Hand ultrasound: comparative study between "no rhupus" lupus erythematosus and rheumatoid arthritis

To compare hand US between systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients.

Hands (1st-5th metacarpophalangeal [MCP] and 1st-5th proximal interphalangeal [PIP] joints) and wrists (radiocarpal and distal radioulnar joints) of 62 "no rhupus" SLE and 60 RA patients were compared through US (linear probe, 6-18 MHz). The findings were compared to clinical, functional, serological outcomes, and disease activity indices.

2108 and 2040 joint recesses were evaluated in SLE and AR patients, respectively. Synovitis was found in 46.8% and 75% of wrists, 83.9% and 86.7% of MCPs and 58.1% and 70% of PIPs in the SLE and RA groups, respectively. More significant US findings were found in RA group. Greater values of synovitis (mm) in RA group were only found in the joint recesses of wrist (p < 0.001-0.002). In SLE group, US findings were associated with "puffy hands," Health Assessment Questionnaire score and dynamometry. Twenty-two SLE patients (35.5%) had erosion in any of joints studied. SLE patient subgroup with US erosion was associated with hematological involvement and Jaccoud's arthropathy.

US of "no rhupus" SLE and RA patients is different, especially in wrists. In SLE patients the clinical variable most associated with US findings was "puffy hands."