Thrombosis

Question 1

What is factor V leiden?

Answer 1

An inherited disorder, factor V is RESISTANT to degradation by activated PROTEIN C. Most common cause of inherited HYPERCOAGULABILITY in caucasians.

Get VENOUS THROMBOSIS

Question 2

Complications of factor V leiden?

Answer 2

VENOUS THROMBOSIS

Question 3

What is anti-thrombin deficiency?

Answer 3

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

Question 4

What is protein C/S deficiency?

Answer 4

INABILITY TO INACTIVATE FACTORS Va and VIIIa

RISK OF THROMBOTIC SKIN NECROSIS WITH HAEMORRHAGE AFTER ADMINISTRATION OF WARFARIN

Question 5

Features of obstetric haematology?

Answer 5

Volume expansion- DILUTIONAL ANAEMIA
THROMBOCTYOPENIA- RETURNS TO NORMAL POST PARTUM
HYPERCOAGULABLE AND HYPOFIBRINOLYTIC STATE- INCREASED RISK OF VENOUS THROMBOEMOBOLISM

Question 6

Blood results that go down in pregnancy?

Answer 6

HAEMOGLOBIN
HAEMATOCRIT
PLATELETS
FACTOR XI
PROTEIN S

Question 7

Blood results that go up in pregnancy?

Answer 7

PLASMA VOLUME
RED CELL MASS
MCV
WCC
FACTORS VII, VIII, IX, X, XII

Question 8

Action of warfarin?

Answer 8

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.

Question 9

How to reverse vitamin K effect?

Answer 9

IV vitamin K (delayed)

FFP or PCC reverses immediately and can be given with vitamin K in severe cases of bleeding.

Question 10

Which coagulation factor does warfarin affect first?

Answer 10

Factor 7, shortest half life.

Question 11

DVT prophylaxis?

Answer 11

Daily subcutaneous LMWH (prophylactic dose), TED stockings

Question 12

How is VTE treated?

Answer 12

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.

Question 13

Treatment for 1st VTE known cause?

Answer 13

3 months warfarin (INR target 2.5)

Question 14

Treatment for first VTE unknown cause?

Answer 14

6 months warfarin (INR target 2.5)

Question 15

Treatment for malignancy VTE?

Answer 15

6 months LMWH NOT warfarin

Question 16

Recurrent VTE treatment?

Answer 16

Lifelong warfarin (target INR 3.5)

Question 17

Action of Protein C and S?

Answer 17

Thrombomodulin (activated by thrombin) activates protein C, which complexes with protein S to inhibit co-factors 5 and 8.

Question 18

Administration and monitoring for LMWH?

Answer 18

Given SC once daily, does not require monitoring (except late pregnancy and renal failure).

Question 19

When is unfractionated heparin used and what monitoring is required.

Answer 19

If renal impairment.
Given IV, loading dose then infusion.
MONITOR APTT

Question 20

Target INR for 1st episode DVT or PE?

Answer 20

2.5 (2-3)

Question 21

Target INR for atrial fibrillation?

Answer 21

2.5 (2-3)

Question 22

Target INR for recurrent DVT or PE?

Answer 22

3.5 (2.5-3.5)

Question 23

Target INR for mechanical prosthetic valve?

Answer 23

3.5 (2.5-3.5)

Question 24

What to do if INR 5-8 with no bleeding?

Answer 24

Withhold a few doses, reduce maintenance.

Restart when INR <5

Question 25

What to do if INR 5-8, minor bleeding

Answer 25

Stop warfarin, give IV vitamin K slowly. Restart when INR <5

Question 26

What to do if INR >8, no bleed/minor bleed?

Answer 26

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

Question 27

What to do if major bleeding (including intracranial haemorrhage)?

Answer 27

Stop warfarin
Give prothrombin complex concentrate (PCC). If unavailable give FFP.
Also give Vitamin K IV.

Question 28

How do you reverse the effects of unfractionated heparin?

Answer 28

Protamine sulphate- of limited use on LMWH!

Question 29

Side effects of unfractionated heparin use?

Answer 29

Heparin induced thrombocytopenia, osteoporosis with long term use.