Physiological congestion

Pathological congestion

Tissues and organs increase in size, become bright red in color, and increase in temperature

Dilated arterioles and capillaries can be seen under the microscope

venous compression

venous lumen obstruction

heart failure

To the naked eye, the organs and tissues are swollen, dark red, hardened, cyanotic, and the body temperature drops.

Microscopic venules and telangiectasia

Congestive bleeding or edema

Congestive sclerosis

parenchymal cell atrophy

chronic pulmonary congestion

Mostly caused by right heart failure

Betel nut liver: red and yellow betel nut-like stripes on the cut surface

Microscopically, the central veins and liver sinusoids are dilated, the central lobular liver cells atrophy, disappear, degenerate and necrosis

Long-term liver congestion leads to interstitial fibrous tissue proliferation and forms congestion cirrhosis.

DIC (disseminated intravascular coagulation)

vortex formation

slow blood flow

Increased platelets or clotting factors

Increased blood viscosity

Increased fibrinolytic system activity

Small gray-white nodules or vegetations, rough and corrugated, hard and compact

Platelets, fibrin, red blood cells and some white blood cells can be seen under the microscope

Dark red, brittle, easy to fall off

Fibrin can be seen under the microscope, which is common in DIC

pulmonary embolism

systemic arterial embolism

Often caused by comminuted fractures of long bones or severe fat tissue contusion

A small amount entering the blood will be engulfed by phagocytes, and some entering the pulmonary blood vessels will cause damage to pulmonary microvascular endothelial cells.

If 9~20g of fat enters the lungs, 75% of the pulmonary circulation will be embolized, leading to asphyxia or acute right heart failure.

With a diameter less than 20 microns, it can enter the left heart and reach the corresponding organs, causing corresponding damage and clinical manifestations.

air embolism