Diagnostic yield of fibreoptic bronchoscopy in smear negative new cases of pulmonary tuberculosis

ABSTRACT

To assess the diagnostic yield of bronchial washings for detection of AFB in clinically suspected new smear negative cases of pulmonary tuberculosis. Non-interventional analytical Combined Military Hospital Quetta and Fatima Jinnah General and Chest Hospital Quetta, Pakistan. From outpatient departments of these two hospitals, fifty smear negative new cases of pulmonary tuberculosis [PTB] were included in whom diagnosis was made on the basis of clinical findings and x-ray. All these patients underwent fibrotic bronchoscopy for collection of bronchial washings from the lobe1 segment where lesions were evident on plain chest x-ray. These secretions were sent to microbiology department for preparation of smear and detection of acid-fast bacilli [AFB] with Zeihl- Nelson staining. Out of 50 patients, 33 [66%] were males and 17 [34%] were females. On smear of bronchial washings, 21 [42%] were positive for AFB while 29 [58%] were still negative. Bronchial washings were found to have better diagnostic yield of AFB on direct smears as compared to standard sputum smear examinations. Moreover, clinical suspicion of PTB is not always correct, as significant numbers of clinically suspected cases did not yield AFB in bronchial washings. Where feasible, fibreoptic bronchoscopy and direct washings should be employed for confirming the clinical impression of PTB in smear negative cases