Venous thromboembolism

Deep Vein Trombosis

Low risk if distal to knee, high risk if proximal to knee.

Clinical features

ΔΔx. cellulitis, ruptured baker's cyst.

Pulmonary embolus




PIOPED study (Prospective Investigation of Pulmonary Embolism Diagnosis) Worsley, Alavi. J Nucl Med, December 1995; 36(12):2380-2387.

Risk factors

  1. immobility (56%)
  2. surgery (54%)
  3. malignancy
  4. high oestrogen state (oral contraceptive pill, pregnancy)
  5. previous PE/DVT
  6. cardiac disease

Consider thrombophilia (Factor V Leiden mutation, Protein C, Protein S). Factor V Leiden mutation (=Activated Protein C resistance) is present in 5% of caucasians, but 20% of patients presenting with venous thromboembolic disease.


  1. atelectasis (51%)
  2. pleural effusion
  3. pulmonary oedema
  4. Hampton's Hump (wedge infarct) (23%)
  5. Westermark's sign (regional oligaemia) (11%)
  6. Fleischner's sign (prominent pulmonary artery)


D-dimer test.

Other imaging


Mortality in treated PE is 2.5%