Induced Sputum Versus Bronchoscopy in Smear Negative Pulmonary Tuberculosis

Comparison of Induced Sputum and Bronchoscopic Approach (BAL, Fluoroscopy-guided Transbronchial Biopsies) in Patients Suspected of Pulmonary Tuberculosis With Negative Direct Exam on Three Consecutive Non-induced Sputum Samples

This is a randomised study that compares different diagnostic approaches for diagnosing pulmonary tuberculosis in patients suspected of pulmonary tuberculosis in whom the three classic (non-induced) sputum samples didn't show tuberculous bacillus on direct examination. The investigators compare the sensibility of induced sputum technique with an endoscopic approach (CT-scan followed by BAL and fluoroscopy-guided transbronchial biopsies and eventually sputum collection immediately after the bronchoscopy). People in high risk population for tuberculosis undergoing screening by chest X-ray or symptomatic patients will be admitted to the hospital if their chest X-ray shows a suspicion of active tuberculosis. According good clinical practice: (non-induced) sputum samples will be taken at admission and every following morning. If direct examination and PCR of the first three classic sputum samples are negative: patients will be randomised in two groups with a different diagnostic approach (induced sputum versus endoscopic approach) The aim of our study is to proof that a thoroughgoing endoscopic approach has a higher sensibility than an induced sputum in the diagnosis of pulmonary tuberculosis in patients with a high suspicion of active tuberculosis on the chest X-ray but with a negative direct examination and/or PCR on three consecutive normal sputum samples. The investigators will include 154 patients (based on a statistical analysis for a hypothesis that the endoscopic approach has a sensibility that's twice the sensibility of the induced sputum). first arm: 2 consecutive induced sputum using an ultrasonic nebulizer. second arm: CT thorax to evaluate the exact anatomic localisation of the disease followed by fluoroscopy-guided bronchoscopy for BAL (bronchoalveolar lavage) and transbronchial biopsies. A sputum sample immediately after the endoscopy will be collected if possible.

CT thorax is done in all patients to localize the exact anatomical site of the disease. This evaluation is followed by fluoroscopy-guided bronchoscopy for BAL (bronchoalveolar lavage) and TBB (transbronchial biopsies). A sputum sample immediately after the endoscopy will be collected if possible.

Sputum induction after administration of 6-8 mL 3% NaCl aerosol by an ultrasonic nebulizer; sputum will be collected 15-30 minutes after administration of the aerosol. This process will be done twice in every patient.

Two different methods to obtain a diagnosis of pulmonary tuberculosis in patients with negative classic sputum samples are compared.

Inclusion Criteria: Patient suspected of pulmonary tuberculosis with 3 consecutive (non-induced) sputum samples negative on direct exam and PCR. Exclusion Criteria: Age < 18 Pregnancy Actual asthma exacerbation Participation to study refused by patient