A case of recurrent pleural effusion: Can we think beyond tuberculosis and malignancy?

Pleural effusion can occur due to a variety of causes such as infectious, neoplastic, inflammatory, autoimmune, traumatic, etc. Recurrent pleural effusions have always been a diagnostic challenge. Here, we present a case of recurrent exudative pleural effusion in a male patient, which was the first clinical manifestation of rheumatoid arthritis. Of note was the absence of articular involvement at the onset of the disease. The low glucose concentration, low pH and low C4 level in the pleural fluid were the most valuable findings to distinguish it from tuberculous and malignant pleural effusions. Pleural biopsy also helped in making such a distinction. Thus, in a patient with recurrent pleural effusion, rheumatoid etiology should also be kept in mind as a differential diagnosis