GRANULOMATOUS DISEASES OF THE PLEURA

Granulomatous disease of the pleura is most often due to tuberculosis, which should be a major consideration in the evaluation of a chronic undiagnosed effusion. Good approaches to the work-up of such effusions are described elsewhere and will be summarized here. The causes of granulomatous pleural disease frequently have similar clinical and radiographic presentations and, like neoplastic involvement of the pleura, the pleural fluids are often lymphocytic exudates. In the case of such effusions, Gram, acid fast, and fungal stains of pleural fluid and sputum should be done. The pleural fluid should be submitted for cytology. Aerobic, anaerobic, mycobacterial, and fungal cultures should be done. If no diagnosis is obtained after the initial thoracentesis, a second aspiration of pleural fluid with pleural biopsies should be done. A PPD should also be done and a fungal serology panel and pleural fluid cryptococcal antigen should also be considered. A perfusion lung scan or angiogram should be done to exclude pulmonary embolus. If there is not diagnosis after these studies, patients with a positive tuberculin test can be given interim antituberculous treatment pending the mycobacterial culture results. If the PPD is initially negative and remains so on repeat testing at six weeks, clinical follow-up off antituberculous medication is reasonable, provided that the patient is not anergic. If the PPD becomes positive at repeat testing, the patients should be treated for tuberculosis. If the diagnosis remains uncertain, the PPD as well as all cultures prove negative and the effusion resolves on follow-up, no further studies are needed. If the effusion persists or increases in size, additional invasive studies, including repeat pleural biopsy, thoracoscopy or open biopsy may be needed to establish a diagnosis. If the problem is an underlying pleural malignancy, the delay in diagnosis carries little consequence for the patient as these are virtually all incurable. In some cases, the diagnosis will not be established after open pleural biopsy, suggesting that these effusions may be of viral origin.