thromboembolic disease

Question 1

what is difference between clot and thrombus?

Answer 1

clot = extravascular (outside vessel) = like bruise, fibrin, platelets etc

thrombus = intravascular, trigger of coagulation

Question 2

what are the 2 pathways for coagulation cascade?

Answer 2

1. extrinsic = starts with tissue factor (generated when endothelial injury)
2. intrinsic (activation of factor XII)

Question 3

what is intrinsic measured by?

Answer 3

prothrombin time (PT)

Question 4

what is extrinsic coagulation measured by?

Answer 4

activated partial Thromboplastin Time (APTT)

Question 5

what is coagulation cascade end point?

Answer 5

prothrombin → thrombin and fibrin

Question 6

where is thrombosis favoured?

Answer 6

can occur anywhere but favoured in

• sites of endothelial injury
• turbulent blood flow
• hypercoagulable blood (more inclined for coagulation)

Question 7

what type of pathway is endothelial?

Answer 7

=extrinsic pathway
weak vessel walls, atheroma, aneurysms, lots of surface thrombosis

Question 8

what are causes of endothelial injury?

Answer 8

• autoimmune diseases (primary vasculitis)
• toxins
• infectious agents
• smoking related

Question 9

what are primary causes of hypercoagulability?

Answer 9

• factor V Lieden
• Protein C deficiency
• Protein S deficiency
• Antithrombin III deficiency

Question 10

what are secondary causes of hypercoagulability?

Answer 10

• Prolonged immobility
• Significant tissue injury – burns, RTA
• Antiphospholipid syndrome – autoimmune
• Myocardial infarction
• Atrial fibrillation (irregular cardiac rhythm)

Question 11

what is embolism?

Answer 11

generally referring to thrombus that has been transported through vasculature to point where it gets stuck

Question 12

what are common sites of embolism?

Answer 12

• leg
• iliac veins
• inferior vena cava
• RA
• RV

Question 13

how is cancer related to hypercoagulability?

Answer 13

=cancer can cause hypercoagulability = lead to thrombus
- cancer
- active coagulation cascade through tumour produced TF, mucin, inflammatory cytokines - These factors promote a state of hypercoagulability by initiating the clotting process
- therapy: many chemotherapeutic agents injure endothelium and increase risk of thrombosis
- marantic endocarditis (don’t worry too much about this yet)

Question 14

what is ischaemia?

Answer 14

insufficient blood supply

Question 15

what is infarction?

Answer 15

death of tissue as result of ischaemia

Question 16

what is effect of hypoxic injury?

Answer 16

no oxygen = no energy (ATP)

Increased calcium stimulates

1. ATPase (makes things worse)
2. Phospholipase (membrane damage)
3. Proteases (membrane and cytoskeleton damage)
4. Endonuclease (DNA damage and breakdown)
5. Mitochondrial permeability (release pro death factors)

Question 17

what is air embolism?

Answer 17

bubbles of gas instead of clot

• The Bends - can’t go up to quickly in deep sea diver
• Breathing at high pressure results in more dissolved gas
• As pressure reduces nitrogen comes out of solution
• Multiple bubbles – decompression sickness

Question 18

what is amniotic fluid embolism?

Answer 18

A rare complication of childbirth

1/40,000

5th most common cause of maternal mortality

Tear in placenta or uterine vessels with secondary infusion of amniotic fluid or fetal material

Identify fetal skin (squamous cells) and hair etc in pulmonary vessels

Question 19

what are tumour emboli?

Answer 19

Usually associated with true thrombus

Tumours are thrombogenic

Some tumours have a propensity for vascular invasion

Tumours are often friable by their nature

Failed metastases?

Question 20

what is fat embolism?

Answer 20

• fat & marrow
• after large skeletal injuries where marrow contents are embolized - marrow is mainly fat after 30’s
• Occurs in 90% of sig injuries but only 10% symptomatic

Question 21

what is septic emboli?

Answer 21

Specific intravascular infections

Thrombus forms in association with an infectious agent

Abnormal cardiac valves

Mycotic aneurysm

In the heart – infective endocarditis

Symptoms from numerous septic emboli

Question 22

what is iatrogenic?

Answer 22

conditions caused by medical intervention

Question 23

what is iodopathic?

Answer 23

conditions with an unknown or undefined cause

Question 24

what is laminar blood flow?

Answer 24

blood flow under normal conditions described as laminar = smooth and has layers with most blood constituents concentrated in centre

Question 25

what can stasis mean for blood?

Answer 25

stasis = slow blood
- increased contact between blood constituents (e.g., platelets) and the walls of the blood vessels

• in areas of stasis, there is a reduced or absence of the normal flushing or washing out of blood components. Normally, blood flow helps maintain the integrity and health of the vessel walls by ensuring a continuous exchange of substances