thrombotic disorders

Question 1

virchows triad - risk factors for thrombosis

Answer 1

vascular injury

• atheroscerlosis
• trauma
• surgical manipulation
• prior thrombosis

stasis

• immobility
• pressure
• increased viscosity

hyper coagulability

• increased procoagulants
• decreased inhibitors

Question 2

describe deep vein thrombosis and its presentation

Answer 2

thrombosis of left veins

leg swelling, pitting oedema, leg pain
venous discolouration

often clot can break off and cause emboli (PE)

Question 3

signs and symptoms of pulmonary embolism

Answer 3

symptoms

• chest pain
• SOB
• blood in cough

signs

• tachycardia
• tachypnoea
• hypoxia

Question 4

testing for PE

Answer 4

D-dimer

CT pulmonary angiogram performed

V/Q scan

Question 5

define D-dimer

Answer 5

measure the products of fibrin breakdown

• positive in DVT and PE
• also positive with inflammation, surgery etc

Question 6

define thrombophilia

Answer 6

• tendency to develop thrombosis
• acquired and/or inherited
• manifests as VTE

Question 7

causes of VTE

Answer 7

1/3 = spontaneous
2/3 = provoked events
 - surgery, trauma
 - immobility, hospitalisation
 - malignancy
 - HRT, COCP, pregnancy

Question 8

inherited thrombophilia

Answer 8

abnormal inhibitor function

• resistant to activated protein C
• due to mutant factor V Leiden

deficiency of inhibitors
- antithrombin, protein C and S

increased factor levels

• prothrombin gene mutation
• elevated factor VIII

Question 9

factor V leiden

Answer 9

normal coagulation factor Va is inactivated by protein C

factor V leiden is the mutation form and as a result can’t be inactivated by protein C so continues

leading to increased risk of venous thrombosis

single point mutation

Question 10

thrombophilia testing

Answer 10

• measuring factor V leiden and prothrombin gene mutation
• also measure natural inhibitors
  more sever

Question 11

number 1 treatment for VTE

Answer 11

LMWH and warfarin

Question 12

heparin

Answer 12

• increases antithrombin effect (inhibits thrombin)
• given initially, immediate effect
• prolongs APTT however this can be reversed with protamine

Question 13

LMWH effect

Answer 13

increases antithrombin effect (inhibits Xa)

subcutaneous with better bioavailability

doesn’t cause significant APTT or TCT prolong

Question 14

warfarin

Answer 14

• monitor with INR
• interaction with many drugs
• lag between starting drug and effect, due to vitamin K stores

Question 15

positives and negatives of direct acting oral anticoagulants

Answer 15

positives

• no monitoring required
• fixed dose
• less intracranial haemorrhage (compared to warfarin)

negatives
- kidney excretion

Question 16

dabigatran

Answer 16

DOAC

• inhibits IIa (thrombin)
• TCT extremely sensitive
• APTT prolonged

Question 17

dabigatran antidote

Answer 17

= idarucrizumab

Question 18

direct acting oral anticoagulants

Answer 18

direct inhibitors of activated clotting factors