Unilateral leg swelling: Clues to cause and ways to treat

STUART D. GOULD, MD, Internal Medicine Resident, Thomas Jefferson University Hospital, Philadelphia, Pa.

JOHN M. SPANDORFER, MD, Associate Professor, Jefferson Medical College, Philadelphia, Pa.

Unilateral leg swelling is a concern for patients and a challenge for physicians. The condition may be uncomfortable and unattractive, and it can cause fears for patients about what to expect in the future. For the physician, unilateral edema requires a detailed history and physical examination. Major areas of focus are location, inciting events, and significant past medical history such as recent infections, malignancy, radiation, surgery, or thrombophilia.

The acute condition Acute unilateral leg swelling may be caused by deep vein thrombosis (DVT), ruptured popliteal cyst, cellulitis, erythema nodosum, trauma, or gastrocnemius musculotendinous rupture. The presence of pain is usually due to an inflammatory process as seen in cellulitis, venous thrombosis, trauma, or ruptured Baker's cyst.

DVT Perhaps the most important cause of unilateral leg edema is DVT. Thromboembolism has an incidence of more than 1 per 1000 in this country, nearly equivalent to that of stroke, the second-leading cause of cardiovascular disease.¹ Many prospective studies have shown that up to three fourths of patients who present with unilateral leg swelling and suspected DVT actually have nonthrombotic causes of edema.²

Key parts of the history should increase your suspicion for DVT, particularly prolonged immobilization, recent trauma or surgery, history of cancer, history of blood clots, and oral contraceptive use. Patients may complain of an aching, deep pain that worsens with ambulation or weight bearing. Often the swelling starts around the foot and ankle and extends to the upper portions of the leg. The extremity may be warm to the touch and erythematous.