aetiology and pathogenesis
Last reviewed 01/2018
Infection and necrotic tissue are critical to the development of a lung abscess.
The organisms most commonly involved are aerobic and anaerobic streptococci, Staphylococcus aureus and a variety of different gram-negative organisms. Anaerobes normally found in the oral cavity occur exclusively in 60% of cases - including Bacteroides, Fusobacterium, and Peptococcus.
Organisms may be introduced through:
- aspiration
- antecedent primary bacterial infection
- septic emboli
- neoplasia
- other factors
Primary cryptogenic lung abscesses describe those for which no cause can be ascertained.