Disease-modifying antirheumatic drugs and organising pneumonia

Organising pneumonia (OP) in rheumatoid arthritis (RA) may be part of pulmonary manifestation (disease related) or disease-modifying antirheumatic drugs (DMARDs) related. We report a case series of RA patients with DMARDs related OP. A 65-year-old woman developed OP 3 weeks after initiation of methotrexate (MTX). High-resolution CT (HRCT) scan of the thorax revealed bilateral consolidations in the lung bases. She had complete radiological resolution 6 months after corticosteroid therapy with cessation of MTX. The second case was of a 60-year-old woman on MTX with recent addition of leflunomide due to flare of RA. She developed worsening cough 4 months later and HRCT scan revealed consolidation in the left upper lobe with biopsy proven OP. She responded within 6 months of corticosteroid therapy with clinical and radiological resolution. This case series highlights that OP may developed with low-dose MTX (as early as 3 weeks) and leflunomide and the diagnosis requires a high index of suspicion.