Collection of pus and fluid from infected tissue. Normally refers to a pleural infection (empyema thoracis), but can also refer to other sites, such as the gallbladder.
- Aspiration with M C&S - 40% cultures negative
- Low glucose (Tuberculosis only slightly low)
- Low pH in pleural fluid - typically < 7.2
- Community acquired
- Anaerobes in 20%
- Hospital acquired
- Staphylococcus aureus - MRSA - 25%
- Enterobacter - 18%
- Enterococci - 12%
- Pseudomonas - 5 %
- Overall mortality better for community acquired (about 15%), steptococci and anaerobes than hospital acquired (about 50%)
- Mortality much higher in elderly
Do not under treat pneumonia. There is some evidence that use of antibiotics ineffective against Pneumococcus are more likely to be followed by an empyema. Ergo, include penicillin or something effective against pneumococcus in the first treatment of chest infections even if they seem likely to be "atypical".
- Should cover anaerobes
- Drainage - size of tube irrelevant. No present RCT case for fibrinolytics
- Surgery (decortication) needed in 15%. Evidence of selection bias against elderly.