Deep Vein Thrombosis

Deep Vein Thrombosis (DVT)

What is deep vein thrombosis?

Deep vein thrombosis (DVT) occurs when a blood clot forms within deep-lying veins, usually in your legs. The clot may break loose, travel through your bloodstream, and block arteries in your lungs, causing permanent damage or death.

How does it occur?

DVT may occur when the blood moves through deep veins in your legs more slowly than normal or when there is some factor that makes your blood more likely to clot. When you are bedridden (after surgery, for example) or when you sit still for a long time (such as during a long plane flight) your blood moves more slowly. Blood pools in the larger veins of your legs, and clots may form. Also, injury, major illness, and some medications increase the tendency for blood to clot.

Conditions and circumstances that increase the risk of your developing DVT include:

stroke
immobility and bed rest
congestive heart failure
varicose veins
certain cancers
fractures of the hip, femur, or lower leg
orthopedic surgery
pelvic surgery
heart attack.

What are the symptoms?

About half of people with DVT have no symptoms until a clot blocks a major vein. When DVT causes symptoms and blocks blood flow, symptoms may include:

a general swelling in the calf, ankle, foot, or thigh
increased warmth of the leg
redness
pain in the leg
night leg cramps
bluish discoloration of the skin on the leg or toes.

How is it diagnosed?

Because the symptoms can be caused by other conditions, tests are needed to confirm the diagnosis. Commonly used tests include:

Ultrasound tests, which use very high frequency sound waves to create an image
IPG (impedance plethysmography), a test that checks blood pressures at different places in the leg
Contrast venography, which involves injecting a substance into the veins that shows up on x-ray.

Blood clots are sometimes discovered by doing a CT (computed tomography) scan of the pelvis.

How is it treated?

Blood thinners (anticoagulant drugs that prevent blood clots) are used to treat DVT. Heparin is injected into a vein while you are hospitalized. Leg compression devices are often used to prevent DVT while you are in the hospital. Warfarin (Coumadin), given by mouth, is also started while you are in the hospital and will be continued after you are released. You may need to take warfarin for at least 6 months after you develop a DVT. You will have blood tests from time to time to check how well the drugs are working.

Some people have a tendency to form blood clots more easily than others. They may have DVT frequently and may have to take anticoagulants for the rest of their lives.

How can I help myself?

For people who have had DVT or have risk factors for development of DVT, prevention measures are recommended:

Avoid prolonged bed rest or immobility.
Wear special elastic stockings. Take them off once a day to allow the skin to be cleaned and inspected for discoloration or irritation. You should have at least two pairs of the stockings to allow for washing and drying each day. Stocking lengths vary from those that extend to the knee to those that cover the thigh. Be sure that the stockings fit smoothly and do not roll. Too much elastic on one place can block blood flow.
Keep your legs elevated when you are in bed or sitting down. Leg elevation promotes the return of blood through the leg veins.
Leg exercises are important to prevent pooling of blood in the legs. For those who are unable to exercise, it is important for the caregiver to massage the lower legs and move the legs through some range-of-motion exercises. If you have had major surgery, walking as soon as possible after the surgery will help lower your risk of developing DVT.

If you take anticoagulants:

Be sure to take the right amount of medicine at the right time each day.
Blood tests will be needed on a regular basis to monitor how fast your blood clots for as long as you are taking anticoagulants. Follow instructions as to when to have these tests.
Wear a Medic-alert bracelet showing which drug you take.
Before taking any new medications, even nonprescription drugs, contact your primary health care provider. Most medicines and all antibiotics can interfere with or exaggerate the effects of anticoagulants.
Tell your other health care providers, such as dentists or podiatrists, that you are taking anticoagulants.
Avoid aspirin unless specifically prescribed by your doctor.

If you take anticoagulants, call your primary health care provider immediately if you have any of the following symptoms:

faintness
dizziness
severe headaches
severe stomach pain
increased weakness
red or brown urine
bruises that increase in size without further injury
red or black bowel movements
cuts that do not stop bleeding
coughing up blood
unexpected bleeding from any source.