The excessive accumulation of fluid within body tissues or cavities is called edema. It results from seepage of fluid from blood or lymphatic vessels, or as a result of their inability to drain adequately an area of fluid and return it to the heart. Fluid retention may be localized to an area or region of the body, or be generalized. It is only a symptom and may have a number of causes and is often first noticed as puffiness around the face and eyes, an increased tightness of rings on fingers or swelling of the ankles.
Causes
Most commonly, fluid retention is preceded by accumulation of fluids within the veins (venous congestion), which causes an increase of fluid pressure and fluid seepage if this increases sufficient. Many people develop swelling of the ankles when they stand for long periods during hot weather. Veins are already distended because of the heat, and the absence of the pumping action of the leg muscles that occurs with walking leads to local fluid accumulation. Normally, gravitational effects are counteracted by the muscles squeezing blood towards the heart by means of one way valves of the veins.
A similar mechanism of venous congestion occurs with heart failure (congestive cardiac). Congestion occurs when the pumping action of the heart becomes impaired and the blood returning to it by means of the veins cannot be handled satisfactorily.
Obstruction of veins or lymphatic vessels results in fluid accumulation within that particular area; deep venous thrombosis and pressure from an enlarged pregnant womb are examples. Lymphatic vessel obstruction or abnormality leading to leakage of lymph fluid is called lymphedema. The parasitic infection filariasis may obstruct these vessels, or they may be blocked by cancer cells accumulating in lymph nodes. Lymph node damage resulting from injury, radiation or surgery is another cause. Lymphedemic of the arm may follow breast and armpit surgery on that side when performed for cancer of the breast.
Other conditions that most commonly cause fluid accumulation are varicose veins, some forms of kidney disease, liver disease and severe malnutrition. Varicose veins occur when one or more of the one-way valves within these vessels become ineffective, so that pressure builds up and leakage frequently follows. Fluid accumulates if in adequate quantities of urine are produced, as in severe kidney disease.
This accumulation will also occur if excessive quantities of protein are lost in the urine. Proteins within the blood attract a certain amount of fluid by a mechanism termed osmotic pressure which helps to maintain the blood volume. If protein levels fall, as may occur in some forms of kidney disease, severe malnutrition, and severe liver disease, the osmotic pressure of the blood falls and fluid accumulates within body tissues and cavities.
The liver manufactures most of the body’s protein. In cirrhosis of the liver, obstruction of blood flow through its tissues leads to accumulation of fluid within the abdominal cavity (ascites).
Treatment
Management of fluid accumulation depends primarily on the cause. Firm pantyhose, bandaging, or elevation of the feet for fix periods each day will help people who have a tendency to develop swollen ankles. Varicose veins can be dealt with surgically and malnutrition may be overcome with an adequate diet, often initially with one rich in protein.
Diuretics are drugs that increased urine production and they are often used to treat fluid accumulation or fluid overload associated with heart or kidney disease.
Source:
Fluid retention, Better Health Channel, Nov 2007
