1. Unilateral lower extremity edema
Among common causes of unilateral lower extremity swelling, DVT is the most life-threatening. Clues suggesting DVT include a history of cancer, recent limb immobilization, or confinement to bed for at least 3 days following major surgery within the past month (Table 2–4). Adults with varicose veins have a significantly increased risk of DVT. Lower extremity swelling and inflammation in a limb recently affected by DVT could represent anticoagulation failure and thrombus recurrence but more often are caused by postphlebitic syndrome with valvular incompetence. A search for alternative explanations is equally important in excluding DVT. Other causes of a painful, swollen calf include cellulitis, musculoskeletal disorders (Baker cyst rupture [“pseudothrombophlebitis”]), gastrocnemius tear or rupture, calf strain or trauma, and left common iliac vein compression (May-Thurner syndrome), as well as other sites of nonthrombotic venous outflow obstruction, such as the inguinal ligament, iliac bifurcation, and popliteal fossa. Swelling of the ankle can be a manifestation of Charcot neuropathic osteoarthropathy.
Table 2–4.Risk stratification of adults referred for ultrasound to rule out DVT. ||Download (.pdf) Table 2–4. Risk stratification of adults referred for ultrasound to rule out DVT.
|Step 1: |
Score 1 point for each
Paralysis, paresis, or recent plaster immobilization
Recently bedridden for > 3 days due to major surgery within 4 weeks
Localized tenderness along distribution of deep venous system
Entire leg swelling
Swelling of one calf > 3 cm more than the other (measured 10 cm below tibial tuberosity)
Ipsilateral pitting edema
Collateral superficial (nonvaricose) veins
Previously documented DVT
|Step 2: |
|Subtract 2 points if alternative diagnosis has equal or greater likelihood than DVT |
|Step 3: |
|Obtain sensitive D-dimer for score ≥ 0 |
|Score ||D-Dimer Positive1 ||D-Dimer Negative |
|0–1 ||Obtain ultrasound ||Ultrasound not required |
|≥ 2 ||Obtain ultrasound || |
2. Bilateral lower extremity edema
Bilateral involvement and significant improvement upon awakening favor systemic causes (eg, venous insufficiency) and can be presenting symptoms of volume overload (HF, cirrhosis, kidney disease [eg, nephrotic syndrome]). The sensation of “heavy legs” is the most frequent symptom of chronic venous insufficiency, followed by itching. Chronic exposure to elevated venous pressure accounts for the brawny, fibrotic skin changes observed in patients with chronic venous insufficiency as well as the predisposition toward skin ulceration, particularly in the medial malleolar area. Pain, particularly if severe, is uncommon in uncomplicated venous insufficiency.
Lower extremity swelling is a familiar complication of therapy with calcium channel blockers (particularly felodipine and amlodipine), pioglitazone, gabapentin, and minoxidil. Prolonged airline flights (longer than 10 hours) are associated with edema even in the absence of DVT. Lymphedema and lipedema are other causes of bilateral lower extremity edema. Pelvic congestion syndrome worsens symptoms of chronic venous symptoms of the lower extremities.
Physical examination should include assessment of the heart, lungs, and abdomen for evidence of pulmonary hypertension (primary or secondary to chronic lung disease), HF, or cirrhosis. Some patients with cirrhosis have pulmonary hypertension without lung disease. There is a spectrum of skin findings related to chronic venous insufficiency that depends on the severity and chronicity of the disease, ranging from hyperpigmentation and stasis dermatitis to abnormalities highly specific for chronic venous insufficiency: lipodermatosclerosis (thick, brawny skin; in advanced cases, the lower leg resembles an inverted champagne bottle) and atrophie blanche (small depigmented macules within areas of heavy pigmentation). The size of both calves should be measured 10 cm below the tibial tuberosity and pitting and tenderness elicited. Leg edema may also be measured by ultrasonography with a gel pad if physical examination is equivocal. Swelling of the entire leg or of one leg 3 cm more than the other suggests deep venous obstruction. The left calf is normally slightly larger than the right as a result of the left common iliac vein coursing under the aorta.
An ulcer located over the medial malleolus is a hallmark of chronic venous insufficiency but can be due to other causes. Shallow, large, modestly painful ulcers are characteristic of venous insufficiency, whereas small, deep, and more painful ulcers are more apt to be due to arterial insufficiency, vasculitis, or infection (including cutaneous diphtheria). Diabetic vascular ulcers, however, may be painless. When an ulcer is on the foot or above the mid-calf, causes other than venous insufficiency should be considered.
The physical examination is usually inadequate to distinguish lymphedema from venous insufficiency. Sensitivity and specificity of clinical signs in predicting lymphoscintigraphy-confirmed lymphedema were 17% and 88%, respectively. Only the Kaposi-Stemmer sign (the inability to pinch or pick up a fold of skin at the base of the second toe because of its thickness) was a significant predictor of lymphedema (odds ratio, 7.9; P = 0.02).
Patients without an obvious cause of acute lower extremity swelling (eg, calf strain) should have an ultrasound performed, since DVT is difficult to exclude on clinical grounds. A prediction rule allows a clinician to exclude a lower extremity DVT in patients without an ultrasound if the patient has low pretest probability for DVT and a negative sensitive D-dimer test (the “Wells prediction rule”). It is important to ensure a follow-up venous ultrasound is done if the first one incompletely assesses all lower extremity veins. The diagnostic study of choice to detect chronic venous insufficiency due venous incompetence is duplex ultrasonography. Assessment of the ankle-brachial pressure index (ABPI) is important in the management of chronic venous insufficiency, since peripheral arterial disease may be exacerbated by compression therapy. This can be performed at the same time as ultrasound. Caution is required in interpreting the results of ABPI in older patients and diabetics due to the decreased compressibility of their arteries. A urine dipstick test that is strongly positive for protein can suggest nephrotic syndrome, and a serum creatinine can help estimate kidney function. Lymphoscintigraphy can be used to confirm a clinical suspicion of lymphedema. Ambulatory sensors for measuring circumference of lower limbs to assist management of chronic venous insufficiency and lymphedema are being developed.