Abstract
Pleural involvement is the most frequent thoracic complication of rheumatoid arthritis (RA), usually occurring in patients with known RA. Typical rheumatoid pleural effusion is an exudate characterized by low pH and glucose levels and high LDH activity. Rarely, it has features of pseudochylothorax. Other uncommon complications are pneumothorax, hydropneumothorax, empyema, and bronchopleural fistula. The case of a 51-year-old man with a spontaneous, small, and asymptomatic hydropneumothorax with features of pseudochylothorax is presented. After careful clinical and laboratory evaluation, he was diagnosed with rheumatoid arthritis, and we admitted that the pleural changes were secondary to the connective tissue disease. He started immunosuppressive treatment and maintained stability during follow-up, without need of specific pleural treatment. We hypothesized that the pleural nodule found on the chest computed tomography scan was related with the simultaneous occurrence of pleural effusion and pneumothorax. This is a rare presentation and complication of RA, highlighting the utility of a comprehensive clinical and laboratory evaluation and focusing on the importance of pleural rheumatoid nodules in the pathogenesis of RA pleural disease.