Pathophysiology of Congestion and Oedema Flashcards
What law governs the relationship between blood flow and pressure?
Darcy’s Law
What is the equation for Darcy’s Law?
Q = deltaP/R
Where:
Q = Blood flow
deltaP = Change in pressure
R = Resistance
What three types of congestion are there/
- Local acute congestion
- Local chronic congestion
- Generalised acute congestion
Deep Vein Thrombosis typically causes what kind of congestion?
Local acute
What is the pathophysiology of DVT?
- Deep veins of leg (typically) blocked by thrombus
- Blood backs up and outflow decreases
- Pressure gradient decreases
- No perfusion leads to ischaemia and infarction
What liver condition typically causes local chronic congestion?
Hepatic cirrhosis
What causes serious lung damage in cirrhosis?
High blood volume or prolonged excessive alcohol intake
What is the associated histology with liver cirrhosis?
Regenerating liver tissue forms modules of hepatocytes with intervening fibrosis
What two clinical presentations are indicators of chronically blocked portal blood flow?
Portal systemic shunts:
- Oesophageal varices (cause massive GI bleeds if ruptured)
- Caput medusae (anastomotic enlarged veins on abdominal wall)
What pathology typically causes generalised acute congestion in the CV system?
Congestive cardiac failure
What is the pathophysiology of congestive heart failure?
Decreased cardiac output and GFR, activation of RAAS causing fluid overload in veins leading to oedema
How can the effect of heart failure indicated what side of the heart has failed?
Left - lungs
Liver - right
What are the consequences of left sided heart failure?
Pulmonary oedema causing crepitations and tachycardia
What are the consequences of right sided heart failure?
Increased JVP and hepatomegaly alongside peripheral oedema
What is oedema?
An accumulation of abnormal amounts of fluid in the extracellular compartment
