Haemostasis 4

Question 1

What are senile purpura?

Answer 1

Bleeding from small blood vessels that are poorly supported by connective tissue
History: recurrent bruising for many months or years in skin areas exposed to superficial knocks. Bruises resolve slowly.

Question 2

What are purpura due to meningococcal septicaemia?

Answer 2

History of acute onset of progressively enlarging purple red areas with stellate or sharply demarcated irregular edge. Z

Question 3

Name some acquired vascular disorders.

Answer 3

Easy bruising - women and children
Senile purpura - purpura of old age, atrophy of supporting connective tissue, bruising in skin
Purpura from prolonged steroid medication - reduced anabolic production of supporting connective tissues, catabolism continues - turnover is unbalanced
Scurvy - defective collagen production due to a lack of Vit C, vascular fragility develops

Question 4

Name some acquired vascular disorders (2).

Answer 4

Severe atherosclerosis weakens arterial wall - aneurysm and possible rupture
Disorders of vessel wall structure (common in elderly):
- telangiectases = abnormally dilated capillaries and veins
- recurrent GI bleeding causing iron deficiency
- abnormal connective tissue

Question 5

Name some acquired vascular disorders (3).

Answer 5

Purpura associated with infection

Question 6

What increases bleeding time?

Answer 6

Aspirin

Platelet function defects

Question 7

Name the 4 causes of thrombocytopenia.

Answer 7

Reduced production of platelets
Shortened survival of platelets
Dilution - massive transfusion
Sequestration in spleen

Question 8

NB: if the spots do not blanch on pressure, the blood is not inside the blood vessels!!!!

Answer 8

xxx

Question 9

What is important to remember about the APTT and PT in liver disease?

Answer 9

Protein C and S will partly balance the reduced thrombin burst, the bleeding risk is not as bad as the APTT and PT suggest.

Question 10

What does tranexamic acid do to clots?

Answer 10

Antifibrinolytic effect
Tranexamic acid binds to plasminogen (and plasmin)
Blocks binding of tPA to plasminogen resulting in a stable clot
Bleeding is controlled

Question 11

What do reduced plasma and platelet vWF levels cause?

Answer 11

Reduced platelet adhesion
Reduced platelet activation
Prolonged bleeding from cuts and increased bleeding

Question 12

What type of inheritance is vW disease?

Answer 12

Autosomal dominant

Question 13

What is type 1 vW disease?

Answer 13

Reduced production of the vWF protein

Question 14

What is type 2 vW disease?

Answer 14

Production of an abnormal protein

Question 15

What factor does vWD disease affect and why?

Answer 15

Mild reduction in factor VIII

- needed as a carrier protein for Factor VIII. therefore stability of factor VII is reduced

Question 16

What are clinical signs of vWD

Answer 16

Platelet capillary bleeding

• mucosal bleeding = nosebleeds, menstruation
• easy bruising
• prolonged bleeding

Question 17

What are the diagnostic tests for vWD?

Answer 17

Bleeding time/PFA-100 test prolonged
Normal or reduced vWF antigen (type 1 - reduced, type 2 - normal)
vWF functional activity always reduced
Mildly reduced factor FVIII

Question 18

What is the treatment for vWD and mild platelet function defects?

Answer 18

• boost vWF/FVIII with Desmopressin (boosts release of vWF) or with blood product FVIII-vWF
• inhibit fibrinolysis with tranexamic acid

Question 19

What is the inheritance pattern of haemophilias?

Answer 19

X-linked recessived

Question 20

What is reduced in haemophilia?

Answer 20

FVIII - Haemophilia A
FIX - Haemophilia B
Mutations cause reduced functional activity of the protein

Question 21

State the different levels and risk of bleeding for haemophilia.

Answer 21

Severe - bleeding spontaneous and after minor trauma
Moderate - bleeding after minor/moderate trauma
Mild - bleeding after moderate/major trauma

Question 22

Explain the joint bleeding problems in Haemophilia.

Answer 22

Pain and limited ROM
Cartilage is damaged and worn out after recurrent inflammation caused by bleeding
Synovium of knee is stained brown from macrophages
May need reconstructive joint surgery by middle age if effective treatment has not been provided

Question 23

What is the clinical bleeding in haemophilia?

Answer 23

Mostly joint bleeding - haemoarthrosis
Muscle bleeding - skin

All due to reduced thrombin burst (fibrin strands are thinner and weaker and are easily disrupted physically and by fibrinolysis)

Question 24

What is heparin?

Answer 24

An anticoagulant

Question 25

How does heparin work?

Answer 25

Binds to antithrombin and increases activity 
Neutralizes FIIa (thrombin), FXa, FIXa

Question 26

How do we monitor heparin therapy?

Answer 26

APTT
Dose control is needed to achieve the required level of anticoagulation.
APTT provides a useful clinical measure of heparin effect.
Individual sensitivity to heparin effect may change over several days - continue to test.