Bleeding Disorders

Question 1

What is Von Willebrand Disease (vWF)?

Answer 1

A genetic disorder characterised by missing or defective vWF.

Question 2

What is the function of von Willebrand Factor (vWF)?

Answer 2

vWF is a protein that promotes platelet aggregation to vascular walls and subsequent clot formation.
It also plays a role in the transport of Factor VIII and in preventing its premature destruction

Question 3

Describe the defect in each of the three types of vWD

Answer 3

Type I: Reduced levels of normal vWF
Type II: Production of defective vWF
Type III: A total lack of vWF, and a reduced level of Factor VIII.

Question 4

Which of the three types of vWD are of autosomal dominant and autosomal recessive inheritance?

Answer 4

Type I and II are AD.

Type III is AR.

Question 5

What treatment options are available for vWD?

Answer 5

Anti-fibrinolytic drugs - Tranexamic acid - given to reduce bleeding.
DDAVP (Desmopressin) - a synthetic vasopressin analogue. DDAVP helps release vWF and Factor VIII from stores. Not useful in Type II and III vWD.
For vWD Type II and III, give Factor VIII concentrate, FFP and cryoprecipitate if severe.

Question 6

What is TTP?

Answer 6

Thrombotic Thrombocytopenic Purpura

Question 7

What is the pathophysiology in TTP?

Answer 7

ADAMTS-13 deficiency, leading to increase vWF.

There is also thrombocytopenia and increased bleeding time.

Question 8

What are the 5 characteristic features of TTP?

Answer 8

1. Anaemia
2. Thrombocytopenia
3. Fever
4. Neurological symptoms
5. Renal dysfunction

Question 9

What clotting factors are Vitamin K dependent clotting factors?

Answer 9

Clotting factors II, VII, IX and X.

Question 10

Which clotting factors are in the intrinsic pathway?

Answer 10

Clotting factors VIII, IX, XI and XII

Question 11

Describe the pathophysiology of Haemophilia A and B.

Answer 11

Haemophilia A: Deficiency of Factor VIII

Haemophilia B: Deficiency of Factor IX

Question 12

What are the diagnostic features of DIC?

Answer 12

Low platelet count
Prolonged PT and APTT
Low Fibrinogen
High D-dimer

Question 13

What types of defect causing abnormal bleeding often presents with bleeding into joints and soft tissue (internal bleeding)?

Answer 13

Defective coagulation - often with bleeding into joints and internal bleeding.

Vascular disorders, thrombocytopaenia and defective platelet function - tend to be associated with bleeding from mucous membranes and into the skin.