A 52-year-old woman comes to the emergency department with left leg pain and swelling. She is a commercial truck driver and first noticed the swelling 3 days ago. The patient initially attributed the swelling to a long haul truck ride as she often gets mild "puffiness" of her ankles by the end of the day. However, the swelling has persisted and now involves her entire left leg below the knee. She has discomfort with walking but no chest pain, palpitations, syncope, or difficulty breathing. The patient has a history of hypothyroidism and hypertension and takes levothyroxine and hydrochlorothiazide. She has also been on menopausal hormone therapy using estrogen-progestin for intractable hot flashes. She smokes a pack of cigarettes daily and drinks 2 beers each night. Temperature is 37.2 C (99 F) , blood pressure is 134/89 mm Hg, and pulse is 78/min. BMI is 31 kg/m². Extremity examination reveals a normal right leg and pitting edema and warmth over the left lower leg. ECG shows normal sinus rhythm, and chest x-ray is normal with no infiltrates. Serum creatinine level is 0.7 mg/dL. Duplex ultrasound of the lower extremities reveals noncompressibility of the left popliteal and femoral veins.
Which of the following is the best next step in management of this patient?

Question

Quizplus · Accepted Answer

Explanation: 11ec2b69_be67_63fc_8f63_5127095f71e1_MD0005_00 This patient on menopausal hormone therapy with unilateral lower extremity edema has ultrasound evidence of a deep venous thrombosis (DVT). Recent clinical guidelines by the American College of Chest Physicians recommend ≥3 months of an oral factor Xa inhibitor (eg, rivaroxaban) for patients with DVT or pulmonary embolism (PE). Factor Xa inhibitors are considered the first-line therapy because they are administered orally (unlike low-molecular-weight heparin) and do not require a heparin bridge or laboratory monitoring (unlike warfarin). (Choice A) A CT scan of the chest is typically recommended for patients with DVT who have pulmonary symptoms (eg, chest pain, shortness of breath, hemoptysis). Treatment of PE is often the same as for DVT. (Choice B) Antiplatelet therapy such as aspirin is often used for primary or secondary prevention of cardiovascular disease (eg, coronary artery disease, heart attack, stroke). Antiplatelet therapy is not commonly used in the treatment of DVT. (Choice D) Oral vitamin K antagonists such as warfarin take several days to achieve full effect and may transiently result in a hypercoagulable state; patients initiated on vitamin K antagonists require several days of heparin bridging. (Choice E) Protein C, protein S, and antithrombin III deficiencies are congenital causes of hypercoagulability that can increase risk of DVT. Testing for an inherited thrombophilia is typically considered for patients who are young, have a strong family history of DVT, or have had multiple occurrences of DVT. This patient has several risk factors for acquired DVT including menopausal hormone therapy and immobility. In addition, screening for congenital causes is not immediately undertaken as an active thrombus often interferes with testing results. Educational objective: Patients with deep venous thrombosis or pulmonary embolism are typically treated with ≥3 months anticoagulation with an oral factor Xa inhibitor such as rivaroxaban.

A 52-Year-Old Woman Comes to the Emergency Department with Left