Thrombosis Flashcards
What is factor V leiden?
An inherited disorder, factor V is RESISTANT to degradation by activated PROTEIN C. Most common cause of inherited HYPERCOAGULABILITY in caucasians.
Get VENOUS THROMBOSIS
Complications of factor V leiden?
VENOUS THROMBOSIS
What is anti-thrombin deficiency?
Inherited deficiency of antithrombin.
Highest inheritable tendency to clot.
Develop thromboembolism in unusual locations (e.g. splenic or mesenteric veins)
Anti-thrombin assay used to make diagnosis
What is protein C/S deficiency?
INABILITY TO INACTIVATE FACTORS Va and VIIIa
RISK OF THROMBOTIC SKIN NECROSIS WITH HAEMORRHAGE AFTER ADMINISTRATION OF WARFARIN
Features of obstetric haematology?
Volume expansion- DILUTIONAL ANAEMIA
THROMBOCTYOPENIA- RETURNS TO NORMAL POST PARTUM
HYPERCOAGULABLE AND HYPOFIBRINOLYTIC STATE- INCREASED RISK OF VENOUS THROMBOEMOBOLISM
Blood results that go down in pregnancy?
HAEMOGLOBIN HAEMATOCRIT PLATELETS FACTOR XI PROTEIN S
Blood results that go up in pregnancy?
PLASMA VOLUME RED CELL MASS MCV WCC FACTORS VII, VIII, IX, X, XII
Action of warfarin?
Inhibits vitamin K epoxide reductase enzyme, needed for regenerating active form of vitamin K and so inhibits synthesis of factors 2, 7, 9 and 10 and proteins C and S.
How to reverse vitamin K effect?
IV vitamin K (delayed)
FFP or PCC reverses immediately and can be given with vitamin K in severe cases of bleeding.
Which coagulation factor does warfarin affect first?
Factor 7, shortest half life.
DVT prophylaxis?
Daily subcutaneous LMWH (prophylactic dose), TED stockings
How is VTE treated?
LMWH treatment dose followed by warfarin, can stop LMWH when INR is in therapeutic range (2.5) as initially warfarin as procoagulant effect as protein C and S are inhibited too, so for first few days there is procoagulant state before the anticoagulant effect.
Treatment for 1st VTE known cause?
3 months warfarin (INR target 2.5)
Treatment for first VTE unknown cause?
6 months warfarin (INR target 2.5)
Treatment for malignancy VTE?
6 months LMWH NOT warfarin
Recurrent VTE treatment?
Lifelong warfarin (target INR 3.5)
Action of Protein C and S?
Thrombomodulin (activated by thrombin) activates protein C, which complexes with protein S to inhibit co-factors 5 and 8.
Administration and monitoring for LMWH?
Given SC once daily, does not require monitoring (except late pregnancy and renal failure).
When is unfractionated heparin used and what monitoring is required.
If renal impairment.
Given IV, loading dose then infusion.
MONITOR APTT
Target INR for 1st episode DVT or PE?
2.5 (2-3)
Target INR for atrial fibrillation?
2.5 (2-3)
Target INR for recurrent DVT or PE?
3.5 (2.5-3.5)
Target INR for mechanical prosthetic valve?
3.5 (2.5-3.5)
What to do if INR 5-8 with no bleeding?
Withhold a few doses, reduce maintenance.
Restart when INR <5
What to do if INR 5-8, minor bleeding
Stop warfarin, give IV vitamin K slowly. Restart when INR <5
What to do if INR >8, no bleed/minor bleed?
Stop warfarin. IV vitamin K (can use oral if no bleeding), repeat vitamin K if INR still high after 24 hours. Restart warfarin when <5.0
What to do if major bleeding (including intracranial haemorrhage)?
Stop warfarin
Give prothrombin complex concentrate (PCC). If unavailable give FFP.
Also give Vitamin K IV.
How do you reverse the effects of unfractionated heparin?
Protamine sulphate- of limited use on LMWH!
Side effects of unfractionated heparin use?
Heparin induced thrombocytopenia, osteoporosis with long term use.
