Edema

Edema 

Definition

Edema is a condition of abnormally large fluid volume in the circulatory system or in tissues between the body's cells (interstitial spaces).

Description

Normally the body maintains a balance of fluid in tissues by ensuring that the same of amount of water entering the body also leaves it. The circulatory system transports fluid within the body via its network of blood vessels. The fluid, which contains oxygen and nutrients needed by the cells, moves from the walls of the blood vessels into the body's tissues. After its nutrients are used up, fluid moves back into the blood vessels and returns to the heart. The lymphatic system (a network of channels in the body that carry lymph, a colorless fluid containing white blood cells to fight infection) also absorbs and transports this fluid. In edema, either too much fluid moves from the blood vessels into the tissues, or not enough fluid moves from the tissues back into the blood vessels. This fluid imbalance can cause mild to severe swelling in one or more parts of the body.

Causes and symptoms

Many ordinary factors can upset the balance of fluid in the body to cause edema, including:

Some medical conditions may also cause edema, including:

Some conditions that may cause swelling in just one leg include:

Symptoms vary depending on the cause of edema. In general, weight gain, puffy eyelids, and swelling of the legs may occur as a result of excess fluid volume. Pulse rate and blood pressure may be elevated. Hand and neck veins may be observed as fuller.

Diagnosis

Edema is a sign of an underlying problem, rather than a disease unto itself. A diagnostic explanation should be sought. Patient history and presenting symptoms, along with laboratory blood studies, if indicated, assist the health professional in determining the cause of the edema.

Treatment

Treatment of edema is based on the cause. Simple steps to lessen fluid build-up may include:

The three "Ds"—diuretics, digitalis, and diet-are frequently prescribed for medical conditions that result in excess fluid volume. Diuretics are medications that promote urination of sodium and water. Digoxin is a digitalis preparation that is sometimes needed to decrease heart rate and increase the strength of the heart's contractions. Dietary recommendations include less sodium in order to decrease fluid retention. Consideration of adequate protein intake is also made.

For patients with lymphedema, a combination of therapies may prove effective. Combined decongestive therapy includes the use of manual lymph drainage (MLD), compression bandaging, garments and pumps, and physical therapy. MLD involves the use of light massage of the subcutaneous tissue where the lymph vessels predominate. Massage begins in an area of the body trunk where there is normal lymph function and proceeds to areas of lymphatic insufficiency, in an effort to stimulate new drainage tract development. (MLD should not be used for patients with active cancer, deep vein clots, congestive heart failure, or cellulitis.) MLD sessions are followed by application of compression garments or pumps. Physical therapy is aimed at strengthening the affected limb and increasing joint mobility.

Alternative treatment

Dietary changes, in addition to cutting back the amount of sodium eaten, may also help reduce edema. Foods that worsen edema, such as alcohol, caffeine, sugar, dairy products, soy sauce, animal protein, chocolate, olives, and pickles, should be avoided. Diuretic herbs can also help relieve edema. One of the best herbs for this purpose is dandelion (Taraxacum mongolicum), since, in addition to its diuretic action, it is a rich source of potassium. (Diuretics flush potassium from the body and it must be replaced to avoid potassium deficiency.) Hydrotherapy using daily contrast applications of hot and cold (either compresses or immersion) may also be helpful.

Key terms

Digitalis — A naturally occuring compound used in the preparation of the medication, digoxin, prescribed to increase the heart rate and strengthen the force of the heart's contractions.

Diuretics — Medications used in the treatment of fluid overload, to promote excretion of sodium and water.

Interstitial spaces — Areas of the body occuring outside the vessels or organs, between the cells.

Pitting edema — A swelling in the tissue under the skin, resulting from fluid accumulation, that is measured by the depth of indentation made by finger pressure over a boney prominence.

Resources

Organizations

Lymphedema and Wound Care Clinic of Austin. 5750 Balcones Dr., Ste. 110, Austin, TX 78731. (512) 453-1930.

---

edema /ede·ma/ (e-de´mah) an abnormal accumulation of fluid in intercellular spaces of the body.edem´atous

---

angioneurotic edema  angioedema.

cardiac edema  a manifestation of congestive heart failure, due to increased venous and capillary pressures and often associated with renal sodium retention.

cytotoxic edema  cerebral edema caused by hypoxic injury to brain tissue and decreased functioning of the cellular sodium pump so that the cellular elements accumulate fluid.

dependent edema  edema in lower or dependent parts of the body.

edema neonato´rum  a disease of premature and feeble infants resembling sclerema, marked by spreading edema with cold, livid skin.

pitting edema  that in which pressure leaves a persistent depression in the tissues.

pulmonary edema  diffuse edema in pulmonary tissues and air spaces due to changes in hydrostatic forces in capillaries or to increased capillary permeability, with intense dyspnea.

vasogenic edema  cerebral edema in the area around tumors, often due to increased permeability of capillary endothelial cells.

---

e·de·ma (-dm)

n. pl. e·de·mas or e·de·ma·ta (-m-t)

An accumulation of an excessive amount of watery fluid in cells, tissues, or serous cavities.

---

edema,

n abnormally high fluid accumulation in the interstitial tissues; often an indication of other health problems.

Edema.

---

edema (edē´m),

n the accumulation of fluid in the tissues or in the peritoneal or pleural cavities. Primary factors favoring edema are increased capillary hydrostatic pressure (increased venous pressure), decreased osmotic pressure of plasma (hypoproteinemia), decreased tissue tension and lymphatic drainage, increased osmotic pressure of tissue fluids, and increased capillary permeability. Additional renal and hormonal factors are important. Clinical manifestations may consist of a steady weight gain or localized or generalized swelling.

Eczema.

edema, angioneurotic

(an´jēōnerto´ik),
n See angioedema.

edema, cardiac,

n an edema caused by venous congestion in association with congestive heart failure; tends to appear first in such dependent parts as the legs.

edema, dependent,

n an edema that changes its position with the posture of dependent parts (e.g., edema of the legs in progressive heart failure).

edema of glottis

(glot´is),
n an edema caused by fluid accumulation in the soft tissues of the larynx. The condition, usually inflammatory, may result from an infection, injury, allergy, or inhalation of toxic substances.

edema, periorbital

(per´ēor´bitl),
n an edema of the eyelids in association with local injury, allergic reactions, hypoproteinemia, trichinosis, and myxedema.

Periorbital edema.

edema, pitting,

n a persistent indentation of the skin when pressure is applied to an edematous area.

---

edema

an abnormal accumulation of fluid in the cavities and intercellular spaces of the body.

Edema can be caused by a variety of factors, including hypoproteinemia, in which a lowered concentration of plasma proteins decreases the osmotic pressure, thereby permitting passage of abnormal amounts of fluid out of the blood vessels and into the tissue spaces. Some other causes are poor lymphatic drainage, increased capillary permeability (as in inflammation), and congestive heart failure. See also anasarca, ascites, hydrothorax, hydropericardium and anatomically located edemas, e.g. brain, corneal, pulmonary edema.

---

angioneurotic edema

see angioedema.

cardiac edema

is part of the syndrome of congestive heart failure. It comprises 'bottle jaw', jugular vein engorgement, edema of the brisket and underline, and ascites, hydrothorax and hydropericardium. See also congestive heart failure.

dependent edema

edema affecting most severely the lowermost parts of the body.

edema disease

1. in pigs a highly fatal disease of young pigs in the weaner and grower age groups characterized by incoordination, a hoarseness of voice, weakness, flaccid paralysis and blindness. Edema of the eyelids, face and ears is diagnostic but is seldom visible on clinical examination. The course is short, often less than 24 hours, and many pigs are just found dead. The disease is caused by the opportunistic proliferation of specific serotypes of Escherichia coli in an intestinal environment brought about by a change to a diet more dense in carbohydrates. These have pilus attachment antigens that allow attachment of the organism to the small intestines and produce a verotoxin (VT2e) which produces an increase in vascular permeability in the target vessels in the CNS with resultant neurological disease. Called also gut edema, bowel edema.

2. in goats a disease caused by Mycoplasma F38; a fatal cellulitis.

gravitational edema

see dependent edema (above).

gut edema

see edema disease (above).

hepatic edema

edema is a common accompaniment of hepatic disease because of the decline in production of plasma proteins and a fall in the blood's hydrostatic pressure. Ascites may occur independently because of portal hypertension when there is severe liver disease and obstruction to blood flow in the portal vein.

hypoproteinemic edema

caused by insufficient production of albumin or excess loss through a protein losing enteropathy. See hepatic edema (above), Johne's disease, proliferative enteropathy, type II ostertagiasis.

laryngeal edema

see laryngeal edema.

leg edema

a disease of market age turkeys of unknown cause and characterized by edema of the legs and focal muscle necrosis.

low-pressure edema

noncardiogenic pulmonary edema. See acute respiratory distress syndrome.

edema neonatorum

edema of the newborn. See lymphatic vessel obstruction.

pitting edema

edema in which pressure by the clinician's finger leaves a persistent depression in the tissues.

subcutaneous edema

may be generalized and constitute anasarca. Local areas of edema occur in such other conditions as angioedema and urticaria, edematous plaques in dourine and infectious equine anemia, and in purpura hemorrhagica.

vasogenic edema

that characterized by increased permeability of capillary endothelial cells; the most common form of brain edema.