What is deep vein thrombosis?
A deep vein thrombosis (DVT, also called venous thrombosis) is a blood clot that forms in a vein deep in your body. The clot may limit or completely block blood flow through the vein. Most DVTs form in the lower leg, thigh and pelvis. But, they can happen in other parts of the body, such as the arm, brain, intestines, liver and kidneys
What is the danger of DVT?
A DVT, itself, is not life-threatening. But, the blood clot can break free and travel through the bloodstream and get stuck in a blood vessel inside your lung. This condition is called a pulmonary embolism and can be life-threatening. It is important to find out if you have a DVT as soon as possible and get treatment.
Another problem caused by a DVT is chronic venous insufficiency (also called post-thrombotic syndrome). This means the walls and/or valves of the veins in your legs aren’t working well. Blood collects in the veins and causes chronic leg swelling, increased pressure, dark or discolored skin, and open sores on the legs called venous stasis ulcers.
What is the difference between DVT and a superficial venous thrombosis?
A superficial venous thrombosis (also called phlebitis or superficial thrombophlebitis) is a blood clot that develops in a vein close to the surface of the skin. These types of blood clots do not usually travel to the lungs unless they move from the superficial system into the deep venous system first.
What are the symptoms of DVT?
DVT most commonly occurs in just one leg or one arm. Not everyone with DVT will experience symptoms, although when present, they may include:
- Swelling of the leg or arm (sometimes this happens suddenly)
- Pain or tenderness in the leg (may only be present when standing or walking)
- The area of the leg or arm that is swollen or hurts may be warmer than usual
- Skin that is red or discolored
- The veins near the skin’s surface may be larger than normal
Symptoms of a pulmonary embolism include:
- Sudden shortness of breath or fast breathing
- Sharp chest pain that often comes with coughing or movement
- Pain in the back
- Cough (sometimes with bloody sputum/phlegm)
- Sweating more than normal
- Fast heartbeat
- Feeling dizzy or fainting
Some people do not know they have DVT until the clot moves from their leg or arm and traveled to their lung.It is important to notify your doctor right away or go to the emergency room if you have symptoms of a pulmonary embolism or DVT. Do not wait to see if the symptoms will “go away.” Get treatment right away to prevent serious complications.
What causes a DVT?
The following conditions can increase your risk of a DVT:
- An inherited (genetic) condition that increases your risk of blood clots
- Cancer and some of its treatments (chemotherapy)
- Limited blood flow in a deep vein, due to injury, surgery, or immobilization
- Long periods of inactivity that decrease blood flow, such as:
- Sitting for a long period of time on trips in a car, truck, bus, train or airplane
- Immobility after surgery or a serious injury
- Pregnancy and the first 6 weeks after giving birth
- Being over age 40 (although a DVT can affect people of any age)
- Being overweight
- Taking birth control pills or hormone therapy
Having a central venous catheter or pacemaker.
How is DVT diagnosed?
An appointment to find out if you have a DVT includes an exam and review of your medical history. You will also need testing. Common tests to diagnose a DVT are:
A duplex venous ultrasound. This is the most common test used to diagnose a DVT. It shows the blood flow in the veins and any blood clots that exist. An ultrasound technician will apply pressure while scanning your arm or leg. If the pressure does not cause the vein to compress, it could mean there is a blood clot.
Venography. This test uses X-rays to show your deep veins. A special dye (contrast material) is injected into your veins so the X-rays show the veins and any blood clots. Any blockage in blood flow may also be seen. Venography may be used if the results of the duplex ultrasound aren’t clear.
Other tests you may have include:
- Magnetic Resonance Imaging (MRI) or Magnetic Resonance Venography (MRV): MRI shows pictures of organs and structures inside the body, and MRV shows pictures of the blood vessels in the body. In many cases, MRI and MRV can offer more information than an X-ray.
- Computed tomography (CT) scan: A type of X-ray that shows structures inside the body. A CT scan may be used to find a DVT in the abdomen or pelvis, as well as blood clots in the lung (pulmonary embolism).
If your doctor thinks you may have a genetic disorder that causes blood clots, you may need blood tests. This may be important if:
- You have a history of blood clots that cannot be linked to any other cause
- You have a blood clot in an unusual location, such as in a vein from the intestines, liver, kidney or brain
- You have a strong family history of blood clots
A DVT may make it harder for you to get around at first. You should slowly return to your normal activities. If your legs feel swollen or heavy, lie in bed with your heels propped up about 12.5 to 15 centimeters (5 to 6 inches). This helps improve circulation and decreases swelling.
- Exercise your lower leg muscles if you are sitting still for long periods of time
- Stand up and walk for a few minutes every hour while awake
- Don’t wear tight-fitting clothing that could decrease the circulation in your legs
- Wear compression stockings as recommended by your doctor
- Avoid activities that may cause a serious injury
What treatments are available for patients with a DVT?
Patients with a DVT may need to be treated in the hospital. Others may be able to have outpatient treatment.
Treatments include medications, compression stockings and elevating the affected leg. If the blood clot is extensive, you may need more invasive testing and treatment. The main goals of treatment are to:
- Stop the clot from getting bigger
- Prevent the clot from breaking off in your vein and moving to your lungs
- Reduce the risk of another blood clot
- Prevent long-term complications from the blood clot (chronic venous insufficiency)
Treatment for a DVT can include:
Anticoagulants (“blood thinners”). This type of medication makes it harder for your blood to clot. Anticoagulants also stop clots from getting bigger and prevent blood clots from moving.
Anticoagulants do not destroy clots. Your body may naturally dissolve a clot, but sometimes clots do not completely disappear.
There are different types of anticoagulants. Your doctor will talk to you about the best type of medication for you.
If you need to take an anticoagulant, you may only need to take it for 3 to 6 months. But, your treatment time may be different if:
- You have had clots before, your treatment time may be longer
- You are being treated for another illness (such as cancer), you may need to take an anticoagulant as long as your risk of a clot is higher
The most common side effect of anticoagulants is bleeding. You should call your doctor right away if you notice that you bruise or bleed easily while taking this medication.
Important information about your medicine
- Take your medications exactly as your doctor tells you
- Have blood tests as directed by your doctor and keep all scheduled laboratory appointment
- Do not stop or start taking any medication (including non-prescription/ over-the-counter medications and supplements without asking your doctor
- Talk to your doctor about your diet. You may need to make changes, depending on the medication you take
You will likely need to wear graduated compression stockings to get rid of leg swelling. The swelling is often because the valves in the leg veins are damaged or the vein is blocked by the DVT.
Most compression stockings are worn just below the knee. These stockings are tight at the ankle and become looser as they go up the leg. This causes gentle pressure (compression) on your leg.
DVT treatment procedures
Vena cava filters are used when you cannot take medications to thin your blood or if you have blood clots while taking this type of medication. The filter prevents blood clots from moving from the vein in your legs to the lung (pulmonary embolism). The filter is put in place during minor surgery. It is inserted through a catheter into a large vein in the groin or neck, then into the vena cava (the largest vein in the body). Once in place, the filter catches clots as they move through the body. This treatment helps prevent a pulmonary embolism, but does not prevent the formation of more clots.
Can a DVT be prevented?
After you have a DVT, you will need to reduce your risk of future clots by:
- Taking your medications exactly as your doctor tells you to.
- Keeping your follow-up appointments with your doctor and the laboratory. These are needed to see how well your treatment is working.
If you have never had a DVT, but have an increased risk of developing one, be sure to:
- Exercise your lower leg muscles if you need to sit still for a long time. Stand up and walk at least every half hour if you are on a long flight. Or get out of the car every hour if you are on a long road trip.
- Get out of bed and move around as soon as you can after you are sick or have surgery. The sooner you move around, the less chance you have of developing a clot.
- Take medications or use compression stockings after surgery (if prescribed by your doctor) to reduce your risk of a clot.
- Follow-up with your doctor as directed to and follow your doctor’s recommendations to reduce your risk of a clot.