Patient education: Deep vein thrombosis (blood clot in the arm) (The Basics)

What is deep vein thrombosis? — Deep vein thrombosis, or "DVT," is a blood clot in the deep veins (figure 1). Blood clots happen when a blood vessel is narrowed. This slows the blood flowing through the area and can make clots form.

Blood clots in the arm happen more often in people who have a "central venous catheter" in their arm. This is a long, thin, flexible tube, or "IV." It can be placed in a vein located deep in the arm, with the end of the catheter in a larger vein near the heart. DVTs in the arm are also more common in people who have:

●Cancer

●Thoracic outlet syndrome – In this condition, the blood vessels, nerves, and muscles are compressed between the collarbone and the first rib.

●A hemodialysis "access" in their arm – This is a way for blood to leave and return to the body during dialysis.

DVTs can be dangerous.

Why are blood clots 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 this happens to 1 of the veins deep within the arm, blood can back up and cause swelling and pain.

Blood clots in veins can also travel to other parts of the body and clog blood vessels there. For example, in rare cases, a clot that forms in the arm could end up blocking a blood vessel in the lung. This can make it hard to breathe. Sometimes, if the clot is large, it can lead to death. When a blood clot travels to the lungs, doctors call it "pulmonary embolism," or "PE."

What are the symptoms of DVT? — DVT can cause these symptoms in the affected arm:

●Swelling or a feeling of fullness in the arm

●Pain

●Warmth and a change in skin color

Sometimes, clots form in the veins that are closer to the surface of the skin, called the "superficial veins." This causes different symptoms. Blood clots in the veins near the surface of the skin are more painful and cause redness or infection. These clots can also move into the deeper veins. Blood clots in the deeper veins are more likely to cause swelling.

If you think that you have a blood clot in your arm, 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 arm are more serious. Your doctor or nurse can do tests to find out if you do have a clot in or near a deep vein that needs treatment. This might include imaging tests such as ultrasound, CT, or MRI. Imaging tests create pictures of the inside of the body.

How is DVT treated? — If the blood clot was caused by an IV catheter, your doctor or nurse will remove the catheter if you no longer need it.

DVT is treated with medicines that keep the clot from getting bigger and traveling to the lung. These medicines are called "anticoagulants." They are also sometimes called "blood thinners," although they do not actually thin the blood. Some come as shots, and others come as pills. DVT is usually treated first in the hospital.

●If you had a clot, your doctor will prescribe an anticoagulant medicine to lower your risk of getting more clots in the future. You 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 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: Jantoven). Each medicine is different in 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 1 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 might 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 to make sure that 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. These medicines help prevent dangerous blood clots, but they also make it harder for your body to control bleeding after an injury. Try to avoid getting injured, and tell your doctor right away if you have signs of bleeding.

In some cases, doctors can give medicine to dissolve severe clots. This is sometimes called "clot-busting" medicine. It is given through a special catheter. In some cases, doctors will do surgery to remove the clot and fix the area that was narrowed. This helps to prevent the clot from happening again.

More on this topic

Patient education: Deep vein thrombosis – Discharge instructions (The Basics)
Patient education: Pulmonary embolism (blood clot in the lung) (The Basics)
Patient education: Superficial vein phlebitis and thrombosis (The Basics)
Patient education: How to give an anticoagulant shot (The Basics)
Patient education: Choosing an oral medicine for blood clots (The Basics)
Patient education: Taking oral medicines for blood clots (The Basics)

Patient education: Deep vein thrombosis (DVT) (Beyond the Basics)
Patient education: Pulmonary embolism (Beyond the Basics)
Patient education: Warfarin (Beyond the Basics)