DVT

Question 1

Which veins can be affected by DVT?

Answer 1

deep veins of the leg (femoral and popliteal) and pelvis (iliac veins)

Question 2

What is DVT?

Answer 2

Blockage of the vein by a thrombus

Question 3

Where does the thrombus usually first appear?

Answer 3

Calf

Question 4

What is thrombophilia?

Answer 4

tendency to develop thrombosis

Question 5

What % of DVT patients have at least one hereditary thrombophilia (e.g. deficiency in factors or mutations)?

Answer 5

35%

Question 6

What are the most common risk factors for DVT?

Answer 6

recent surgery or hospital stay

Question 7

What are the other risk factors for DVT?

Answer 7

age
obesity
infection
immobilisation 
hormonal contraception containing oestrogen
air travel 
smoking
family history

Question 8

Symptoms

Answer 8

Swelling of calf
Pain
Sudden pulmonary embolus

Question 9

Signs

Answer 9

Swelling and redness of the leg and dilation of surface veins
tenderness
(physical examination fairly unreliable for diagnosis of DVT)

Question 10

Abnormal test results

Answer 10

ultrasound - reduction of venous flow and presence of thrombus
High D-dimer levels

Question 11

Why do DVTs occur on planes?

Answer 11

Immobility - calf muscle is not contracting to help return blood to the heart

Stasis of blood flow -

Question 12

What is Virchow’s triad?

Answer 12

Thrombosis is the result of interplay between 3 factors:
changes in blood flow
changes in vessel wall
changes in blood constituents

Question 13

Which aspects of Virchow’s triad are present in DVT?

Answer 13

changes in blood flow

Question 14

Why does blood stasis cause thrombosis?

Answer 14

Platelets in contact with endothelium and activated clotting factors not diluted by blood flow
inflow of anticoagulant factors is slow
activation of endothelial cells is promoted

Question 15

How does aspirin work?

Answer 15

Inhibits prostaglandins which increase platelet aggregation and vasoconstriction

ANTIPLATELET

Question 16

What is an embolus?

Answer 16

material that is carried by the blood from one point in the body to lodge at another point

Question 17

What does V/Q mismatch cause?

Answer 17

hypoxaemia

Question 18

What is the difference between primary and secondary varicose veins?

Answer 18

primary - due to gravitational venous pooling and vein-wall laxity
secondary - due to obstruction of the deep venous outflow (DVT, malignancy) or incompetence of the deep valves

Question 19

How do varicose veins contribute to DVT?

Answer 19

stasis of blood can cause thrombus

Question 20

How does smoking contribute to DVT?

Answer 20

Changes in blood constituents

Question 21

What treatment could be given for DVT?

Answer 21

immediate anticoagulation with low molecular weight heparin

longer term warfarin

Question 22

What factors does warfarin target and how?

Answer 22

10
9
7
2
 vitamin k metabolism

Question 23

What factors does low molecular weight heparin target?

Answer 23

10

thrombin