Methods: The study included 77 patients (3 females, 74 males; mean age 23±6 years; range 18 to 52 years) with a definite diagnosis of pleural tuberculosis. Patients with a positive sputum smear or gastric lavage smear for acidfast bacilli and/or positive sputum culture or gastric lavage culture for M. tuberculosis were considered possibly infectious.

Results: When sputum and gastric lavage results were taken together, smear positivity was found in six (7.8%) and culture positivity was found in 21 cases (27.3%). Overall, 21 patients (27.3%) had bacillus-positive pulmonary tuberculosis. Chest X-ray revealed PD in 29 patients (37.7%). Highresolution computed tomography (HRCT) was performed in 55 patients and PD was found in 48 patients (87.3%). Of the patients with PD on chest radiograms, five (17.2%) had positive smears and 13 (44.8%) had positive cultures of sputum or gastric lavage. Of 48 patients without PD on chest radiograms, one (2.1%) had smear positivity and eight (16.7%) had culture positivity. Sputum or gastric lavage samples showed one smear positivity (2.1%) and 12 culture positivity (25%) among 48 patients who were found to have PD by HRCT. Of seven cases in which HRCT did not show PD, two (28.5%) had positive cultures and none had positive smears. Although HRCT was more sensitive to detect PD, infectiousness rate was significantly higher in patients who had PD on chest radiograms (p=0.007).

Conclusion: We suggest that pleural tuberculosis cases may be infectious despite lack of radiological evidence for parenchymal involvement.