10. disorders of haemostasis cont.

Question 1

3 types of inherited coagulation defects

Answer 1

Haemophilia A
Haemophilia B
von Willebrand’s disease

Question 2

what factor does haemophillia A affect

Answer 2

factor 8

Question 3

in terms of genetics what kind of disorder is haemophillia A

Answer 3

x linked recessive disorder
(but can alsos be spontatneous mutation with no family history)

Question 4

why is there vaiability on haemophillia A symptoms

Answer 4

depends on factor 8 level

Question 5

sever haemophillia symptoms

Answer 5

• Bleeding into joints and less frequently muscles
• Knees, elbows and ankles most commonly affected
• Majority of bleeds that require treatment.
• Presenting symptoms: pain in affected areas.
• Intracranial bleeding: main cause of death from the disease.

Question 6

what is bleeding into joints called

Answer 6

haemarthrosis

Question 7

how is haemophillia A diagnosed

Answer 7

• prolonged APTT
• confirmed by factor 8 clotting assay
• IF family suspects haemophillia, then chorionic biopsy at 8-10 weeks can be done to analyse DNA

Question 8

at what % of factor 8 will symptoms start to show

Answer 8

under 50%
so between 25-50, will see bleeding after severe trauma

Question 9

what symptoms to we see in mild haemophillia

Answer 9

5-25% factor 8 in blood

• severe bleeding after surgery
• slight bleeding after minro trauma

Question 10

symotoms seen in moderate haemophillia A

Answer 10

1-5% factor 8 in blood

• severe bleeding after slight trauma

Question 11

symptoms in severe haemophillia A

Answer 11

less than 1% of factor 8

severe frequent spontaneous bleeds in joints and muscles

Question 12

how is haemophillia A treated during a bleed

Answer 12

recombinant factor 8 used to replace factor 8

Question 13

how is mild haemophillia A treated

Answer 13

DDAVP
a vasopressin
which molibilises factor 8 from endothelial cells

Question 14

what factor does haemophillia B affect

Answer 14

factor 9

Question 15

how does haem B present compared to haem A

Answer 15

no difference
clinically undistinguishable
(but much less common)

Question 16

in terms of genetics what kind of disorder is haemophillia A

Answer 16

X linked recessive bleeding disorder

Question 17

how is haem B diagnosed

Answer 17

APTT prolonged
Diagnosis is confirmed by factor IX clotting assay.

Question 18

how is haem B treated

Answer 18

factor 9 replacement

Question 19

in terms of genetics, what kind of disease is VWD

Answer 19

autosomal dominant
affects 1 in 100 but is only clinicall significant in 1 in 10,000

Question 20

3 different types of VWD

Answer 20

• type 1 and 3 = based on number of molecules
  = partial reduction or near absence of VWD molecules
• type 2 = abnormal function of the protein

Question 21

why would VWD diagnosis inclued testing for factor 8

Answer 21

VWD is a carrier for factor 8
so would be decreased in VWD as well

Question 22

what could be tested to diagnose VWD

Answer 22

would have impaired platelet aggregation

Question 23

what is the bleeding characteristics in VWD

Answer 23

extent is variable
- might have spontaneous in mucous membranes and skin
- severe haemorrage after surgiccal procedures

Question 24

what is used to treat VWD

Answer 24

DDAVP
mobilises both VWf and factor 8

Question 25

which type of VWD is the DDAVP treatment effective for

Answer 25

Type1 = reduced amount, but still some, so can mobilise what is inside cells already

Question 26

what could cause acquired coagulation disorders

Answer 26

• vit K deficiency
• disseminated intravascular coagulation
• liver disorders

Question 27

what is thrombus made up of

Answer 27

platelets and fibrin

Question 28

thromboembolism definition

Answer 28

occlusion of a vessel by a blood clot which has moved from its starting position

Question 29

what is thrombophilia

Answer 29

a condition that increases your risk of blood clots

Question 30

what is virchows triad

Answer 30

outlinesthe presence of three factors that predisposes a person to develop vascular thrombosis =
- endothelial injury (changes in blood vessel walls)
- hypercoagubility (changes in blood constituents)
- venous stasis (sitting for long times)

Question 31

2 diseases caused by arterial thrombosis

Answer 31

stroke
myocardial infarction

Question 32

stroke

Answer 32

• Disturbance in blood supply to brain
• Thrombotic stroke: thrombus usually forms around atherosclerotic plaque with gradual blockage of artery

Question 33

Myocardial infarction

Answer 33

• Caused by an infarct (death of tissue due to ischemia)
• after obstruction of coronary artery

Question 34

how can myocardial infarction be treated

Answer 34

only if within 12 hrs of intial attack
then thrombolytic theraoy (e.g. tPA) can be initiated

Question 35

where is deep vein thrombosis most common

Answer 35

lower limbs

Question 36

symptoms of DVT

Answer 36

swelling
pain
pulmonary embolism

Question 37

pulmonary embolism symptoms

Answer 37

• dysponea
• tachypnoea
• pleuritic chest pain

Question 38

risk factors for venous thrombosis

Answer 38

• hereditary
  = factor 5 leiden
• or raised levels of other factors
• oral contraceptives
• malignancy
• stasis

Question 39

what is factor 5 leiden

Answer 39

• most common inherited cause of increased risk of venoue thrombosis
• point mutation in factor 5 gene
• which means factor 5 less susceptible to cleavage by protein C
• homo = 50x increase risk of thrombosis
• het = 7 x increased risk

Question 40

what is used for antithrombotic therapy

Answer 40

anticoagulants = prevention
thrombolytic agents = dissolve thrombus

Question 41

2 anticoagulants

Answer 41

heparin
warfarin

Question 42

how do thrombolytic agents work

Answer 42

• act as plasminogen activators, converting plasminogen into plasmin
• Plasmin will then dissolve the fibrin of a blood clot

Question 43

2 commonly used thrombolytic agents

Answer 43

streptokinase
tissue plasminogen activator