Diagnostic implications of bronchial lavage in patients with pleural tuberculosis

The presence of Mycobacterium tuberculosis in a respiratory specimen is diagnostic in patients with pleural effusion. It is difficult to obtain sputum even after induction in these patients. An alternative method of acquiring respiratory specimens is via bronchial lavage. This study was undertaken to evaluate the diagnostic yield of acid-fast bacilli (AFB) smear, AFB culture, and Xpert assay of bronchial lavage fluid in the workup of pleural tuberculosis patients.

All patients who met the inclusion criteria of the study underwent thoracentesis, pleural biopsy, and bronchial lavage. Specimens of pleural fluid, pleural biopsy, and bronchial lavage fluid were sent for acid fast bacilli smear, culture, and Xpert assay.

Bronchial lavage AFB smear, culture, and Xpert assay was positive in 9.5%, 17.9%, and 26.2% of patients, respectively. It gave an immediate diagnosis in 22 (26.2%) patients.

Bronchial lavage, though not a surrogate to pleural biopsy, offers an additional approach to the early diagnosis of pleural tuberculosis in patients not producing sputum. Besides being diagnostic, this method also has epidemiologic significance in containing the tuberculosis epidemic because detecting Mycobacterium in bronchial lavage confirms that the patient is infectious.