DVT (Deep Venous Thrombosis) - Diagnosis : Wheeless' Textbook of Orthopaedics

Clinical signs

Work up for DVT

arterial blood gas/pulse oximetry
coagulation labs (for HCT & platelet count)
EKG and CXR (if PE is suspected)
D-dimer
- level below 0.5 mg per liter should rule out the presence of circulating fibrin and thus essentially rules out a dx of venous thromboembolism
- dimer levels will be elevated in:
  - patients older than 80 years
  - hospitalized patients
  - cancer patients
  - pregnant women
reference - Evaluation of D-Dimer in the Diagnosis of Suspected Deep-Vein Thrombosis

MRI

may emerge as the new gold standard for diagnosis of DVT
can diagnosis pelvic DVT, and can be used to diagnose DVT in patients who have femoral or tibial frx

Impedence phlebography

Venography

remains the gold standard for diagnosis of DVT
venograms should meet at least one of the following direct or indirect criteria
- a constant defect in filling seen on two views
- an abrupt discontinuation of visible filling at a constant site in the vein
- the absence of filling in the entire deep-vein system (without external compression), w/ or w/o venous flow through collaterals
disadvantages
- some have questioned whether venography might actually cause DVT to form due to vessel inflammation from the contrast dye (estimated that 1-3% of venograms lead to DVT); this complication is now less common with newer contrast dye
- systemic reactions
- skin necrosis from extravasation from dye
- inability to diagnose pelvic venous thrombi
- cannot be used when there is ipsilateral femoral or tibial frx