Leg edema: clinical clues to the differential diagnosis.

Leg edema is a common problem in older patients, with a wide range of possible causes. The diagnosis can be narrowed by categorizing the edema according to its duration (acute or chronic), distribution (unilateral or bilateral), and accompanying symptoms (such as dyspnea, pain, thickening of skin, and pigmentation). The differential diagnosis includes systemic illnesses such as heart failure, liver disease, malnutrition, and thyroid disorder; local conditions such as pelvic tumors, infection,, trauma, and venous thrombosis; and various medications known to increase the risk of edema of the lower extremities. Appropriate therapy is based on the presentation of edema and its identified cause.