Diseases of Veins Flashcards
True or false: The lupus anticoagulant causes a clotting tendency.
True. Although the lupus anticoagulant may cause a prolonged partial thromboplastin time (PTT), the patient has a tendency toward thrombosis. Look for associated lupus symptoms, positive results on the Venereal Disease Research Laboratory (VDRL) or rapid plasma reagin (RPR) tests for syphilis, or a history of miscarriages to help you recognize this condition.
What genetic and acquired causes of an increased tendency toward clot formation may appear on the Step 3 exam?
The list keeps growing. Watch for factor V Leiden mutation (or activated protein C resistance), prothrombin G20210A mutation, hyperhomocysteinemia, elevated factor VIII level, and deficiencies in protein C, protein S, or antithrombin III as genetic causes of an increased tendency toward thrombosis. Acquired causes include antiphospholipid syndrome (lupus anticoagulant and anticardiolipin antibody), hyperhomocysteinemia, pregnancy, cancer, and estrogen-containing medications. Note that hyperhomocysteinemia can be genetic or acquired. All are treated with anticoagulant therapy to prevent DVT and pulmonary embolus. Suspect these conditions if a patient develops recurrent clots or develops a clot in the absence of risk factors for clot development.
What is the Virchow triad?
The Virchow triad consists of three findings associated with DVT: endothelial damage, venous stasis, and hypercoagulable state. These three broad categories should help you remember when to think about the possibility of DVT.
List the common clinical scenarios for the development of DVT.
- Surgery (especially orthopedic, pelvic, abdominal, or neurosurgery)
- Malignancy
- Trauma
- Immobilization
- Pregnancy
- Use of birth control pills
- Disseminated intravascular coagulation
- Hypercoagulable states such as factor V (Leiden), antithrombin III deficiency, protein C deficiency, protein S deficiency, prothrombin G20210A gene mutation, hyperhomocysteinemia, and antiphospholipid antibodies
Describe the physical signs and symptoms of DVT. How is it diagnosed?
Signs and symptoms include unilateral leg swelling, pain or tenderness, and/or the Homan sign (present in 30% of cases). Superficial palpable cords imply superficial thrombophlebitis rather than DVT (see later discussion). DVT is best diagnosed by Doppler compression ultrasonography of the veins of the extremity. The gold standard is venography, but this invasive test is reserved for situations in which the diagnosis is not clear.
How is DVT treated? For how long?
Systemic anticoagulation is necessary. Use intravenous heparin or subcutaneous low–molecular-weight heparin initially, followed by crossover to oral warfarin. Patients should be maintained on warfarin for at least 3 to 6 months, and possibly for life if more than one episode of clotting occurs.
What is the best way to prevent DVT in patients undergoing surgery?
Prophylactic measures for patients undergoing surgery depend on the risk of developing DVT or pulmonary embolism. Early ambulation is recommended for low-risk patients. Low–molecular-weight heparin, low-dose unfractionated heparin, or fondaparinux is recommended for patients at moderate risk. High-risk patients should be given low–molecular-weight heparin, fondaparinux, or an oral vitamin K antagonist. Pneumatic compression stockings should be used instead if the patient is at moderate or higher risk and at high risk of bleeding.
True or false: DVT can lead to a stroke.
False, with one rare exception. Embolization of left-sided heart clots (caused by atrial fibrillation, ventricular wall aneurysm, severe CHF, or endocarditis) leads to arterial infarcts (stroke and renal, gastrointestinal, or extremity infarcts), not pulmonary emboli. Deep venous thrombi (or right-sided heart clots) that embolize cause pulmonary emboli, not arterial emboli. The exception is a patient with a right-to-left shunt, such as a patent foramen ovale, atrial or ventricular septal defect, or pulmonary arteriovenous fistula. In such patients, a venous clot may embolize and cross over to the left side of the circulation, causing an arterial infarct. This event is quite rare.
True or false: A superficial palpable cord is a fairly specific sign of DVT.
False. A superficial palpable cord usually represents superficial thrombophlebitis.
Describe the usual history of a patient with superficial thrombophlebitis. How is the condition treated?
Patients often have a history of varicose veins and exhibit localized leg pain with superficial cordlike induration, reddish discoloration, and mild fever. Superficial thrombophlebitis is not a significant risk factor for pulmonary embolus and patients do not need anticoagulation. Treatment is usually conservative and includes nonsteroidal antiinflammatory drugs (NSAIDs) and warm compresses. The condition generally subsides on its own within a few days. A thrombectomy under local anesthesia can be performed for severe or nonresolving symptoms.
True or false: Superficial thrombophlebitis is a risk factor for pulmonary embolus.
False. Superficial thrombophlebitis (erythema, tenderness, edema, and a palpable clot in a superficial vein) affects superficial veins and does not cause pulmonary emboli. It is considered a benign condition, although recurrent superficial thrombophlebitis can be a marker for underlying malignancy (e.g., Trousseau syndrome, or migratory thrombophlebitis, is a classic marker for pancreatic cancer). Treat affected patients with NSAIDs and warm compresses.
What are the signs and symptoms of venous insufficiency? How is it treated?
Venous insufficiency generally occurs in the lower extremities. Patients may have a history of DVT, varicose veins, and/or swelling in the extremity with pain, fatigability, or heaviness. Symptoms are relieved by elevating the extremity. Patients may also have increased skin pigmentation around the ankles with possible skin breakdown and ulceration. Treatment is at first conservative, including elastic compression stockings, elevation with minimal standing, and treatment of ulcers with cleaning and wet-to-dry dressings, and antibiotics if cellulitis occurs.
