CausesBy Mayo Clinic staff
Edema occurs when tiny blood vessels in your body (capillaries) leak fluid and the fluid builds up in surrounding tissues, leading to swelling.
Mild cases of edema may result from:
- Sitting or staying in one position for too long
- Eating too much salty food
- Premenstrual signs and symptoms
Edema can be a side effect of some medications, including:
- Drugs that open blood vessels
- Calcium channel blockers
- Nonsteroidal anti-inflammatory drugs
- 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 your heart's lower chambers lose their 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. Fluid may accumulate in your abdominal cavity (ascites) and in your legs as a result of cirrhosis, a liver disease often caused by alcoholism.
- Kidney disease. When you have kidney disease, extra fluid and sodium in your circulation may cause edema. The edema associated with kidney disease usually occurs in your legs and around your eyes.
- Kidney damage. Damage to the tiny, filtering blood vessels in your kidneys can result in nephrotic syndrome. In nephrotic syndrome, declining levels of protein (albumin) in your blood can lead to fluid accumulation and edema.
- Weak or damaged leg veins (chronic venous insufficiency). One-way valves keep the blood in your leg veins moving toward your heart. If the valves stop working properly, blood can pool in your lower legs and cause swelling.
- Inadequate lymphatic system. Your body's lymphatic system helps clear excess fluid from tissues. If this system is damaged — for example, by cancer surgery — the lymph nodes and lymph vessels draining an area may not work correctly and edema results.
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