Haematology 3 - Coagulation Flashcards Preview

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Flashcards in Haematology 3 - Coagulation Deck (25)
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1

Recall 4 endogenous anti-coagulants

Anti-thrombin
TFPI
Protein C
Protein S

2

Recalll 3 procoagulant factors and 1 anticoagulant factor that are synthesised in vascular endothelium

PGI2
vWF
Plasminogen activators
Thrombomodulin

3

Recall the 2 possible mechanisms of platelet activation

1. vWF binds to Gp1b which binds to platelets to activate them
2. Endothelial Gp1a binds directly to the platelet to activate

4

Via which receptors to platelets adhere to each other, and what is needed for this to happen?

GpIIb/IIIa using fibrinogen and calcium

5

Recall one inducer and one inhibitor of platelet aggregation, and the enzyme required for the synthesis of both

Thromboxane A2 increases aggregation
PGI2 inhibits platelet aggregation
COX enzyme

6

Why does aspirin have an anticoagulant effect?

Inhibits COX enzyme which is necessary for thromboxane A2 production

7

What is the rate-limiting step in fibrin formation?

Factor Xa

8

Which clotting factors are vitamin K dependent?

II, VII, IX and X

9

How does vitamin K activate clotting factors?

Via gamma decarboxylation

10

Recall 4 factors that promote fibrinolysis

Factor IXa, Xa, TPA and urokinase
These all increase plasmin production which cleaves fibrin

11

What is the role of plasmin?

Breaks down fibrin in fibriolysis

12

What is the mechanism of action of heparin?

Augments anti-thrombin effect

13

What is the role of proteins C and S?

Inactivate Factors 5 and 8

14

What are the roles of tissue factor and TFPI

Tissue factor activates factor Xa
TFPI neutralises tissue factor

15

How can platelet and coagulation factor disorders be distinguisghed clinically?

Platelet problems --> immediate superficial bleeding
Coagulation factor deficiencies --> delayed, deep bleeding and haemarthroses

16

Recall 4 possible causes of ITP

Vancomycin
SLE
Sarcoidosis
Lymphoproliferative disease

17

Why does DIC cause thrombocytopaenia?

Increased utilisation

18

How does the presentation of auto-immune thrombocytopaenia differ between children and adults?

In children it tends to be acute whereas it is chronic in adults

19

How should autoimmune ITP be treated?

Steroids
IV Ig (to compete with auto-antibody)

20

What is the expected APTT and PT results in haemophilia?

APTT prolonged
Normal PT

21

What is the inheritance pattern of von willebrand disease?

Autosomal dominant

22

What are the 3 different types of von willebrand disease?

Type 1: partial quantitative deficiency
Type 2: qualitative deficiency
Type 3: complete quantitative deficiency

23

Recall some causes of DIC

Sepsis
Trauma
Cancer
Obstetric complications
Vascular disorders
Reaction to a toxin

24

What is DIC?

Activation of both coagulation and fibrinolysis causing both thrombosis and bleeding

25

What is the antidote to heparin?

Protamine sulphate

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