Congestion Flashcards
What is the similarity between hyperemia and congestion
Hyperemia(increase in redness ) and congestion(engorgement of vessel in blood of blood vessel ) both indicate an increase in the content of blood in vessels of a particular tissue or organ
Discuss hyperaemia
- Active process
- Augmented tissue inflow due to dilation of arteries and arterioles
- The affected tissue appears redder as a result of engorgement of vessels with oxygenated blood
- There is a pathological and physiologic hyperaemia
Pathologic hyperaemia
Pathological vasodilation occurs when there is an increase in pCO2 in septicaemia (blood stream infection )
- increased cardiac output in anaemia / thyrotoxicosis
- sites of inflammation
Physiological hyperaaemia
Increased in flow of oxygenated blood into skeletal muscles during exercise
CNS mediated arteriolar dilation occurs in blushing
Congestion
- Passive process
- Results from impaired blood outflow of deoxygenated blood from tissues
- Tissues appears bluish- purple due to engorgement of the part or organ with deoxygenated blood + a condition known as cyanosis
- Congestion may be generalized or localized
Localized passive venous congestion
> obstruction to venous return
- thrombus
- Pressure from without vessel eg tumor ,enlarged lymph nodes
- Increased in venous pressure eg Portal hypertension - gut , spleen and development of collateral venous return
Generalized passive venous congestion
- Congestive heart failure
- left hear failure : congestion in the lungs
- Right heart failure : systemic venous system congestion
Pathologic effects of congestion - Chronic passive congestion
*Stasis of poorly oxygenated blood causes chronic hypoxia > parenchymal cell degeneration or death
> capillary capture ,with small foci of hemorrhage due to increased pressure in the capillary venule
> Anoxia of the vessel wall also causes increased permeability
> breakdown of the red cells with phagocytosis of red cell debris > clusters of haemosiderin laden macrophage with associated fibrosis
Acute pulmonary congestion
*Alveolar capillaries engorged with blood - fluid extravasation and associated alveolar septal edema
*fluid in alveolar spaces ; ,pulmonary edema
‘
*interferes with gas exchange ,capillary walls undergoes anoxic damage
*intra- alveolar hemorrhage
*red cells can be coughed up together with edema fluid as pink tinged frothy sputum
Chronic pulmonary congestion
- usually occurs inside patients with left sided cardiac failure
- changes most marked in patients with mitral stenosis
- Lungs are heavy ,wet and congested
- Alveolar spaces contain numerous haemosiderin laden macrophages
> Septa are thickened and fibrotic haemosiderin laden macrophages accumulates in interstitial tissue > elicit fibrous reaction
> Iron deposited on surface of elastic fibers; excite foreign body giant cell reaction (ferruginisation)
Lung brown or rusty appearance caused by iron salts (“brown induration”)
Hepatic congestion
- mostly seen with right heart failure
* Rarely from obstruction of the inferior vena cava or hepatic vein
Acute Hepatic Congestion
- Central vein and sinusoids are distended with blood
- Central hepacyte degeneration
- The periportal hepatocytes better oxygenated because of their close proximity to the hepatic arterioles and may show fatty change
Chronic passive congestion
- central region of the liver are red and brown and slightly depressed due to loss of cells
- surrounding zones of uncongested tan liver
- This is term nutmeg liver
- Centrilobular necrosis with hepatocyte drop out and hemorrhage ,including hemosiderin laden macrophages
- if severe long standing congestion ,there may be grossly evident cirrhosis > cardiac cirrhosis
Splenic congestion
- Also occurs in right sided heart failure and may occur in cirrhosis of the liver with portal hypertension.
- spleen is enlarged and reddish purple
- Rounder and firmer than normal ,termed cricket ball spleen and may be 2x larger than normal
- Sinusoidal congestion with thickening and fibrosis of the sinusoidal walls
- Severe portal hypertension ,haemosiderin deposition and fibrosis may be marked
- Ferruginsed nodules - called gemma - gandy bodies may occur in the red pulp
