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

• 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

• 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 features1. Active cancer (treatment within 6 months)2. Paralysis, paresis, or immobilization of lower extremity3. Bedridden for more than 3 days because of surgery

(within 4 weeks)4. Localized tenderness along distribution of deep veins5. Entire leg swollen6. Unilateral calf swelling of greater than 3 cm (below

tibial tuberosity)7. Unilateral pitting edema8. Collateral superficial veins9. Alternative diagnosis as likely as or more likely than

DVT

Points

1

1

1

1

1

1

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

• 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

• “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