Deep Vein Thrombosis (DVT) and Traveler's Thrombosis

Deep vein thrombosis (DVT) occurs when blood clots form in the large veins of the legs. Should a blood clot break free it is called an embolism—a free-floating blood clot traveling through the blood vessels. If the blood clot lodges in the lungs, heart or brain, serious damage can result. Deep vein thrombosis can occur when sitting for long periods, so DVT associated with traveling is often called traveler's thrombosis.

The risk of deep vein thrombosis increases with age: Most DVT blood clots develop after age sixty. Deep vein thrombosis can, however, occur at any age. Women are particularly susceptible to DVT. These are the most common risk factors:

The risk of blood clot formation increases dramatically in the presence of two or more DVT risk factors.

A blood clot in the leg often produces no symptoms, so you may have deep vein thrombosis and not know it. When DVT symptoms develop, they are usually only apparent in one leg (a blood clot developing in each leg simultaneously is a particularly rare occurrence).

When symptoms are present, they may include:

Diagnosing deep vein thrombosis through physical examination alone is very difficult. While DVT symptoms and risk factors may be suggestive of a blood clot, diagnostic tools are required to make a firm diagnosis.

Ultrasonography, the use of ultrasound imaging, is commonly used to detect deep vein thrombosis, and to determine the size and location of the blood clot. Venography, an x-ray that uses contrast dye to define blood vessels on the x-ray film, is also used to detect blood clots.

A blood test called d-dimer testing may be performed during DVT diagnosis to indicate whether a blood clot has formed and whether the clot is beginning to break down. Other blood work may be needed to determine whether coagulation disorders are the cause of deep vein thrombosis.

Deep vein thrombosis may require anticoagulant therapy to dissolve the blood clot. The anticoagulants heparin and warfarin are usually employed to "thin" the blood. If the risk of recurring blood clots is high, long-term anticoagulant therapy may be called for, either with heparin, warfarin or low dose aspirin.

Traveler's thrombosis is a case of deep vein thrombosis caused by sitting for long periods while traveling. Traveler's thrombosis was first observed in people after long flights, from which the disorder gets its other name, economy class syndrome. However, sitting for long periods using any mode of transport can cause blood clot formation in people susceptible to deep vein thrombosis, so traveler's thrombosis is the more appropriate name.

Prevention of DVT is the best treatment for traveler's thrombosis. When traveling, try to observe the following guidelines:

Many airlines now provide information about traveler's thrombosis that includes foot and leg exercises to help reduce the risk of a blood clot while traveling.

If you're at risk for deep vein thrombosis or have a history of DVT, consult with your doctor before traveling. He or she may recommend the use of special anti-embolic stockings to lower the risk of traveler's thrombosis.

A low dose of aspirin or anticoagulant therapy prior to travel may be required if the risk of deep vein thrombosis is high. Don't attempt to self-medicate with aspirin to prevent traveler's thrombosis: Aspirin can have serious side effects and should be used as DVT therapy only under the advice of a physician.

Resources

British Airways. (nd). Traveler's thrombosis.

Kearon, C., Ginsberg, J.S., Douketis, J., Crowther, M.A., Turpie, A.G., Bates, S.M., Lee, A., et al. (2005, April 5). Diagnosing deep vein thrombosis. Annals of Internal Medicine, 142(7), 490-496.

NASA Occupational Safety. (2001). Flight-related deep vein thrombosis (DVT): Economy class syndrome.

National Library of Medicine. (Updated 2003). Deep venous thrombosis. MedlinePlus Medical Encyclopedia.