Organizing pneumonia in rheumatoid arthritis

Abstract

Organizing pneumonia (OP) is one of the extra-articular manifestations in rheumatoid arthritis (RA). OP is noninfectious pneumonia with less responsiveness to antibiotics, occasionally mimicking bacterial pneumonia. RA patients with OP typically experience flu-like symptoms and respiratory symptoms such as nonproductive cough and dyspnea at the onset of OP. However, some RA patients do not reveal any respiratory symptoms. The characteristics of chest imaging include bilateral/multiple consolidations or ground-glass opacities with normal lung volumes. The lung lesions are occasionally unilateral/solitary and are frequently observed in the lower zone of the lungs. In the pathophysiology of OP with RA, Th1-dominant response and pro-inflammatory cytokines are associated with the development of OP with RA. In general, intermediate-high dose of prednisolone ameliorates OP with RA. The prognosis is good for OP with RA, although OP relapse is noted in 10-20% of RA-OP cases. OP is not a direct cause of death in RA.