Haematology - Haematosis & Thrombosis

Question 1

What is the triad of symptoms in thrombophlebitis syndrome?

Answer 1

Recurrent pain
Swelling
Ulcers

Question 2

What catalyses the conversion of fibrinogen to fibrin?

Answer 2

Thrombin

Question 3

Which 4 anticoagulant molecules are expressed on the blood vessel wall?

Answer 3

Thrombomodulin
Endothelial Protein C receptor
TFPI (Tissue Factor Pathway Inhibitor)
Heparans

Question 4

How does inflammation affect the blood vessel wall?

Answer 4

It makes it prothrombotic

Question 5

Recall 4 effects of inflammation on the blood vessel wall

Answer 5

1. Anticoagulant molecules are downregulated
2. TF expressed
3. Prostacyclin decreased
4. Adhesion molecules upregulated

Question 6

How do neutrophils contribute to immunothrombosis?

Answer 6

Neutrophils release DNA, which is procoagulant

Question 7

What is the mechanism of action of clopidogrel?

Answer 7

Inhibits ADP receptors

Question 8

Give 4 ways in which blood stasis promotes thrombosis

Answer 8

1. Accumulation of activated factors
2. Promotes platelet adhesion
3. Promotes leukocyte adhesion and transmigration
4. Hypoxia produces inflammatory effect on endothelium

Question 9

What is the broad mechanism of action of heparins?

Answer 9

Potentiate antithrombin
antithrombin inhibits thrombin and factor 9 & Xa,

Question 10

What is one risk of long term heparin use?

Answer 10

Osteoporosis

Question 11

Give an example of an anti-Xa drug

Answer 11

Rivaroxaban/Apixaban

Question 12

Give an example of an anti-2a drug

Answer 12

Dabigatran

Question 13

How does warfarin affect vit K?

Answer 13

vitamin K epoxide reductase (VKER) inhibitor
vitamin K antagonist

Question 14

Which procoagulant factors fall as a result of warfarin medication?

Answer 14

2,7, 9, 10, protein c and protein s
factor 7 and protein c drop first

Question 15

How is warfarin monitored?

Answer 15

INR measure
INR will usually be between 0.9 and 1.3. if not taking warfarin
if you are target is usually 2.5

A low INR = coagulates too easily and puts you at risk of developing a blood clot.
A high INR result = thin blood, you risk bleeding.

Question 16

Why should warfarin never be given to pregnant women?

Answer 16

It is teratogenic

Question 17

Give an example of an LMWH

Answer 17

Enoxaparin/ Tinzaparin

Question 18

What scoring system is used to calculate risk of thrombosis?

Answer 18

Chads-vasc

Question 19

Which surgeries carry the highest risk of thrombosis?

Answer 19

Orthopaedic

Question 20

Which surgeries carry highest risk of bleeding?

Answer 20

Neuro, spinal or eye surgery

Question 21

Which class of anti-coagulants carries a significantly lower risk of intracranial bleeding?

Answer 21

DOACs

Question 22

What is the best drug to use as a long-term anticoagulant in a patient who has had an idiopathic VTE?

Answer 22

DOACs

Question 23

Recall 3 minor precipitants of thrombosis

Answer 23

COPD
flights
trauma

Question 24

After someone has suffered a thrombosis due to a minor precipitant, how long should they be anti-coagulated for?

Answer 24

3 months

Question 25

Recall the order in which the different coagulation factors in the intrinsic pathway catalyse each other?

Answer 25

12 11 9 8 10 - common

Question 26

Which coagulation measure is used to monitor heparin therapy?

Answer 26

APTT

Question 27

Which coagulation measure is used to monitor warfarin therapy?

Answer 27

(INR) you must monitor

Question 28

Which factor does the extrinsic pathway start with?

Answer 28

tissue factor which goes on to activate factor VII to factor VIIa

Question 29

5 things that increase risk of thrombosis?

Answer 29

 Reduced prothrombin  Thrombocytopenia  Reduced protein C  Elevated anti-thrombin  Increased fibrinolysis

Question 30

Virchow triad?

Answer 30

intravascular vessel wall damage, stasis of flow, and the presence of a hypercoagulable state.

Question 31

give 2 antiplatelet factors secreted by vessel wall

Answer 31

 Prostacyclin (PGI2) from vessel wall  NO

Question 32

which factors confers the highest risk of thrombosis?

Answer 32

first antithrombin deficiency then APC, FVL

Question 33

what is factor 2 and 2a?

Answer 33

2 - prothrombin 2a - thrombin

Question 34

give an advantage of DOAC's over warfarin?

Answer 34

no monitoring required

Question 35

how do you monitor heparin therapy and what for?

Answer 35

LMWH - anti-10a assay - renal failure, weight loss/gain unfractionated - anti 10a assay or APTT

Question 36

which factor has the shortest half life and which has the longest

Answer 36

7 - 6 hours = shortest 2 - 60 hours = longest

Question 37

give 4 methods of thromboprophylaxis

Answer 37

 LMWH – Tinzaparin or Clexane, not monitored  TED (Thrombo-Embolus Deterrent (TED) ) stockings for surgery or if heparin CI  Flowtron – intermittent compression – increases flow  Sometimes DOAC +/- aspirin

Question 38

when is no coagulation, short term and long term indicated?

Answer 38

o After a surgical precipitant, no long-term anticoagulation needed o After minor precipitants, 3 months anticoagulation usually adequate o If idiopathic cause  long-term anticoagulation (10-20% recurrence in 2 years)

Question 39

what score to predict probability of a PE? what's the treatment?

Answer 39

wells score if over 4 CTPA Low molecular weight heparin (LMWH).

Question 40

what are factor 1,2,3 known as?

Answer 40

Factor I - fibrinogen Factor II - prothrombin Factor III - tissue thromboplastin (tissue factor)

Question 41

liver must be able to use vitamin k to produce which factors?

Answer 41

2,7,9,10

Question 42

which factor remains at the same level throughout life from brith to adulthood

Answer 42

factor 8 (called stable factor)

Question 43

what is the extrinsic pathway

Answer 43

The Extrinsic pathway is the other route to coagulation. It requires Tissue Factor (tissue thromboplastin), a substance which is "extrinsic to", or not normally circulating in the vessel. Tissue Factor is released when the vessel wall is ruptured. starts w Factor 7 to 7a intrinsic - aptt (heparin acts here) extrinsic - pt

Question 44

explain link between INR and PT

Answer 44

``` An INR (international normalized ratio) is a type of calculation based on PT test results. Prothrombin is a protein made by the liver. It is one of several substances known as clotting (coagulation) factors. INR of 2-3 = prothrombin time 2 to 3 times as long as in a person not on warfarin with normal clotting, using standardised conditions ```

Question 45

outline the interpretation of PT and APTT together in bleeding

Answer 45

both prolonged = DIC both normal = thrombocytopenia, factor XIII deficiency, mild form of von Willebrand’s disease, PT prolonged, APTT normal = liver disease, decreased vitamin K, decreased or defective factor VII APTT prolonged, PT normal = decreased or defective factor VIII, IX, XI or XII, von Willebrand disease, or lupus anticoagulant present

Question 46

what begins the common pathway

Answer 46

factor 5