Deep Vein Thrombosis

Question 1

Define deep vein thrombosis

Answer 1

Clot in the deep venous system of the lower limbs

Question 2

What are the causes of DVT?

Answer 2

• Active malignancy
• Recent major surgery (esp. orthopaedic surgery)
• Recent hospitalisation
• Recent trauma
• Increasing age
• Pregnancy
• Obesity
• Thrombophilias e.g. factor V Leiden, protein C/S deficiency
• Recent long haul flights
• Oestrogen e.g. OCP, HRT
• smoking
• polycythaemia

Question 3

What are the symptoms of DVT?

Answer 3

• Calf swelling

* Calf pain

Question 4

What are the signs of DVT?

Answer 4

• Unilateral oedema

* Calf tenderness

Question 5

What are the investigations fr DVT?

Answer 5

• Well’s score
- <2 = unlikely -> proceed to D-dimer
- >2 = likely -> proceed to venous duplex USS
• D-dimer (sensitive but non-specific)
- Normal – excludes DVT if Well’s score is also <2
- Elevated – proceed to venous duplex USS
• Venous duplex USS
• Venography is definitive but invasive
• Compression USS is preferred

Question 6

What is the management for DVT?

Answer 6

Anticoagulation
• IV or SC unfractionated heparin
- Increased risk of bleeding (short half-life plus reversal with protamine sulphate and FFP)
- Renal/hepatic impairment
• IV or SC LMWH e.g. enoxaparin, tinzaparin
- Active cancer
- Pregnancy (SC)
• IV or SC fondaparinux
• IV or SC direct factor Xa inhibitors e.g. rivaroxaban
• Warfarin
- Co-administered with heparin/fondaparinux until INR is between 2 and 3
- Continue for at least 3 months

Monitoring
• INR
- Target range 2-3
- Monitor whilst co-administering warfarin
• APTT
- Monitor every 6h for first 24h
• Platelet count (HIT –see complications)

VTE prophylaxis
• Stockings
• Physical activity

Question 7

What are the complications of DVT?

Answer 7

• Pulmonary embolism
• Bleeding
• Post-phlebitic syndrome
• Heparin-induced thrombocytopenia