A venous disease is a medical condition caused by abnormal or damaged veins, the blood vessels that carry blood toward the heart. Venous diseases occur when a vein has suffered damage to the valves that regulate the direction of blood flow, resulting in what is called venous insufficiency, as the circulatory system's ability to send deoxygenated blood back to the heart becomes impaired. This allows blood passing through the damaged veins to pool or leak, most commonly in the legs, which further damages the veins by distending them and can cause damage to nearby tissues. Some forms of venous disease have effects that are primarily cosmetic, but more severe forms can cause pain, impairment of mobility, and health problems such as skin ulcers. In some cases, venous disease can be fatal, causing skin cancer or a fatal blood clot.
Venous diseases have several potential causes. In some cases, they are the result of congenital defects in the veins that prevent the valves from functioning properly. They can be caused by inflammation of the veins, called phlebitis, which can in turn be caused by infections, physical trauma, or chemical irritants. Blood clots can lead to venous disease by stretching or inflaming veins. The diseases can be caused by injuries to blood vessels, activities or occupations that place physical stress on the legs, or pregnancy. The disease is more common in women than men due to hormonal effects, and risk is increased in people who are overweight or tall.
The effects of venues disease are usually seen primarily in the legs and feet. In a person suffering from venous insufficiency, the pooling and leakage of blood in the lower extremities can cause pain, inflammation, and a feeling of heaviness when standing or walking. Skin discoloration may occur around the ankles, and in more severe cases ulcers can appear on the skin in the same area. In severe cases, venous disease can cause enough pain or heaviness in the legs to interfere with the sufferer's ability to stand up or walk for extended periods of time. Accumulation of blood in the legs can also cause what would normally be minor injuries to result in severe blood loss.
Some effects of venous disease are seen directly in the veins themselves. Distension of small veins at the surface of the sufferer's skin can cause clusters of distended blood vessels known as spider veins, colored blue, red, or purple, to become visible on the skin and in some cases become painful. A similar problem in larger veins results in varicose veins, which cause the affected veins to become twisted and enlarged, often bulging visibly against the skin and becoming gnarled or cord-like in appearance. Both conditions most commonly occur in the legs, but can also appear elsewhere.
Venous disease makes blood clots more likely to form, because the damaged veins have slowed blood flow and greater susceptibility to inflammation from injuries. If the clot remains in place, it causes further inflammation of the vein, or thrombophlebitis, which further aggravates the damage to the vein. If a clot forms in a deep vein, a condition called deep vein thrombosis develops, where there is a significant risk that the clot will be dislodged and begin traveling through the circulatory system until it becomes stuck in the arteries of the lungs, causing a potentially fatal blockage called a pulmonary embolism.
Long-term venous disease can become worse over time as damage accumulates, resulting in a condition called chronic venous insufficiency. Swelling and inflammation become more severe, eventually impeding blood flow so severely that it interferes with the flow of nutrients and oxygen to the sufferer's skin. The skin becomes damaged and inflamed, eventually resulting in a condition known as venous stasis dermatitis in which the skin becomes dry, leathery, and discolored. The increased pooling of blood in the legs can also produce ulcers in the skin known as venous stasis ulcers, which are painful and in some cases become cancerous.