thrombosis

Question 1

how does thrombosis presents as

Answer 1

characterised by the lines of Zahn (platelets and red blood cells held together by fibrin)
and attachment to vessel walls

Question 2

what are the 3 risk factor of thrombosis called

Answer 2

Virchow’s triad

Question 3

1st point of Virchow’s triad (1) D_ o_ B_ F_

Answer 3

Disruption of blood flow
- immobilisation (flight/bedrest)
-cardiac wall dysfunction
-Aneurysm
-atrial fibrillation

Question 4

2nd of Virchow’s traid (2) E_ C_ D_

Answer 4

Endothelial cell damage
-Atheroscelrosis (reptured plaque)
-vasculitis
-high levels of homocysteine (low B12)
-turbulent blood flow of arterial bifurcation
-oxidised LDL
-cigarrette smoke
-cytokines

Question 5

3rd of Virchow’s traid (3) H_ S_

Answer 5

Hypercoaguable states
-due to excessive procoagulant factors /defective anticoagulants
-may be inherited (AT3 deficiency), acquired (DIC)
(classic presentation is recurrent DVT or DVT at early age)

Question 6

what is the most common cause and site of venous thrombosis

Answer 6

Stasis of blood
most common site is deep vein of lower limbs

Question 7

what is the presentation of DVT

Answer 7

Red swollen painful legs with skin discolouration

Question 8

what can happen if a person has DVT

Answer 8

can dislodge to the lungs and cause a pulmonary embolism

Question 9

Arterial thrombosis is commonly due to what - and what is an rare cause

Answer 9

common = endothelial damage related to turbulent blood flow at bifurcation or over atherosclerotic plaque in high velocity vessels
rare = hypercoagulabilty + stasis

Question 10

Arterial thrombosis causes -(3)

Answer 10

myocardial infarctions
small bowel infarction
strokes

Question 11

what is INR

Answer 11

International normalised ratio

Question 12

what is normal INR

Answer 12

1

Question 13

what is INR used for

Answer 13

montiter warfarin therapy

Question 14

what is INR=2.5

Answer 14

treatment of DVT, pulmonary/arterial embolsim, atrial fibrillation, myocardial infraction

Question 15

what is INR=3.5

Answer 15

treatment of recurrent DVT or pulmonary embolism

Question 16

describe Prothrombin time (PT)

Answer 16

-evaluates the extrinsic coagulation system to formation of the fibrin clots
-monitored person taking warfarin + liver synthesis function

Question 17

what is normal PT

Answer 17

11-15 second

Question 18

Time is prolonged when clotting factor level is

Answer 18

30-40% of normal PT

Question 19

what is a pulmonary embolism

Answer 19

An intravascular mass that travels and occludes pulmonary blood vessels
Most common cause is a dislodged thrombus (thromboembolus) – 95%

Question 20

what is used to treat AIS

Answer 20

Alteplase
Aspirin (24h after thrombolysis)

Question 21

what is used to treat venous thrombosis

Answer 21

Rivaroxaban + Apixaban

Question 22

what is used to treat arterial thrombosis

Answer 22

inhibitor of platelets aggregation prevent formation - Aspirin

Question 23

what is thrombin

Answer 23

acts on fibrinogen to produce fibrin monomers
activates fibrin stabilising factor 13 (13a)

Question 24

thrombin (extensive mechanims)

Answer 24

• converts these monomers to cross linked fibrin which strengthens blood clots
• acts on a feedback loop to activates several other coagulation factors and is therefore pivitol in the amplification system

Question 25

what switches off thrombin

Answer 25

natural anticoagulant antithrombin 3 - limits clot formation

Question 26

What does plasmin does

Answer 26

- breaks down clots, cleave fibrin & fibronigen into degradation products (fragments known as D-dimers) - degrades some clotting factors + blocks platelet aggregation

Question 27

what are the three stages of platelet activation

Answer 27

adhesion, release reaction, aggregation

Question 28

platelet undergo shape changes and degranulation which causes -

Answer 28

-release mediator ADP (from dense core granules) -ADP induces the expression of GP2b/3a (GPIIb/IIIa) another essential receptor of aggregation and and fibrinogen which acts as a linker molecule in the developing clot - production thromboxane A2 (TXA2)(a derivative of platelets cyclooxygenases) its a vasocontrictor that also promotes platelets aggregation -releases calcium

Question 29

Plaque formation (using LDL and anti-inflammatory systems)

Answer 29

-Circulating LDL gains access to subendothelial spaces where their oxidised -cytokines IL-1 and MCP-1 attract circulating monocytes

Question 30

macrophages phagocytose LDL to form _ in plaque formation

Answer 30

foam cells

Question 31

what happens after foam cells formation

Answer 31

smooth muscle cells migrate and proliferate under the influence of smooth muscle mitogens

Question 32

A primative plaque is formed of

Answer 32

Foam cells, smooth muscle cells, lipids & necrotic cells

Question 33

how does plaques mature

Answer 33

the plaque enlarged, develops a fibrous capsule and protrudes in vessel lumen