Hypermia and Congestion 

Definition: Both of them can be defined as a local increase in volume of blood in a particular tissue. 

 Hypermia 

-  is an active process resulting from an increased inflow of blood into a tissue because of arteriolar vasodilation. 

-  commonly occurs in exercising skeletal muscle or acute inflammation. 

-  Affected tissue becomes red as there is engorgement with oxygenated blood. 

Congestion 

 -  is a passive process resulting from impaired outflow of blood from a tissue.

-  occurs systemically as in cardiac failure or locally as in isolated venous obstruction. 

-  Affected tissue appears blue-red due to accumulation of deoxygenated blood. 

-  In long-standing congestion (also called chronic passive congestion states), poorly oxygenated blood causes hypoxia  → results in parenchyma cell degeneration or cell death. 

a) Pulmonary congestion

Cut surface: hemorrhagic & wet.

1.  Acute pulmonary congestion: 

ƒ-  Alveolar capillaries engorged with blood 

ƒ- Septal edema 

2.  Chronic pulmonary congestion: 

-  Thickened & fibrotic septa 

-  Alveolar spaces contain hemosiderin-laden macrophages resulting in an appearance termed brown indurations.

-  Can result in pulmonary hypertension.

b) Hepatic congestion

1) Acute hepatic congestion: 

- Central vein & sinusoids are distended 

- There may be even central hepatocyte degeneration. 

- Peripheral hepatocytes better oxygenated & develop only fatty changes. 

2) Chronic passive congestion of liver:

-  Central lobules grossly depressed because of loss of cells & appear red brown (nutmeg liver).

-  Hemosiderin laden macrophages 

-  In longstanding hepatic congestion, commonly associated with cardiac failure, there is a grossly evident hepatic fibrosis called cardiac cirrhosis 

References

Bezabeh ,M. ; Tesfaye,A.; Ergicho, B.; Erke, M.; Mengistu, S. and Bedane,A.; Desta, A.(2004). General Pathology. Jimma University, Gondar University Haramaya University, Dedub University.