Congestion Flashcards
How do you calculate blood flow?
Q=P/R
Q - blood flow
P - Pressure
R - resistance
What is congestion
Relative excess of blood in vessels of tissue or organ
- passive process, secondary phenomenon
- not like acute inflammation - active hyperaemia
- acute or chronic
What are the different types of congestion
Local acute congestion - DVT
Local chronic congestion - Hepatic cirrhosis
Generalised acute congestion - congestive cardiac failure
How does DVT in the legs cause congestion
Vein blocked causing localised acute congestion
Blood backs up in veins, venues, capillaries
Dec in outflow of blood, dec pressure gradient (Q=P/R)
No O2 = ischamia and infarction
How does cirrhosis lead to local chronic congestion?
Results from serious live damage i.e HBV, alcohol
Liver forms nodules of hepatocytes with intervening fibrosis
Loss of normal architecture - altered hepatic blood flow
Portal blood flow blocked
-congestion in portal vein and branches
- inc portal venous pressure
- collateral circulation - several site anastomose with systemic circulation
Local chronic congestion - a risk for haemorrhage
Bascially blood flow blocked - pressure inc, site anastomose which means they bleed out kinda
What is congestive cardiac failure?
R and L heart failure at the same time
Heart unable to clear blood - ineffective pump
What is the Pathophysiology of congestive cardiac failure
Dec cardiac output
Dec renal glomerular filtration rate (GFR)
-activates RAAS system so Na and H2O retention inc
Leads to fluid overload in the veins - treat with diuretic
What are the effects of congestive cardiac failure?
Heart can’t clear blood from ventricles
This leads to back pressure, blood dammed back in veins
Can result in pulmonary oedema as a result of LHF so blood dams into lungs
Clinically you get crepitations as a result
In the liver you will get central venous congestion as a result of RHF
Raised JVP, hepatomegaly, peripheral oedema
How does hepatic central venous congestion
Nutmeg liver red/brown & pale, spotty appearance macroscopically
Peri central hepatocytes (red), stasis of poorly oxygenated blood
Peripheral hepatocytes (pale) relatively better oxygenated due to proximity of hepatic arterioles
