Haematology 1a Haemostasis & Bleeding disorders

Question 1

What two mechanisms act simultaneously during Haemostasis?

Answer 1

• Primary

- Secondary

Question 2

What is the role of vWF? (2)

Answer 2

• Being the intermediary that joins platelet to collagen

- Allows platelet aggregation

Question 3

Describe the events during primary haemostasis (2)

Answer 3

• Reflex vasoconstriction amongst damaged and adjacent vessels
• Platelet plug formation via vWF

Question 4

What are the three pathways in secondary haemostasis?

Answer 4

• Intrinsic Pathway
• Extrinsic Pathway
• Final Common Pathway

Question 5

What is the essential role of the coagulation cascade?

Answer 5

The aim of coagulation is ultimately to reinforce the platelet plug with fibrin

Question 6

When is the intrinsic pathway initiated?

Answer 6

When collagen is exposed

Question 7

When is the extrinsic pathway initiated?

Answer 7

The extrinsic pathway is initiated when damaged tissue releases the protein, tissue factor (Factor III)

Question 8

Which factor is ultimately activated through both pathways?

Answer 8

Factor X

Question 9

All clotting factors with the exception of Factor VIII are manufactured where?

Answer 9

The Liver

Question 10

All clotting factors are manufactured in the Liver besides?

Answer 10

Factor VIII

Question 11

Where are Factor VIII and vWF produced?

Answer 11

Endothelial cells of blood vessels

Question 12

Which factors are vitamin K-dependent?

Answer 12

Factors II, VII, IX and X

2,7,9,10

Question 13

Vascular disorders are which type of haemostatic disorder?

Answer 13

Primary haemostatic disorder

Question 14

vWF disease is which type of haemostatic disorder?

Answer 14

Primary and Secondary haemostatic disorder

Question 15

Platelet disorders are which type of haemostatic disorder?

Answer 15

Primary haemostatic disorder

Question 16

Clotting Factor disorders are which type of haemostatic disorder?

Answer 16

Secondary haemostatic disorder

Question 17

What is a congenital disorder

Answer 17

A congenital disorder is a medical condition that is present at or before birth.

Question 18

Explain how vWF disease is both a primary and secondary disorder

Answer 18

• vWF helps to strengthen factor VIII

- Therefore a deficiency in vWF also affects secondary

Question 19

Haemophilia A and Haemophilia B are examples of congenital or acquired disorders?

Answer 19

Congenital disorders

Question 20

Haemophilia A affects which clotting factor?

Answer 20

Factor VIII

Question 21

Haemophilia B affects which clotting factor?

Answer 21

Factor IX

Question 22

Hereditary Haemorrhagic Telangiectasia:

• Inheritance?
• Appearance?
• Clinical features? (2)

Answer 22

• Autosomal dominant hereditary condition
• Malformations in the skin, mucosa and viscera
• Recurrent nose bleeds
• GI lining bleeding due to chronic iron deficiency

Question 23

What are the dental aspects to consider with Hereditary Haemorrhagic Telangiectasia? (2)

Answer 23

• Bleeding from oral surgery (not troubling)

- Regional LA, Best avoided due to risk of deep tissue bleeding

Question 24

Von Willebrand disease (vWD):

• Causation?
• Inheritance?
• Clinical features? (3)

Answer 24

• Caused by vWF deficiency
• Inherited but not sex linked
• Bruising
• Nose Bleeds
• GI bleeding

Question 25

What drug would be given to manage mild Form Von Willebrand disease (vWD)?

How does it help?

Answer 25

• Desmopressin

- Stimulates release of vWF and factor VIII

Question 26

Dental Relevance of Von Willebrand disease (vWD)? (3)

Answer 26

• Prolonged bleeding into muscles post extraction
• Avoid regional LA
• Avoid NSAIDs

Question 27

What does a dentist need to investigate when treating someone with platelet deficiency?

Answer 27

Need to investigate platelet count before treating as there may be a risk of spontaneous bleeding

Question 28

What are the dental aspects to consider when someone has platelet dysfunction? (3)

Drugs they are taking?
Treatment given?
Problems post treatment?

Answer 28

• Can continue medication during minor dental procedures
• Limit initial treatment area (single extraction at a time)
• Combat post extraction bleeding (ie suture)

Question 29

What type of inheritance causes Haemophilia?

Answer 29

X-Linked inheritance

Question 30

Severity of bleeding in Haemophilia:

• Mild?
• Moderate?
• Severe?

Answer 30

• Bleed minimally, and is usually associated with surgery
• Bleed after minor injury and requires urgent attention
• Bleed very often with or without provocation

Question 31

Haemophilia:

Comment on surgical intervention
This condition increases the risk of what?
What clotting factors have to be regulated?

Answer 31

• Minimise surgical intervention
• High risk of haemorrhage post surgery/LA
• Regulate levels of clotting factor (VIII/IX)

Question 32

List some complications treated by anticoagulant therapy

Answer 32

• Myocardial infarctions
• Strokes or transient ischaemic attacks (mini strokes)
• Deep vein thrombosis
• Pulmonary embolus, a blocked blood vessel in your lung.
• Thrombosis on prosthetic heart valves

Question 33

What does warfarin inhibit? (4)

Answer 33

Inhibits vitamin K dependent clotting factors II, VII, IX, X

Question 34

What are the dental aspects to consider with a patient who is on Warfarin? (2)

Answer 34

• Minimise surgical intervention

- Measure INR 24 hours within surgery

Question 35

How would you manage severe Form Von Willebrand disease (vWD)?

Answer 35

vWF replacement using human plasma rich in vWF and factor VIII