Inherited and acquired bleeding disorders (haematology)

Question 1

What causes bleeding disorders? (4)

Answer 1

Vascular disorders
Platelets disorders
Von willebrand factor disorders
Defective coagulation

Question 2

What do …. deficiency mean?
1. Quantitative
2. Qualitative

Answer 2

1. Not enough platelets, clotting factors etc.
2. There are platelets, clotting factors etc but they are not working (have a defect).

Question 3

What are the vascular bleeding disorders we have? (2)

Answer 3

•Inherited
-Hereditary haemorrhagic telangiectasia
-Connective tissue disorders
•Acquired
-Senile purpura
-Steroid purpura
-Scurvy

Question 4

What are the causes of thrombocytopenia? (5)

Answer 4

Inherited
-Failure of platelet production.
Acquired
-Failure of platelet production.
-Sequestration
-Dilution
-Increase in platelet destruction.

Question 5

What are the disorders of platelet function? (7)

Answer 5

•Hereditary
-Bernard-soulier syndrome
-Storage pool diseases
-Thrombasthena
•Acquired
-Antiplatelet drugs
-Hyperglobulinaemia
-Uraemia
-Myeloproliferative amd myelodysplastic disorders.

Question 6

What are the hereditary coagulation disorders we have? (4)

Answer 6

-Factor VIII deficiency (haemophilia A)
-Factor IX deficiency (haemophilia b)
-Von willebrand disease
-Deficiencies of other coagulation factors.

Question 7

What are the acquired coagulation disorders? (5)

Answer 7

-Massive transfusion syndrome
-Deficiency of Vit-K dependent clotting factors (2,7,9,10)
-Liver disease
-Disseminated intravascular coagulation.
-Coagulation caused by antibodies.

Question 8

What is the diagnostic approach towards bleeding disorders? (4)

Answer 8

-Take family history.
-Physical examination
-Laboratory screening
-Confirmatory testing

Question 9

Why is calcium removed when the blood lab test is done?

Answer 9

To prevent clotting of the blood.

Question 10

What is Prothrombin Time (PT) ?

Answer 10

It is the time required for fibrin clot to form after the addition of thromboplastin to citrated platelet poor plasma.

Question 11

What is the normal range for PT?

Answer 11

10-14 seconds

Question 12

What does the PT test results indicate when they are:
1. Isolated prolonged
2. Shortened
3. Also aPTT is prolonged

Answer 12

1. Factor VII deficiency
2. Vitamin K supplementation, Fresh frozen plasma transfusion.
3. Vitamin K deficiency, Vitamin K antagonists, liver disease, Direct thrombin inhibitors, Factor V and VIII deficiency, afibrinogenaemia or dysfibrinogenaemia.

Question 13

What is Activated Partial Thromboplastin Time (aPTT)?

Answer 13

It is the time required for a fibrin clot to form after the addition of contact activator, phospholipid and calcium in citrated platelet poor plasma.

Question 14

What is the normal range of aPTT?

Answer 14

25-38 seconds

Question 15

Which clotting factors are vitamin K dependent?

Answer 15

II, VII, IX and X.

Question 16

What does the aPTT test results indicate, when they are:
1. Shortened
2. Prolonged (3)

Answer 16

1. Elevated factor VIII activity.
2. Deficiency in factor II, V, VIII, IX, X and XII (any).
   Non-specific inhibitors
   Specific coagulation factor inhibitors .

Question 17

What is Thrombin Time (TT)?

Answer 17

It is the time required for a fibrin clot to form after the addition of thrombin to citrated platelet poor plasma.

Question 18

Normal range for TT?

Answer 18

15-19 seconds

Question 19

What does the TT results indicate if they are:
1. Shortened
2. Prolonged (6)

Answer 19

1. Coagulation activation
2. Hypoalbuminaemia
   Hypofibrogenaemia
   Increased concentration of fibrin degradation products.
   Dysfibrogenaemia
   Thrombin inhibitors
   Paraproteinaemia

Question 20

Which test should be performed after aPTT and/or PT were prolonged, and does that test help us with? (3)

Answer 20

-Perform mixing or correction assay, it helps to determine where the prolonged clotting times are due to:
-Circulating inhibitors of coagulation factors.
-Clotting factor deficiency

Question 21

How do we know whether the problem is with factor deficiency or inhibitors?

Answer 21

If the clotting time normalize, it is a factor deficiency, if it remains prolonged it is inhibitors.

Question 22

What are the confirmatory tests that are done after the mixing studies? (2)

Answer 22

-In a case of a factor deficiency, factor assay is performed to measure the specific factor activity.
-In a case of inhibitor a factor assay is done to measure the specific factor activity and inhibitor assay to measure the concentrations of the inhibitor of the deficient coagulation factor and/or lupus anticoagulant.