PULMONARY TUBERCULOSIS TREATED WITH DIRECTLY OBSERVED THERAPY - SERIAL CHANGES IN LUNG STRUCTURE AND FUNCTION

Objectives: (1) To correlate structure (CT) with function in pulmonary tuberculosis (TB), and (2) to describe the evolution of structural an d functional abnormalities when pulmonary TB is treated with directly observed therapy. Subjects and methods: Twenty-five patients with drug -susceptible pulmonary TB, 15 cavitary and 10 noncavitary, were studie d prospectively. Conventional CT and pulmonary function testing (spiro metry, diffusing capacity, and arterial blood gases) were performed at baseline, and after 1 and 6 months of directly observed therapy. Resu lts: All but one patient with noncavitary miliary TB had CT evidence o f endobronchial disease, and all patients with cavitary disease had co existent reduced lung attenuation, the latter presumably a result of g as trapping, hypoxic vasoconstriction, and vascular injury. Functional impairment was minimal and in proportion to the number of diseased se gments and cavitary volume. Bronchiectasis was significantly more like ly to complicate cavitary than noncavitary disease (64 vs 11%; p<0.05) . Conclusions: CT findings correlate well with function in pulmonary T B. Physiologic data were consistent with the concept that pulmonary TB is an endobronchial disease that causes parallel reductions in ventil ation and perfusion. This concurrent involvement of both airways and c ontiguous pulmonary blood supply offers an explanation for the minimal respiratory limitation experienced by these patients despite often ex tensive lung disease. Supervised therapy of drug-susceptible disease r esults in minimal structural and functional residua.