SYMPTOMS

Symptoms of edema depend upon the cause, but may include:

• Swelling or puffiness of the skin, causing it to appear stretched and shiny. This is typically seen in the lower legs (called peripheral edema) or lower back (called sacral edema, frequently seen in those who have been in bed for long periods). Swelling is often worst after sitting or standing for a period of time (due to gravity), and may be worst at the end of the day. Pushing on the swollen area for a few seconds will leave a dimple in the skin.

• Increased size of the abdomen (with ascites)

• Shortness of breath or difficulty breathing (with pulmonary edema)

CAUSES - In most cases, the process of edema formation begins when fluid leaks from the body's smallest blood vessels, called capillaries, into the surrounding tissues. The leakage can occur because of changes in pressure in the capillaries, weakening of the capillary wall from disease, or other factors.

Usually, the leakage itself is not enough to cause noticeable edema. However, when the body senses that fluid is being lost from the capillaries, it signals the kidneys to hold on to sodium and water. This results in an increase in the volume of fluid circulating in the blood vessels, which, in turn, leads to additional leakage of fluid from the capillaries. It is typically at this point that edema can be seen.

CONDITIONS ASSOCIATED WITH EDEMA  - A number of different problems can cause edema. Some of the most common are unrelated to any specific disease. For example, damage to the veins in the legs (venous insufficiency) can cause abnormal pooling or clotting of blood in these vessels, leading to edema. Pregnancy, drug effects, and problems with drainage in the lymphatic system can also cause peripheral edema. Diseases commonly associated with edema include kidney disease, heart failure, and cirrhosis of the liver.

Venous insufficiency - A common cause of peripheral edema in clinical practice is venous insufficiency, one cause of which is a syndrome that may occur after an episode of venous blood clots (called deep vein thrombosis). In this case, the edema is usually limited to the lower extremities (feet or ankles) and may affect only one side (the left or right); other conditions that cause edema usually cause swelling of both extremities.

Pregnancy - Pregnant women retain a significant amount of sodium and water. Some of this excess fluid is required by the fetus and placenta. Edema of the hands, feet, and face is commonly seen.

Premenstrual syndrome - Edema that appears in a cyclic pattern (usually once per month) may occur due to premenstrual syndrome (PMS). Diuretics are of no benefit for edema related to PMS.

Drugs - Edema can be a side effect of a wide variety of medications.

Kidney disease - The edema of kidney disease causes swelling in the legs and around the eyes. It is caused by an increase in pressure in the blood vessels; this occurs when the kidneys excrete an insufficient amount of sodium and fluid. The extra fluid increases pressure on the blood vessel walls, which allows fluids to move from inside the blood vessel to the space around the vessel. Low levels of protein (albumin) in the blood may also contribute to the movement of fluid from the capillaries.

Heart failure - In heart failure, also called congestive heart failure, the heart is weakened and its pumping action is impaired. It can affect the right heart chambers, which receive blood from the body and pump it to the lungs to be filled with oxygen; or it can affect the left heart chambers, which pump oxygenated blood to the rest of the body.

Heart failure develops as a result of other conditions that damage the heart. These include heart attacks due to coronary heart disease, diseases of the heart valves, and hypertension (high blood pressure).

In right heart failure, pressure builds in the right chambers because they fail to pump blood efficiently. The pressure is reflected back to the blood vessels in the body that lead to the right chambers, frequently causing peripheral edema and, sometimes, ascites. The patient therefore notices swelling in the legs and abdomen, as well as other symptoms.

In left heart failure, pressure builds in the left chambers because they are failing to pump blood efficiently. The increased pressure affects the large blood vessels that connect the left side of the heart with the lungs. This causes edema in the lungs, or pulmonary edema, causing shortness of breath.

Cirrhosis - With cirrhosis, congestion in the liver leads to an increase in pressure within the blood vessels in the liver and subsequently, in the blood vessels leading into the liver, causing ascites. The patient may have pronounced swelling in the abdomen, as well as edema in the feet or, if the patient is lying down most of the day, swelling in the lower back (also called sacral edema).

DIAGNOSING THE CAUSE - A healthcare provider may use a number of different tools to determine the most likely cause for edema. For example, close examination of the legs and veins in the neck provide valuable clues. By listening to the lungs through a stethoscope or viewing the lungs on x-ray, providers can detect the presence of fluid, which indicates pulmonary edema. Blood and urine tests give information about possible kidney or liver disease.

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EditText of this page (last edited December 19, 2009)