Tehran University Medical Journal

Background and Aim: Tuberculous pleural effusion occurs in 30% of patients with tuberculosis (TB). Rapid diagnosis of a tuberculous pleural effusion would greatly facilitate the management of many patients. The purpose of this study was to determine sensitivity, specificity, and predictive values of clinical, laboratory, radiographic findings in patients with tuberculous pleural effusion.

Materials and Methods: The cross sectional study was performed between august 2002 and March 2004 at a referral teaching hospital. Major clinical, laboratory, and radiographic findings were evaluated in 88 cases of pleural effusion, 33 with confirmed TB pleural effusion (TBPE) and 55 with a diagnosis other than TB (NTBPE).

Results: The sensitivity of culture of pleural effusion and tissue were 3% and 9.1% respectively. The mean of adenosine deaminase (ADA) values in TBPE was 36.7 U/L (±18.72), and the mean in the NTBPE was 28.2 U/L (±17.0). Both the sensitivity and specificity of ADA estimation in diagnosing tuberculosis were 55%. The sensitivity of PCR was 3% with specificity of 12.7% (positive predictive value, 50% negative predictive value, 70%). Younger age (p<0.024), positive history of exposure to TB patient (p<0.02), and the combination of fever, weight loss and sweating (p<0.01), were associated with tuberculous pleural effusion. There were also significant association between Positive sputum smear (p<0.001), positive sputum culture (p<0.006), positive pleural biopsy (p<0.001), pleural LDH>200 (p<0.005), pleural lymphocytes>50% (p<0.015) and TBPE.

Conclusions: In our region with a high incidence of tuberculosis, the most frequent cause of exudative pleural effusion is tuberculosis. We suggest that the diagnostic planning of pleural effusion should be determined in each region with a view to the adoption of regionally optimized diagnostic and therapeutic facilities.