Deep Vein Thrombosis (DVT)

Question 1

How common is it?

Answer 1

Annual incidence of about 1 in 1000 people.

Question 2

Risk factors/causes?

Answer 2

Prior history of DVT (biggest risk factor)
age over 60 years
surgery
obesity
prolonged travel
acute medical illness
cancer, immobility
thrombophilia and pregnancy
COP
HRT therapy.

Question 3

How does it present?

Answer 3

• Limb pain and tenderness along the line of the deep veins.
• Swelling of the calf or thigh (usually unilateral). Involvement of the iliac bifurcation, the pelvic veins, or the vena cava produces leg oedema that is usually bilateral.
• Distension of superficial veins.
• Increase in skin temperature.
• Skin discolouration (erythema or occasionally purple or cyanosed).
• A palpable cord (hard, thickened palpable vein).
• Low-grade fever (said to be rare but perhaps not sought often enough).
• Homans’ sign: positive when there is pain or resistance in the calf or popliteal region with abrupt passive dorsiflexion of the patient’s foot at the ankle while the knee is fully extended.

Question 4

Which other conditions may present similarly?

Answer 4

• Trauma, superficial thrombophlebitis, post-thrombotic syndrome, peripheral oedema, heart failure, cirrhosis, nephrotic syndrome, venous or lymphatic obstruction, arteriovenous fistula and congenital vascular abnormalities, vasculitis, ruptured Baker’s cyst, cellulitis, arthritis

Question 5

How would you investigate the patient?

Answer 5

• Offer patients in whom DVT is suspected and with a likely two-level DVT Wells’ score (see below) either: a proximal leg vein ultrasound scan carried out within 4 hours of being requested and, if the result is negative, a D-dimer test; or
  a D-dimer test and an interim 24-hour dose of a parenteral anticoagulant. (D-dimer test = specific cross-linked products of fibrin degradation and are raised in patients with VTE).
• Imaging can be by venography, by two-dimensional ultrasound, or by magnetic resonance imaging.
• Offer all patients diagnosed with unprovoked DVT or PE, who are not already known to have cancer, the following investigations for cancer: a physical examination (guided by the patient’s full history), CXR, blood tests (FBC, serum calcium and LFTs) and urinalysis.

Question 6

What treatment/s would you consider? What risks and benefits of treatment are there?

Answer 6

• Offer a choice of low molecular weight heparin (LMWH) or fondaparinux to patients with confirmed proximal DVT or PE.
• Offer below-knee graduated compression stockings.
• Offer temporary inferior vena caval filters to patients with proximal DVT or PE who cannot have anticoagulation treatment, and remove the inferior vena caval filter when the patient becomes eligible for anticoagulation treatment.