Organizing pneumonia in a patient with rheumatoid arthritis with progression to usual interstitial pneumonia.
A 63-year-old Japanese man with a history of diabetes mellitus and a 30-pack-per-year smoking history presented with a 2-month history of polyarthralgia and bilateral reticulation on a thoracic radiograph obtained during a health examination. Upon examination, the patient had a body temperature of 36.4 C, a blood pressure of 116/71 mmHg, a heart rate of 80 beats per minute, a respiratory rate of 16 breaths per minute, and an oxygen saturation of 98% in ambient air. Auscultation revealed fine crackles at the bilateral lung bases, with no cardiac murmur or rub. There was tenderness in the bilateral shoulders, left knee, right proximal interphalangeal joints and metatarsal joints of both feet. Laboratory tests revealed elevated levels of C-reactive protein (5.77 mg/dl), rheumatoid factor (121 IU/ml), anti-citrullinated peptide antibody (57.1 U/ml) and Klebs von-6 (670 U/ml). Chest CT revealed bilateral opacities in sub-pleural areas of the lung bases (Figure 1a). The patient underwent transbronchial lung biopsy, which revealed alveoli filled with granulation tissue composed of fibroblasts and collagen, consistent with a diagnosis of organizing pneumonia (OP) (Figure 1b). The patient was diagnosed with RA associated with OP. Since naproxen only provided temporary relief from arthralgia, we treated the patient with salazosulfapyridine (1000 mg/day) and prednisolone (PSL) (30 mg/day, 0.4 mg/kg/day). Three months after the initiation of treatment, a follow-up chest CT revealed an improvement of the opacities at the lung bases (Figure 1c). We therefore reduced the PSL dose until it was stopped 1 year later. Since the arthralgia and ILD were exacerbated 9 months after PSL discontinuation, PSL (15 mg/day) was recommenced. Despite adding bucillamine, mizoribine, tacrolimus, iguratimod and abatacept to the patient’s treatment regimen, his dyspnea, arthralgia and radiological findings progressively worsened (Figure 1d) 10 years after recommencement of treatment. We were unable to reduce the PSL dose from 15 mg/day. The patient had difficulties attending our clinic, and was referred to a clinic near his residence.