Pathophysiology Of Congestion

Question 1

What is congestion?

Answer 1

Relative excess of blood in the vessels of tissue or organ

Question 2

Give 3 clinical pathology examples of congestion

Answer 2

Local acute congestion e.g DVT
Local chronic congestion e.g hepatic cirrhosis
Generalised acute congestion e.g congestive heart failure

Question 3

Describe the pathology of how a DVT can cause a decrease in flow resuling in ischaemia

Answer 3

A deep vein thrombosis causes blood to back up in the veins, venules and capillaries
This causes a decrease outflow of blood back into the vena cava
This causes local acute congestion
The congestion results in a decreased pressure gradient so there is decreased flow across the system
Decreased flow = decreased oxygen = ishaemia and infarction

Question 4

What causes hepatic cirrhosis?

Answer 4

Serious damage to the liver

E.g alcohol, HBV

Question 5

Decrive how hepatic cirrhosis causes congestion.

Answer 5

The regenerating liver forms nodules of hapatocyes and also undergos fibrosis as it trys to heal.
This reuslts in abnormal architecture of the liver and therefore altered haptic blood flow
The altered hepatic blood flow = blocked portal blood flow causing increased portal venous pressure
Several sites of collateral circulation then anastemose with systemic circulation
= local chronic congestion

Question 6

Wha is a patient with local chronic congestion of hepatic cirrhosis at risk of?

Answer 6

Haemorrhage

Question 7

Hepatic cirrhosis resulting in congestion causes portal systemic shunts. Give 2 examples of portal shstemic shunt consequences.

Answer 7

Oesophageal varices

Caput medusae

Question 8

What is congestive heart failure?

Answer 8

The heart is unable to clear blood from the right and left ventricles
The heart is an ineffective pump resulting is valve disease or ischamiA

Question 9

describe the pathophysiology of congestive heart failure.

Answer 9

Inability to clear blood from ventricles = decrease in cardiac output
Decrease in glomerular filtration rate
This causes activation of renin-angiotensin-aldosterone system cauzing sodium and water retension
This results in an increase in fluid in the body/veins

Question 10

Describe the effects of congestive heart failure in general, in the lungs and in the liver.

Answer 10

The heart canot clear blood from the ventricles so this causes back pressure and blood is damed in the veins

lungs- in left heart failure blood dams back into the lungs causing pulmonary oedema.
Liver- central venous congestion. Right heart failure, blood dams back into the systemic circulation

Question 11

Congestion in the pulmonary circulation is due to what?

Answer 11

Left heart failure

Question 12

Congestion in the liver is due to what?

Answer 12

Right heart failure

Liver is the central venous system therefore central is affected hy centrL venous congestion

Question 13

What are the clinical signs of pulmonary congestion?

Answer 13

Crepitations, tachycardia

Question 14

What are the clinical signs of congestion in the liver?

Answer 14

Hepatomegaly, increased JVP, peripheral oedema

Question 15

What is the apperance of the liver with hepatic central venous congestion?

Answer 15

Nut meg liver

Red/brown and pale spotty appearance microscopically

Question 16

What hepatocytes are pale and which ones are red in colour and why?

Answer 16

Pericentral hepatocytes are red - stasis of poorly oxygenated blood
Periportal hepatocytes are pale- relatively better oxygenated due to proximity of hepatic arterioles

Question 17

What 3 components affect net flux and filtration?

Answer 17

Hydrostatic pressure
Oncotic pressure
Permeability characteristics and area of endotheliun