Are pleural fluid parameters related to the development of residual pleural thickening in tuberculosis?

STUDY OBJECTIVE Identification of predictive factors for the development of residual pleural thickening (RPT). DESIGN Retrospective study. LOCATION A 1,500-bed tertiary hospital. PATIENTS Patients with pleural tuberculosis diagnosed between December 1991 and February 1995 in our Respiratory Disease Service. INTERVENTIONS The clinical and radiologic characteristics, and measurements of microbiological and biochemical parameters and markers in pleural fluid were studied. RPT was defined in a posteroanterior chest radiograph as a pleural space of >2 mm measured in the lower lateral chest at the level of an imaginary line intersecting the diaphragmatic dome. MEASUREMENTS AND RESULTS In 56 patients studied, 11 (19.6%) had RPT 10 mm and 24 (42.8%) had RPT >2 mm. The pleural fluid of patients with RPT 10 mm had a significantly lower glucose concentration and pH and higher lysozyme and tumor necrosis factor-alpha levels than the other patients. The pleural fluid of patients with RPT >2 mm showed no significant differences. CONCLUSIONS The development of RPT 10 mm was related to higher concentrations of lysozyme and tumor necrosis factor-alpha and lower glucose concentration and pH in pleural fluid compared with development of lower measurements of RPT.