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Flashcards in Bleeding and Thrombosis Deck (54)
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1

List causes of failure of platelet plug formation (failure of primary haemostasis)

Vascular disease
Low platelet count (thrombocytopenia)
Impaired platelet function
Von Willbrand Factor disease

2

What is the main vascular cause of failed primary haemostasis?

Vasculitis e.g. Henoch-Schonlein purpura

3

Thrombocytopenia can be due to what 2 factors?

Reduced platelet production (marrow disorder)
Increased platelet destruction

4

List the main causes of platelet destruction

Coagulopathy (DIC)
Autoimmunity
Hypersplenism

5

Von Willebrand Factor deficiency is mainly hereditary and follows what inheritance pattern?

Autosomal dominant

6

List causes of failure of fibrin clot formation (failure of secondary haemostasis)

Multiple clotting factor deficiency
Single clotting factor deficiency

7

List causes of multiple clotting factor deficiency

DIC
Liver failure
Vitamin K deficiency
Warfarin therapy

8

What is the main cause of single clotting factor deficiency?

Haemophilia

9

Which clotting factors are carboxylated (activated) by vitamin K?

II
VII
IX
X

10

List causes of vitamin K deficiency

Poor dietary intake
Malabsorption
Obstructive jaundice
Antagonists (warfarin)
Haemorrhagic disease of newborn

11

What is disseminated intravascular coagulation (DIC)?

Excessive activation of the haemostatic system, causing depletion of all clotting factors

12

What are the main signs of DIC?

Abdominal bruising/purpura
Generalised bleeding

13

What are the main screening tests/investigations for haemostasis?

Platelet count
Prothrombin time
APT time

14

List the main causes of DIC

Sepsis
Obstetric emergencies
Malignancy
Hypovolaemic shock

15

How is DIC treated?

Treat underlying cause
Replace clotting factors

16

What pattern of inheritance does haemophilia follow?

X-linked

17

What are the two types of haemophilia? Which is more common?

Haemophilia A (VIII deficiency)
Haemophilia B (IX deficiency)
A is more common than B

18

Where does bleeding usually occur in haemophilia?

Ankles
Knees
(haemarthroses)

19

Is haemophilia a disorder of primary or secondary haemostasis?

Secondary haemostasis

20

Prothrombin time is usually normal in a haemophiliac. True/False?

True
Isolated prolonged APT time

21

What is the main cause of arterial thrombosis?

Atherosclerosis

22

How is atherosclerosis treated?

Antiplatelet (aspirin)

23

Venous thrombosis is caused by Virchow's triad. List the components of this triad

Hypercoagulability
Vessel wall damage
Stasis of blood flow

24

What is the risk of a deep vein thrombosis in the leg?

Clot can form and end up in pulmonary circulation, causing pulmonary embolism

25

List risk factors for venous thromboembolism

Age
Obesity
Pregnancy
Oestrogen therapy (OCP)
Trauma/surgery
Infection
Paralysis
Thrombophilia
Previous DVT/PE

26

What are the main mechanisms of thrombophilia?

Increased coagulation activity
Decreased fibrinolytic activity
Decreased anticoagulant activity

27

What are the main naturally occuring anticoagulants?

Serine protease inhibitors (antithrombin)
Protein C and S

28

What is Factor V Leiden?

Variant of factor V that cannot be inhibited as effectively - increases risk of venous thrombosis due to less anticoagulation

29

List the main hereditary thrombophilias

Factor V Leiden
Antithrombin deficiency
Protein C and S deficiency
Prothrombin mutation

30

What is the main acquired thrombophilia?

Antiphospholipid syndrome