Week 3

Question 1

How are platelets formed?

Answer 1

Budding off from megakaryocytes

Question 2

What is the lifespan of platelets?

Answer 2

7-10 days

Question 3

What causes platelet adhesion after vessel wall injury in primary haemostasis?

Answer 3

Exposure of collagen and releasing of vWF

Question 4

What are the two stages of haemostasis?

Answer 4

Primary - formation of platelet plug

Secondary - formation of fibrin clot

Question 5

What 3 things can use failure of platelet plug formation?

Answer 5

Vascular - loss of collagen
Platelets - decrease in number or function (drugs)
Decrease in vWF

Question 6

What symptoms would you see in primary haemostasis failure?

Answer 6

Spontaneous bleeding and purpura
Mucosal bleeding - epistaxis, gi, menorrhagia
Intracranial haemorrhage

Question 7

How can you screen for primary haemostasis failure?

Answer 7

Platelet count

Question 8

What causes production of megakaryocytes and platelets?

Answer 8

Thrombopoietin

Question 9

What causes conversion of prothrombin to thrombin?

Answer 9

V/Xa

Question 10

What causes conversion of fibrinogen into fibrin?

Answer 10

Thrombin

Question 11

What affect does thrombin have on IX?

Answer 11

Activates it

Question 12

What 3 things could case failure of secondary haemostasis?

Answer 12

Single clotting factor deficiency
Multiple clotting factor deficiency
Increased fibrinolysis

Question 13

What 2 tests can you do for fibrin clot formation and what factors do they represent?

Answer 13

Prothrombin time - TF, VIIa

Activated partial thromboplastin time - VIII/IXa

Question 14

What breaks down fibrin to fibrin degradation products?

Answer 14

Plasmin

Question 15

What does antithrombin do?

Answer 15

Inactivates Xa and thrombin

Question 16

What do protein C and S do?

Answer 16

Inactivate Va and VIIIa

Question 17

What is the commonest cause of platelet plug formation failure?

Answer 17

Thrombocytopenia

Question 18

What are the 2 causes of thrombocytopenia?

Answer 18

Increased destruction - DIC, immune thrombocytpoenic purpura, hyersplenism
Reduced production

Question 19

Name 2 causes of reduced platelet function?

Answer 19

Drugs - aspirin, NSAIDS

Renal failure

Question 20

What mode of inheritance if von willebrands disease?

Answer 20

Autosomal dominant

Question 21

Name 1 vascular cause of platelet plug formation failure?

Answer 21

Henoch schonlein purpura

Question 22

What are the 3 causes of multiple clotting factor deficiencies?

Answer 22

Liver failure
Vitamin K deficiency
Complex coagulopathy

Question 23

What does liver failure cause clotting factor deficiencies?

Answer 23

Because clotting factors are produced in hepatocytes

Question 24

Which clotting factors are carboxylated by vitamin K?

Answer 24

II, VII, IX, X

Question 25

What is required for vitamin k absorption?

Answer 25

Bile salts

Question 26

Name the 3 steps of disseminated intravascular coagulation?

Answer 26

Excessive activation of haemostasis Microvascular thrombus Clotting factor consumption

Question 27

Which types of haemophilia is more common?

Answer 27

A

Question 28

What factors are involved in haemophilia A and B?

Answer 28

A - VIII | B - IX

Question 29

What is the normal PT time?

Answer 29

10-14 seconds

Question 30

Where is the abnormality of PT is prolonged?

Answer 30

Extrinsic pathway

Question 31

Causes of prolonged PT?

Answer 31

Liver disease, warfarin, DIC

Question 32

What is the normal APTT time?

Answer 32

30-40 seconds

Question 33

Where is the abnormality if the APTT is prolonged?

Answer 33

Intrinsic pathway

Question 34

Causes of prolonged APTT?

Answer 34

Liver disease Heparin Haemophilia DIC

Question 35

How does Heparin work?

Answer 35

It potentiates anti thrombin

Question 36

What is the benefit of LMWH over unfractionated?

Answer 36

Less monitoring needed

Question 37

Name 2 LMWH's?

Answer 37

Fragmin, dalteparin

Question 38

How do you monitor unfractionated heparin?

Answer 38

APTT

Question 39

What can be used to reverse heparin?

Answer 39

Protamine Sulphate

Question 40

How does warfarin work?

Answer 40

Block ability of vitamin K to carboxylate

Question 41

How is INR calculated?

Answer 41

Patients PT/Mean normal PT

Question 42

How does dabigatran work?

Answer 42

Thrombin inhbitor

Question 43

How to rivaroxiban and apixiban work?

Answer 43

Xa inhbitors

Question 44

What sort of drugs are needed to treat an arterial thrombosis?

Answer 44

Anti platlets

Question 45

What sort of drugs are needed to treat a venous thrombosis?

Answer 45

Anti-coagulants

Question 46

Name 4 risk factors for arterial thrombosis?

Answer 46

High cholesterol Diabetes Hypertension Smoking

Question 47

Name 2 conditions caused by a stable atherosclerotic plaque?

Answer 47

Stable angina and intermittent claudication

Question 48

Name 2 conditions caused by an unstable atherosclerotic plaque?

Answer 48

MI or stroke

Question 49

How does clopidogrel?

Answer 49

ADP receptor antagonist

Question 50

What type of dipyridamole?

Answer 50

Phosphodiesterase

Question 51

When should anti platelets be stopped before elective surgery?

Answer 51

7 days