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.

— Kathleen D. Wright, RN

1. Pathology. An excessive accumulation of serous fluid in tissue spaces or a body cavity.
2. Botany. Extended swelling in plant organs caused primarily by an excessive accumulation of water.

[Middle English ydema, from Greek oidēma, a swelling, from oidein, to swell.]

For more information on edema, visit Britannica.com.

An abnormal accumulation of fluid in the cells, tissue spaces, or cavities of the body, also known as dropsy. An excess of fluid in the pleural spaces is referred to as hydrothorax, in the pericardial sac as hydropericardium, and in the peritoneal cavity as ascites. Anasarca is a generalized subcutaneous edema.

There are three main factors in the formation of generalized edema and a fourth which plays an important role in the formation of local edema. They are (1) permeability of the capillary wall, (2) colloid osmotic pressure of the plasma proteins, (3) hydrostatic pressure in the capillaries, and (4) lymphatic obstruction.

The management of patients with edema is directed toward the treatment of the underlying medical condition. Diuretics are often used, most successfully in cardiac edema.

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 (hypo-proteinemia), decreased tissue tension and lymphatic drainage, increased osmotic pressure of tissue fluids, and increased capillary perme-ability. Additional renal and hormonal factors are important. Clinical manifestations may consist of a steady weight gain or localized or generalized swelling.

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 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 & Symptoms

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

• Immobility. The leg muscles normally contract and compress blood vessels to promote blood flow with walking or running. When these muscles are not used, blood can collect in the veins, making it difficult for fluid to move from tissues back into the vessels.
• Heat. Warm temperatures cause the blood vessels to expand, making it easier for fluid to cross into surrounding tissues. High humidity also aggravates this situation.
• Medications. Certain drugs, such as steroids, hormone replacements, nonsteroidal anti-inflammatory drugs (NSAIDs), and some blood pressure medications may affect how fast fluid leaves blood vessels.
• Intake of salty foods. The body needs a constant concentration of salt in its tissues. When excess salt is taken in, the body dilutes it by retaining fluid.
• Menstruation and pregnancy. The changing levels of hormones affect the rate at which fluid enters and leaves the tissues.

Some medical conditions may also cause edema, including:

• Heart failure. When the heart is unable to maintain adequate blood flow throughout the circulatory system, the excess fluid pressure within the blood vessels can cause shifts into the interstitial spaces. Left-sided heart failure can cause pulmonary edema, as fluid shifts into the lungs. The patient may develop rapid, shallow respirations, shortness of breath, and a cough. Right-sided heart failure can cause pitting edema, a swelling in the tissue under the skin of the lower legs and feet. Pressing this tissue with a finger tip leads to a noticeable momentary indentation.
• Kidney disease. The decrease in sodium and water excretion can result in fluid retention and overload.
• Thyroid or liver disease. These conditions can change the concentration of protein in the blood, affecting fluid movement in and out of the tissues. In advanced liver disease, the liver is enlarged and fluid may build up in the abdomen.
• Malnutrition. Protein levels are decreased in the blood, and in an effort to maintain a balance of concentrations, fluid shifts out of the vessels and causes edema in tissue spaces.

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

• Blood clots. Clots can cause pooling of fluid and may be accompanied by discoloration and pain. In some instances, clots may cause no pain.
• Weakened veins. Varicose veins, or veins whose walls or valves are weak, can allow blood to pool in the legs. This is a common condition.
• Infection and inflammation. Infection in leg tissues can cause inflammation and increasing blood flow to the area. Inflammatory diseases, such as gout or arthritis, can also result in swelling.
• Lymphedema. Blocked lymph channels may be caused by infection, scar tissue, or hereditary conditions. Lymph that can't drain properly results in edema. Lymphedema may also occur after cancer treatments, when the lymph system is impaired by surgery, radiation, or chemotherapy.
• Tumor. Abnormal masses can compress leg vessels and lymph channels, affecting the rate of fluid movement.

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

Simple steps to lessen fluid build-up may include:

• reducing sodium intake
• maintaining proper weight
• exercise
• elevation of the legs
• use of support stockings
• massage
• travel breaks

Nutritional Therapy

A naturopath or a nutritionist may recommend the following dietary changes:

• Reduction of salt intake, including salty foods such as olives, soy sauce, or pickles. Cutting back the amount of sodium eaten may help reduce edema.
• Limited use of alcohol, caffeine, sugar, and dairy products.
• Increased consumption of whole grain foods, cucumbers, apples, potatoes, grapes, onions, cabbage, and oranges.
• Daily vitamin and mineral supplements.

Herbal Therapy

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

Hydrotherapy using daily contrast applications of hot and cold (either compresses or immersion) may also be helpful.

Other Alternative Treatments

Other alternative therapies may also reduce edema. They include traditional Chinese medicine, Ayurveda, juice therapy, and bodywork. Traditional Chinese medicine and acupuncture have an elaborate diagnostic system to determine the pattern causing the edema. Thus treatment, if done correctly, results not only in the removal of fluid, but also with the correction of the problem.

Allopathic Treatment

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. One dietary recommendation includes 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.

Resources

Books

The Burton Goldberg Group. "Edema." in Alternative Medicine: The Definitive Guide. Tiburon, CA: Future Medicine Publishing, Inc., 1999.

Monahan, Frances D., and Marianne Neighbors. Medical-Surgical Nursing: Foundation for Clinical Practice, 2nd ed. Philadelphia: W. B. Saunders, 1998.

Organizations

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

[Article by: Mai Tran]

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 e. — see angioedema.
• cardiac e. — 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 e. — edema affecting most severely the lowermost parts of the body.
• e. 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 e. — see dependent edema (above).
• gut e. — see edema disease (above).
• hepatic e. — 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 e. — 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 e. — see laryngeal edema.
• leg e. — a disease of market age turkeys of unknown cause and characterized by edema of the legs and focal muscle necrosis.
• low-pressure e. — noncardiogenic pulmonary edema. See acute respiratory distress syndrome.
• e. neonatorum — edema of the newborn. See lymphatic vessel obstruction.
• pitting e. — edema in which pressure by the clinician's finger leaves a persistent depression in the tissues.
• subcutaneous e. — 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 e. — that characterized by increased permeability of capillary endothelial cells; the most common form of brain edema.

Not to be confused with Adema or enema.

"Dropsy" redirects here. For other uses, see Dropsy (disambiguation).

Oedema

ICD-10	R60.9
ICD-9	782.3
DiseasesDB	9148
MeSH	D004487

Periorbital edema

Edema (American English) or oedema (British English; both words from the Greek οἴδημα), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body. Generally, the amount of interstitial fluid is determined by the balance of fluid homeostasis, and increased secretion of fluid into the interstitium or impaired removal of this fluid may cause edema.

Contents 1 Formation 2 Mechanism 3 Generalized edema 4 Organ-specific edema 5 In plants 6 Image gallery 7 References 8 External links

Formation

Five factors can contribute to the formation of edema:

1. It may be facilitated by increased hydrostatic pressure or,
2. reduced oncotic pressure within blood vessels;
3. by increased blood vessel wall permeability as in inflammation;
4. by obstruction of fluid clearance via the lymphatic; or,
5. by changes in the water retaining properties of the tissues themselves. Raised hydrostatic pressure often reflects retention of water and sodium by the kidney.^[1]

Mechanism

Generation of interstitial fluid is regulated by the forces of the Starling equation.^[2] Hydrostatic pressure within blood vessels tends to cause water to filter out into the tissue. This leads to a difference in protein concentration between blood plasma and tissue. As a result the oncotic pressure of the higher level of protein in the plasma tends to suck water back into the blood vessels from the tissue. Starling's equation states that the rate of leakage of fluid is determined by the difference between the two forces and also by the permeability of the vessel wall to water, which determines the rate of flow for a given force imbalance. Most water leakage occurs in capillaries or post capillary venules, which have a semi-permeable membrane wall that allows water to pass more freely than protein. (The protein is said to be reflected and the efficiency of reflection is given by a reflection constant of up to 1.) If the gaps between the cells of the vessel wall open up then permeability to water is increased first, but as the gaps increase in size permeability to protein also increases with a fall in reflection coefficient.

Changes in the variables in Starling's equation can contribute to the formation of edema either by an increase in hydrostatic pressure within the blood vessel, a decrease in the oncotic pressure within the blood vessel or an increase in vessel wall permeability. The latter has two effects. It allows water to flow more freely and it reduces the oncotic pressure difference by allowing protein to leave the vessel more easily.

Generalized edema

A rise in hydrostatic pressure occurs in cardiac failure. A fall in oncotic pressure occurs in nephrotic syndrome and liver failure. It is commonly taught that these facts explain the occurrence of edema in these conditions. However, it has been known since the 1950s that the situation is more complex and it is still far from completely understood.^[3]

Causes of edema which are generalized to the whole body can cause edema in multiple organs and peripherally. For example, severe heart failure can cause pulmonary edema, pleural effusions, ascites and peripheral edema, the last of which effects can also derive from less serious causes.^[4]

Although a low plasma oncotic pressure is widely cited for the edema of nephrotic syndrome, most physicians note that the edema may occur before there is any significant loss of protein in the urine or fall in plasma protein level. Fortunately there is another explanation available. Most forms of nephrotic syndrome are due to biochemical and structural changes in the basement membrane of capillaries in the kidney glomerulae, and these changes occur, if to a lesser degree, in the vessels of most other tissues of the body. Thus the resulting increase in permeability that leads to protein in the urine can explain the edema if all other vessels are more permeable as well.

Organ-specific edema

Left and right ring fingers of the same individual. The distal phalanx of the finger on the right exhibits edema due to acute paronychia.

Edema will occur in specific organs as part of inflammation, as in pharyngitis, tendonitis or pancreatitis, for instance. Certain organs develop edema through tissue specific mechanisms.

Examples of edema in specific organs:

• Cerebral edema is extracellular fluid accumulation in the brain. It can occur in toxic or abnormal metabolic states and conditions such as systemic lupus. It causes drowsiness or loss of consciousness.

• Pulmonary edema occurs when the pressure in blood vessels in the lung is raised because of obstruction to 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. It may produce coloured haloes around bright lights.

• Edema surrounding the eyes is called periorbital edema or eye puffiness. The periorbital tissues are most noticeably swollen immediately after waking, perhaps due to 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,^[5] 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 due to an increased tendency of the tissue to hold water within its extracellular space. In myxedema this is because of an increase in hydrophilic carbohydrate-rich molecules (perhaps mostly hyaluronan) deposited in the tissue matrix. Edema forms more easily in dependent areas in the elderly (sitting in chairs at home or on aeroplanes) and this is not well understood. Estrogens alter body weight in part through changes in tissue water content. There may be a variety of poorly understood situations in which transfer of water from tissue matrix to lymphatics is impaired because of changes in the hydrophilicity of the tissue or failure of the 'wicking' function of terminal lymphatic capillaries.

(Foot, c. 2 weeks post surgery because of compartment syndrome)

• In the case of human feet, the Starling forces are always a long way out of balance, because the variation in hydrostatic pressure in the vessels in the feet as compared to the face is about a metre of water. In severe heart failure the change in central venous pressure is tiny in comparison and cannot explain why edema of the feet develops simply through an effect on capillary leakage. Three other factors may be involved. If the central venous pressure rises to equal that of the thoracic lymph duct then clearance of fluid from the tissue will be impeded (see below). That is to say the edema may actually be caused by a change in output of fluid from the tissue, as much as input to the tissue. Secondly, severe heart failure is one of the most exhausting conditions there is. The sufferers tend to spend what little effort they can make trying to breathe with edematous lungs. They tend to sit up to make breathing easier and their feet hang immobile on the floor. Immobility is perhaps the commonest of all causes of edema, because clearance of fluid via the lymphatics needs muscle action. Thirdly, in severe heart failure endocrine and neural changes alter the way tissues are perfused in ways that are not fully understood.

• In lymphedema abnormal removal of interstitial fluid is caused by failure of the lymphatic system. This may be due to obstruction from, for example, pressure from a cancer or enlarged lymph nodes, destruction of lymph vessels by radiotherapy, or infiltration of the lymphatics by infection (such as elephantiasis). It is most commonly due to a failure of the pumping action of muscles due to immobility, most strikingly in conditions such as multiple sclerosis, or paraplegia. Lymphatic return of fluid is also dependent on a pumping action of structures known as lymph hearts. It has been suggested that the edema that occurs in some people following use of aspirin-like cyclo-oxygenase inhibitors such as ibuprofen or indomethacin may be due to inhibition of lymph heart action.

In plants

Edema in plants is the extended swelling in plant organs caused primarily by an excessive accumulation of water. This occurs since the cell walls are composed of flexible cellulose.

Image gallery

Profound pitting edema of the lower extremity in a person with chronic hepatic failure, signs of venous stasis also present.

References

1. ^ Kumar, Abbas, Fausto (1999). Pathologic Basis of Disease, 7th edition. China: Elsevier Saunders. pp. 122. ISBN 0-7216-0187-1. 
2. ^ Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch, Elsevier/Saunders. ISBN 1-4160-2328-3.
3. ^ Renkin EM. (1994) Cellular aspects of transvascular exchange: a 40-year perspective. Microcirculation 1(3):157–67.
4. ^ Cho S, Atwood J (2002). "Peripheral oedema". Am J Med 113 (7): 580–6. doi:10.1016/S0002-9343(02)01322-0. PMID 12459405. 
5. ^ C.Michael Hogan (2008) "Western poison-oak: Toxicodendron diversilobum", GlobalTwitcher, ed. Nicklas Strömberg

External links

• Edema - HAE Patient organization Israel
• Medline Encyclopedia - Swelling

v • d • e Symptoms and signs: skin and subcutaneous tissue (R20-R23, 782) Disturbances of skin sensation/ somatosensory disorder Hypoesthesia · Paresthesia (Formication) · Hyperesthesia Hypoalgesia · Hyperalgesia Circulation Cyanosis · Pallor · Flushing · Petechia Edema Peripheral edema · Anasarca Other Rash · Desquamation · Induration · Diaphoresis integument, SF, LCT navs: anat/physio, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc skin appendage navs: anat, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc

v • d • e Pathology: hemodynamics Decreases Thrombus/thrombosis Renal vein thrombosis Ischemia Brain ischemia · Ischaemic heart disease Infarction general: Anemic infarct · Hemorrhagic infarct regional: Myocardial infarction · Splenic infarction · Cerebral infarction Increases Hemorrhage general Bruise/Hematoma: Petechia · Purpura · Ecchymosis regional: head (Epistaxis, Hemoptysis, Intracranial hemorrhage, Hyphema) · torso (Hemothorax, Hemopericardium) · abdomen (Gastrointestinal bleeding, Haemobilia, Hemoperitoneum, Hematocele, Hematosalpinx ) · joint (Hemarthrosis) Edema general: Anasarca · Angioedema/Lymphedema · Exudate/Transudate regional: Cerebral edema · Pulmonary edema · Hydrothorax · Ascites/hydroperitoneum · Hydrosalpinx Other Hyperemia

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Dansk (Danish)
n. - ødem, væskesamling

Nederlands (Dutch)
oedeem

Français (French)
n. - ¯dème

Deutsch (German)
n. - (Med.) Gewebewassersucht, Ödem

Ελληνική (Greek)
n. - οίδημα, πρήξιμο

Italiano (Italian)
edema

Português (Portuguese)
n. - edema (m)

Русский (Russian)
отек

Español (Spanish)
n. - edema

Svenska (Swedish)
n. - ödem

中文（简体）(Chinese (Simplified))
水肿

中文（繁體）(Chinese (Traditional))
n. - 水腫

한국어 (Korean)
n. - 부종, 수종

日本語 (Japanese)
n. - 浮腫, 水腫様膨潤

العربيه (Arabic)
‏(الاسم) الاستسقاء, ارتشاح مصلي في الأنسجه الرخوة‏

עברית (Hebrew)
n. - ‮בצקת, מיימת‬

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