- Cavitary lung lesions produced by infectious agents
- They may be consequences of aspiration (most commonly) or pneumonia or they may be secondary to bronchial obstruction, bronchiectasis, bacterial endocarditis or spread of infection from elsewhere in the lung
- Most abscesses are caused by mouth anaerobes in patients with pre-existing periodontal disease
- Alcoholics (most commonly), those with seizure disorders leading to aspiration and those with poor dentition are at a higher risk
- Anaerobes are most frequent cause; most lung abscesses are polymicrobial in etiology
- Streptococcus pyogenes
- Haemophilus influenzae
- Actinomyces species
- And, rarely
- Typically take 7-14 days from pneumonia to abscess formation, depending on agent
- Foul-smelling sputum production
- Night sweats
- Anorexia and weight loss
- On conventional radiography
- Cavities typically have a
- Thick-wall (which may become thinner as the surrounding inflammation resolves)
- Smooth inner margin
- Air-fluid level
- More frequent in superior segments of lower lobes or posterior segments of lower lobes
- Unlike pleural collections, lung abscesses frequently have a fluid level which is approximately the same length on both the frontal and lateral projection
- About 1/3 may have an associated empyema
- Helpful in differentiating between a lung abscess and an empyema
- Cavity may be seen as rounded with a thick wall and an air-fluid level
- Lung abscesses, being intraparenchymal, form an acute angle where they meet the chest wall
- Antibiotics for 4-6 weeks or until the chest radiograph shows resolution
- Percutaneous catheter drainage
- Surgery, either a lobectomy or pneumonectomy, may be used for patients who fail to respond to medical therapy
- With proper antibiotic treatment, over 90% are cured
- Those who are immunocompromised or have a bronchial obstruction have a high mortality rate
Lung abscess. A single, contrast-enhanced axial CT scan image of the chest shows a large cavitary lesion in the left lower lobe with a relatively thick wall(black arrows). The cavity has a smooth inner margin and an air-fluid level (white arrow). There is inflammatory reaction in the surrounding lung (yellow arrow). Notice the acute angle the abscess makes with the posterior chest wall.
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Lung Abscess. There is a thick-walled cavity with a smooth inner margin, located in the left lower lobe. An air-fluid level is present.
Lung Abscess. There is a thick-walled cavity with a smooth inner margin (red and white arrows). An air-fluid level is present (black arrow).
Lung Abscess. There is a thick-walled cavity (white arrow) with a smooth inner margin (red arrow), located in the right lung.
An air-fluid level is present (black arrow).
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Lung abscess eMedicine Sharma, S. MD, FRCPC