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  • Blood clot
  • Deep vein thrombophlebitis
  • Venous thrombosis
  • Venous thromboembolism

  • 453.4 Acute venous embolism and thrombosis of deep vessels of the lower extremity
  • 453.5 Chronic venous embolism and thrombosis of deep vessels of lower extremity

  • I74.9 Embolism and thrombosis of unspecified artery
  • I82.4 Acute embolism and thrombosis of deep veins of lower extremity
  • I82.90 Acute embolism and thrombosis of unspecified vein


  • Clot formation and acute inflammation of deep vein
  • Associated with Virchow’s triad:2
    • Decreased rate of blood flow (venous stasis)
    • Damage to blood vessel
    • Hypercoagulation
  • Most commonly occurs in lower extremity (LE)
  • Pulmonary embolism (PE) occurs when blood clot breaks off and settles in lung

Essentials of Diagnosis

  • Clinical decision rule for outpatients suspected of having a proximal DVT3
  • History: family history, recent trauma, cancer, oral contraceptives
  • Subjective report of pain
  • Visual examination
  • Reproduction of symptoms with dorsiflexion of the ankle (Homan’s sign) and palpation2
  • Diagnostic ultrasound of affected veins
  • Ankle-brachial index
  • D-dimer test
  • Well’s score or criteria: possible scores range from −2 to 9
    • Active cancer (treatment within last 6 months or palliative): +1 point
    • Calf swelling ≥ 3 cm compared to asymptomatic calf (measured 10 cm below tibial tuberosity): +1 point
    • Swollen unilateral superficial veins (non-varicose) in symptomatic leg: +1 point
    • Unilateral pitting edema in symptomatic leg: +1 point
    • Previous documented DVT: +1 point
    • Swelling of entire leg: +1 point
    • Localized tenderness along deep venous system: +1 point
    • Paralysis, paresis, or recent cast immobilization of lower extremities: +1 point
    • Recently bedridden ≥ 3 days, or major surgery requiring regional or general anesthetic in past 12 weeks: +1 point
    • Alternative diagnosis equally or more likely: −2 points

General Considerations


  • Individuals subjected to prolonged hospitalization or immobilization (orthopedic cast, long airplane flight, bed rest)
  • Prevalence increases with age
  • Women at increased risk while taking oral contraceptives and during pregnancy

Signs and Symptoms

  • May be asymptomatic in early stage
  • Sudden unilateral leg symptoms including:
    • Edema
    • Swelling, inflammation
    • Skin discoloration, redness
    • Warmth
    • Tenderness
  • Low-grade fever
  • Tachycardia
  • Pain exacerbated with exercise but still present at rest

Functional Implications

  • If DVT suspected, initiate therapeutic interventions
  • Pulmonary embolism
  • Cerebrovascular accident
  • Death

Possible Contributing Causes

  • Family history of DVT
  • Older age
  • Protein C or S deficiencies
  • Oncology treatment
  • Recent surgery
  • Post-operative4
  • Post-pregnancy up to 6 weeks
  • ...

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