It can develop following pneumonectomy, lung ablation, post-traumatically, or with certain types of infection.
[1][2] It may also develop when large airways are in communication with the pleural space following a large pneumothorax or other loss of pleural negative pressure, especially during positive pressure mechanical ventilation.
[3] On imaging, the diagnosis is suspected indirectly on radiograph.
Infectious causes include tuberculosis, Actinomyces israelii, Nocardia, and Blastomyces dermatitidis.
Malignancy and trauma can also result in the abnormal communication.