CT assessment of axillary lymphadenopathy in patients with rheumatoid arthritis: association with disease activity and severity

Background Axillary lymph nodes (ALNs) are often seen on chest computed tomography (CT) in rheumatoid arthritis (RA) patients. Early reports described lymphadenopathy as one of the systemic manifestations rather than regional lymphadenopathy secondary to drainage from the affected joints. Subsequently, the importance of the immunological events occurring in draining lymph nodes in the development of arthritis was documented. Objective To identify the relationships of local disease activity and background characteristics, including systemic disease activity, systemic disease activity, with axillary lymphadenopathy (AL) in RA using CT. Methods RA patients who had undergone chest CT were retrospectively analyzed. The maximum short axis of the ALNs was measured, and the number of positive ALNs >= 5 mm was counted. Tender and swollen joints in the upper limbs were counted as indicators of local disease activity. Background characteristics and systemic disease activity were assessed based on the selected RA indicators. Correlations between AL and both local disease activity and background characteristics including systemic disease activity were analyzed. Results Of 135 patients, 58 had positive ALNs (average size 7.97 mm, range up to 15 mm). The presence of positive unilateral ALNs was correlated with the severity of ipsilateral upper limb arthritis. Multivariate analysis showed correlations between AL and both local disease activity and serological findings such as serum C-reactive protein (CRP) and immunoglobulin (Ig) G. Conclusion AL in patients with RA was correlated with local arthritis activity, as well as background characteristics and systemic disease activity.