Vascular system pathology

Question 1

What factors favor fluid retention in the interstitium and body cavities?

Answer 1

• Low hydrostatic pressure
• Osmotic pressure

Question 2

What factors retain fluid within circulation?

Answer 2

• Higher oncotic pressure in plasma due to ions & proteins
• The selective permeability of the endothelium which can open to allow fluid & ions through

Question 3

What is exudate (inflammatory) oedema classified as?

Answer 3

Serous, fibrinous and suppurative

Question 4

How does oedema form when there is a imbalence on fluid retaining factors?

Answer 4

• decreased plasma osmotic pressure
• Increase in capillary permeability, hydrostatic pressure and in osmotic pressure of interstitium (salt retention)

Question 5

How does a lymphatic blockage cause vessel damage?

Answer 5

• vessel damage or scarring with fibrosis
• nodule pathology (tumour, hyperplastic inflammatory response))

Question 6

What can lead to increased caillary hydrostatic pressure in terms of blood stagnation?

Answer 6

Increased capillary hydrostatic pressure caused by increased venous pressure from heart disease or with decreasing venous outflow

Question 7

What are the different ways oedema could present?

Answer 7

• Ascites (fluid filling abdomen).
• Hydrothorax
• Subcutaneous oedema

Question 8

What is hyperaemia?

Answer 8

increase inflow of blood causing erythema and acute inflammation

Question 9

What is localised venous congestion?

Answer 9

• e.g intestinal torsion
  
  • vessel compression occludes veins but blood still enters via arteries
  • venous blood accumulates in capillaries and veins
  • Hypoxic necrosis of tissue

Question 10

What is generalised venous congestion?

Answer 10

• obstruction of blood flow due to decreased heart function
• blood retains behind obstruction

Question 11

What tissue is affected if there is congestion on the left side of the heart?

Answer 11

pulmonary circulation congestion

Question 12

What tissue is affected if there is congestion on the right side of the heart?

Answer 12

hepatic circulation congestion

Question 13

What does generalised congestionin the lungs?

Answer 13

• Diffuse reddening
• Darkening due to the process of hypostatic congestion
• Oedema

Question 14

What is the appearnace of congestion in the liver?

Answer 14

In liver there is a nutmeg appearance and there is a congestion around the central veins

Question 15

How does a haemorrhage present in the GIT or UT?

Answer 15

-inflammaiton or ulcers
-haematemesis
-melena
-dysentry

Question 16

What is insidious haemorrhage?

Answer 16

-damage to endothelium
-coagulopathy

Question 17

what are the types of coagulopathies?

Answer 17

-haemophilia
-anticoagulants
-consumption coagulopathies

Question 18

What is Thrombocytopenia?

Answer 18

platlet deficiency in the blood

Question 19

What is Septicaemia?

Answer 19

blood poisoning - large amount of bacteria entering blood stream

Question 20

How can clotting be restricted?

Answer 20

avoid coagulation of the entire vascular tree
-thrombomodulin converts thrombin to anticoag enzyme
-plasmin cleaves fibrin

Question 21

What are causes of hypercoagulability?

Answer 21

-increased number of platelets
-increased fibrin, clotting factors
-decreased activity of fibrinolysis

Question 22

What are thhe different fates of a thrombus?

Answer 22

1. dissolution (fibrinolysis)
   2.vessel obstruction (fibrosis)
2. organisation and recanilisation
3. embolisation- fragment breaks away

Question 23

What are the different types of embolism’s?

Answer 23

-from thrombi-thromboembolism
-fat
-fibrocartilagenous
-tumour cells
-parasites
-bacterial/infectious/septic
-gas/air

Question 24

Where do arterial emboli lodge?

Answer 24

downstream at bifurcation sites

Question 25

Where do venous emboli lodge?

Answer 25

pulmonary circulatiopn

Question 26

What is a saddle thromboembolus?

Answer 26

-in distal aorta where bifurcates to form iliac arteries -thrombi form and more or less occlude iliac artery -signs of pain and coldness in hindfeet

Question 27

Where can fat emboli come from?

Answer 27

fragments of fat from medullary cavity after fracture

Question 28

Where can fibrocartilaginous emboli come from?

Answer 28

-from degenerate intervertebral disc, dogs -ruptured -material get into vessels and vertebral canal and travel to lungs

Question 29

What are malignant tumour emboli?

Answer 29

-rafts of tumour cells -may establish as secondary tumour-metastasis

Question 30

What are parasitic emboli?

Answer 30

-infrequent -vessel with profiles of one or more parasites within -inside thrombus

Question 31

What are bacterial emboli?

Answer 31

-septicemia or bacteriaemia -bacterial colonies lodge in capillaries

Question 32

What does the outcome of the embolism depend on?

Answer 32

-extent of occlusion -nature of embolus -site-tissue vunerability and embolus moves -brain, heart, kidney affected by short period of anaxia

Question 33

What does a occusion at end of artery cause?

Answer 33

ischaemic necrosis

Question 34

What are common causes of ischemia?

Answer 34

-thrombosis -embolism -compression -vasoconstriction -vasculitis

Question 35

What are the effects of infarction dependent on?

Answer 35

-sensitivity to hypoxia -local circulation -duration of ischaemia

Question 36

What is shock?

Answer 36

state of generalised tissue hypoperfusion caused by decrease effective circulating blood volume and/or decreased peripheral vascular resistance

Question 37

What is hypovolaemic shock?

Answer 37

-Blood/fluid loss--> reduced circulating bolume -Haemorrhage, diarrhoea or severe bones -10% decrease in blood vol- no fall in BP >35% loss of vol, BP falls significatnyl, tissue perfusion inadequate

Question 38

What is cardiogenic shock?

Answer 38

-Cardiac dysfunction -Infarction, area of anoxia to myocardium or serious cardiac arrythias -Compensatory mechanisms (symp NS) But, if unsuccessful--> stagnation of blood

Question 39

What is blood maldistribution?

Answer 39

-Increased peripheral vascular diameter -Created blood pooling/stagnation -Anaphylaxis, neurogenic, septic

Question 40

what is disseminated intravascular coagulation?

Answer 40

A coagulopathy in which clotting and anticlotting mechanisms occur at the same time

Question 41

what are the steps in disseminated intravascular coagulation

Answer 41

1. TF release and platelet aggregation 2. widespread thrombosis 3. activation of fibrinolysis/inhibition of thormbin, platelet activation and fibrin formation OR widespread vascular occlusion 4. lysis of thrombi and consumption of clotting factors OR widespread ischaemia 5. widepread haemorrages (or widepread ischaemia)