Induced sputum versus fiberoptic bronchoscopy in the diagnosis of pulmonary tuberculosis

ABSTRACT

Tuberculosis still constitutes a major health problem despite advances in diagnosis and treatment. The diagnosis of TB is difficult in patients who cannot produce sputum spontaneously. This study aimed to compare between sputum induction using nebulized hypertonic saline, and fiberoptic bronchoscopy in the diagnosis of pulmonary TB, in clinically and radiologically suspected cases. Thirty suspected pulmonary tuberculosis cases were subjected to 1-Tuberculin skin test. 2-Sample collection a. Three successive spontaneous morning sputum samples, b. Sputum induction for 3 successive mornings c. Fiberoptic bronchoscopy with bronchial washing, brushing and Post-bronchoscopic sputum collection. All samples were stained with Ziehl-Neelsen stain. Induced sputum [SI] and bronchial wash were also cultured on Lowenstein-Jensen [L.J] medium. According to L J cultures there were 25[83.3%] positive bronchial wash samples VS 22[73.3%] induced sputum samples. The diagnostic yields of sputum induction and post-bronchoscopic sputum were similarly significant. Also, the yields of bronchial washing and bronchial brushing were similarly highly significant .The differences between all these procedures was non significant. The third SI sample was the most sensitive in the detection of AFB There was no significant difference between SI and Bronchial washing whether by using Z-N stain or L-J culture. Sensitivity, specificity and predictive values of different methods of specimen collection in diagnosing pulmonary TB gave non-significantly different results. Sputum induction is an easy, cheap and non invasive procedure that has a significantly high diagnostic yield for clinically and radiologically suspected cases of pulmonary tuberculosis who have dry cough or whose sputum for three successive days are negative. The third SI sample is the most significant one. There is no significant difference between SI and FOB using any of its procedures