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Flashcards in Bleeding and coagulation Deck (54)
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1

What is haemostasis?

The arrest of bleeding and maintenance of vascular patency

2

What is primary and secondary haemostasis?

Primary haemostasis is the formation of a platelet plug

Secondary haemostasis is the formation of a fibrin clot

3

Where are platelets formed?

Platelets are formed in the bone marrow by budding from megarokaryocytes

4

What is the life span of a platelet?

7-10 days

5

What are some of the possible causes of failure of platelet plug formation?

Vascular causes
E.g reduced collagen in blood vessels in elderly patients and inherited causes such as marfan's

Thrombocytopenia due to anti-platelet medications and NSAIDs

Von Willebrand disease

Lack of vitamin C e.g scurvy

6

Which is generally more severe, failure of primary haemostasis or failure of secondary haemostasis?

Failure of secondary haemostasis

7

How does failure of platelet plug formation present?

Spontaneous bruising and purpura (usually in the lower limbs due to gravity)

Mucosal bleeding (epistaxis, GI, conjunctival and menorrhagia)

Intracerebral bleeds in severe cases

8

What is the screening test for primary haemostasis?

Platelet count

9

What are the screening tests for secondary haemostasis?

Prothrombin time

Activated partial thromboplastin time

10

What are some of the naturally occurring anticoagulants?

Anti-thrombin

Protein C and S

11

Does prothrombin time test the extrinsic or the intrinsic pathway?

Extrinsic pathway

It measures the propagation side of fibrin clot formation

12

What is the normal range for prothrombin time?

12-13 seconds

13

What are some of the causes of a prolonged PT?

Warfarin therapy

DIC

Liver disease

Vitamin K deficiency (premature babies and ITU patients)

14

Does the APTT test the extrinsic or the intrinsic pathway?

Intrinsic pathway

Measure the amplification side of fibrin clot formation

15

What is the normal range for APTT?

30-40 seconds

16

What are some of the possible causes of prolonged APTT?

Heparin therapy

Haemophilia

VW disease

Antiphospholipid syndrome

17

Thrombocytopenia is the most common cause of primary haemostatic failure. What are some of the possible cause of thrombocytopenia?

Cancer

DIC

Immune thrombocytopenic purpura

18

What is immune thrombocytopenic purpura?

An autoimmune cause of thrombocytopenia which involves antibodies against platelets

19

how is immune thrombocytopenic purpura managed?

Prednisolone (steroids)

20

VWF deficiency can be acquired or hereditary. Which is more common?

Mostly hereditary

21

What mode of inheritance does VWF disease involve?

Autosomal dominant

22

VWF affects men and women equally, so why are men less likely to be diagnosed?

Women are more likely to present as they may have the symptom of menorrhagia

The condition may not become apparent in men until they have an accident or operation and notice abnormal bleeding

23

Is haemophilia due to a single or multiple clotting factor deficiencies?

Single clotting factor deficiency

24

Where are coagulation factors synthesised?

In hepatocytes in the liver

25

What happens to coagulation factors in liver failure?

Coagulation factors are reduced

26

What are the four clotting factors?

II, VII, IX and X

(2,7,9 and 10)

27

Where is vitamin K absorbed?

What does it require for absorption?

Vitamin K is absorbed in the upper intestine

Requires bile salts for absorption

28

What are some of the possible causes of vitamin K deficiency?

Warfarin

Diet/ malabsorption

Obstructive jaundice
(e.g pancreatic cancer)

Haemorrhagic disease of the newborn

29

Why does DIC occur?

All the clotting factors are used up in thrombus formation

30

What are some of the possible causes of DIC?

Sepsis

Obstetric emergencies

Malignancy

Hypovolaemic shock (hypoxia causes tissue damage)