DVT: Symptoms
and work-up
Sean Stoneking
DVT Epidemilogy
• Approximately 600,0000 new cases of
DVT each year
• 50% in hospitalized patients or nursing
home residents
Clinical Signs and Symptoms
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Up to 50% are asymptomatic
Pain
Edema
Warmth
Discoloration
Palpable cord of a thrombosed vein
Homan’s sign (present 1/3 of cases)
DDx of acute edema/leg pain?
• Infection
• Trauma/injury
• Venous insufficiency
Risk Factors: Virchow’s Triad
• Stasis
• Venous endothelial injury
• Hypercoagulable state
Risk factors
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Past DVT
Immobilization
Pregnancy
OCP and HRT
Trauma
Obesity
Age
Sepsis
Cancer
Diseases that alter blood viscosity (sickle cell,
polycythemia, multiple myeloma)
Risk Factors: Thrombophilias
• Anticoagulant protein deficiency (Protein
C/S, Antithrombin Plasminogen, Heparin
cofactor II)
• Dysfibrinogenemia
• Antiphospholipid antibodies
• Factor V Leiden mutation (heterozygous)
• Prothrombin G20210A mutation
(heterozygous)
Wells pretest probability
Clinical features
Points
1. Active cancer (treatment within 6 months)
1
2. Paralysis, paresis, or immobilization of lower extremity
3. Bedridden for more than 3 days because of surgery 1
(within 4 weeks)
4. Localized tenderness along distribution of deep veins
5. Entire leg swollen
1
6. Unilateral calf swelling of greater than 3 cm (below 1
tibial tuberosity)
7. Unilateral pitting edema
8. Collateral superficial veins
1
9. Alternative diagnosis as likely as or more likely than
1
DVT
1
1
-2
Pretest Probability Interpretation
• >=3 points: high risk (75%)
• 1 to 2 points: moderate risk (17%)
• <1 point: low risk (3%).
Ramzi and Leeper, Am Fam Phys 2004;69 (12).
Testing Modalities
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Ulrasonography
D-dimers
Contrast venography
MRI
Spiral CT
Ultrasound
• In the proximal veins sensitivity is 97%
• In the calf veins sensitivity is only 73%
• It cannot distinguish between an old clot
and a new clot.
D-dimers
• Degradation product of a cross-linked
fibrin blood clot.
• Levels also elevated in recent major
surgery, hemorrhage, trauma, pregnancy
or cancer.
• Sensitive but nonspecific
• The value is in a negative test result
Contrast venography
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“Gold Standard” for imaging DVT
can image entire lower extremities
Sensitive in asymptomatic patients
Limitations: invasive, contrast
reactions
MRI
• Good test for suspected iliac vein or
inferior vena caval thrombosis
• More sensitive than any other noninvasive
study in suspected calf vein thrombosis.
• Expense, lack of general availability
Spiral CT
• When PE is suspected, can scan chest
and lower extremities with same amount of
contrast.
• ~50% more costly than ultrasound
• Risk of contrast reaction
Summary
• Use risk stratification of H&P with diagnostic
testing to make the diagnosis
• Up to 50% of pts with DVT are asymptomatic
• Negative D-dimer rules out DVT in low
probability
• Ultrasound useful for diagnosing proximal
thromboses
• MRI and contrast venography useful for
diganosing distal thromboses