Lung abscess

This chapter highlights lung abscess, which is a chronic or subacute lung infection initiated by the aspiration of contaminated oropharyngeal secretions. The result is an indolent, necrotizing infection in a segmental distribution, usually dependent, limited by the pleura. Lung abscess is almost always associated with anaerobic bacteria, although the majority of infections are polymicrobial with microaerophilic and aerobic bacteria present. In contrast, necrotizing pneumonia is an acute, often fulminant, infection characterized by irregular destruction of alveolar walls and therefore multiple cavities. This infection spreads rapidly through lung tissue, frequently crossing interlobar fissures, and is often associated with pleural effusion and empyema. The duration of illness before recognition is usually only a few days. The chapter then looks at the diagnosis and therapy of anaerobic lung abscess.