Etiological Diagnosis of Pleural Effusion by Pleural Biopsy

Pleural effusion in previously healthy, usually young adults has always posed a diagnostic problem to the medical profession. The general opinion is that 70 to 80% of such effusions represent pleural manifestations of tuberculosis¹; however, a multiplicity of etiological factors account for the other 20 to 30% of pleural effusions. Among them may be listed primary or secondary carcinoma of the lungs, bacterial or viral pneumonia, lymphoblastoma, acute rheumatic fever, nephrosis, panserositis, cirrhosis, lung abscess, congestive heart failure, pulmonary embolism, acute polyarthritis, ovarian neoplasm, blood dyscrasia, infectious mononucleosis, and cholesterol effusion.² There are considerable differences in the ability of various laboratories to demonstrate tubercle bacilli in pleural fluid bacteriologically or by guinea pig inoculation. The best of results run as high as 90%,³but, in general, 70% may be considered as excellent, with no more than 50% reported by most workers.⁴Results depend to a considerable