Empyema (Pleural Infection)
Empyema is infected pleural fluid, usually arising from pneumonia and progressing from a simple parapneumonic effusion to loculated pus; antibiotics are essential but source control requires image-guided drainage, with intrapleural therapy or surgery when drainage is incomplete.
Definition
Empyema is infected fluid or pus in the pleural space, usually arising from pneumonia. Pleural infection includes a spectrum from a complicated parapneumonic effusion with bacterial invasion and adverse fluid chemistry to frank purulence, and requires antibiotics plus appropriate source control.
First principles
Pleural infection is a spectrum, not only visible pus
A parapneumonic effusion may begin as a sterile inflammatory exudate, then become bacterially invaded with low pH and glucose, and finally organise into frank pus. A patient can therefore have clinically important pleural infection even when aspiration is not visibly purulent; fluid chemistry, microbiology, ultrasound and the clinical trajectory determine the need for drainage.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.