Deep vein thrombosis
Updates to Article Attributes
Body
was changed:
The term deep vein thrombosis (DVT) is practically a synonym for those that occur 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 specific sections.
Epidemiology
- 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)
Risk factors
- age (relative risk increase ~2 per 10-year increase)
- surgery (orthopaedic 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)
- oestrogen replacement (2-4x increased risk)
- immobilisation (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)5
Radiographic features
Ultrasound
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 manoeuvre
- absent colour flow: if completely occlusive
- increased flow in superficial veins
- lack of flow augmentation with calf squeeze
- anechoic thrombus: acute thrombus
- echogenic thrombus: chronic thrombus
Treatment and prognosis
Treatment is with anticoagulation, often for at least 3 months in duration 4.
Complications
Practical points
- "above knee", or proximal DVT, is a lower limb DVT involving the popliteal vein or more proximal vessels 4
-<li>in-dwelling vascular device (e.g. <a title="PICC lines" href="/articles/peripherally-inserted-central-catheters-1">PICC line</a> and upper limb DVT)<sup>5</sup>- +<li>in-dwelling vascular device (e.g. <a href="/articles/peripherally-inserted-central-catheters-1">PICC line</a> and upper limb DVT)<sup>5</sup>
-<li><a href="/articles/phlegmasia-surelea-dolens">phlegmasia surelea dolens</a></li>- +<li><a title="Phlegmasia cerulea dolens" href="/articles/phlegmasia-cerulea-dolens">phlegmasia curelea dolens</a></li>