Edema is a condition of abnormally high fluid volume in the circulatory system or in tissues between the body's cells. It is a sign of an underlying problem or problems, rather than a disease unto itself.
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 circulatorysystem transports fluid within the body via its network of blood vessels. Thefluid, 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 carries lymph, acolorless 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.
Many ordinary factors can upset the balance of fluid in the body to cause edema, including immobility (when muscles are inactive for long periods, fluidstend to remain in one place); heat and humidity, which make it easier for fluid to cross into surrounding tissues; medications (steroids, hormone replacements, nonsteroidal anti-inflammatory drugs (NSAIDs), and some blood pressuremedications can affect how fast fluid leaves blood vessels); salty foods (thebody dilutes excess salt by retaining fluid); menstruation; and pregnancy.
Some medical conditions may also induce edema, including left-sided heart failure, which can cause pulmonary edema as fluid shifts into the lungs; right-sided heart failure, which can cause swelling in the tissue of the lower legsand feet; kidney disease, because the accompanying decrease in sodium and water excretion can result in fluid retention and overload; thyroid or liver disease, which change fluid movement in and out of the tissues; and malnutrition.
Edema may occur in a single leg because of blood clots, which cause pooling of fluid; weakened veins that allow blood to gather; inflammatory diseases such as gout or arthritis; lymphedema (blocked lymph channels that prevent proper draining); and tumors that compress leg vessels and lymph channels.
Symptoms vary depending on the cause of edema. In general, weight gain, puffyeyelids, and swelling of the legs may occur as a result of excess fluid volume. Pulse rate and blood pressure may be elevated, while hand and neck veinsmay appear swollen.
Treatment of edema depends on its cause, but generally the patient may be told to reduce sodium intake; maintain proper weight (extra weight slows fluid circulation and puts pressure on the veins); exercise to stimulate circulation; elevate the legs; use support stockings to promote circulation and decreasepooling of fluid due to gravity; get regular massages, unless blood clots are a problem; and stand and/or walk at least every hour or two during travel.
In addition, physicians frequently prescribe the three "Ds"--diuretics, digitalis, and diet--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 can decrease heart rate and increase the strength of the heart's contractions. Adequate non-animal-source protein intake is also important, and patients should avoid alcohol, caffeine, sugar, dairy products, soy sauce, animal protein, chocolate, olives, and pickles.
In terms of alternative treatments, 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 toavoid a deficiency of this essential element mineral.) Hydrotherapy using daily contrast applications of hot and cold (either compresses or immersion) mayalso be helpful.