Lung Abscess
A lung abscess is a localised collection of pus within necrotic lung parenchyma, commonly following aspiration of oral flora; it presents subacutely with fever and purulent or foul sputum, and requires prolonged specialist antimicrobial treatment while excluding empyema, obstruction, malignancy, tuberculosis and septic emboli.
Definition
A lung abscess is a circumscribed collection of pus within necrotic lung parenchyma, usually caused by infection and often communicating with a bronchus to produce an air-fluid level. It is distinct from empyema, which is infected fluid in the pleural space.
First principles
Necrotising infection creates a cavity
A focal infection can destroy lung tissue, liquefy it into pus and form a cavity. Communication with a bronchus produces an air-fluid level and allows drainage into the airway, causing productive or foul sputum. The appearance is a consequence of necrosis and drainage, not a diagnosis of a particular organism.
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