Phlebitis

Definition

Thrombophlebitis is the inflammation of a vein, with blood clots forming inside the vein at the site of inflammation. Thrombophlebitis is also known as phlebitis, phlebothrombosis, and venous thrombosis.

Description

There are two aspects of thrombophlebitis, inflammation of a vein and blood clot formation. If the inflammation component is minor, the disease is usually called venous thrombosis or phlebothrombosis. Thrombophlebitis can occur in both deep veins and superficial veins, but most often occurs in the superficial veins of the extremities (legs and arms). Most cases occur in the legs. When thrombophlebitis occurs in a superficial vein, one that is near the surface of the skin and is visible to the eye, the disease is called superficial thrombophlebitis. Any form of injury to a blood vessel can result in thrombophlebitis. In the case of superficial thrombophlebitis, the blood clot usually attaches firmly to the wall of the affected blood vein. Since superficial veins do not have muscles that massage the veins and help the blood to circulate, blood clots in superficial veins tend to remain where they form and seldom break loose. When thrombophlebitis occurs in a deep vein, a vein that runs deep within muscle tissue, it is called deep venous thrombosis. Deep venous thrombosis presents the threat of producing blood clots that will break loose to form emboli. Emboli are clumps of cells that are carried by the circulation to other tissues where they can lodge and block the blood supply. Emboli typically come to rest in the lungs and cause tissue damage that can sometimes be serious or fatal.

Causes & symptoms

The main symptoms of phlebitis are tenderness and pain in the area of the affected vein. Redness and/or swelling may also be seen. In the case of deep venous thrombosis, there is more swelling than is caused by superficial thrombophlebitis, and the patient may experience muscle stiffness in the affected area. There are many causes of thrombophlebitis. The main causes can be grouped into three categories: injury to veins, increased blood clotting, and blood stasis. When blood veins are damaged, collagen in the vein wall is exposed. Platelets respond to collagen by initiating the clotting process. Damage to a vein can occur as a consequence of in-dwelling catheters, trauma, infection, Buerger's disease, or the injection of irritating substances. Increased tendency of the blood to clot can be caused by malignant tumors, genetic disorders, high-fat diets, and oral contraceptives. Stasis, in which the blood clots due to decreased blood flow in an area, can happen following surgery, as a consequence of varicose veins, as a complication of postpartum states, and following prolonged bed rest. In the case of prolonged bed rest, blood clots form because of inactivity, allowing blood to move sluggishly and stagnate (collect) in the veins. Stasis can lead to blood clots. These clots (also called emboli) are sometimes released when the patient stands up and resumes activity. Emboli can present a problem if they lodge in vital organs. In the case of postpartum patients, a fever developing four to 10 days after delivery may indicate thrombophlebitis. It is also known that thrombophlebitis in some patients involves hereditary factors, including mutations of genes that control the amount of clotting factors in the blood.

Questions have been raised in recent years as to whether frequent long-distance air travel increases the risk of thrombophlebitis in airline pilots and passengers. As of 2001, studies of the effects of long-distance flights on blood circulation in human test subjects have yielded conflicting results.


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