A case report of rheumatoid arthritis complicated with rapidly progressive interstitial pneumonia, multiple bullae and pneumomediastinum, which was successfully treated with tacrolimus.

A 64-year-old woman had been treated with prednisolone (PSL) for interstitial pneumonia (IP) of unknown origin since 1988. The IP progressed gradually, however, and home oxygen therapy was instituted in 1993. In 2002, persistent arthritis of the hands appeared and diagnosis of rheumatoid arthritis (RA) was finally established based on radiological and pathological findings. Salazosulfapyridine was given with only partial effect. On October 2002, she was hospitalized because of back pain followed by dyspnea. Chest X-ray revealed multiple giant bullae on bilateral upper lung fields, accompanied by deterioration of IP. Methyl-prednisolone pulse therapy followed by 30 mg/day of PSL was instituted and the bullae were diminished with gradual improvement of IP and synovitis. On the 55th hospital day, she complained of chest oppression, and chest X-ray revealed a complication of pneumomediastinum. Since IP was still active and serum KL-6 remained high, 3 mg/day of tacrolimus was added to control IP further and to reduce the dosage of PSL which was recognized as one of the aggravation factors of pneumomediastinum. As a result, pneumomediastinum disappeared gradually along with amelioration of IP. PSL was successfully tapered to 15 mg/day by the 87th hospital day and the patient was discharged. Although the efficacy of tacrolimus on IP complicated with polymyositis / dermatomyositis and other autoimmune diseases has been reported, this case first suggests its efficacy on IP associated with RA.