September 15, 2015 - SG - Thrombosis

Question 1

Well’s Criteria for PE

Answer 1

Clinical signs and symptoms of DVT +3

PE is #1 diagnosis +3

Heart rate > 100 +1.5

Immobilization for 3 days +1.5

Surgery in last 4 weeks +1.5

Previously diagnosed PE or DVT +1.5

Hemoptysis +1

Active cancer +1

Score > 4 means a PE is likely.

Question 2

Well’s Criteria for DVT

Answer 2

Active cancer: +1

Bedridden for >3 days: +1

Major surgery in last 3 months: +1

Collateral superficial veins present: +1

Entire leg swollen: +1

Localized tenderness along the deep venous system: +1

Pitting edema, confined to one leg: +1

Paralysis, paresis, or recent plaster of lower extremity: +1

Previously documented DVT: +1

Alternative diagnosis at least as likely: -2

2 > means DVT is likely

Question 3

CT Pumonary Angiography (CTPA)

Answer 3

Can be used to investigate a PE.

Question 4

Doppler U/S

Answer 4

Can be used to investigate a DVT.

Question 5

Bridging onto Warfarin

Answer 5

It is important that you need another drug for the short term while you build up a dose of warfarin. This is because warfarin inhibits protein C (along with 3, 7, 9 and 10) which can actually lead to a hypercoagulable state initially. Also, you need something that will work right away.

Question 6

Warfarin Mechanism

Answer 6

Inhibits the vitamin K factors. These are 3, 7, 9 and 10. Additionally, protein C is inhibited which can actually lead to a hypercoagulable state, initially.

Question 7

Protamine

Answer 7

Protamine sulfate is the antidote for a heparin overdose.

Question 8

Indications for Fibrinolytic Therapy

Answer 8

Life-threatening emergency. Or a stroke with the potential for damage.

Contraindicated by recent surgery or ulcers, etc. Big risks are that it can cause hemorrhaging.

Question 9

Big Genetic Risk Factors for Thrombosis

Answer 9

Protein C Deficiency

Protein S Deficiency

Factor V Leiden

Anti-thrombin Deficiency

Question 10

D-Dimer

Answer 10

Very good negative predictive value. Used to rule out the possibility of a DVT when it is unlikely.

Question 11

Heparin-Induced Thrombocytopenia (HIT)

Answer 11

Antibodies are formed against the heparin-platelet complex, which destroys large numbers of platelets. This induces a hypercoaguable state because the antibodies activate clotting cascades.

When this occurs, you need to stop heparin and switch to argatroban or you will be sued for medical malpractice.

Question 12

Rivaroxaban

Answer 12

Inhibits factor 10a.

No antidote.

Question 13

Apixaban

Answer 13

Inhibits factor 10a.

No antidote.

Question 14

Argatroban

Answer 14

Inhibits factor 2a.

Question 15

Dabigatran

Answer 15

Inhibits factor 2a.