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How Edema Works

Edema Diagnosis and Treatment

Make an appointment with your doctor if you think you have edema. He or she will obtain a detailed medical history and conduct a full exam -- an examination of the legs and veins in the neck can provide valuable clues. The doctor will also listen to your lungs through a stethoscope, which can detect the presence of fluid, which indicates pulmonary edema.

Your doctor might order tests to help make a diagnosis. Blood and urine tests are useful in diagnosing certain forms of edema related to kidney or liver disease. If heart failure is suspected, your doctor may order tests to detect abnormalities in your heart's electrical activity, size, shape and function during rest and exercise.

How Is Edema Treated?

When edema isn't too severe, it can be treated with a program of diet and lifestyle changes.

When water builds up in your tissues, one of the most effective ways of getting rid of it is to reduce the amount of salt or sodium in your diet. The typical American diet is very high in sodium. Even if you don't add salt while cooking or avoid using the salt shaker at the table, you're probably eating too much sodium. That's because we eat processed foods, like frozen dinners, boxed noodle and rice dishes and canned soups and vegetables. Most processed foods are high in sodium.

Leg, ankle and foot edema can be improved if you elevate your legs above the level of your heart for 30 minutes three or four times each day. Leg edema can also be prevented and treated with the use of support stockings (also called compression hose).

Your doctor may prescribe oral medicines (diuretics or water pills) to reduce your edema. Diuretics cause the kidneys to pass more water and sodium, reducing fluid volume throughout the body. Unfortunately, these oral medicines typically become less effective over time, and many people with severe edema eventually require hospitalization.

Typically, an in-hospital treatment for a serious case of edema includes intravenous medications (given with a needle into the bloodstream) that remove excess fluid from the body. In addition to the diuretics, some commonly used medications include:

  • Vasodilator drugs, which cause blood vessels to expand, thereby increasing blood flow
  • Inotropic drugs, which stimulate the heart to expel more blood with each beat

Intravenous drug therapy requires an average hospital stay of six days.

If the intravenous drug therapy doesn't relieve the edema, patients receive a procedure known as ultrafiltration or aquapheresis (an advanced and highly automated form of ultrafiltration). In this procedure, blood containing excess fluid is withdrawn, passed through a special filter and returned to the body. Aquapheresis therapy usually requires a three- to four-day hospital stay.

Follow the links below to learn more about edema.­­

Related HowStuffWorks Articles

  • How Heart Failure Works
  • How Fluid Overload Works
  • How Diuretics Work
  • How Low-Sodium Diets Work
  • How Ultrafiltration Works
  • How Aquapheresis Works

More Great Links


  • ­Costanzo MR, Guglin ME, Saltzberg MT, et al. Ultrafiltration versus ­intravenous diuretics for patients hospitalized for acute decompensated heart failure. J Am Coll Cardiol. 2007; 49:675-683.
  • Costanzo MR, O'Sullivan J, et al. Early ultrafiltration in patients with decompensated heart failure and diuretic resistance. J Am Coll Cardiol. 2005; 46:2047-2051.
  • ­Elkayam U, Hatamizadeh P, Janmohamed M. The challenge of correcting volume overload in hospitalized patients with decompensated heart failure. J Am Coll Cardiol. 2007; 49:684-686.