Deep vein thrombosis

The term deep vein thrombosis (DVT) is practically a synonym for clots occuring in the lower limbs. However, it can also be used for those that occur in the upper limbs and neck veins. Other types of venous thrombosis, such as intra-abdominal and intracranial, are discussed in separate articles.

  • 1.6 new cases per 1000 per year
  • 2.5-5% of population is affected
  • >50% have long terms symptoms of post-thrombotic syndrome
  • 6% of DVT patients report eventual venous ulcers (0.1% general population)
  • age (relative risk increase ~2 per 10-year increase)
  • surgery (orthopedic patients at highest risk: hip 48%, knee 61%)
  • trauma
  • history of venous thromboembolism (2-9% increase)
  • primary hypercoagulable states
    • protein A, C, and S deficiency (10x increased risk)
    • factor V Leiden (heterozygous 8x increased risk, homozygous 80x)
  • estrogen replacement (2-4x increased risk)
  • immobilization (2x increased risk)
  • pregnancy (0.075% of pregnancies)
  • malignancy (4-6x increased risk)
  • in-dwelling vascular device (e.g. PICC line and upper limb DVT) 6

In the lower limbs, patients often present with unilateral leg pain, swelling, and erythema. On physical examination, the affected leg is often tender and warm, and there may be dilation of superficial veins. Additionally, some patients may have a positive Homan sign on physical examination, whereby there is pain on forceful dorsiflexion while the knee is extended.

The majority of deep venous thromboses occur in the lower extremities and begin in the soleal veins of the calf. Doppler compression sonography is the imaging modality of choice. Features include:

  • non-compressible venous segment
  • increased venous diameter: acute thrombus
  • decreased venous diameter: chronic thrombus
  • loss of phasic flow on Valsalva maneuver
  • absent color flow: if completely occlusive
  • increased flow in superficial veins
  • lack of flow augmentation with calf squeeze
  • anechoic thrombus: acute thrombus
  • echogenic thrombus: chronic thrombus

vascular structures should always be interrogated during routine assessment of the peripheries. Incidental DVT has a prevalence of around 0.3% on routine  outpatient knee MRI.4

  • luminal abnormalities (abnormal flow voids or filling defects)
  • vein wall thickening
  • perivascular edema
  • perifascial edema
  • local intramuscular T2 / PD hyperintensity
  • subcutaneous edema
  • dermal thickening (related to venous obstruction)

Treatment is with anticoagulation, often for at least 3 months in duration 5.

  • "above knee", or proximal DVT, is a lower limb DVT involving the popliteal vein or more proximal vessels 5
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Article information

rID: 1204
Synonyms or Alternate Spellings:
  • Deep vein thrombosis (DVT)
  • DVT
  • Deep venous thrombosis
  • Deep vein thromboses
  • DVT's
  • DVTs
  • Deep vein thrombi
  • Deep venous thrombi
  • Deep venous thromboses
  • Deep vein thrombus
  • Deep venous thrombus

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Cases and figures

  • Case 1: subclavian and internal jugular
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  • DVT Left Poplitea...
    Case 2: in left popliteal vein
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  • Case 3
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  • Case 4: on left
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  • Longitudinal popl...
    Case 5
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  • Case 6
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  • Common femoral ve...
    Case 7
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  • Case 8
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