Prolonged bleeding

Question 1

What are congenital causes of prolonged bleeding?

Answer 1

Haemophilia A and B
Von Willebrand’s Disease

Question 2

How does renal failure impact bleeding?

Answer 2

Impairs platelet function

Question 3

What are acquired causes of prolonged bleeding?

Answer 3

• Therapeutic use of:
  Anticoagulants
  Antiplatelets
• Renal failure
• Hepatic failure
• Bone marrow failure

Question 4

What is purpose of haemostasis?

Answer 4

Prevent blood loss

Question 5

When does haemostasis start?

Answer 5

When BV damaged / severed / ruptured

Question 6

What are the mechanisms of haemostasis?

Answer 6

Vascular spasm
Platelet activation
Platelet aggregation
Activation of factor X and prothrombin
Fibrin mesh
Blood coagulation

Question 7

How does hepatic failure impact bleeding?

Answer 7

Liver = source of clotting factors
Can impair absorption of vit K to synthesise factors 2, 7, 9, 10

Question 8

How does bone marrow failure impact bleeding?

Answer 8

Reduce production of functional platelets

Question 9

What can lead to bone marrow failure?

Answer 9

Leukaemia
Therapeutic drugs
Renal failure
Alcohol abuse

Question 10

How does Warfarin work?

Answer 10

Interferes with vit K metabolism
Preventing synthesis of factors 2,7, 9, 10
Affects both intrinsic and extrinsic pathways

Question 11

Importance of factor X?

Answer 11

Gets converted to factor Xa which converts prothrombin to thrombin which converts fibrinogen to fibrin which forms the clot

Question 12

How do DOACs work?

Answer 12

Affects factor X conversion into factor Xa

Question 13

What type of drug is Warfarin?

Answer 13

Vitamin K antagonist
Type of anticoagulant

Question 14

Examples of DOACs?

Answer 14

Apixaban
Rivaroxaban
Edoxaban
Dabigatran

Question 15

Disadvantages of warfarin over DOACs?

Answer 15

• Affected by foods
• Takes a long time to work
• Long time for effects to wear off after meds stopped
• Affects both intrinsic and extrinsic pathways, not specific, less predictable

Question 16

Which foods can interact with Warfarin?

Answer 16

Green tea
Liver
Broccoli
Sprouts
Grapefruit
Alcohol
Pomegranate / cranberry juice

Items rich in Vitamin K

Question 17

Which drugs interact with Warfarin and increase INR?

Answer 17

Miconazole
Fluconazole
Metronidazole
Erythromycin

All increase risk of haemorrhage

Question 18

What prevents activation of platelets and clotting factors in BV normally?

Answer 18

Endothelial cells lining BV wall

Question 19

What happens when BV wall damaged?

Answer 19

Lining of endothelial cells gone
Collagen fibres exposed
Foreign material introduced into BV
Platelets activated
Intrinsic and extrinsic mechanisms activated

Question 20

How is blood clotting balanced?

Answer 20

Thrombin simultaneously catalyses plasminogen conversion to plasmin
Plasmin breaks down fibrin clots
Process fibrinolysis

Question 21

Warfarin pt needs XLA what to do?

Answer 21

Never stop medx
Evidence base says stopping Warfarin cause more problems and SDCEP guidance
Check INR yellow book
If stable get INR within 72 hours of XLA
If unstable get INR within 24 hours of XLA
INR 4 or below
Proceed with XLA
Local haemostatic measures

Question 22

What is most prolonged bleeding caused by in practice?

Answer 22

Iatrogenic
AKA Prescribed medx
E.g. oral antiplatelets, anticoagulants

Question 23

Examples of oral anti platelets

Answer 23

Aspirin
Clopidogrel
Dipyramidole
Ticlopidine

Question 24

How do anti platelets work?

Answer 24

Aspirin irreversibly binds to platelets, prevents aggregation
Clopidogrel irreversibly binds to receptors, prevents aggregation
Ibuprofen reversibly binds to platelets

Question 25

How often are platelets renewed?

Answer 25

10 days

Question 26

Which pts likely to take aspirin / clopidogrel?

Answer 26

Stroke Vascular disease Ischaemic heart disease Thromboembolic disease

Question 27

How to manage aspirin pt?

Answer 27

Do not stop aspirin Takes 10 days for platelets to renew Weeks for effects to be reversed Risk of stopping greater than risk of continuing Use local haemostatic measures

Question 28

What is thrombocytopenia?

Answer 28

Reduced platelet count

Question 29

What is normal platelet count?

Answer 29

150 000 - 450 000 / microlitre

Question 30

What can cause thrombocytopenia?

Answer 30

Leukaemia Anaemia Pregnancy Chronic alcohol abuse Medx Hereditary

Question 31

How to manage pt with thrombocytopenia?

Answer 31

Safe to treat platelet count < 80 000 Get advice haematologist May require steroids / platelet transfusion Bruise very easily = ecchymosis

Question 32

What types of pt on Warfarin?

Answer 32

Atrial fibrillation Recurrent DVT or prev pulmonary embolism Prosthetic heart valve

Question 33

How is haemostasis measured?

Answer 33

Prothrombin time

Question 34

What does prothrombin time reflect?

Answer 34

Activity of factor 7 in clotting cascade

Question 35

How is PT used?

Answer 35

Calculate INR

Question 36

What is INR?

Answer 36

International Normalised Ratio = PT of pt / Mean PT of healthy group

Question 37

What is INR in health compared to therapeutic warfarin range?

Answer 37

Health = 1 Warfarin = 2 - 4

Question 38

What should anticoagulation record contain?

Answer 38

Yellow book Reason for anticoagulation Target INR Contact details of clinic Warfarin dosages Recent INR records - stable or unstable?

Question 39

What is half life of Warfarin? What does this mean?

Answer 39

48 hours Takes 2 days for changes in dose to affect INR

Question 40

Management of Warfarin pt using anti fungal for angular chelitis?

Answer 40

Antifungals = metronidazole / fluconazole / miconazole Antifungals contraindicated for Warfarin pts as increase INR Do not stop Warfarin Prescribe another anti fungal agent

Question 41

Risks associated with increased INR <4?

Answer 41

- Increase risk of haemorrhage - Retinal haemorrhage = visual loss - Haemoarthrosis = loss knee function - Subdural haematoma = death

Question 42

Which drugs interact with Warfarin to decrease INR?

Answer 42

Carbamazepine Increases risk of thrombosis

Question 43

What drug can reduce prolonged bleeding?

Answer 43

Tranexamic acid

Question 44

How does tranexamic acid work and when used?

Answer 44

Stops plasminogen being converted to plasmin So no fibrinolysis Stops clots being digested Not commonly used Mouthwash

Question 45

Why do not prescribe aspirin to children U16

Answer 45

Reyes syndrome

Question 46

Which aspect of haemostasis do antiplatelets affect?

Answer 46

Platelet aggregation

Question 47

Which aspect of haemostasis does Warfarin affect?

Answer 47

Clotting cascade Factors 2, 7, 9, 10

Question 48

Virchow's Triad?

Answer 48

1. Damage to endothelial lining 2. Hyper coagulable state 3. Arterial / venous blood stasis Predispose to thrombosis