Pathophysiology of Congestion and Oedema

Question 1

does water flow down hill or up hill?

Answer 1

down! gravity, tis a wonderful thing!

Question 2

in the equation Q=deltaP/R, what does the Q,P and R stand for?

Answer 2

Q: blood flow
P: pressure
R: resistance

Question 3

what is congestion?

Answer 3

relative excess of blood in vessels of tissue or organ

Question 4

give an example of local acute congestion

Answer 4

deep vein thrombosis

Question 5

give an example of chronic congestion

Answer 5

hepatic cirrhosis

Question 6

give an example of generalised acute congestion

Answer 6

congestive cardiac failure

Question 7

what is the affect of outflow of blood in deep vein thrombosis?

Answer 7

there is a decrease in outflow of blood

Question 8

in deep vein thrombosis what is the affect on the pressure gradient in the leg?

Answer 8

there is a decrease in the pressure gradient

Question 9

what happens to the flow across the system in deep vein thrombosis of the leg?

Answer 9

there is a decrease in flow

Question 10

what is hepatic cirrhosis?

Answer 10

the liver is damaged and regenerative nodules of hepatocytes with intervening fibrosis occurs to repair it. this happens as the structure has been destroyed.

Question 11

what can hepatic cirrhosis result from?

Answer 11

liver damage (HBV or alcohol)

Question 12

what are the affects of hepatic cirrhosis?

Answer 12

> altered hepatic blood flow
portal blood flow is blocked
there is local chronic congestion leading to haemorrhage risk

Question 13

describe the affect hepatic cirrhosis has on portal blood flow?

Answer 13

the portal blood flow is blocked because of the fibrous bands. the congestion in portal vein and branches increases portal venous pressure. in the collateral circulation several sites anastomose with systemic circulation, disrupting the circulation of the blood.

Question 14

what are the consequences of hepatic cirrhosis?

Answer 14

> portal-systemic shunts
oesophageal varices
caput medusae

Question 15

why is the heart describes as an ineffective pump?

Answer 15

it is unable to clear blood from the right and left ventricles

Question 16

describe the pathophysiology of congestive cardiac failure

Answer 16

there is a decrease in the cardiac output and then a decrease in renal glomerular filtration rate (resulting in an increase in sodium and h2o retention). This creates an increase in the amount of fluid in the veins and fluid overload in the veins

Question 17

what are the effects of congestive heart failure in liver central venous congestion?

Answer 17

> elevated JVP
hepatomegaly
peripheral oedema

Question 18

what are the effects of congestive heart failure in acute and chronic changes in the lugs?

Answer 18

> blood dams into the lungs

> crepitation’s in lungs

Question 19

what does a liver look like on hepatic central venous congestion?

Answer 19

nutmeg, with red/brown and pale spotty appearance macroscopically

Question 20

what are pericentral hepatocytes a statis of?

Answer 20

poorly oxygenated blood

Question 21

why are periportal hepatocytes a relatively better sign that pericentral hepatocytes?

Answer 21

they are oxygenated due to proximity of hepatic arterioles

Question 22

what drives the constant movement of fluid through capillary beds?

Answer 22

hydrostatic pressure of the heart

Question 23

capillary hydrostatic pressure is ……. than capillary oncotic pressure on the arterial side.

Answer 23

more, filtration

Question 24

what three components affect net flux and filtration?

Answer 24

> hydrostatic pressure
oncotic pressure
permeability characteristics and area of the endothelium

Question 25

what does disturbance of the normal components of microcirculation cause?

Answer 25

oedema

Question 26

what is oedema?

Answer 26

accumulation of abnormal amounts of fluid in the extravascular space.

Question 27

what is an effusion?

Answer 27

when fluid collects in a body cavity

Question 28

what makes up the transudate in oedema?

Answer 28

> little protein/albumin
lots of h2o
lots of electrolytes

Question 29

what does the histology of a liver with hepatic cirrhosis look like?

Answer 29

there are hepatocytes in lumps with broad bands of fibrous tissue, normal vascular pattern is lost. this is chronic inflammation due to the tissue damage.

Question 30

what clinical problems can arise form oesophageal varices?

Answer 30

haemorrhage

Question 31

what is congestive heart failure?

Answer 31

failure of the right and left ventricle at the same time

Question 32

what is a collection of fluid in the abdominal cavity called?

Answer 32

ascites

Question 33

how does left ventricle failure lead to oedema?

Answer 33

there is an increase in left atrial pressure resulting in passive retrograde flow to pulmonary veins, capillaries and arteries. this increases pulmonary vascular pressure and increases pulmonary blood volume. there is therefore an increase in capillary hydrostatic pressure which increases filtration and creates a pulmonary oedema

Question 34

what happens to the alveolar sept in pulmonary oedema?

Answer 34

there is progressive oedematous widening of alveolar septa

Question 35

what is the pathophysiology of peripheral oedema?

Answer 35

right heart failure means that the right ventricle cannot empty in systole. blood is therefore retained in the systemic veins increasing the pressure in capillaries, which increases filtration and causes peripheral oedema.

Question 36

what oedema can congestive heart failure lead to?

Answer 36

pulmonary oedema and peripheral oedema at the same time as there is failure of both the left and right ventricle.

Question 37

what happens if lymphatic system is blocked?

Answer 37

there is lymphoedema

Question 38

how does breast cancer therapy lead to oedema?

Answer 38

there is radiotherapy of the axilla leading to fibrosis and a decrease in outflow. this creates oedema of the upper arm.

Question 39

what is the affect of heart failure on renal blood flow

Answer 39

there is reduced renal blood flow (this is secondary)

Question 40

how does abnormal renal function lead to oedema?

Answer 40

there is reduced renal function that leads to an increase in salt and h2o retention creating an increase in intravascular fluid volume. there is therefore a secondary increase in capillary pressure resulting in an oedema.

Question 41

what is a primary cause of abnormal renal function?

Answer 41

acute tubular damage (such as hypotension)

Question 42

what is the affect of hypoalbuminaemia on filtration?

Answer 42

there is an increase in filtration due to a decrease in capillary oncotic pressure

Question 43

describe the pathophysiology of permeability oedema

Answer 43

there is damage to the endothelial lining creating an increase in pores pushing the osmotic pressure coefficient of endothelium towards zero. proteins and larger molecules can then leak out.