Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Lower leg pain, swelling, erythema Palpable cord, especially in the calf Duplex ultrasound evidence of thrombus Evidence of thrombus on CT or magnetic resonance angiography +++ GENERAL CONSIDERATIONS ++ There are 3 basic mechanisms of venous thrombus formation (Virchow’s triad): – Venous stasis – Vessel wall damage – Hypercoagulability Venous stasis is usually caused by: – Extrinsic compression from adenopathy or tumors – Intrinsic fibrosis or venous extension of tumors – Also can be caused by low-flow states, such as heart failure Endothelial damage, such as during limb surgery, exposes blood to the vessel media that contains tissue factors that initiate the cascade leading to blood clotting Hypercoagulability can be genetic or acquired – Genetic examples are deficiencies in factors V Leiden and protein C or S – Acquired examples are estrogen therapy and antiphospholipid antibody syndrome +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Pain and swelling in an extremity, usually a lower leg Bilateral swelling less likely thrombotic in origin +++ PHYSICAL EXAM FINDINGS ++ Pitting edema Tenderness to palpation along the deep vein distribution Homan’s sign (pain on dorsiflexion of the foot) is uncommon A palpable venous cord is unusual unless there is also superficial venous involvement Phlegmasia cerulea dolens is rare (ie, severe pain and swelling accompanied by cyanosis [tissue ischemia]) +++ DIFFERENTIAL DIAGNOSIS ++ Ruptured Baker’s cyst Abscesses Ruptured plantaris tendon Muscle strain Tumors +++ DIAGNOSTIC SCHEMA: WELLS RULE ++ One point for each of the following: – Cancer – Leg immobilization – Patient immobilization: > 3 days; surgery < 4 weeks ago – Tender deep vein palpation – Swollen leg – Calf circumference difference > 3 mm – History of deep vein thrombosis (DVT) Alternative diagnosis (see Differential Diagnosis above) more likely (subtract 2 points) DVT diagnosis likely ≤ 1 point; DVT likely > 1 point +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ D-dimer (thrombin breakdown products) positivity is nonspecific, but a negative test is very specific. It is generally safe to withhold anticoagulant treatment without further diagnostic testing if the D-dimer is negative and the Wells Rule score is ≤ 1 Factors II, VIII, and V Leiden; proteins S and C; antithrombin III; anticardiolipin antibodies, and homocysteine levels +++ ELECTROCARDIOGRAPHY ++ Could show right ventricular hypertrophy if pulmonary emboli are present +++ IMAGING STUDIES ++ Duplex ultrasonography can identify thrombus in veins MRI is useful for distinguishing new from old thrombi CT scan of the leg is becoming more widely used in conjunction with CT scans of the chest for pulmonary emboli +++ DIAGNOSTIC PROCEDURES ++ ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.