The prevalence of pulmonary parenchymal tuberculosis in patients with tuberculous pleuritis

STUDY OBJECTIVE: To examine the prevalence and characteristics of parenchymal tuberculous pleuritis in adult patients. DESIGN: Prospective cohort study. SETTING: Three hospitals affiliated with Seoul National University in South Korea. PATIENTS: All patients > 15 years old with a diagnosis of tuberculous pleuritis were enrolled prospectively between January 1, 2004, and October 31, 2004. INTERVENTIONS: Diagnostic thoracocentesis and CT of the chest were done for each patient. Acid-fast bacilli (AFB) smears and cultures for Mycobacterium tuberculosis were requested if patients produced any sputum. A board-certified radiologist reviewed the chest radiographs for the presence and characteristics of any lesions. MEASUREMENTS AND RESULTS: One hundred six patients with tuberculous pleuritis were enrolled (median age, 53 years; range 16 to 89 years). Among them, 33 patients (31%) had sputum or bronchial washing findings positive for AFB smears or for M tuberculosis by culture. Lung parenchymal lesions were observed in 91 of the patients (86%) using chest CT; 39 patients (37%) with parenchymal lesions had radiographic characteristics of active pulmonary tuberculosis. In total, 62 patients (59%) had bacteriologically or radiographically active pulmonary tuberculosis. In addition, 78 patients (74%) had features of reactivated pulmonary tuberculosis. CONCLUSIONS: Lung parenchymal lesions were more common in this series of patients with tuberculous pleuritis than has been reported in previous studies. The patients mostly had radiographic features of reactivated, rather than primary, tuberculosis