Quick Review: Deep Venous Thrombosis
T Fujii, B Phillips
Citation
T Fujii, B Phillips. Quick Review: Deep Venous Thrombosis. The Internet Journal of Internal Medicine. 2002 Volume 3 Number 2.
Abstract
Deep Venous Thrombosis (DVT)
Virchow's Triad
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Stasis
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abnormalities of vessel wall
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alterations of the blood coagulation system
Thrombosis occurs when blood coagulation overwhelms the natural anticoagulant mechanisms and the fibrinolytic system; usually occurs at sites of vessel damage, in the region of an anatomical valve
Risk Factors:
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Recent Surgery
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Trauma
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Immobilization
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Serious Illness- CHF, CVA, Cancer, IBD
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Chronic Venous Insufficiency
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Hypercoagulability or Thrombophilia
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Exogenous Estrogen Use or Oral Contraceptives
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Pregnancy
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Obesity
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History of Thrombosis
Clinical Features:
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Localized swelling, particularly unilateral
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Redness or discoloration
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Pain or tenderness
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Distal edema
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Homan Sign: discomfort in the calf muscles on forced dorsiflexion of the foot
Clinical Diagnosis is NOT accurate
Differential Diagnosis:
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Baker's Cyst (ruptured)
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Muscle tear or cramp
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Hematoma
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Cellulitis
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Postthrombotic Syndrome
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Superficial Thrombophlebitis
Diagnostic Studies:
Suspicion of a D.V.T. from history and physical examination requires confirmation with further testing
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Venography:
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The Gold Standard
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Invasive, expensive, can be painful, may produce superficial thrombophlebitis [can be complicated by a D.V.T. (1-2%)]
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Impedance Plethysmography:
Noninvasive
Useful for diagnosing proximal vein thrombosis, but yield is low with most
Calf vein thrombi
False positive results can occur with chronic heart failure, postoperative leg swelling, or external compression
Venous Ultrasonography:
Noninvasive method of choice due to high sensitivity and specificity
Treatment:
Once diagnosis confirmed, begin Treatment !
Goals of Treatment:
To prevent P.E., postthrombotic syndrome, and thromboembolic pulmonary hypertension
Calf Vein Thrombi:
Therapy controversial, either anticoagulation or close follow- up with serial testing is recommended
Treatment: Heparin
Continuous IV, Intermittent IV, Intermittent SQ
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maintain PTT 1.5-2.5 times the control value
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important to achieve and maintain therapeutic ptt values
Side Effects
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Thrombocytopenia
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Osteoporosis
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Bleeding
Treatment: Low-molecular Weight Heparin LMWH
trials underway for use as outpatient therapy of D.V.T.
Advantages
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less bleeding
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longer half lives
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no laboratory monitoring necessary
Treatment: Coumadin
Begin within 24 hours after initiation of heparin
Maintain PT at INR of 2.0 to 3.0
Continue IV heparin until INR in therapeutic range for two consecutive days
Continue Therapy for At Least 3 Months, then Reassess
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In patients with known, acute, transient risk factor, four to six weeks of therapy adequate if risk factor is no longer present
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In patients with certain diseases (malignancy) or recurrence, long term therapy is indicated
Side Effects
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skin necrosis
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bleeding
Treatment: Thrombolytics
Reserved for patients with life-threatening pulmonary embolism or with extensive iliofemoral venous thrombosis & low risk of bleeding
Streptokinase
TPA
Urokinase
Treatment: Invasive Intervention
Vena Caval Filter
Indications include failed oral anticoagulant therapy, or instances where anticoagulation is contraindicated (bleeding, necrosis, etc)
Surgical Thrombectomy
Indications include chronic thromboembolic pulmonary hypertension and massive pulmonary embolism in patients with contraindications to thrombolytic therapy