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Pulmonary gangrene and the air crescent sign
1Division of Pulmonary Medicine, Bess Kaiser Medical Center, Portland, Oregon.
Background:
A study was carried out to increase familiarity with the aetiology, pathogenesis, and radiographic features that characterise pulmonary gangrene.
Patients:
Four patients with one of the disorders vasoinvasive aspergillosis, infarcted tuberculous cavity, chronic necrotising aspergillosis, and gangrene due to Pseudomonas aeruginosa were selected because they showed the variations of the typical radiographic pattern and illustrated the pathogenesis. A fifth case is also presented, in which pulmonary gangrene was simulated by the invagination of a loculated pleural effusion into the wall of a contiguous lung abscess.
Conclusions:
Evolution of a crescent or rim of air within a homogeneous shadow is the feature that both heralds the development and facilitates the recognition of pulmonary gangrene. It is most often the result of vascular thrombosis induced by the infecting organism. The outcome of treatment is often unfavourable, principally because of the severity of the predisposing systemic or local underlying disorder, although a delay in diagnosis, possibly due to unfamiliarity with the radiographic pattern, may have contributed to the adverse outcome in some instances.
Insights
Pulmonary gangrene diagnosis is aided by recognizing air crescent formation on X-rays. Early detection of this severe lung condition is crucial for better outcomes.
Area of Science:
- Pulmonology
- Radiology
- Infectious Diseases
Background:
- Pulmonary gangrene is a severe lung condition with complex etiology and pathogenesis.
- Familiarity with its radiographic features is essential for timely diagnosis and management.
Observation:
- The study reviewed five cases illustrating varied radiographic presentations of pulmonary gangrene.
- Cases included invasive aspergillosis, tuberculous cavities, chronic necrotizing aspergillosis, and Pseudomonas aeruginosa infections.
- A unique case simulated pulmonary gangrene due to pleural effusion invagination.
Findings:
- The hallmark radiographic sign heralding pulmonary gangrene is the evolution of an air crescent within a homogeneous shadow.
- This air crescent often results from vascular thrombosis caused by the infecting organism.
- Diagnosis can be delayed due to unfamiliarity with the radiographic patterns.
Implications:
- Prompt recognition of the air crescent sign is critical for early diagnosis of pulmonary gangrene.
- Treatment outcomes are often poor due to underlying severe conditions and potential diagnostic delays.
- Increased awareness of radiographic findings may improve patient outcomes for this severe lung disease.