Edema is a general term for swelling in the body due to the buildup of excess fluid in the tissues. It may be in one specific area (such as an ankle) or in multiple locations throughout the body. It is not a condition, but is a symptom of an underlying condition.

Minor, temporary edema can be caused by pregnancy or inactivity and is rarely serious. However, longer and more severe episodes of edema could be a sign of a serious underlying medical condition, such as heart failure, kidney failure or cirrhosis of the liver. There are several types of edema due to a number of causes. A patient’s physician can best determine the type of edema and possible contributing factors. 

Treatment depends on the underlying cause of the edema. It may range from simple changes, such as a different sleeping position, to prescribing diuretic medications for flushing fluids from the body. Physicians may also recommend reduced intake of salt, which causes the body to retain water. Some lifestyle changes may treat the condition as well as prevent its initial occurrence. Individuals who experience any unexplained edema should consult with their physician.

About edema

Edema is a general term for swelling in the body due to the buildup of excess fluid in the tissues. It generally occurs when the pressure on oxygen-poor blood in the veins increases, and the fluid portion of the blood is forced out of the veins and into the surrounding soft tissues. This expands or swells the tissues. Edema is not a condition itself, but is the symptom of an underlying condition. Edema may occur in different parts of the body due to a variety of underlying causes, only some of which may be serious. For example, edema in the legs and ankles may be related to heart failure.
The most serious form of edema is pulmonary edema, a buildup of fluid in the lungs. Pulmonary edema is usually a sign of heart failure, in which the heart is not pumping well enough to meet the body’s demand for oxygen. Patients with pulmonary edema usually complain of shortness of breath.

Although pulmonary edema is most often caused by heart disease, it can also be caused by high altitude (above 8,000 feet). Accompanied by shortness of breath, pronounced weakness, and a cough that produces a white or frothy fluid, high altitude pulmonary edema (HAPE) is a life-threatening scenario requiring the individual to immediately descend and get prompt medical treatment.
Some common types of edema are as follows:

  • Anasarca. Refers to a generalized edema or swelling throughout the body.
  • Dependent edema. Involves swelling of the feet, legs and ankles. It occurs most often at the end of the day or after long periods of traveling while in a seated position.
  • Periorbital edema. Refers to the swelling around the eyes commonly seen when first waking up. It may also occur during allergic or hypersensitivity reactions.
  • Pitting edema. Refers to a pit or depression in the swollen tissues that remains after the skin has been pressed down.
  • Mechanical edema. Can be caused by tight socks, stockings or undergarments. The pressure of a pregnant uterus on pelvic veins can also cause mechanical edema.
  • Lymphedema. Caused by obstruction of the lymph vessels (not the veins) and can appear either in the arms or the legs. It is commonly seen in the arms of post-mastectomy or lumpectomy patients on the same side as their surgery.
  • Laryngeal edema.  May occur in upper respiratory tract infections (particularly in children), allergic reactions and with exposure to toxins. The condition may be life threatening and requires immediate medical attention.

Edema can also be caused by factors such as medication use, burns, and conditions such as venous insufficiency. Venous insufficiency occurs when the veins of the leg no longer allow normal blood flow, usually because the valves in these veins stop functioning properly. Under normal circumstances, blood in the veins is only allowed to flow in one direction, back toward the heart. If, however, the valves are compromised for some reason, blood is allowed to flow backward, away from the heart. This raises blood pressure in the veins of the legs, which may lead to a variety of health problems, including edema, pain, discoloration or ulcers that do not heal.

Edema has also been shown to affect heart attack victims. During a heart attack, the heart sends a signal to the arteries near the site of the attack that promotes the growth of new blood vessels. The signal, however, also causes the arteries to become more permeable, so liquid can more easily leak through the blood vessel walls, resulting in edema. This edema continues to kill heart tissue even after blood flow is restored following the onset of the heart attack. Researchers are working to develop medications that reduce damage from this kind of edema, although the therapy is still experimental.

Role of edema in heart failure

There are two types of heart failure, based on which side of the heart is most affected. Each type is associated with a different type of edema:

  • Left–sided heart failure. Occurs when the left ventricle cannot adequately pump oxygen-rich blood from the heart to the rest of the body. As a result, the oxygen-rich blood that normally travels through the pulmonary veins from the lungs to the heart begins to get backed up, leading to the buildup of fluid in the lungs (pulmonary edema). Additional symptoms of left-sided heart failure include shortness of breath, fatigue and coughing, especially at night and/or while lying down.
  • Right-sided heart failure. Takes place when the right ventricle is not pumping adequately. As a result, the oxygen-poor blood that normally travels through the veins from the rest of the body to the heart begins to get backed up, causing fluid buildup in the veins and swelling (edema) in the legs and ankles. Right-sided heart failure usually occurs as a direct result of left-sided heart failure. It can also be caused by severe lung disease (e.g., pulmonary hypertension) in which the right side of the heart cannot generate enough force to pump blood through a diseased pair of lungs (cor pulmonale).

Other symptoms related to edema

People who have edema may notice changes, such as the following:

  • Tightness of jewelry, such as rings
  • Tightness of clothing or accessories, such as belts and pants
  • Low output of urine, even when people are drinking as much fluids as they normally do
  • "Pitting” of the skin, in which pits or depressions remain in the skin after a pressing finger has been released
  • Prolonged edema, which may lead to hardening or reddening of the skin

People who have a more serious form of edema (e.g., pulmonary edema) may also experience the following:

  • Rapid and labored breathing
  • Shortness of breath (dyspnea)
  • Coughing, sometimes with frothy blood
  • Bluish tint to the skin, lips, fingernails and other areas of the body (cyanosis)
  • Cold extremities (e.g., cold feet)
  • Sense of feeling suffocated

Treatment options for edema

Before starting any treatment plan, the cause of the edema should be determined. If there is pulmonary edema caused by another condition, such as heart failure, the physician will attempt to treat to the underlying cause.

In most mild to moderate cases, edema may improve after a good night’s sleep in a horizontal position, which allows redistribution of the fluids causing the swelling. Edema may also be relieved by changing position, elevating feet higher than the heart or just getting up and walking around. A physician may also suggest that elastic support hose be worn to aid in circulation in the lower body and reduce the swelling. For edema in the legs and arms, patients may benefit from massage and lymph drainage by a trained physical or occupational therapist.
In addition to these strategies, patients may be counseled to lower their salt intake. Table salt (sodium chloride) is known to increase fluid retention and should be avoided by patients with or at risk for edema. Certain drugs known to cause edema may be discontinued. These include corticosteroids, androgens (male hormones), high-estrogen contraceptives and some anti-hypertensive drugs.
If lifestyle changes are not enough to relieve the edema, medications may be prescribed by a physician. These medications often include diuretics ("water pills"), which flush sodium and other minerals from the body in the urine.

If heart failure is diagnosed, then other heart medications may be prescribed. These include ACE inhibitors, a class of medications that relax the blood vessels, lower blood pressure and minimize the stress on the heart muscle. Some cases of heart failure will require cardiac surgery.

Diagnosis methods for edema

A physician will obtain a detailed medical history of the patient and conduct a physical examination before making a diagnosis of edema. In many cases, the presence of edema can be determined by visual inspection of the patient.  Blood tests and urine tests are also useful in diagnosing certain forms edema, such as pulmonary edema. Low levels of albumin may be detected in patients with liver dysfunction or with other conditions such as nephritic syndrome. Abnormal kidney function can be assessed by blood tests.

If heart failure is suspected, the physician may order tests such as the following:

  • Electrocardiogram (EKG). A test that measures the heart’s electrical activity. It is designed to detect any abnormal rhythms, heart chamber enlargement, conduction defects and heart attack (recent or old).
  • Exercise stress test. A test in which an EKG is performed at rest and then under the physical stress of exercise, to compare the heart's performance at rest and during times of physical exertion.
  • Chemical stress test. A test that uses chemicals rather than physical exercise to determine a patient’s heart response to stress. This test is used for patients who are unable to participate in an exercise stress test.
  • Echocardiogram. This test uses ultrasound technology to closely examine the overall muscle function of the heart, allowing the physician to evaluate the size, thickness and pumping action of the heart, and how well the heart valves are functioning. A stress echocardiogram may also be useful in assessing how well the heart is functioning at rest and during exercise.


  • Radionuclide imaging tests, such as a radionuclide ventriculogram. These provide contrast images of the heart, which can pinpoint areas of damage and/or dysfunction and determine how well the heart is pumping.
  • Chest x-ray to evaluate the size and shape of the heart, as well as to view the lungs and any fluid that may have built up, as with pulmonary edema.

More invasive exploratory tests may be ordered in conjunction with, or instead of, the above. These tests can include a coronary angiogram, in which a contrast dye is delivered by catheter to the coronary arteries to visualize the blood vessels and left ventricle. It is used to identify heart damage or dysfunction. In addition, cardiac catheterization can evaluate the function of the various heart valves.

Prevention methods for edema

Temporary, less serious edema may be prevented by strategies such as the following:

  • Changing position
  • Getting regular exercise
  • Increasing muscle activity throughout the day by moving legs and flexing ankles up and down
  • Avoiding sitting or standing in one position for long periods of time
  • Reducing salt in the diet

In addition, individuals who are at risk for edema should closely monitor their limbs for signs of edema. It is easier to treat edema in the early stages rather than when it becomes more advances, such as with pitting edema.  More serious edema, resulting from congestion in the lungs, usually involves treatment of the underlying condition (e.g., heart failure) by a physician rather than preventive strategies.

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