Management of Infectious Processes of the Pleural Space: A Review

Table 2

Different stages in the evolution of an infected pleural effusion with associated pathological changes and pleural fluid findings.

Phase	Pathology	Pleural fluid findings
Exudative	Increased permeability of vascular and visceral pleural membranes VEGF	Nonviscous
		Free flowing
		Readily drained
		Pleural fluid Cx negative
Fibrinopurulent	Fibrin deposition on visceral pleura Locules formation IL-8, TNF-α	pH > 7.20
		Glucose within normal ranges
		LDH < 3 times ULN
		Viscous
		More viscous
		Pleural fluid cx positive
		Typical “complicated” effusion
Organizing	Fibroblast entry Pleural peel; TGF-β	Thick pus
		Very viscous
		pH < 7.20
		Glucose < 40
		LDH > 3 times ULN

LDH: lactate dehydrogenase.
ULN: upper limits of normal.
VEGF: vascular endothelial growth factor.
IL-8: interleukin 8.
TNF-α: tumor necrosis factor-alpha.
TGF-β: transforming growth factor-beta.