Haematology 3 - Coagulation Flashcards

1
Q

Recall 4 endogenous anti-coagulants

A

Anti-thrombin
TFPI
Protein C
Protein S

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2
Q

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

A

PGI2
vWF
Plasminogen activators
Thrombomodulin

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3
Q

Recall the 2 possible mechanisms of platelet activation

A
  1. vWF binds to Gp1b which binds to platelets to activate them
  2. Endothelial Gp1a binds directly to the platelet to activate
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4
Q

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

A

GpIIb/IIIa using fibrinogen and calcium

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5
Q

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

A

Thromboxane A2 increases aggregation
PGI2 inhibits platelet aggregation
COX enzyme

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6
Q

Why does aspirin have an anticoagulant effect?

A

Inhibits COX enzyme which is necessary for thromboxane A2 production

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7
Q

What is the rate-limiting step in fibrin formation?

A

Factor Xa

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8
Q

Which clotting factors are vitamin K dependent?

A

II, VII, IX and X

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9
Q

How does vitamin K activate clotting factors?

A

Via gamma decarboxylation

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10
Q

Recall 4 factors that promote fibrinolysis

A

Factor IXa, Xa, TPA and urokinase

These all increase plasmin production which cleaves fibrin

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11
Q

What is the role of plasmin?

A

Breaks down fibrin in fibriolysis

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12
Q

What is the mechanism of action of heparin?

A

Augments anti-thrombin effect

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13
Q

What is the role of proteins C and S?

A

Inactivate Factors 5 and 8

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14
Q

What are the roles of tissue factor and TFPI

A

Tissue factor activates factor Xa

TFPI neutralises tissue factor

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15
Q

How can platelet and coagulation factor disorders be distinguisghed clinically?

A

Platelet problems –> immediate superficial bleeding

Coagulation factor deficiencies –> delayed, deep bleeding and haemarthroses

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16
Q

Recall 4 possible causes of ITP

A

Vancomycin
SLE
Sarcoidosis
Lymphoproliferative disease

17
Q

Why does DIC cause thrombocytopaenia?

A

Increased utilisation

18
Q

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

A

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

19
Q

How should autoimmune ITP be treated?

A
Steroids
IV Ig (to compete with auto-antibody)
20
Q

What is the expected APTT and PT results in haemophilia?

A

APTT prolonged

Normal PT

21
Q

What is the inheritance pattern of von willebrand disease?

A

Autosomal dominant

22
Q

What are the 3 different types of von willebrand disease?

A

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

23
Q

Recall some causes of DIC

A
Sepsis
Trauma
Cancer
Obstetric complications
Vascular disorders
Reaction to a toxin
24
Q

What is DIC?

A

Activation of both coagulation and fibrinolysis causing both thrombosis and bleeding

25
Q

What is the antidote to heparin?

A

Protamine sulphate