Emphysema and bronchiectasis in COPD patients with previous pulmonary tuberculosis: computed tomography features and clinical implications

Background Pulmonary tuberculosis (PTB) is a risk factor for COPD, but the clinical characteristics and the chest imaging features (emphysema and bronchiectasis) of COPD with previous PTB have not been studied well. Methods The presence, distribution, and severity of emphysema and bronchiectasis in COPD patients with and without previous PTB were evaluated by high-resolution computed tomography (HRCT) and compared. Demographic data, respiratory symptoms, lung function, and sputum culture of Pseudomonas aeruginosa were also compared between patients with and without previous PTB. Results A total of 231 COPD patients (82.2% ex- or current smokers, 67.5% male) were consecutively enrolled. Patients with previous PTB (45.0%) had more severe (p=0.045) and longer history (p=0.008) of dyspnea, more exacerbations in the previous year (p=0.011), and more positive culture of P. aeruginosa (p=0.001), compared with those without PTB. Patients with previous PTB showed a higher prevalence of bronchiectasis (p<0.001), which was more significant in lungs with tuberculosis (TB) lesions, and a higher percentage of more severe bronchiectasis (Bhalla score ≥2, p=0.031), compared with those without previous PTB. The overall prevalence of emphysema was not different between patients with and without previous PTB, but in those with previous PTB, a higher number of subjects with middle (p=0.001) and lower (p=0.019) lobe emphysema, higher severity score (p=0.028), higher prevalence of panlobular emphysema (p=0.013), and more extensive centrilobular emphysema (p=0.039) were observed. Notably, in patients with TB lesions localized in a single lung, no difference was found in the occurrence and severity of emphysema between the 2 lungs. Conclusion COPD patients with previous PTB had unique features of bronchiectasis and emphysema on HRCT, which were associated with significant dyspnea and higher frequency of severe exacerbations. While PTB may have a local effect on bronchiectasis, its involvement in airspace damage in COPD may be extensive, probably through interactions with cigarette smoke.