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Deep Vein Thrombosis

Deep Vein Thrombosis

What is deep vein thrombosis? — Deep vein thrombosis is the medical term for blood clots in the deep veins of the leg (figure 1). Deep vein thrombosis, or "DVT" for short, can be dangerous.
If a blood clot forms inside a blood vessel, it can clog the vessel and keep blood from getting where it needs to go. When that happens to 1 of the veins deep within the leg, blood can back up and cause swelling and pain.
Another problem with blood clots in veins is that they can travel to other parts of the body and clog blood vessels there. Blood clots that form in the legs, for example, can end up blocking blood vessels in the lungs. This can make it hard to breathe and sometimes, when they are large, can lead to death. When blood clots travel to the lungs doctors call it "pulmonary embolism" or "PE."
What are the symptoms of DVT? — DVT can cause the following symptoms in the involved leg:
Warmth and redness
Sometimes clots form in the veins that are closer to the surface of the skin, called the "superficial veins." Those blood clots cause a different set of symptoms. Blood clots in the veins near the surface of the skin are more painful and cause redness or infection. These clots sometimes also cause the veins to harden and bulge into ridges that look like cords. This is most common with the veins below the knee.
If you think you have a blood clot in your leg, call your doctor or nurse right away. Blood clots in the veins near the surface of the skin are less dangerous. But blood clots in the deep veins of the leg are more serious. Your doctor or nurse can run tests to find out if you do have a clot that needs to be treated.
What are the symptoms of blood clots in the lungs? — Blood clots in the lungs can cause:
Panting, shortness of breath, or trouble breathing
Sharp, knife-like chest pain when you breathe in or strain
Coughing or coughing up blood
A rapid heartbeat
If you get any of these symptoms, especially if they happen over a short period of time (hours or days) or get worse quickly, call for an ambulance (in the US and Canada, dial 9-1-1). At the hospital, doctors can run tests to find out if you do have a clot. Blood clots in the lungs can lead to death. That's why it's important to act fast and find out if there is a clot.
How is DVT treated? — DVT is treated with medicines that keep the clot from getting bigger and travelling to the lung. These medicines are called "anticoagulants" or "blood thinners," although they do not actually thin the blood. Some come in shots and others come in pills. DVT is usually treated first in the hospital.
If you have had a clot, your doctor will prescribe 1 of these medicines to lower your risk of getting more clots in the future. You will need to take the medicine for at least 3 months (and sometimes longer). Some people are first put on a medicine that comes as a shot, called heparin. This might be for a few days, or longer if for some reason you can't take pills.
The medicines do not dissolve existing blood clots, but they do keep them from getting bigger. They also help keep new blood clots from forming. Taking the medicine for a few months is important because it gives your body time to dissolve the old clot. It's also important because people who have a clot are at risk of developing another clot, especially in the first few months.
There are different oral medicines (pills) used to prevent and treat blood clots. They include apixaban (brand name: Eliquis), dabigatran (brand name: Pradaxa), edoxaban (brand names: Savaysa, Lixiana), rivaroxaban (brand name: Xarelto), and warfarin (brand name: Coumadin). Each medicine is different in terms of the dose, how often you take it, the cost, and how your diet or other medicines might affect it (table 1). Your doctor can talk to you about your options and preferences.
If your doctor prescribes one of these medicines:
Take it exactly as your doctor tells you to – If you forget or miss a dose, call your doctor to find out what to do. When you start taking the medicine, you will need to have your blood tested. If you take warfarin, you will need regular blood tests to check how your blood is clotting. This is important in order to make sure you get the correct dose of warfarin for you.
Follow your doctor's instructions about diet and medicines – Depending on which medicine you take, you might need to pay special attention to what you eat. Also, certain other medicines can affect the way these medicines work.
Watch for signs of bleeding – Abnormal bleeding is a risk with any of the medicines used to prevent and treat blood clots. That's because while these medicines help prevent dangerous blood clots, they also make it harder for your body to control bleeding after an injury. So it's important to try to avoid getting injured, and to tell your doctor right away if you do have signs of bleeding.
People who cannot take medicines to prevent and treat blood clots, or who do not get enough benefit from the medicines, can get a different treatment. This is called an "inferior vena cava filter" (also called an IVC filter). The inferior vena cava is the large vein that carries blood from your legs and the lower half of your body back up to your heart. IVC filters go inside the inferior vena cava. They filter and trap any large clots that form below the location of the filter. Your doctor might suggest one of these filters for you if:
You cannot safely take a medicine for blood clots
You form clots even while taking a medicine for blood clots
You have a dangerous bleeding problem while taking a medicine for blood clots
You are so sick that if a blood clot that travels from your legs to your lungs it could kill you
In some cases, a person has a clot that is severe enough to cause gangrene (cut off the blood supply to your leg). If this happens, doctors can give medicine to dissolve the clot. This is sometimes called "clot-busting" medicine, and is given through a catheter (a small tube inserted into the vein). In some cases, doctors will do surgery to remove the clot.
Can I do anything on my own to prevent blood clots? — Yes. People sometimes form clots because they have been sitting still for too long. People who travel on long airplane flights, for example, are at increased risk of blood clots. Here are some things you can do to help prevent a clot during a long flight:
Stand up and walk around every 1 to 2 hours
Do not smoke just before your trip
Wear loose, comfortable clothes
Shift your position while seated, and move your legs and feet often
Wear knee-high compression stockings
Avoid alcohol and medicines that make you sleepy, because they can impair your ability to move around
All topics are updated as new evidence becomes available and our peer review process is complete.
This topic retrieved from UpToDate on: Mar 30, 2020.
Topic 15362 Version 17.0
Release: 28.2.2 - C28.105
© 2020 UpToDate, Inc. and/or its affiliates. All rights reserved.

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