Coagulation factors and related bleeding factors

Question 1

Screening tests used to diagnose coagulation disorders.

What are the abnormalities indicated by prolongation of Thrombin Time?

Answer 1

Deficiency or abnormality of FIBRINOGEN
OR
Inhibition of thrombin by heparin or FDPs.

Common cause of this coagulation disorder is DIC and HEPARIN THERAPY.

heparin is found in the liver and inhibits caogulation

Question 2

Screening tests used to diagnose coagulation disorders.

What are the abnormalities indicated by prolongation of Prothrombin Time?

Answer 2

Caused by deficiency or inhibition of one of the following factors, Factor II, V, VII, IX, X and Fibrinogen.

This is caused by LIVER DISEASE, DIC and WARFIN THERAPY (Common Causes)

Increased prothrombin time is cased by warfin therapy, liver disease &DI

Question 3

Screening tests used to diagnose coagulation disorders.

What are the abnormalities indicated by prolongation of APTT, Activated Partial Thromboplastin Time?

Answer 3

Deficiency or inhibition of one or more of the following factors
Factor 2, 5, 8(Haemophilia), 9(Christmas disease), 10, 11, 12 and fibrinogen.

Question 4

Screening tests used to diagnose coagulation disorders.

What are the abnormalities indicated by prolongation of Fibrinogen Quantitation?

Answer 4

Fibrinogen Deficiency

Common caused are Liver Disease and DIC.

Question 5

Give Functions of Factor I

Answer 5

Factor I is Fibrinogen
It is converted to Fibrin by thrombin,
Fibrin functions in making a blood clot.

Question 6

Give functions of factor II

Answer 6

Factor II is prothrombin

It is enzymatically cleaved into thrombin by Factor Xa, and then thrombin converts fibrinogen into fibrin.

It also activates protein C

Question 7

Give functions of factor III

Answer 7

Factor III is tissue factor
found in endothethelium

function of tissue factor (TF) is to initiate extrinsic pathway

tissue factor has high affinity for F VII and acts as a catalyst in conversion of Factor X to Factor Xa.

Question 8

Give functions of Factor V

Answer 8

Co-factor with F Xa

Deficiency in factor V results in Owren’s disease, which is a bleeding disorder.

Question 9

Give Functions Of Factor VII

Answer 9

Factor 7 is vitamin dependent

It initiates coagulation by activating Factor X into Factor Xa in the EXTRINSIC PATHWAY.

Deficiency of Factor 7 results in bleeding disorders.

Question 10

Give functions of Factor VIII(8)

Answer 10

Factor VIII is a cofactor in the activation of factor X to F Xa.

Factor 8 is activated by the factor 9a in the presence of Calcium and phospholipids

(NB) Deficiency or mutation of factor 8 results in Haemophilia A.

Factor 8 deficiency results in Haemophilia A.

Question 11

Give function of Factor IX

factor 9 is also called the Christmas Factor.

Answer 11

It activates factor X in the presence of Calcium

Deficiency in Factor IX results in Haemophilia B (also called the ‘Christmas Disease’.

Question 12

Give Function of Factor X

Answer 12

Cleaves Prothrombin into Thrombin.

Question 13

Give function of Factor XI or 11

and describe management of Rosenthal Syndrome

Answer 13

no identified function

deficiency results in Haemophilia C and Haemorrhage

Activated by Factor XIIa

Cyklokapron is used in management of haem C and factor replacement is not necessary unless in surgery. FFP (Fresh Frozen Plasma) may be used or Recombinant Factor XI.

Question 14

Give function of Factor XII

Answer 14

Activates factor XI

Deficiency results in decreased fibrinolysis, hence increase thrombosis.

Deficiency of factor twelve does not result in Haemorrhage.

Question 15

List factors that are Vitamin K dependent

Answer 15

Factor 2,7,9 and 10

Question 16

List modes of inheritence for hereditary coagulation factor defects, that is
Haemophilia A,B,C and Von Willebrand Disease.

Answer 16

Von Willebrand Disease= Autosomal Dominant
Haemophilia A and B= X linked recessive
Haemophilia C= Autosomal Recessive

Question 17

Describe the Management of Haemophilia A and B

Answer 17

1. Factor Replacement
2. DDAVP- a drug that releases vWF from its stores
3. Supportive measures such as joint replacement, physio and genetic counselling
4. gene therapy

Question 18

Basic Mixing Study Concept is a tool we use to determine whether there’s a factor inhibitor or just deficiency of the factor.

Explain how this works.

Answer 18

Sample is mixed with normal pooled plasma (npp) and a mixture of formed.
If the factor is corrected then there’s factor deficiency
if not corrected then there’s a factor inhibitor.

Question 19

Describe the function of factor 13 (XIII) and describe the management of F XIII.

Answer 19

Function is to stabilise clot: Form bonds between fibrin molecules.

Deficiency of F XIII results in bleeding with NORMAL apTT, TT, PT

Manage F XIII deficiency with Cryoprecipitate.

Question 20

Describe the Function of Von Willebrand Factor

Answer 20

It carries Factor VIII and prolongs it’s plasma half life and forms links between subendothelium and platelets