|Other names||Oedema, œdema, fluid retention, water retention, dropsy, hydropsy, swelling|
|Symptoms||Skin which feels tight, area may feel heavy|
|Usual onset||Sudden or gradual|
|Causes||Venous insufficiency, heart failure, kidney problems, low protein levels, liver problems, deep vein thrombosis, lymphedema|
|Diagnostic method||Based on a physical exam|
|Treatment||Based on cause|
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area may feel heavy, and joint stiffness. Other symptoms depend on the underlying cause.
Causes may include venous insufficiency, heart failure, kidney problems, low protein levels, liver problems, deep vein thrombosis, infections, angioedema, certain medications, and lymphedema. It may also occur after prolonged sitting or standing and during menstruation or pregnancy. The condition is more concerning if it starts suddenly, or pain or shortness of breath is present.
Treatment depends on the underlying cause. If the underlying mechanism involves sodium retention, decreased salt intake and a diuretic may be used. Elevating the legs and support stockings may be useful for edema of the legs. Older people are more commonly affected. The word is from the Greek οἴδημα oídēma meaning 'swelling'.
Signs and symptoms
An edema will occur in specific organs as part of inflammations, tendinitis or pancreatitis, for instance. Certain organs develop edema through tissue specific mechanisms. Examples of edema in specific organs:
- Peripheral edema (dependent edema of legs) is extracellular fluid accumulation in the legs. This can occur in otherwise healthy people due to hypervolemia or maintaining a standing or seated posture for an extended period of time. It can occur due to diminished venous return of blood to the heart due to congestive heart failure or pulmonary hypertension. It can also occur in patients with increased hydrostatic venous pressure or decreased oncotic venous pressure, due to obstruction of lymphatic or venous vessels draining the lower extremity. Certain drugs (for example, amlodipine) can cause pedal edema.
- Cerebral edema is extracellular fluid accumulation in the brain. It can occur in toxic or abnormal metabolic states and conditions such as systemic lupus or reduced oxygen at high altitudes. It causes drowsiness or loss of consciousness, leading to brain herniation and death.
- Pulmonary edema occurs when the pressure in blood vessels in the lung is raised because of obstruction to the removal of blood via the pulmonary veins. This is usually due to failure of the left ventricle of the heart. It can also occur in altitude sickness or on inhalation of toxic chemicals. Pulmonary edema produces shortness of breath. Pleural effusions may occur when fluid also accumulates in the pleural cavity.
- Edema may also be found in the cornea of the eye with glaucoma, severe conjunctivitis or keratitis or after surgery. Affected people may perceive coloured haloes around bright lights.
- Edema surrounding the eyes is called periorbital edema (puffy eyes) . The periorbital tissues are most noticeably swollen immediately after waking, perhaps as a result of the gravitational redistribution of fluid in the horizontal position.
- Common appearances of cutaneous edema are observed with mosquito bites, spider bites, bee stings (wheal and flare), and skin contact with certain plants such as poison ivy or western poison oak, the latter of which are termed contact dermatitis.
- Another cutaneous form of edema is myxedema, which is caused by increased deposition of connective tissue. In myxedema (and a variety of other rarer conditions) edema is caused by an increased tendency of the tissue to hold water within its extracellular space. In myxedema, this is due to an increase in hydrophilic carbohydrate-rich molecules (perhaps mostly hyaluronin) deposited in the tissue matrix. Edema forms more easily in dependent areas in 