Deep vein thrombosis

VOL 108 / NO 4 / SEPTEMBER 15, 2000 / POSTGRADUATE MEDICINE

You probably have not heard much about deep vein thrombosis, even though it is a fairly common problem. It is a disorder that affects mainly the veins of the lower leg and thigh. A blood clot (or thrombus) can form in the veins deep in these areas, and the clot then blocks the flow of blood and causes swelling and inflammation. This swelling and redness are sometimes called thrombophlebitis, or just phlebitis. In the most serious cases, a blood clot from the leg breaks off and travels through the bloodstream. The moving clot is called an embolus, and it can lodge in the lungs, brain, or heart and cause serious damage.

Who is likely to have thrombosis?
Deep vein thrombosis occurs in about 2 of every 1,000 people. Most often it affects persons over age 60. It tends to develop during long periods of inactivity, such as lengthy road trips or airplane flights, as well as during illness or after surgery. Sometimes it occurs because a person's blood clots too quickly, and sometimes it is associated with trauma. Old age, overweight, and some types of drug therapy also increase the risk.

What do you need to know about it?
Blood clots in the veins buried deep in the calf or thigh can be difficult to detect. Symptoms typically occur in just one leg and may include:

• Pain or tenderness in one leg but not the other
• Swelling (edema) in one leg
• Increased warmth in one leg
• Changes in color, such as a reddish or bluish color, in one leg
• Joint pain

If you have any of these, check with your doctor immediately.

What might happen next?
In most cases, deep vein clots heal without any special treatment, but extra care may be needed to keep the clot from breaking off and traveling to the lungs, heart, or brain. Hospitalization is a good idea in many cases, at least at first. Bed rest, elevation of the leg, and warm, moist heat to the area may relieve pain. Prolonged sitting must be avoided.

Why be concerned?
Although most blood clots in the leg dissolve on their own, complications may occur and can be life-threatening. The most dangerous complication is called pulmonary embolism. In pulmonary embolism, a blood clot moves into the lung and lodges there. It often cuts off circulation, making it difficult for the heart to pump blood and decreasing the amount of oxygen available to the rest of the body. About 90% of blood clots that travel to the lungs start in the legs.

Pulmonary embolism requires immediate medical care. It can occur with no warning whatsoever, but being aware of possible leg symptoms can be a great help in prevention. The best way to protect yourself from pulmonary embolism is to keep it from happening. And that involves getting up and moving around during long trips and following your doctor's advice if you are recovering from illness or taking drugs.

Words that might be confusing

Your doctor might use some of these terms when discussing deep vein thrombosis.

Anticoagulant drugs: Medications used to stop blood clots from getting bigger and to keep new clots from forming; sometimes called blood thinners

Deep vein thrombosis (DVT): A condition in which a blood clot forms in the deep veins in the calf or thigh

Edema: Swelling caused by an accumulation of fluid

Embolectomy: A surgical procedure to remove a large clot

Embolus: A blood clot that breaks off from its original site, moves through the bloodstream, and lodges in another blood vessel

Phlebitis: Shortened term for thrombophlebitis (see below)

Pulmonary embolism: The closure of a pulmonary artery or one of its branches by a pulmonary embolus

Pulmonary embolus: A blood clot that has lodged in an artery in the lungs

Thrombolytic agents: Drugs that can break up large clots; also called clot busters

Thrombophlebitis: Name for tenderness, pain, redness, and swelling that occur when a clot and inflammation develop in a vein

Thrombosis: Formation of a blood clot in a blood vessel

Thrombus: A stationary blood clot that forms along the wall of a blood vessel

This information is not a substitute for medical treatment.

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