Edema , also spelled edema or edema , is the accumulation of abnormal fluid in the interstitium, located under the skin and in the body cavity, which can cause pain that is severe. Clinically, edema manifests as a swelling. The amount of interstitial fluid is determined by the balance of fluid homeostasis; and increased secretion of fluid to the interstitium. This word is derived from the Greek ?????? oÃÆ'd? Ma which means "swelling". This condition is also known (mostly archaic) as dropsy .
Video Edema
Classification
Cutaneous edema is referred to as "pitting" when, after pressure is applied to a small area, indentation continues after pressure release. Peripheral pitting edema, as shown in the illustration, is a more general type, resulting from water retention. This can be caused by systemic disease, pregnancy in some women, either directly or as a result of heart failure, or local conditions such as varicose veins, thrombophlebitis, insect bites, and dermatitis.
Non-pitting edema is observed when indentation does not continue. This is related to conditions such as lymphedema, lipedema, and myxedema.
Edema caused by malnutrition defines kwashiorkor, an acute form of childhood protein-protein malnutrition characterized by edema, irritability, anorexia, ulcerative dermatosis, and enlarged liver with fatty infiltrate.
General
An increase in hydrostatic pressure occurs in heart failure. A decrease in osmotic pressure occurs in nephrotic syndrome and liver failure.
The causes of generalized edema throughout the body can cause edema in many organs and peripheries. For example, severe heart failure can cause pulmonary edema, pleural effusion, ascites, and peripheral edema. Such severe systemic edema is called anasarca. In rare cases, Parvovirus B19 infection can cause generalized edema.
Although low plasma oncotic pressures are widely cited for edema of nephrotic syndrome, most doctors note that edema may occur before there is a significant protein in urine (proteinuria) or a decrease in plasma protein levels. Most forms of nephrotic syndrome are due to biochemical and structural changes in the capillary basement membrane in the renal glomeruli, and this change occurs, if to a lesser degree, in the vessels of most other body tissues. Thus increased permeability leading to protein in the urine may explain edema if all other vessels are also more permeable.
As well as the conditions mentioned earlier, edema often occurs during the late stages of pregnancy in some women. This is more common in a history of lung problems or poor circulation that is also intensified if arthritis is present in the woman. Women who already have rheumatic problems most often have to seek medical help for pain caused by excessive swelling. Edema that occurs during pregnancy is usually found at the bottom of the foot, usually from the calf down.
Organ-specific
Edema will occur in certain organs as part of inflammation, tendonitis or pancreatitis, for example. Certain organs develop edema through tissue-specific mechanisms.
Example of edema in a particular organ:
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- Cerebral edema is the accumulation of extracellular fluid in the brain. May occur in toxic or abnormal metabolic conditions and conditions such as systemic lupus or reduced oxygen at high altitudes. It causes drowsiness or loss of consciousness, which causes brain herniation and death.
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- Pulmonary edema occurs when the pressure in the blood vessels in the lung increases due to obstruction at the discharge of blood through the pulmonary vein. This is usually due to left ventricular heart failure. Can also occur in altitude sickness or inhaling toxic chemicals. Pulmonary edema produces shortness of breath. Pleural effusions can occur when fluids also accumulate in the pleural space.
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- Edema can also be found in the cornea of ââthe eye with glaucoma, severe conjunctivitis or keratitis or after surgery. Patients can see a colored halo around a bright light.
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- The edema that surrounds the eye is called periorbital edema or swollen eyes. The most periorbital tissue feels swollen immediately upon awakening, perhaps as a result of the redistribution of the gravity of the fluid in a horizontal position.
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- The general appearance of cutaneous edema is observed with mosquito bites, spider bites, wheal and flare, and skin contact with certain crops such as Poison Ivy or Western Poison Oak, the latter called contact dermatitides .
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- Another form of skin edema is myxedema, caused by increased sedimentary tissue uptake. In myxedema (and other more rare conditions) edema is caused by increased tissue tendency to hold water in its extracellular space. In myxedema this is due to an increase in hydrophilic carbohydrate-rich molecules (probably most hyaluronin) stored in the network matrix. Edema is formed more easily in areas depending on the elderly (sitting in a chair at home or on a plane) and this is not well understood. Estrogen changes the weight partly through changes in tissue water content. There may be a variety of underutilized situations where water transfer from the network matrix to the lymphatics is impaired due to changes in tissue hydrophilicity or malfunction of the terminal lymphatic captive 'wicking' capillaries.
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- In lymphoedema, abnormal removal of interstitial fluid is caused by failure of the lymphatic system. This may be due to obstruction from, for example, the pressure of cancer or enlargement of lymph nodes, the destruction of lymph vessels by radiotherapy, or infiltration of lymphatics by infection (such as elephantiasis). This is most often due to the failure of the action of pumping muscles due to immobility, most noticeably in conditions such as multiple sclerosis, or paraplegia. It has been argued that edema that occurs in some people following the use of aspirin cyclo-oxygenase inhibitors such as ibuprofen or indomethacin may be caused by inhibition of lymphatic heart action.
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- Fetalis hydrops are fetal conditions characterized by fluid accumulation, or edema, at least in two fetal compartments.
Maps Edema
Mechanism
Six factors can contribute to the formation of edema:
- increase in hydrostatic pressure;
- reduce colloid or oncotic pressure in the blood vessels;
- increased tissue or oncotic colloid pressure;
- increased permeability of blood vessel walls (eg, inflammation);
- liquid cleansing obstruction in the lymphatic system;
- changes in the water retention properties of the network itself. Increased hydrostatic pressure often reflects water retention and sodium by the kidneys.
The interstitial fluid generation is governed by the power of the Starling equation. Hydrostatic pressure in blood vessels tends to cause water to filter into the tissues. This leads to differences in protein concentrations between blood plasma and tissue. As a result, colloid or oncotic pressure from higher plasma levels of the protein tends to draw water back to the blood vessels from the tissues. The Starling equation states that the fluid leakage rate is determined by the difference between the two forces and also by the permeability of the vessel wall to water, which determines the flow rate for given force imbalances. Most water leaks occur in capillary or capillary capillaries, which have semi-permeable membrane walls that allow water to flow freer than proteins. (The protein is said to be reflected and the reflection efficiency is given by the constant reflection up to 1.). If the gap between the cells of the vessel wall is exposed then the permeability of the water rises first, but when the gap increases in the permeability measure to the protein also increases with the decrease of the reflection coefficient.
The change of variables in the Starling equation can contribute to the formation of edema either by increasing the hydrostatic pressure in the blood vessels, decreasing the oncotic pressure in the blood vessels or increasing the permeability of the blood vessel wall. The latter has two effects. This allows the water to flow more freely and reduce the difference in colloid or oncotic pressure by allowing the protein to leave the blood vessel more easily.
Treatment
If possible, treatment involves solving the underlying causes.
Treatment may also involve positioning affected body parts to improve drainage. For example, swelling in the legs or ankles can be reduced by having people lie in bed or sitting with their legs propped on a pillow. Intermittent pneumatic compression may be used to suppress tissue in the extremities, forcing fluids - both blood and lymph - to flow out of pressurized areas. Treatment of persistent edema, such as idiopathic bilateral lymphedema, may also use manual lymphatic drainage, a low-pressure massage technique designed to pump lymphatic fluid by a similar mechanism.
Gallery
See also
- Water retention (medicine)
References
External links
Source of the article : Wikipedia