Nature Of Patient

Primary lymphedema is an inherited defect in the lymphatic system caused by hypoplasia, aplasia, or digitation of the lymphatic vessels. In the neonate, unilateral edema of a leg is termed congenital lymphedema and is caused by a form of primary lymphedema. If the swelling of the leg becomes apparent around 10 years of age, it is called lymphedema praecox. Traumatic thrombophlebitis, cellulitis, arthritis, and compartment syndromes also cause unilateral leg edema in children. Also in children, bilateral leg edema is usually caused by a systemic illness, such as acute glomerulonephritis, nephrotic syndrome, hypoproteinemia, or primary lymphedema.

Unilateral or bilateral edema in adolescents or older women may be caused by constricting garments such as tight jeans, pantyhose, and (rarely) garters. In a runner, the sudden onset of painful calf swelling suggests a ruptured gastrocnemius muscle, whereas intermittent pain and swelling of the upper or lower leg suggest a compartment syndrome. Unilateral or bilateral edema of the lower leg may be caused by elastic bands used for tenodesis.

In obese women, the development of bilateral leg swelling that spares the feet suggests lipedema, which occurs almost exclusively in women and is a bilateral and symmetrical deposition of fat in the lower extremities. The foot is not involved in lipedema, whereas in lymphedema the swelling starts in the most distal part of the foot; this pattern differentiates the two conditions.

In a chronic alcoholic, bilateral edema of the leg suggests that it is caused by cirrhosis with or without ascites. In a diabetic patient, unilateral and occasional bilateral swelling of the legs suggests cellulitis, especially if it is accompanied by warmth and tenderness. Leg swelling due to venous insufficiency is more common in women, and there is frequently a history of varicose veins in female relatives of affected women. In patients with heart failure or cirrhosis, bilateral leg edema is usually a manifestation of the systemic disease. In patients with rheumatoid arthritis, painful unilateral swelling of the calf may result from a ruptured Baker’s cyst, sometimes referred to as pseudophlebitis. Localized pretibial swelling in a patient with tachycardia, exophthalmos, or other signs or symptoms of hyperthyroidism suggests pretibial myxedema, which is a rare finding in hyperthyroidism.

Unilateral swelling of the lower leg may be the presenting complaint in patients with Kaposi’s sarcoma, which is more common in acquired immunodeficiency syndrome (AIDS).

Nature of Symptoms

Unilateral swelling of the lower or upper leg suggests local mechanical or inflammatory processes. These include lymphedema, venous insufficiency (the most common cause of unilateral leg edema), thrombophlebitis, cellulitis, a ruptured gastrocnemius muscle, compartment syndrome, ruptured Baker’s cyst, and only rarely an acquired or inherited arteriovenous fistula. Bilateral leg swelling is most often caused by systemic conditions, including heart failure, nephrotic syndrome, cirrhosis, hypoalbuminemia, acute glomerulonephritis, drugs (Table 31-1), constricting garments, and prolonged dependency of the legs. Less common causes of bilateral leg swelling include idiopathic edema, lipedema, primary lymphedema, and exposure to extremes of temperature.

TABLE 31-1 Drugs Associated with Causing Edema

A sudden onset of calf swelling suggests ruptured Baker’s cyst, ruptured gastrocnemius muscle, arterial occlusion, thrombophlebitis, cellulitis, or compartment syndrome. Chronic bilateral swelling of the legs occurs in the systemic illnesses mentioned as well as in lymphedema, lipedema, lymphatic obstruction, chronic venous insufficiency, and cellulitis, which may be secondary to bilateral venous stasis dermatitis. The gradual onset of edema that starts in the distal part of the foot and involves the dorsum of the foot and ankle suggests lymphedema. Painless unilateral leg edema in a woman older than 40 years should prompt suspicion of gynecologic cancer with obstruction of the lymphatics causing secondary lymphedema.