Flexible bronchoscopy as a diagnostic tool in the evaluation of pulmonary tuberculosis in an elderly population.

Abstract

This study intends to determine what role fiberoptic bronchoscopy (FOB) plays in the diagnosis of tuberculosis (TB), particularly in a geriatric population. Cases of tuberculosis reported to the Tennessee Department of Health during the years 1989 and 1990 were divided into two age groups: Group A (< 65 years) and Group B (> or = 65 years). Natural sputum smears and cultures positive for M. tuberculosis (M. TB) in each group were compared with FOB specimens, acid-fast bacilli (AFB) smears and cultures. Data were analyzed by chi-square tests of independence for each year, then compared to determine statistical significance. Of the 601 TB cases reported to the State of Tennessee in 1989, 285 patients were in Group A and 316 in Group B. For 1990, 525 cases were reported, 269 in Group A and 256 in Group B. All cases met CDC-approved criteria for diagnosis of tuberculosis. The number of positive AFB smears and M. TB cultures were compared in each group. In cases with sputum negative but FOB specimens positive for TB, identification was made by FOB only. In Group A, 26 (9.1%) were diagnosed by FOB; only eight of these had positive sputum cultures. In Group B, 77 (24.4%) were diagnosed by FOB. Of these, 23 had positive sputum cultures; the remaining 54 patients (17.1%) had diagnoses based on FOB alone. In 1990, 269 cases of TB were reported in Group A. Of these, 38 (14.1%) were diagnosed by FOB. There were 256 TB cases reported among Group B, 83 (32.4%) of which were diagnosed by FOB. Of these 83 cases, 60 (23.4%) were diagnosed by FOB only. While no statistically significant difference was seen between the 1989 and 1990 rates of TB diagnosis by FOB for those in Group A (age < 65), the difference in rates for those in Group B (age > or = 65) was statistically significant (P < 0.05). A steady increase in the use of FOB as a diagnostic tool was noted, suggesting that a significant number (19.9%) of geriatric TB cases might have been missed without the aid of FOB. While the exact reason for its increased utilization is not known, this study indicates that FOB has become a more important source of diagnosis in pulmonary TB, particularly among the elderly.