[A patient with Mycobacterium avium lung disease presenting with rapid, progressive and multiple cavity formation, who had been treated rheumatoid arthritis with disease modifying anti-rheumatic drugs (DMARDs)].

An 80-year-old woman presented with rapid, progressive and multiple cavitary lesions in both lungs. Rheumatoid arthritis had been diagnosed and been treated with prednisolone (5 mg/day) and bucillamine since 1996. Due to worsening of arthralgia, methotrexate (6 mg/week) and leflunomide (10 mg/day) had been added to the medication since 2003. In April 2005, her chest radiography revealed multiple cavities and nodules predominantly in both upper lung fields, although she complained of no respiratory symptoms. No pathogenic organisms were found, and the cavitary and nodular shadows were increased rapidly within the next 2 months. Therefore, the patient was referred to our hospital in July 2005. Repeat microbiologic findings of sputum were negative for bacteria and fungi, except for Mycobacterium avium (M. avium). She was given a diagnosis of M. avium lung disease, and it seemed to be associated with her compromised status caused by disease modifying anti-rheumatic drugs (DMARDs). She was then successfully treated with combined chemotherapy employed clarithromycin, rifampicin, ethambutol and streptomycin. So far, rapid and progressive deterioration of non-tuberculous mycobacterial lung disease accompanied with an intake of DMARDs had not been reported in Japan. An increase of M. avium complex lung disease in the elderly is now becoming a problem among respiratory physicians. This case highlights the fact that patients who are scheduled to be given DMARDs, particularly elderly case, should be considered to be at an elevated risk of developing non-tuberculous mycobacterial (NTM) lung disease, and the risk of NTM infection should be excluded before prescribing drugs.