The diagnostic value of bronchoscopy in smear negative cases with pulmonary tuberculosis

There are many studies showing usefulness of bronchoscopy in patients with suspected pulmonary tuberculosis (Tbc) and negative sputum smear. However, there is no enough data concerning that in which cases bronchoscopy is more useful. We aimed to investigate in which cases bronchoscopy is more diagnostic and also an in which cases presence of endobronchial involvement is more likely. A total of 60 smear negative patients undergoing bronchoscopy due to tuberculosis suspicion were evaluated. The characteristics of cases with or without positive diagnosis via bronchoscopy and also of the ones with or without endobronchial involvement were compared. Bronchoscopy provided positive result for Tbc in 29 (76%) of 38 cases with confirmed as Tbc later and 7 (18%) cases had endobronchial involvement. In the cases who are diagnosed as Tbc via bronchoscopy, the mean serum levels of C-reactive protein (CRP) were significantly higher than those of undiagnosed (p< 0.05). In the cases with endobronchial involvement, the duration of symptoms was significantly shorter (p= 0.01); the diameter of tuberculin skin test induration was significantly smaller (p< 0.05); and mean serum level of CRP was significantly higher (p< 0.05) than those of without endobronchial lesion. The results suggest that it is more likely to diagnose Tbc bronchoscopically in the cases who had increased serum levels of CRP, and possibility of endobronchial involvement may be increased among the cases in active and earlier period of the disease. However, further studies are required to support this hypothesis.