLAM).

RESULTS

US detected inflammatory joint abnormalities in 54/62 patients (87.1%); 72.6% presented involvement of the MTP joints, 46.7% the MCP joints, 19.3% the PIP joints and 53% the wrists. A total of 1984 joints were examined highlighting JE in 19.1% of cases, SH in 6.9% and positive PD in 1.1%. The global US inflammatory score had a mean value of 10.9 (s.d. 15.2). No correlations were found between US findings and SLE disease activity parameters.

CONCLUSION

US demonstrated a high prevalence of inflammatory joint abnormalities in SLE that were also present in asymptomatic patients. Interestingly, the foot joints were the most frequently involved. US is a valuable tool for detecting subclinical synovitis in SLE.