Deep vein thrombosis is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. They also can occur in other parts of the body.
If a clot in a vein breaks off and travels through your bloodstream, it can lodge in your lung. This is called
pulmonary embolism, which is a very serious condition that can cause death. Blood clots in the thigh are usually more likely to break off and cause pulmonary embolism than clots in the lower leg or other parts of the body.
A blood clot also can occur in veins that are close to the surface of the skin. This type of blood clot is called superficial venous thrombosis or phlebitis. Blood clots in superficial veins are not dangerous because they can’t travel to the lungs.
Symptoms
Only about half of the people with deep vein thrombosis have symptoms,
which may include:
- Swollen area of the leg.
- Pain or tenderness in the leg. The pain is usually in one leg and may be
felt only when standing or walking.
- Increased warmth in the area of the leg that is swollen or in pain.
- Red or discolored skin.
Diagnosis
Your doctor will obtain a medical history and examine you to determine if
you have deep vein thrombosis.
Commonly Used Tests
- Duplex
ultrasound is the most commonly used test to diagnose deep vein clots.
It uses sound waves to evaluate the flow of blood in your veins. A gel is
put on the skin of the leg. A handheld device is placed on the leg and
passed back and forth over the affected area. This device sends sound
waves from the leg to an ultrasound machine. A computer then turns the
sound waves into a picture. The picture is displayed on a TV screen where
your doctor can see the blood flow in your leg.
- Venography may be performed if the duplex ultrasound does not provide a
clear diagnosis. A venogram is an x ray used to examine veins. A dye is
injected into a vein and then an x ray is taken of the leg. The dye makes
the vein visible on the x ray. If the blood flow in the vein is slowed, it
will show on the x ray.
Less Frequently Used Tests
- Magnetic
resonance imaging (MRI) shows pictures of organs and structures inside
the body. MRI uses radio waves to make the image. In many cases, MRI can
provide information that would not show up on an x ray. This test is being
used more frequently to diagnose deep vein thrombosis.
- Computed tomography scan is a special type of x ray that can provide
pictures of structures inside the body. This test is rarely used to
diagnose deep vein thrombosis.
If an inherited blood clotting disorder is suspected, tests may be run for
it. The presence of an inherited clotting disorder is suggested by:
- Repeated blood clots that can’t be linked to any other cause
- Development of a blood clot in a vein at an unusual location, such as a
vein in the liver, kidney, or brain
Prevention
Preventing deep vein thrombosis depends on whether you have had a clot
before and on your risk factors for developing a clot.
If you have had a deep vein clot before, future clots may be prevented by:
- Taking the medicines prescribed by your doctor to prevent or treat blood
clots
- Following up with your doctor for medicine changes and blood tests
If you have never had a deep vein clot but have risks factors for
developing one, you may be able to prevent a clot by:
- Exercising your lower leg muscles, if you will be sitting still for long
periods of time.
- Getting out of bed and moving around as soon as you are able to after a
long period of being bedridden, such as after having surgery or being ill.
The sooner you move around, the less chance you have of developing a clot.
- Taking the medicines prescribed by your doctor to prevent or treat blood
clots after some types of surgery.
- Following up with your doctor.
Reference:
National Heart, Lung, and Blood Institute, USA.
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