Disorder of Clot

Question 1

What is a measure of the extrinsic pathway?

Answer 1

Prothrombin Time (PT)

Question 2

What is a measure of the intrinsic pathway?

Answer 2

activated partial thromboplastin time (APTT)

Question 3

What is a measure of the common pathway?

Answer 3

Fibrinogen

Question 4

What are the 2 most common causes of prolonged PT?

Answer 4

Warfarin, Factor VII deficiency

Question 5

What are causes of prolonged APTT?

Answer 5

Heparin, Factor VIII, iX, XI or XIII deficiency, Von Willebrand’s Disease

Question 6

What causes prolonged PT and APTT?

Answer 6

Vit K deficiency + low fibrinogen
Disseminated Intravascular Coagulation
Heparin toxicity

Question 7

Which factors are vit K dependent?

Answer 7

II, VII, IX, X, protein C and S

Question 8

What does PT measure?

Answer 8

VII, X, V, prothrombin and fibrinogen (classic ‘extrinsic’ pathway)

Question 9

What does APTT measure?

Answer 9

measures XII, XI, IX, VIII, X, V, prothrombin and fibrinogen (‘intrinsic’ pathway)

Question 10

What prolongs thrombin time?

Answer 10

fibrinogen deficiency

Question 11

What is haemophilia A?

Answer 11

a disorder where the blood cannot clot properly due to a deficiency of a clotting factor called Factor VIII.

Question 12

How does heparin work?

Answer 12

increases effect of Anti-thrombin III by 2000 fold inhibiting clot formatio

Question 13

How does warfarin work?

Answer 13

reduces Vit K dependent factors

Question 14

What investigations would you carry out in a bleeding patient?

Answer 14

FBC with platelet count
PT - Pro-thrombin time
APTT -Activated partial thromboplastin time Fibrinogen

Question 15

How do you confirm a coagulation factor deficiency?

Answer 15

If abnormal PT or APTT, mix 50:50 patient’s and normal plasma. A deficiency is present if the the PT/APTT corrects.

Question 16

What type of disorder is Haemophilia A

Answer 16

Factor VIII deficiency. X-Linked recessive pattern.

Question 17

What are the clinical features of Haemophilia A?

Answer 17

Spontaneous bleeding into skin, muscle and joints. Retroperitoneal and intracranial bleeding. Muscle haematoma.

Question 18

How is Haemophilia A diagnosed?

Answer 18

Increased APTT, 50:50 Plasma correction, decreased Factor VIII on assay

Question 19

How is Haemophilia A managed?

Answer 19

Desmopressin - minor bleeds

recombinant Factor VIII - major/life-threatening bleeds

Question 20

How does desmopressin work?

Answer 20

causes release of von Willebrand factor (vWF) and releases stored factor VIII

Question 21

What is haemophilia B?

Answer 21

• Aberrations of the factor IX gene, which is also present on the X chromosome, result in a reduction of the plasma factor IX level, giving rise to haemophilia B.

Question 22

How is haemophilia B treated?

Answer 22

Factor IX concentrate

Question 23

How does tranexamic acid work?

Answer 23

slows down plasmin/plasminogen system and prevents fibrinolysis, allows clot to stay intact for longer

Question 24

What is von Willebrand’s disease?

Answer 24

It is a bleeding disorder caused by quantitative (types 1 and 3) or qualitative (type 2) deficiency of von Willebrand factor (vWF),

Question 25

What does vWf do?

Answer 25

involved in both platelet function and coagulation. Carries Factor VIII.

Question 26

What is type 1 vW disease

Answer 26

reduced amount of normal vW protein

Question 27

What is vW disease type 2?

Answer 27

abnormal vW protein

Question 28

What is vW disease type 2b?

Answer 28

Overactive protein which can result in thrombocytopenia

Question 29

What is vW disease type 3?

Answer 29

little or no vW

Question 30

What tests are used in vW disease?

Answer 30

Factor VIII, von willebrand antigen, vW activity

Question 31

How do you differentiate between type 1 and type 2 vW disease?

Answer 31

vWF Activity to vWF Antigen is >0.6 = Type 1 and if <0.6 = Type 2

Question 32

How do you treat type 1 vw disease?

Answer 32

DDAVP + tranexamic acid

Question 33

How do you treat type 2 and type 3 vW disease

Answer 33

vWFactor