Leg and feet swelling that occurs with diseases of the heart, liver and kidneys is caused by salt retention holding excess fluid in the body, states MedicineNet. Edema is a normal response of the body to inflammation or injury and it is also caused by medical problems, notes WebMD.
Edema results when small blood vessels release fluid into nearby tissues, states WebMD. A blood clot in the deep veins of the leg can result in leg edema. Severe leg edema can interfere with blood flow, leading to ulcers on the skin. When the heart weakens and pumps blood less effectively, fluid can slowly build up and create edema that interferes with walking, often causing legs to weigh an extra 5 or 10 pounds each. Severe liver disease results in an increase in fluid retention that can cause leg edema.
A kidney condition called nephrotic syndrome can result in severe leg edema, explains WebMD. A tumor blocking lymph or blood flow causes edema in the affected area. Leg edema is common during pregnancy due to an increase in blood volume. Medications can cause edema, including nonsteroidal anti-inflammatories, corticosteroids and calcium channel blockers. Leg edema related to congestive heart failure or liver disease can be treated with diuretics and a low-sodium diet.