Imaging in pulmonary gangrene shows multiple small cavities joining together to form a large cavity. Mycobacterial
Mycobacteria that can cause cavitations include Mycobacterium tuberculosis and nontuberculous mycobacteria, most commonly Mycobacterium avium complex. Primary tuberculosis is caused by the initial infection with Mycobacterium tuberculosis and rarely results in the formation of lung cavities. 90% of people with primary tuberculosis are able to contain the infection and enter a latent phase. Reactivation tuberculosis, which is caused by the reactivation of latent tuberculosis, results in lung cavities visible on X-ray 30 to 50% of the time. There are frequently multiple cavities, and they most commonly occur in the apical and posterior segments of the upper lobes or the superior segment of the lower lobes. Cavitary tuberculosis is associated with worse outcomes, a higher rate of treatment failure, more frequent relapse after treatment, and a higher risk of transmitting the disease to others. Even after successful treatment with anti-tuberculosis drugs, 20-50% of patients with cavitary tuberculosis have persistent cavities, which results in decreased lung function and increased risk of opportunistic infections by Aspergillus fumigatus and other fungal pathogens.Nontuberculous mycobacteria (NTM) are all mycobacterial species other than Mycobacteria tuberculosis (which causes tuberculosis) and Mycobacterium leprae (which causes leprosy). NTM are found everywhere in the environment but are most commonly found in soil and water. Lung disease is caused by inhaling or ingesting nontuberculous mycobacteria. Unlike tuberculosis, NTM infection is not transmitted from person to person.
Congenital
Congenital lung cavities, or lung cavities present at birth, include bronchogenic cysts, congenital pulmonary airway malformation, and pulmonary sequestration. These congenital lesions are the most common cause of lung cavities in infants, children, and young adults. Bronchogenic cysts are due to abnormal budding of the bronchial tree. About 70% are found in the mediastinum, which is the central part of the chest where the heart is. Another 15 to 20% are intrapulmonary (within the lung), usually in the lower lobes. Congenital pulmonary airway malformation, formerly called congenital cystic adenomatoid malformation, is a benign tumor the results in the formation of single or multiple cysts. Pulmonary sequestration refers to abnormal lung tissue that gets its blood supply from the systemic circulation instead of the pulmonary circulation, like the rest of the lung. This lung tissue is also not connected to the trachea. See also
Focal lung pneumatosis, article comparing lung blebs, bullae, cysts, and cavities


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