Thrombosis Flashcards
1
Q
What is in Virchow’s triad?
A
- Endothelial damage
- Stasis of blood
- Increased coagulation
2
Q
Name some inherited causes for increased thrombosis
A
- Antithrombin deficiency
- Protein C deficiency
- Protein S deficiency
- Factor V Leiden
3
Q
Name some acquired causes for increased thrombosis
A
- Age and obesity
- Previous DVT or PE
- Immobilisation
- Major surgery
- Long distance travel
- Malignancy
- Pregnancy, COCP, HRT
- Antiphospholipid syndrome
- Polycythaemia and thrombocythemia
4
Q
Describe DVT prophylaxis
A
- Daily subcutaneous LMWH
- TED stockings
5
Q
What are the treatment principles of DVT/PE?
A
- High dose LMWH, warfarin/DOACs
- 3-6 months of treatment
- Possibly lifelong treatment for unknown causes or for thrombophilic patients
- Lifelong warfarin for recurrent thrombosis
- TED stockings
6
Q
What is the mechanism of heparin?
A
- Potentiates of antithrombin III, which inactivates thrombin, and factor 9, 10 and 11
- Unfractionated heparin in cases of renal impairment
- Side effects include bleeding and heparin-induced thrombocytopaenia
- Antidote an overdose with protamine sulphate
7
Q
What is the mechanism of warfarin?
A
- Inhibits reductase enzyme responsible for regenerating the active form of vitamin K
- Inhibits the synthesis of factors 2, 7, 9 and 10; and proteins C, S and Z
- Is pro thrombotic before it is antithrombotic (protein C S and K have shorter half lives
- Risks teratogenicity
- Reversal with IV vitamin K
- Dose adjusted to INR
8
Q
What INR is targeted after one episode of thrombosis?
A
2.5
9
Q
What INR is targeted for those with recurrent thrombosis?
A
3.5
10
Q
Describe raised INR protocols
A
5-8, no bleeding:
- Withhold few doses, and reduce maintenance
- Resume after INR <5
5-8, with bleeding:
- Stop warfarin, and give vitamin K slowly
- Restart when INR <5
> 8, no bleeding:
- Stop warfarin, give vitamin K
- Check INR daily
Major bleeding:
- Stop warfarin, and give prothrombin or FFP
- Give IV vitamin K
