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Chronic Venous Insufficiency and Postphlebitic Syndrome
Chronic venous insufficiency is damage to leg veins that prevents blood from flowing normally.
About 5% of people in the United States have chronic venous insufficiency.
Blood returns from the legs through shallow and deep veins. Contraction of leg muscles pushes blood through the deep veins. Valves in the veins keep blood flowing upward toward the heart (see Overview of the Venous System). Chronic venous insufficiency occurs when something widens the veins and/or damages the valves in the veins. These changes decrease blood flow in the veins and increase the pressure in the veins. The increased pressure and low blood flow cause fluid to accumulate in the legs and other symptoms.
The most common cause of chronic venous insufficiency is a previous blood clot in the veins (deep vein thrombosis—see see Deep Vein Thrombosis (DVT)) because scar tissue from the clot may damage the valves in the veins. Chronic venous insufficiency caused by deep vein thrombosis is sometimes called postphlebitic syndrome. Other risk factors for chronic venous insufficiency include injury to the legs, aging, and obesity.
People have leg swelling (edema), that typically is worse at the end of the day because blood must flow upward against gravity when a person is standing or sitting. Overnight, edema subsides because the veins empty well when the legs are horizontal. The swelling may not cause any symptoms, but some people feel fullness, heaviness, aching, cramps, pain, tiredness, and tingling in the legs.
Later on, the skin on the inside of the ankle becomes scaly and itchy and may turn a reddish brown. The discoloration is caused by red blood cells that escape from swollen (distended) veins into the skin. Varicose veins may be present. The discolored skin is vulnerable, and even a minor injury, such as that from scratching or a bump, can break it open, resulting in an ulcer. Ulcers may also develop spontaneously, typically on the inside of the ankle. Ulcers are usually only slightly uncomfotrtable. A very painful ulcer might be infected.
If edema is severe and persistent, scar tissue develops and traps fluid in the tissues. As a result, the calf permanently enlarges and feels hard. In such cases, ulcers are more likely to develop, and they heal less easily.
Doctors usually can diagnose chronic venous insufficiency based on its appearance and symptoms. Sometimes they do ultrasonography of the legs to make sure the edema is not caused by deep vein thrombosis.
Elevating the leg above the level of the heart decreases pressure in the veins, and should be done for 30 minutes or longer at least 3 times per day.
Elastic bandages are used first for compression. Once edema decreases and ulcers begin to heal, people can use commercial compression stockings. Such stockings are available with different amounts of pressure. Higher pressure stockings are more effective for severe problems but are more uncomfortable. Stockings should be put on when people awaken, before leg edema worsens with activity, and worn all day. Many people have difficulty using the stockings regularly. Younger or more active people consider stockings irritating, restricting, or unattractive. Older people may have difficulty putting them on. Intermittent pneumatic compression (IPC) uses a pump to repeatedly inflate and deflate hollow plastic leggings. IPC squeezes blood and fluid out of the lower legs but is cumbersome.
Wound care is important to heal leg ulcers. Various dressings have been developed that can be left under compression stockings for several days to a week. The Unna boot dressing uses zinc oxide–impregnated bandages. Other dressings provide a moist environment for wound healing and promote growth of new tissue.
Drugs and surgery do not help chronic venous insufficiency, although skin grafting can be a last resort for skin ulcers that have not healed with other measures. However, the grafted skin will reulcerate unless the person consistently follows leg elevation and compression instructions.
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