Edema, Lower Extremity

Key Features

Essentials of Diagnosis

• Inquire about

  • History of venous thromboembolism

  • Symmetry of swelling

  • Pain

  • Change with dependence

  • Skin findings: hyperpigmentation, stasis dermatitis, lipodermatosclerosis, atrophie blanche, ulceration

General Considerations

• Lower extremities can swell in response to

  • Increased venous or lymphatic pressures

  • Decreased intravascular oncotic pressure

  • Increased capillary leak

  • Local injury or infection

• Acute lower extremity edema: deep venous thrombosis (DVT)

• Adults with varicose veins have a significantly increased risk of DVT

• Chronic venous insufficiency is the most common cause of chronic lower extremity edema, affecting up to 2% of the population

• Other causes of lower extremity edema

  • Cellulitis

  • Musculoskeletal disorders (Baker cyst rupture, gastrocnemius tear or rupture, diabetic myonecrosis)

  • Calf strain or trauma

  • Left common iliac vein compression (May-Thurner syndrome)

  • Other sites of nonthrombotic venous outflow obstruction, such as the

    • Inguinal ligament

    • Iliac bifurcation

    • Popliteal fossa

  • Medication side effects (eg, calcium channel blockers, gabapentin, minoxidil, or pioglitazone)

Clinical Findings

Symptoms and Signs

• Most common symptom of chronic venous insufficiency is the sensation of "heavy legs," followed by itching

• Assess lungs, heart, and abdomen for evidence of pulmonary hypertension (primary or secondary to chronic lung disease), HF, or cirrhosis

• Size of both calves should be measured 10 cm below the tibial tuberosity

• Swelling of the entire leg or swelling of one leg > 3 cm more than the other suggests deep venous obstruction

• Elicit pitting and tenderness

• Chronic venous insufficiency skin findings range from hyperpigmentation and stasis dermatitis to lipodermatosclerosis and atrophie blanche to skin ulceration

• Stasis dermatitis: brawny, fibrotic skin changes

• Skin ulceration can occur, particularly in the medial malleolar area, when due to chronic venous insufficiency

• Other causes of medial malleolar skin ulceration

  • Arterial insufficiency

  • Vasculitis

  • Infections (including cutaneous diphtheria)

  • Cancer

Differential Diagnosis

• Cardiovascular

  • HF (right-sided)

  • Pericardial effusion

  • Pericarditis

  • Tricuspid regurgitation

  • Tricuspid stenosis

  • Pulmonic stenosis

  • Cor pulmonale

  • Venous insufficiency (most common)

  • Venous obstruction

• Noncardiovascular

  • Cirrhosis

  • Low albumin (nephrotic syndrome, malnutrition, protein-losing enteropathy)

  • Cellulitis

  • Premenstrual fluid retention

  • Medications (vasodilators, eg, calcium channel blockers; salt-retaining medications, eg, nonsteroidal anti-inflammatory drugs, thiazolidinediones)

  • Musculoskeletal (Baker cyst, gastrocnemius tear, compartment syndrome)

  • Lymphatic obstruction

  • Eclampsia

  • Hypothyroidism with myxedema

  • Filariasis

• Unilateral

  • DVT

  • Venous insufficiency

  • Baker cyst

  • Cellulitis

  • Trauma

  • Lymphatic obstruction, eg, obstruction by pelvic tumor

  • Reflex sympathetic dystrophy

Diagnosis

Laboratory Tests

• Serum creatinine, blood urea nitrogen

• D-dimers

• Urinalysis

• Liver chemistries: alkaline phosphatase, aspartate aminotransferase, gamma glutamyl-transpeptidase, total bilirubin, albumin

• Thyroid-stimulating hormone

Imaging Studies

• Ultrasonography: should be performed in patients without an obvious cause of acute lower extremity swelling (eg, calf strain), since DVT is difficult to exclude on clinical grounds

• Ankle-brachial pressure index (ABPI)

Diagnostic Procedures