Role of flexible bronchoscopy in patients with sputum-negative pulmonary tuberculosis

Pulmonary tuberculosis is one of the major health concerns in the developing countries. Isolation of acid-fast bacilli (AFB) or tuberculosis bacilli from the sputum is required for the diagnosis. A proportion of suspected pulmonary tuberculosis (PTB) cases either clinically or radiologically will not produce sputum or will have sputum negative for AFB. These subsets of cases pose a diagnostic challenge to the treating clinicians. In this study, we present our experience and outcomes with flexible bronchoscopy in patients with sputum-negative pulmonary tuberculosis.

This was a prospective cross-sectional study, conducted at SDS Tuberculosis research Centre and Rajiv Gandhi Institute of Chest Diseases, Bengaluru, India, from 2010 to 2016. A total of 1095 flexible bronchoscopies were done during this period, out of which 180 were patients with sputum negative for AFB, but were strongly suspected to have pulmonary tuberculosis on clinical examination or radiologically. There were 106 males and 74 females. The age ranged between 11 and 68 years. All patients underwent complete evaluation of the tracheobronchial tree followed by bronchoalveolar lavage (BAL). Microbiological studies used were Ziehl-Neelsen (ZN) staining and culture in Lowenstein-Jensen (LJ) medium. Mucosal lesions suspected of tuberculosis were subjected to biopsy and histopathological confirmation. The data was analyzed.

Out of 180 patients, 106 (58.88%) cases had positive AFB smear on BAL. The culture confirmed the diagnosis of pulmonary tuberculosis in 120 cases (66.66%). Histopathology showed caseous granuloma in 38 (42.22%) cases, nonspecific inflammation in 40 (44.44%) cases, and malignancy in 12 (13.33%) cases out of 90 cases, who underwent biopsy. There were no post-procedural complications.

Bronchoscopy is the useful tool in the diagnosis of pulmonary tuberculosis in patients with sputum-negative pulmonary tuberculosis. It is also helpful in differentiating conditions having the clinical picture that mimics pulmonary tuberculosis.