Deep Vein Thrombosis
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A deep vein thrombosis (throm-BO-sis) is a blood clot that forms in a vein deep
in the body. Most deep vein clots occur in the leg or hip veins. They also can
occur in other parts of the body. Blood clots in the veins in the thigh are usually
more serious than blood clots that happen in veins in your lower leg. If a clot
in a vein breaks off and travels through your bloodstream, it can lodge in your
lung. This is called a pulmonary embolism, which is a very serious condition
that can cause death. Blood clots also can occur in veins that are close to the
surface of the skin. These types of blood clots are called superficial venous
(fle-BI-tis). Blood clots in superficial veins
cannot travel to the lungs.
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There are many factors that may increase your risk for deep
- An inherited condition that causes increased risk for clotting
- Low blood flow in a deep vein, due to injury, surgery,
- Cancer and its treatment
- Other medical conditions such as varicose veins
- Sitting for a long period of time like on a long trips
in a car or on an airplane
- Pregnancy, especially the first 6 weeks after giving
- Being over age 60 (although deep vein thrombosis can
occur in any age group)
- Being overweight
- Taking birth control pills or hormone therapy, including
for postmenopausal symptoms
- Central venous catheters now account for almost 1 in
Your risk for deep vein clots increases if you have several
risk factors at the same time. For example, a woman with an
inherited condition for clotting who also takes birth control
pills has an even higher risk to have a blood clot.
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Only about half of the people with deep vein thrombosis have
symptoms. The symptoms may include:
Deep vein thrombosis
- Swelling of the leg
- Pain or tenderness in the leg-the pain is usually in
one leg and may only be present when standing or walking
- Feeling of increased warmth in the area of the leg that
is swollen or that hurts
- Red or discolored skin.
- Chest pain when you take a deep breath
- Shortness of breath.
Some people only find out they have a deep vein thrombosis
after the clot has moved from the leg and traveled to the lung
(pulmonary embolism). It is important to see a doctor right
away if you have symptoms of a pulmonary embolism or deep vein
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Your doctor will obtain a medical history and examine you
to determine if you have deep vein thrombosis.
Duplex ultrasound is the most common test used 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 sounds into a picture. The picture is displayed
on a TV screen where your doctor can see the blood flow in
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 (CT) 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
If your doctor suspects that an inherited disorder could be
causing the clots, the doctor may test for these disorders.
This may be important if:
- You have repeated blood clots that cannot be linked to any other cause
- You have a blood clot in a vein at an unusual location,
such as a vein from the liver, kidney, or brain.
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Preventing deep vein thrombosis depends on whether you have
had a clot before or if you are at risk for developing a deep
vein clot but never had one. If you have had a deep vein clot,
then you will need to prevent further clots from developing
- Taking your medications to prevent or treat blood clots as prescribed by
- Following up with your doctor for medication changes
and blood work.
If you have never had a deep vein clot, but are in a situation
that may increase your risk, be sure to:
- Exercise your lower leg muscles if you will be sitting still for long periods
- Get out of bed and move around as soon as you are able
after having surgery or being ill. The sooner you move
around the less chance you have to develop a clot.
- Take medications to prevent clots after some types of
surgery as directed by your doctor.
- Follow up with your doctor.
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The main goals in treating deep vein thrombosis are to:
- Stop the clot from getting bigger
- Prevent the clot from breaking off in your vein and moving
to your lungs
- Reduce your chance of having another blood clot.
There are several medications used to treat and/or prevent
deep vein thrombosis:
(sometimes called blood thinners) decrease
your blood's ability to clot. They are used to stop clots from
getting bigger and to prevent a blood clot from forming. Anticoagulants
do not break up blood clots that have already formed. Your
body's natural system will dissolve the clot. Anticoagulants
can either come as a pill (warfarin) or as an injection or
Heparin and warfarin may be given at the same time. Heparin
will act quickly, while the warfarin will take 2 to 3 days
before it starts to work. Once the warfarin is working, the
heparin will be stopped. Pregnant women cannot take warfarin
and will be treated with heparin only.
Treatment for deep vein thrombosis with anticoagulants usually
lasts for 3 to 6 months. However, the following situations
may change the length of treatment:
- If your blood clot occurred after a short-term risk like surgery, your
treatment may be shorter
- If you have had clots before, you will need longer treatment
- If you have another illness (like cancer) you are being
treated for, you will take anticoagulants for as long as
those risk factors are present.
The most common side effect of anticoagulants is bleeding.
Blood tests will check how well the medicine is working. You
should call your doctor right away if you are taking warfarin
or heparin and have easy bruising or bleeding.
are medications given to quickly dissolve
the blood clot. They are used to treat large clots causing
severe symptoms. Because they can cause sudden bleeding, they
are only used in life-threatening situations.
are new medications that interfere
with the clotting process. They are used in treating some types
of clots and for patients who cannot take heparin.
Vena cava filters
are used when you cannot take medications
to thin your blood, or if you are taking blood thinners and
continue to develop clots. The filter can prevent blood clots
from moving from the vein in your legs to the lung (pulmonary
embolism). The filter is inserted inside a large vein called
the vena cava. It can catch the clots as they try to move through
the body to the lungs. This treatment will prevent a pulmonary
embolism, but will not stop you from developing more clots.
Your doctor may prescribe graduated compression stockings
reduce the chronic swelling that can occur in the leg after
a blood clot has developed. The swelling is due to damage to
the valves in the leg veins.
Compression stockings are worn on the legs from the arch of
the foot to just above or below the knee. These stockings are
tight at the ankle and become looser as they go up the leg.
This causes a gentle compression (or pressure) up your leg.
They have some side effects:
- They can be uncomfortable when worn all day
- They can be hot
- They may be difficult to put on, especially for older
adults and overweight people.
Much of the treatment for deep vein thrombosis takes place
at home. It is important to:
- Take medications correctly.
- Have blood work drawn as directed by your doctor.
- Avoid activities that may cause a serious injury.
- Talk to your doctor before taking any other medications,
especially over-the-counter medications.
- Ask your doctor about your diet. Certain foods affect
how well your anticoagulant works.
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If I have mild symptoms of a deep vein thrombosis, can I wait and see
if the clot will go away on its own?
Are there any foods that change the way my medications work?
No. Not treating a deep vein thrombosis can cause very serious complications.
If you think you have the symptoms or are unsure if you have the symptoms,
see a doctor right away.
I hear that alcohol can thin my blood. Can I drink alcohol while taking
Yes, foods that contain Vitamin K can change how well warfarin (coumadin)
will work. This vitamin is found in green leafy vegetables and in some oils
like canola and soybean oil. It is best if you eat a well-balanced healthy
diet that doesn't vary. For example, you should not make up for having no
vegetables one week by eating extra helpings of vegetables the next week.
Do I need to restrict my activities while I am being treated for a deep
It is important that you discuss with your doctor what amount of alcohol is
safe for you to drink.
Can I take over-the-counter medications while taking anticoagulants (blood
You should discuss your activities with your doctor. In general, your activities
do not need to be restricted.
Why do I need to have blood testing?
Some over-the-counter medications, such as vitamin K in multivitamins, may
change the way your medications work. Aspirin can also thin your blood. Taking
two medications (even if one is over-the-counter) that thins your blood may
increase your risk for excessive bleeding. Always check with your health care
team before taking any other medications while taking anticoagulants.
While you are taking anticoagulants, your doctor will need to carefully monitor
your clotting ability. Blood tests will measure how quickly your blood clots
or if your blood is clotting too slowly. If your lab tests show that your
blood is clotting too slowly or too quickly, your medications may be changed
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