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Condition/Disorder Synonyms

  • Blood clot

  • Deep vein thrombophlebitis

  • Venous thrombosis

  • Venous thromboembolism

ICD-9-CM Codes

  • 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

ICD-10-CM Codes

  • 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

Preferred Practice Pattern

Key Features


  • 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 DVT 3

  • 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

  • DVT may result in a PE, a life-threatening medical emergency

  • DVT and PE are the two manifestations of venous thromboembolism (VTE)

  • Late complication of DVT is post-thrombotic syndrome: results in limb edema, pain, swelling

  • Virchow's triad is primary mechanism of DVT onset2


  • 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

Clinical Findings

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 ...

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