Bronchoscopic, radiologic and pulmonary function evaluation of endobronchial tuberculosis

Abstract

Endobronchial tuberculosis (EBTB) causes problems in both making a diagnosis and following up the endobronchial lesion, because the lesion is not evident in simple chest radiograph. Frequently, the diagnosis and follow up of EBTB lesion during treatment mainly depend on bronchoscopy. Chest computed tomography (CT) and pulmonary function test (PFT) have also been used in evaluating EBTB and differentiating it from the other diseases. Primary purpose of the present study was to observe the change of EBTB lesion during treatment and determine the optimal time and the indication of follow-up bronchoscopy. We also evaluate the usefulness of chest CT and PFT in EBTB. Eighty-one biopsy-proven EBTB patients were enrolled from 1992 to 1997. Endobronchial tuberculosis was classified into seven subtypes: actively caseating, fibrostenotic, oedematous-hyperaemic, tumorous, ulcerative, granular, and non-specific bronchitic type according to bronchoscopic features by Chung's Classification. The change of bronchoscopic findings during treatment in each subtype of EBTB was evaluated prospectively. Follow-up bronchoscopy was done each month until there was no subsequent change in endobronchiat lesion, and every 3 months thereafter, and at the end of treatment. Chest CT and PFT were performed in 26 and 68 patients respectively, at initial bronchoscopy. Twenty-two of the 34 cases of actively caseating EBTB changed into the fibrostenotic type, and the other 12 healed without sequelae. Seven of the 11 cases of oedematous-hyperaemic EBTB changed into the fibrostenotic type, and the other four healed. Nine of the 11 cases of granular EBTB, six cases of non-specific bronchitic EBTB, and two cases of ulcerative EBTB resolved completely. However, the other two cases of granular EBTB changed into the fibrostenotic type. Seven cases of fibrostenotic EBTB did not improve despite antituberculosis chemotherapy. These various changes in bronchoscopic findings occurred within 3 months of treatment. In 10 cases of tumorous EBTB, seven progressed to the fibrostenotic type. In addition, new lesions appeared in two cases, and the size of the initial lesions increased in another two cases, even at 6 months after treatment. On chest CT findings of 26 EBTB patients, the length of bronchial involvement was measured from 10 to 55 mm. Bronchial stricture was noticed in 25 cases and the range of narrowing was from total occlusion to near normal, and there was wide variation in bronchial stricture even within same subtype of EBTB. The dominant feature of PFT in EBTB at the diagnosis was restrictive pattern. The therapeutic outcome of each subtype of EBTB can be predicted by follow-up bronchoscopy during the initial 3 months, with the exception of the tumorous type. In tumorous EBTB, the evolution of the lesions during treatment is very complicated, and bronchial stenosis may develop at a later time. Chest CT was useful in measuring the length of involved bronchus and degree of stricture in EBTB. PFT may be useful in differential diagnosis and follow up of EBTB.