Bronchiectasis in active tuberculosis

Abstract

Background: Bronchiectasis in tuberculosis (TB) is usually considered chronic traction bronchiectasis associated with healed scars. However, bronchiectasis can occasionally be seen in active TB.

Purpose: To evaluate prevalence, appearance, and changes of bronchiectasis associated with active TB on computed tomography (CT).

Material and methods: A total of 391 patients with active TB who had undergone CT scans at the time of diagnosis were included in the study. Active TB was diagnosed when the sputum or the sample obtained by bronchoalveolar lavage tested positive using an acid-fast bacillus (AFB) smear test, polymerase chain reaction (PCR) test, or an AFB culture. The CT scans were reviewed focusing on bronchiectasis within consolidations or nodules. Cases with bronchiectasis beyond the consolidation or nodules were excluded from the study to exclude pre-existing traction bronchiectasis. The prevalence and appearance (cylindrical, varicose, cystic, and presence of focal erosion) of bronchiectasis and its time-dependent changes were analyzed. In addition, the presence of the feeding bronchus sign was checked. Here, the feeding bronchus sign was defined as a CT finding where the cavity communicates with the dilated airway.

Results: In 100 (25%) of the 391 patients, bronchiectasis was present within consolidations or nodules on CT. The shape of the bronchiectasis was cylindrical in all patients and focal erosions were revealed in 75 patients (75%). Nine patients had both cylindrical and varicose forms of the bronchiectasis. The feeding bronchus sign was observed in 42 patients (42%). Follow-up CT was performed on 19 of 100 patients. The bronchiectasis had progressed in 11 patients (58%), improved in four patients (21%), remained unchanged in one patient (5%), and could not be determined in the remaining three patients (16%). In nine patients, CT images prior to diagnosis were available, and in all these cases, bronchiectasis was newly developed.

Conclusion: Bronchiectasis can be seen within active inflammation in one-fourth of active TB on CT. In association with active inflammation, bronchiectasis is mostly cylindrical with focal erosions, occasionally accompanied by the feeding bronchus sign.

Keywords: CT; Infection; lung; tuberculosis.