Pulmonary abscess due to leflunomide use in rheumatoid arthritis: a case report

A 43-year-old woman had rheumatoid arthritis (RA) for 5 years and complained of fever, arthralgia/myalgia, and night sweating for a month. She had been receiving only leflunomide (20 mg/day) for 5 months. On admission, there was no evidence of active arthritis or vasculitic lesion. Laboratory evaluation showed an erythrocyte sedimentation rate of 145 mm/h and C-reactive protein of 160 mg/dl. All cultures were negative. Chest radiograph and computed tomography (CT) revealed a pulmonary abscess. Staphylococcus aureus multiplied in the culture of a purulent sample obtained from the abscess under ultrasonography. The leflunomide was stopped, and sultamicillin (IV 4×2 g/day) was started for a further 6 weeks. Four weeks later, the patient had completely recovered and CT showed significant improvement of the pulmonary abscess. Ten milligrams/day of prednisolone and 7.5 mg/week of methotrexate were started for RA treatment. The patient has been under control for 5 months without any further abscess or RA activation.