DVT - deep vein thrombosis

Question 1

what is a DVT

Answer 1

a thrombus (clot) formed in the deep venous circulation (usually legs) but can be anywhere

Question 2

what is a PE (pulmonary embolism)

Answer 2

a thrombus (clot) that has embolised (travelled) and lodged in the pulmonary circulation

Question 3

what dos distal vein thrombosis refer to

Answer 3

DVT of the calves

Question 4

what does proximal vein thrombosis refer to

Answer 4

DVT of the popliteal vein or the femoral vein.
- proximal as it is closer to the heart

Question 5

Thrombosis is considered to arise from

Answer 5

the interplay between the three factors that make up Virchow’s triad

Question 6

what are the three factors that make up Virchow’s triad

Answer 6

Hypercoagulation
Endothelial injury
Circulatory stasis

Question 7

what causes hyper coagulation

Answer 7

• Malignancy
• Pregnancy
• Oestrogen therapy (birth control)
• IBD
• Sepsis
• Thrombophilia (abnormal tendency to develop blood clots)

Question 8

what causes endothelial injury

Answer 8

• Venous disorders
• Venous valvular damage (e.g. from previous DVT/PE - very strong RF)
• Trauma or surgery
• Indwelling catheters

Question 9

what causes circulatory stasis

Answer 9

• Slowed blood blow, clotting cascade activated
• Left ventricular dysfunction
• Due to:
  
  • Immobility or paralysis
  • Venous obstruction

Question 10

risk factors

Answer 10

• surgery (major and day)
• active malignancy
• pregnancy
• protein s and c deficiency
• smoking
• travelling
• trauma
• factor V leiden mutation

Question 11

where are DVT most common

Answer 11

below the knee

Question 12

where do DVTs form predominantly

Answer 12

in the venous valve pockets and other sites of assumed stasis

Question 13

Symptoms

Answer 13

• Calf - warmth, tenderness, swelling, erythema (unilateral)
• Mild fever

Question 14

Signs

Answer 14

• Pitting oedema

Question 15

investigations

Answer 15

• D-dimer (blood test
• Ultrasound (US) Doppler leg scan diagnostic tes

Question 16

D-dimer (blood test):

Answer 16

measures D-dimer concentration in blood from fibrin breaking down clots
- Used for ruling out DVT, not good for telling you if you have it

Question 17

Ultrasound (US) Doppler leg scan diagnostic test -

Answer 17

used if patient has high D-dimer or Wells score (in which case US would be first line)

Question 18

Acute management

Answer 18

• Anticoagulation - apixaban or rivaroxaban (DOACs) first line
• May be outpatient if patient considered low-risk
• If neither apixaban or rivaroxaban are suitable then either LMWH followed by dabigatran or edoxaban OR LMWH followed by a vitamin K antagonist (VKA, i.e. warfarin)

Question 19

Secondary prevention (long-term)

Answer 19

• Inhibit clotting cascade, prevent clot formation (dont breakdown clots)
• Long term anticoagulation - warfarin, a DOAC or LMWH
• Treatment with a should be continued for at least 3 months

Question 20

how does DVT present

Answer 20

Painful and swollen limb with redness and heat. Tenderness along vein. Sub acute development. No other obvious cause