Pulmonary cavity is a gas-filled area of the lung in the center of a nodule or area of consolidation and may be clinically observed by use of plain chest radiography or computed tomography.
Cavitary lung lesion are solid lesions with gas filled cavities, consolidation, or masses in the lung, and can be seen on imaging studies and are caused by a variety of processes.
Cavities are present in a wide variety of infectious and noninfectious processes.
Differential diagnosis of a solitary cavitary pulmonary lesion can be divided into infectious and non-infectious causes.
Non-infectious causes can be divided into autoimmune disease and cancer.
Autoimmune disease is associated with pulmonary cavitation include granulomatosis with polyangiitis, sarcoidosis, and rheumatoid arthritis.
Both primary lung tumors in metastatic cancer can cause cavitary lung lesions.
Majority of cavitary lung lesions are caused by infections, and a list of potential pathogens is extensive, especially in immunocompromise individuals.
Infectious causes include: bacterial pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, Gram negative bacteria, and anaerobes, mycobacteria both tuberculosis or non tuberculous, fungal organisms including Histoplasma capsulatum, Blastomyces dermatitis, Coccidioides images, and Aspergillus species, and parasites including paragonimiasis, and echinococcosis.
Two infectious diseases that are commonly associated with cavities of lung tissue are Mycobacterium tuberculosis and Klebsiella pneumoniae.
The formation of cavities is due to tissue necrosis and creates an environment that allows the pathogen to expand in numbers and spread further.
On imaging, bacterial pathogens can show a cavity with a wider area of consolidation with an irregular thick wall that may be associated with an air-fluid level.
A cavity in the upper lung lobes favor the tuberculosis and present with either a smooth or irregular inner wall.
Histoplasmosis can form cavities in the upper lobes with pleural thickening. Coccidiomycosis and blastomycosis present with pulmonary infiltrates and may progress to form cavitary lesions.
Septic emboli may appear as multiple pulmonary nodules in various stages of cavitation.
The presence of cavitation in association with right middle lobe and lingular bronchiectasis and nodules often suggests nontuberculous mycobacterial disease.
The most useful tests in evaluating infectious etiology of pulmonary cavitary visions are sputum and bronchial secretions evaluation with Gram stain, acid-fast, and fungal stains along with cultures and molecular testing.
Radiographic studies are rarely definitive.
Diagnostic evaluation, must be supplemented by focused microbiological and pathological evaluations of affected sites, considering likely pathogens.
Culturing respiratory specimens obtained from patients with cavitary lung lesions for bacteria, mycobacteria, and fungi is an appropriate first step in evaluating the etiology of a cavity.
Inflammatory diseases such as rheumatoid arthritis, and granulomatosis with polyangiitis may show multiple bilateral masses with cavitation.
Rheumatoid nodules may be multiple, and may cavitate.
Lung cancers may produce isolated cavitary lung lesions in about 10-15% of cases, with squamous cell carcinoma being the most common.
Wall thickness helps distinguish cavitary lung lesions: With 92% of cavity lesions with wall thickness of 4 mm or less being benign, where is 95% of lesions with wall thickness more than 15 mm being malignant.
Treatment of cavitary pulmonary reasons is based on the underlying etiology.