Congestion

Definition: Congestion is a passive process resulting from impaired outflow from a tissue. It may occur systemically, as in cardiac failure, or it may be local, resulting from an isolated venous obstruction. The tissue has a blue-red color (cyanosis), particularly as worsening congestion leads to accumulation of deoxygenated hemoglobin in the affected tissues.

Localization

 cutaneous congestion
 cerebral congestion
 visceral congestion

• renal congestion

Exemples

 acute pulmonary congestion

• characterized by alveolar capillaries engorged with blood
• associated alveolar septal edema and/or focal intra-alveolar hemorrhage

 chronic pulmonary congestion

• thickened and fibrotic septa
• alveolar spaces containing numerous hemosiderin-laden macrophages (siderophages)

 acute hepatic congestion

• central vein and sinusoids distended with blood
• central hepatocyte degeneration

 chronic passive hepatic congestion of the liver

• central regions of the hepatic lobules grossly red-brown and slightly depressed (owing to a loss of cells)
• accentuated against the surrounding zones of uncongested tan liver (nutmeg liver)
• centrilobular necrosis
• loss of hepatocytes (hepatocytic dropout)
• hemorrhage
• hemosiderin-laden macrophages
• hepatic fibrosis (cardiac cirrhosis)

See also

 Hyperemia
 Edema