Bleeding disorders

Question 1

Three processes that stop bleeding?

Answer 1

1. vasoconstriction
2. platelet aggregation
3. coagulation cascade

Question 2

Vascular and platelet causes

Answer 2

VASCULAR DEFECTS
Inherited 
 - Connective tissue diseases 
Acquired 
 - Infection = meningococcal, measles 
 - Henoch-schoenlein purpura (IgA vasculitis) 

PLATELET DISORDER 
Decreased production 
 - Viral infection 
 - Drugs + Radiotherapy 
 - Bone Marrow failure = aplastic and megaloblastic anaemia, marrow infiltration eg. leukaemia or myeloma 

Increased Destruction

• Autoimmune = ITP, SLE
• Non-immune = DIC, Thrombotic thrombocytpoenic purprura (TTP), Sequestration in hypersplenism

Poorly functioning Platelets

• Myeloproliferative disease
• NSAIDs
• elevated urea

Question 3

Coagulation disorders

Answer 3

INHERITED 
Haemophilia 
  - X linked, mainly affecting men
  - type A = F8 deficiency, Type B = F9 deficiency
  - treat by replacing missing factor 

Von Willebrand’s Disease

• VWF brings platelets together and causes binding with each other and with endothelial wall damage
• give VWF rich factor 8 for surgery etc

ACQUIRED
Anticoagulants
- Warfarin, Rivaroxaban, Dabigatran

Vitamin K deficiency

Liver Disease
- decreased production of all factors except 8

DIC
- widespread activation of coagulation causing thrombus, followed by bleeding/bruising as clotting factors are used up

Massive blood loss
- Loss of factors and dilution of remaining factors with fluids

Question 4

Investigations necessary

Answer 4

1. Platelet count
2. Megakaryocytes in marrow
   - low = decreased production
   - high = increased destruction
3. Anti-platelet AB
4. APTT
   - factors 8,9,11,12 are only assessed using APTT
   - correctable = factor deficiency, not = inhibitor eg. SLE
5. PR
   - 2,5,7,10, fibrinogen, prothrombin = extrinsic and common
   - If PR high and APTT normal then must be factor 7
6. Thrombin Clotting Time (TCT)
   - Fibrinogen deficiency
   - Thrombin inhibitor (eg. heparin and dabigatran)
7. Factor Assays

Question 5

Magegement:

Answer 5

Control any bleeding and eliminate the inhibitor
- reverse and stop Anti-coags
- give steroids and immunosuppresives in acute
avoid giving blood/plasma but give FFP if needed
- educate pts on increased bleeding risk