Acquired bleeding disorders

Question 1

What are the acquired bleeding disorders?

Answer 1

-Vit K deficiency
-Liver disease
-Massive transfusion syndrome
-Disseminated Intravascular coagulation
Iatrogenic
-Acquired inhibitors

Question 2

What is the most important factor when assessing a patient with a potential bleeding disorder?

Answer 2

Family/medical history

Question 3

If the APTT is prolonged, how do we determine if there is a blood deficiency or inhibitor?

Answer 3

Mix 50:50 patient blood with normal blood

If corrected = deficiency of clotting factor

If not corrected = inhibitory substance stopping reactions working

Question 4

What does liver disease do to the platelet count, PT, APTT, and CT?

Answer 4

• reduced platelets (portal hypertension congests spleen where 1/3 platelets are produced)
• prolong PT, APTT,
• Clotting time = normal

Question 5

What does DIC do to the platelet count, PT, APTT, and CT?

Answer 5

Reduces platelets and prolongs all coagulation screening times

Question 6

What does massive transfusion do to the platelet count, PT, APTT, and CT?

Answer 6

Reduced platelets (relative plasma ratio reduces with RBC transfusion)

Prolonged ATPP and TP time

Normal clotting time

Question 7

What does warfarin do to platelet count, PT, APTT, and CT?

Answer 7

Noam platelet time

Prolonged APTT (grossly), PT (mildly) but normal clotting time

Question 8

What does heparin do to platelet count, PT, APTT, and CT?

Answer 8

normal platelet count

Prolonged APTT and prolonged clotting time

Question 9

What does circulating anticoagulant do to platelet count, PT, APTT, and CT?

Answer 9

Normal platelet count, CT

Might prolong PT/APTT

Question 10

What are the vit K dependent clotting factors?

Answer 10

II (prothrombin), VII, IX, X

Question 11

Where are all clotting factors produced?

Answer 11

Liver haptocytes (except for factor 8 - Kuppfer cells?)

Question 12

What is the function of vitamin K?

Answer 12

Cofactor for II, VII, IX, X after they have been synthesised

Add gamma glutamyl carboxylase to end of proteins, which activates them

Question 13

How does warfarin act as an anticoagulant?

Answer 13

Vitamin K antagonist

Blocks recycling of vit K (vitamin K reductase) - II, VII, IX, X cannot function

Question 14

What factors are affected by bit K deficiency?

Answer 14

II, VII, IX, X

Question 15

What are the causes of vitamin K deficiency?

Answer 15

Obstructive jaundice/liver disease

Prolonged nutritional deficiency

Borad spectrum antibiotics - vit K produced by gut flora

Neonates - 1-7 days - Vit k deficient

Question 16

What causes impaired haemostasis in liver disease?

Answer 16

Portal hypertension - thrombocytopenia with congested spleen

Platelet dysfucntion

All clotting factors reduced except 8 (produced in Kuppfer cells)

Excessive plasmin activity

Question 17

What is the definition of a massive transfusion?

Answer 17

Transfusion pf a volume of blood equal to total patients blood volume in less than 24 hrs or 50% of patients total blood volume in less than 3 hrs

Question 18

How does massive transfusion effect haemostats?

Answer 18

Dilution effects of platelets and coagulation factors, mainly factors V, VIII and fibrinogen

Question 19

What are other complications of massive transfusions?

Answer 19

Hypothermia
Citrate toxicity
DIC

Question 20

What is the mechanism by which DIC inhibit haemostats?

Answer 20

Inappropriate activation of coagulation and fibrinolytic systems.

Consumption of clotting factors and platelets with activation of fibrinolysis

Free fibrin plugs also cause thrombosis and organ failure

Question 21

What is the main causes of DIC (acute/chronic)?

Answer 21

Acute
-Sepsis - tissue damage/necrosis

Chronic DIC
- malignancy