Bleeding Disorders

Question 0

Describe the process of haemostasis

Answer 0

1. Damage to vessel wall
2. Collagen and tissue factor are exposed
3. VWF binds to the collagen
4. Platelets adhere to the vWF-collagen
5. Tissue factor and platelets activate clotting factors to make thrombin
6. Thrombin converts fibrinogen to a fibrin clot
7. Stable fibrin clot is formed

Question 1

What are the components of blood?

Answer 1

55% plasma
<1% white blood cells and platelets
45% red blood cells

Question 2

What can go wrong with haemostasis?

Answer 2

1. Abnormal primary haemostasis:
   - reduced platelet number or function
   - reduced von willebrand factor
2. Abnormal coagulation pathway
   - reduced clotting factors

Question 3

What is von willebrand disease?

Answer 3

Most common inherited bleeding disorder. A deficiency of vWF or if vWF doesn’t work properly. Therefore blood can’t clot properly and patient is prone to bleeding and bruising. Inability to carry factor 8 (it normally carries this if working properly)

Question 4

How can you identify patients with abnormal haemostasis?

Answer 4

1. Clinical evaluation (bleeding history, medical history, drug history)
2. Laboratory evaluation (full blood count, clotting screen: PT and aPTT, if abnormal these are usually higher. INR test is a ratio of patients PT to ‘normal’ PT.

Question 5

What’s aPTT?

Answer 5

Activated partial thromboplastin time

Question 6

Can a lab tests tell you whether a bleeding disorder is present?

Answer 6

No as they don’t all cause abnormal FBC, PT 95 aPTT and if they are abnormal doesn’t necessarily mean increased bleeding risk. Further specialist investigation is always required to be sure.

Question 7

What are examples of heritable bleeding disorders?

Answer 7

Vin Willebrand disease

Haemophilia A

Question 8

What are examples of acquired disorders?

Answer 8

Reduced playlet number eg leukaemia
Liver disease
Kidney disease
Anticoagulant or anti-platelet drugs

Question 9

What drugs can be given in mild VWD?

Answer 9

Desmopressin (releases endogenous vWF)
Tranexamic acid (reduces clot break down)

Question 10

What’s immune thrombocytopenia?

Answer 10

Immune mediated destruction of platelets due to autoantibody production. Reduced platelet number. ‘Idiopathic’ or ‘secondary’ infection . Abnormal primary haemostasis.

Question 11

What’s the treatment for immune thrombocytopenia?

Answer 11

Long term disease control: 
-immunosuppression with steroids
-splenectomy
Treatment of bleeding:
-tranexamic acid
-platelet transfusion only in emergencies

Question 12

What can any type of liver disease cause?

Answer 12

Bleeding problems as reduced production of all coagulation factors, low platelets. Causes an abnormal coagulation pathway and primary haemostasis.

Question 13

How can you treat bleeding in liver disease?

Answer 13

Tranexamic acid
Vit K
Fresh frozen plasma for emergency treatment of bleeding.

Question 14

Which drugs affect haemostasis?

Answer 14

Anti-thrombotic drugs
Anti-platelet drugs (inhibit arterial thrombosis) eg: aspirin/clopidogrel, drugs with unintentional platelet effects like NSAID’s, statins etc
Anti-coagulant drugs (inhibit coagulation pathway) eg warfarin, heparin.

Question 15

How does warfarin work?

Answer 15

It’s an oral anticoagulant. Long term treatment to prevent venous and arterial thrombosis. Prevents the synthesis of clotting factors. Increases PT and aPTT (takes longer to clot). Dose can be monitored by looking at the PT which is expressed as INR should be kept between 2 and 3. Tested every 4-6 weeks.

Question 16

What’s low molecular weight and unfractionated heparin used for?

Answer 16

Treatment of prevention of venous and arterial thrombosis (for urgent treatment and pregnancy).
Main anticoagulant used in hospital. Inhibits coagulation factors. UFH is monitored using aPTT. LMWH doesn’t require monitoring.

Question 17

What’s the treatment for immune thrombocytopenia?

Answer 17

Long term disease control: 
-immunosuppression with steroids
-splenectomy
Treatment of bleeding:
-tranexamic acid
-platelet transfusion only in emergencies

Question 18

What can any type of liver disease cause?

Answer 18

Bleeding problems as reduced production of all coagulation factors, low platelets. Causes an abnormal coagulation pathway and primary haemostasis.

Question 19

How can you treat bleeding in liver disease?

Answer 19

Tranexamic acid
Vit K
Fresh frozen plasma for emergency treatment of bleeding.

Question 20

Which drugs affect haemostasis?

Answer 20

Anti-thrombotic drugs
Anti-platelet drugs (inhibit arterial thrombosis) eg: aspirin/clopidogrel, drugs with unintentional platelet effects like NSAID’s, statins etc
Anti-coagulant drugs (inhibit coagulation pathway) eg warfarin, heparin.

Question 21

How does warfarin work?

Answer 21

It’s an oral anticoagulant. Long term treatment to prevent venous and arterial thrombosis. Prevents the synthesis of clotting factors. Increases PT and aPTT (takes longer to clot). Dose can be monitored by looking at the PT which is expressed as INR should be kept between 2 and 3. Tested every 4-6 weeks.

Question 22

What’s low molecular weight and unfractionated heparin used for?

Answer 22

Treatment of prevention of venous and arterial thrombosis (for urgent treatment and pregnancy).
Main anticoagulant used in hospital. Inhibits coagulation factors. UFH is monitored using aPTT. LMWH doesn’t require monitoring.