What is the appropriate workup for lower extremity edema (swelling)?

From the Guidelines

A comprehensive workup for lower extremity swelling should start with a thorough history and physical examination, followed by targeted diagnostic tests, with bilateral lower extremity ultrasound being the initial imaging study to rule out deep vein thrombosis (DVT) 1. The workup should include:

• Detailed patient history: Focus on onset, duration, and progression of swelling, associated symptoms, medications, and relevant medical history (e.g., heart, liver, or kidney disease) 1.
• Physical examination: Check for pitting edema, skin changes, temperature, and pulses. Measure leg circumference for comparison 1.
• Basic laboratory tests: Complete blood count, basic metabolic panel, liver function tests, and urinalysis 1.
• Imaging studies: Start with bilateral lower extremity ultrasound to rule out DVT, and consider additional tests based on suspicion, such as echocardiogram, chest X-ray, CT, or MRI 1.
• Specific tests for suspected conditions: D-dimer if DVT is likely, brain natriuretic peptide (BNP) for heart failure, and thyroid function tests if myxedema is possible 1. The use of US duplex Doppler of the lower extremity is usually appropriate for the initial diagnosis of varicose veins and venous leg ulcers, as it provides valuable information on the condition of the deep venous system, saphenous veins, and perforating veins 1. Compression therapy is also a recommended treatment for venous leg ulcers, with a minimum pressure of 20 to 30 mm Hg, and improved ejection fraction in refluxing vessels and higher extrinsic pressures achieved with higher pressures and negative graduated compression bandages 1.

From the Research

Evaluation of Lower Extremity Edema

The evaluation of lower extremity edema involves a combination of patient history, physical examination, and diagnostic tests to determine the underlying cause.

• The chronicity and laterality of the edema guide the evaluation, with acute unilateral lower-extremity edema warranting immediate evaluation for deep venous thrombosis 2.
• Validated decision rules, such as the Wells and STOP-Bang criteria, can guide decision-making regarding the possibility of venous thromboembolic disease and obstructive sleep apnea, respectively 2.
• Initial diagnostic tests may include a basic metabolic panel, liver function tests, thyroid function testing, brain natriuretic peptide levels, and a urine protein/creatinine ratio 2.

Diagnostic Tests for Specific Causes

• For patients with acute unilateral lower-extremity edema, a d-dimer test or compression ultrasonography can help diagnose deep venous thrombosis 2.
• Duplex ultrasonography with reflux can help diagnose chronic venous insufficiency in patients with chronic bilateral lower-extremity edema 2.
• Computed tomography (CT) venography may be necessary to evaluate for possible May-Thurner syndrome in cases of unilateral lower extremity swelling with a negative initial duplex venous ultrasound 3.
• CT or surgical exploration may be necessary to diagnose rare vascular disorders such as cystic adventitial disease (CAD) 4.

Clinical Diagnosis and Further Investigation

• Lymphedema is often a clinical diagnosis, but lymphoscintigraphy can be performed if the diagnosis is unclear 2.
• A thorough patient history and physical examination are essential in evaluating lower extremity edema, as they can help identify underlying causes such as lipedema 5 or other systemic conditions 6.
• Further investigation, including laboratory tests and imaging studies, may be necessary to determine the underlying cause of lower extremity edema and guide treatment 2, 3, 4.