What is Water Retention and Lower Extremity Edema?
What is Water Retention and Lower Extremity Edema?

Edema occurs when tiny blood vessels in your body (capillaries) leak fluid. This leakage can result from damage to or increased pressure in the capillaries, or from lowered levels of serum albumin, a protein in your blood. When your body senses the capillaries are leaking, your kidneys begin to retain more sodium and water than normal to compensate for the lost fluid from your blood vessels. This increases the amount of fluid circulating through your body, which causes the capillaries to leak more. The fluid from the capillaries leaks into the surrounding tissue, causing the tissue to swell.

Mild cases of edema may result from:

1) Sitting or staying in one position for too long
2) Eating too much salty food
3) Premenstrual signs and symptoms
4) Pregnancy, which can cause swelling in your hands, feet and face from excess fluid retention

Edema can be a side effect of some medications, including:

1) Drugs that open blood vessels (vasodilators)
2) Calcium channel blockers (calcium antagonists)
3) Nonsteroidal anti-inflammatory drugs (NSAIDs)
4) Estrogens
5) Certain diabetes medications called thiazolidinediones

In some cases, however, edema may be a sign of a more serious underlying medical condition.

Diseases and conditions that may cause edema include:

Congestive heart failure. When one or both of the lower chambers of your heart loses its ability to pump blood effectively — as happens in congestive heart failure — the blood can back up in your legs, ankles and feet, causing edema. Cirrhosis. This disease causes scarring of your liver, which interferes with liver function, causing changes in the hormones and chemicals that regulate fluids in your body, as well as increasing pressure within the large blood vessel (portal vein) that carries blood from your intestine, spleen and pancreas into your liver. These problems can result in fluid accumulating in your legs and your abdominal cavity (ascites). Kidney disease. When you have kidney disease, your kidneys may not be able to eliminate enough fluid and sodium from your blood. The extra fluid and sodium increases pressure in your blood vessels, causing edema.

Edema associated with kidney disease usually occurs in your legs and around your eyes. Kidney damage. Damage to the tiny blood vessels in your kidneys (glomeruli) that filter waste and excess water from your blood can result in nephrotic syndrome. One result of nephrotic syndrome is low levels of protein (albumin) in your blood, which can lead to fluid accumulation and edema. Weakness or damage to veins in your legs. Chronic venous insufficiency (CVI) is a condition in which the veins and valves in the veins in your legs are weakened or damaged and can't pump enough blood back to your heart. The remaining blood increases pressure in the veins, causing swelling.Inadequate lymphatic system. Your body's lymphatic system helps clear excess fluid from tissues. If this system is damaged — either due to lymphedema that occurs on its own (primary lymphedema) or because of a disease or medical condition, such as cancer or an infection (secondary lymphedema) — the lymph nodes and lymph vessels draining an area may not work correctly and edema results.


Adopted from Mayo Clinic