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.