Criteria
Development of empyema in association with pneumonia[22]
Stage 1
Parapneumonic effusion (free-flowing exudate): low white cell count, lactate dehydrogenase (LDH) level less than half that in the serum, normal pH and glucose levels, no bacterial organisms.
Stage 2
Fibrinopurulent (bacterial invasion across the damaged lung epithelium with immune response): pH <7.2, glucose <2.2 mmol/L (<40 mg/dL), LDH >1000 IU/L. Called empyema if frank pus is found.
Stage 3
Chronic organising (scar tissue formation): a fibrous pleural cortex begins to form, which may encase the lung, preventing re-expansion, impairing lung function, and creating a persistent pleural space with continuing potential for infection.
Use of this content is subject to our disclaimer