Legionnaires' disease in a patient with rheumatoid arthritis.

A 62-year-old male with rheumatoid arthritis (RA) who was taking nonsteroid anti-inflammatory drug for controlling synovitis developed a flare of his arthritis, hepatitis, and pneumonia due to infection with Legionella pneumophila serotype 1. Adult respiratory distress syndrome (ARDS) occurred following the development of pneumonia. After the introduction of erythromycin and ventilator support with positive end expiratory pressure (PEEP), his condition stabilized and he recovered gradually. We suggest that L. pneumophila should be considered early in the differential diagnosis of pneumonia in RA patients due to their immunocompromised status.