Fluid accumulation and swelling of the lower extremities--including the feet, ankles and legs--is called peripheral edema, according to MedlinePlus. The swelling may be uncomfortable but generally is not painful. It's most commonly seen in elderly people. There are many different causes of lower extremity edema, but a few specific causes constitute most cases--including venous insufficiency, orthostatic edema, certain medications, pregnancy, and lower extremity fluid accumulation from heart, kidney or liver failure.
Venous Insufficiency
Blood is returned to the heart from the lower extremities via low-pressure vessels called veins. To overcome the effects of gravity, veins in the legs have a system of valves that keep the blood moving toward the heart. With age, the valves can degenerate and become incompetent, resulting in venous insufficiency, a condition in which blood pools in the lower extremities. Fluid may seep from the blood vessels into surrounding tissue, causing edema. Venous insufficiency is present in up to 30 percent of the population. It's the most common cause of leg edema in patients older than 50, according to Dr. John Ely and colleagues in an article published in the March-April 2006 issue of the Journal of the American Board of Family Medicine. Leg elevation, support hose and a low-salt diet are useful in treating venous insufficiency, as well as the use of diuretics, a type of medicine that helps get rid of excess fluid.
Orthostatic Edema
Muscle contractions are another mechanism the body uses to move blood out of the lower extremities. PDRhealth reports long periods of inactivity, such as prolonged sitting and standing, may cause a type of edema called orthostatic edema as a result of the lack of muscle activity. Take frequent breaks to walk or stretch the muscles during long car or plane trips to prevent orthostatic edema.
Organ System Failure
Liver, heart and kidney failure are important causes of excess fluid accumulation in the body that result in leg edema as well as pulmonary edema, or fluid in the lungs, according to MedlinePlus. Edema from organ failure often responds, under close medical supervision, to a low-salt diet and medications to treat the underlying organ failure and decrease excess fluid.
Pregnancy
During the later stages of pregnancy, the enlarged uterus pushes on the inferior vena cava, a large central vein that collects blood returning to the heart from the lower extremities. This results in blood backing up into the legs and feet, as reported by Dr. Ely's group in the Journal of the American Board of Family Medicine, with fluid accumulation in the lower extremity tissues.
Medications
Several medications cause leg edema, including calcium channel blockers, certain antidepressants, non-steroidal anti-inflammatory drugs, oral steroids and the use of estrogen, progesterone or testosterone. Calcium channel blockers, a type of blood pressure medicine, cause leg edema in up to 50 percent of patients, according to Dr. Ely and colleagues.
