Pathophysiology of Congestion and Oedema

Question 1

The passive movement of water is

Answer 1

Down its pressure gradient

Question 2

Darcy’s law

Answer 2

Blood flow = change in pressure/resistance (Q=Δ P/R)

Question 3

Congestion

Answer 3

relative excess blood in vessel soft tissue or organ

Question 4

Example of local acute congestions

Answer 4

Deep vein thrombosis

Question 5

Example of local chronic congestion

Answer 5

Hepatic cirrhosis

Question 6

Example of generalise acute congestion

Answer 6

Congestive cardiac failure

Question 7

Deep vein thrombosis of leg

Answer 7

Vein blocked by thrombosis causing localised acute congestion

Question 8

Pathophysiology of deep vein thrombosis

Answer 8

Blood backs up in veins, venules and capillaries - decreased outflow of blood - local acute congestion - decrease in pressure gradient - decrease flow across systems - no oxygen so ischaemia and infarction

Question 9

Why does pressure gradient decrease in deep vein thrombosis

Answer 9

Due to venous pressure rising to match arterial pressure decreasing the difference in pressure between the 2

Question 10

Hepatic cirrhosis results from

Answer 10

Serious liver damage (eg. alcohol damage)

Question 11

Regeneration of liver results in

Answer 11

Formation of nodules of hepatocytes with intervening fibrosis - loss of normal architecture

Question 12

Pathophysiology of hepatic cirrhosis

Answer 12

Loss of normal liver architecture - altered hepatic blood flow - portal blood flow blocked - congestion in portal vein and branches - increased portal venous pressure - collateral circulation

Question 13

Collateral circulation

Answer 13

Several sites anastomosing with systemic circulation

Question 14

Local chronic congestion has a risk of

Answer 14

High pressure haemorrhage

Question 15

Consequence of hepatic cirrhosis

Answer 15

Portal-systemic shunts

Question 16

Congestive cardiac failure arrises from

Answer 16

The heart being unable to clear blood - ineffective pump

Question 17

Pathophysiology of congestive heart failure

Answer 17

Reduced cardiac output - reduced renal glomerular filtration rate (GFR) - activation of renin-angiotensin-aldosterone system - increase in sodium and water retention - increase amount of fluid in body - increase fluid in veins (overload)

Question 18

Treatment of congestive heart failure

Answer 18

Diuretics

Question 19

Effects of congestive cardia failure

Answer 19

Back pressure, blood dammed back in veins
Lungs: pulmonary oedema - left heart failure - blood dams back into lungs
Liver: central venous congestion - right heart failure - blood dams back to systemic circulation

Question 20

Signs of central venous congestion

Answer 20

Elevated JVP
Hepatomegaly
Peripheral oedema

Question 21

2 blood supplies of liver

Answer 21

Systemic blood supply and portal vein

Question 22

Effect of hepatic central venous congestion on pericentral hepatocytes

Answer 22

Stasis of poorly oxygenated blood

Question 23

Effect of hepatic central venous congestion on periportal hepatocytes

Answer 23

Relatively better oxygenated due to proximity of hepatic arterioles

Question 24

Microcirculation is driven by

Answer 24

Hydrostatic pressure from the heart

Question 25

Microcirculation is balance by

Answer 25

Osmotic pressures and endothelial permeability

Question 26

Microcirculation

Answer 26

Constant movement of fluid through capillary beds

Question 27

Filtration of microcirculation

Answer 27

Capillaries - interstitium - capillaries and lymphatics

Question 28

3 components that affect net flux and filtration of microcirculation

Answer 28

Hydrostatic pressure Oncotic pressure Permeability characteristics and area of endothelium

Question 29

Oedema

Answer 29

Accumulation of abnormal amounts of fluid in the extravascular compartment

Question 30

Peripheral oedema

Answer 30

Increased interstitial fluid in tissues

Question 31

Effusions

Answer 31

Fluid collections in body cavities

Question 32

Effusion in abdominal cavity

Answer 32

Ascites

Question 33

Transudate oedema

Answer 33

Alterations in the haemodynamic forces which act across the capillary wall - low protein

Question 34

Exudate oedema

Answer 34

Part of inflammatory process due to vascular permeability - high protein

Question 35

Pulmonary oedema is what kind of oedema

Answer 35

Transudate

Question 36

Pathophysiology of pulmonary oedema relating to left ventricular failure

Answer 36

Increase in left atrial pressure - passive retrograde flow to pulmonary veins, capillaries and arteries - increase in pulmonary vascular pressure - increase in pulmonary blood volume - increase capillary hydrostatic pressure - increase filtration and pulmonary oedema

Question 37

Pathophysiology of pulmonary oedema in the lungs

Answer 37

Progressive oedematous widening of alveolar septa - accumulation of oedema fluid in alveolar spaces

Question 38

Peripheral oedema is caused by

Answer 38

Right heart failure

Question 39

Pathophysiology of peripheral oedema

Answer 39

Right heart failure - can't empty RV in systole - blood retained in systemic veins - increase capillary hydrostatic pressure - increase filtration - peripheral oedema

Question 40

Pathophysiology of lymphatic blockage

Answer 40

Lymphatic obstruction - hydrostatic pressure upset - lymphoedema

Question 41

Abnormal renal function results in

Answer 41

Salt and water retention

Question 42

Secondary abnormal renal function

Answer 42

Heart failure

Question 43

Primary abnormal renal function

Answer 43

Acute tubular damage (eg. hypotension)

Question 44

Pathophysiology of oedema in abnormal renal function

Answer 44

Decreased renal function - increase salt and water - increase in intravascular fluid volume - increase in capillary hydrostatic pressure - oedema

Question 45

Pathophysiology of low protein oedema

Answer 45

Hypoalbuminaemia - decrease in capillary oncotic pressure - increase in filtration - oedema

Question 46

Capillary oncotic pressure requires

Answer 46

Normal protein levels - transudate

Question 47

Examples of low protein oedema

Answer 47

Hepatic cirrhosis Malnutrition Nephrotic syndrome

Question 48

Permeability oedema is what type of oedema

Answer 48

Exudate

Question 49

Low protein oedema is what type of oedema

Answer 49

Transudate

Question 50

Pathophysiology of permeability oedema

Answer 50

Damage to endothelial lining - increase of pores in membrane - osmotic reflection coefficient of endothelium (permeability) decreases towards 0 - proteins and larger molecules can leak out

Question 51

Permeability oedema can result from

Answer 51

Acute inflammation eg pneumonia | Burns