What is deep vein thrombosis?
Deep vein thrombosis (DVT) is when a blood clot forms inside a large vein. Usually the vein is deep in your leg, but a clot may form in a vein in your pelvic area or your arm.
A blood clot is good when it helps you stop bleeding after an injury. But a blood clot that happens when you're not bleeding can be dangerous.
Blood clots may form in deep veins when they're not supposed to
Blood clots may have no symptoms, or they may cause your leg or arm to swell and hurt
Blood clots can break loose and travel to your lung (pulmonary embolism Pulmonary Embolism (PE) A pulmonary embolism is a clump of material (usually a blood clot) that gets stuck while moving through your bloodstream and blocks a blood vessel in your lungs. A pulmonary embolism blocks... read more ), which causes breathing problems and may lead to death
To see if you have a DVT, doctors may do an ultrasound
Doctors may give you medicines to help keep the clot from growing and prevent it from going to your lungs
If medicine doesn't work or you can't take it, your doctor may put a small filter in a vein to keep a clot that breaks loose from going to your lungs
Blood clots in deep veins are more dangerous than blood clots in shallow veins close to your skin. Blood clots in shallow veins are called superficial venous thrombosis Superficial Venous Thrombosis Superficial venous thrombosis is inflammation and clotting in a superficial vein, usually in the arms or legs. The skin over the vein becomes red, swollen, and painful. Doctors examine the area... read more .
What causes DVT?
The main causes of DVT include:
Vein injury: Your vein is injured, such as in an accident
Blood disorder: You have a disorder that causes increased blood clotting Overview of Platelet Disorders Platelets (sometimes called thrombocytes) are cell fragments produced in the bone marrow that circulate in the bloodstream and help blood to clot. Thrombopoietin, primarily produced in the liver... read more
Bed rest: The blood flow in your veins is too slow because you're on bed rest (for example, after surgery or a stroke)
Cast or splint: A cast or splint keeps you from moving your leg
Leg surgery: You had surgery on your leg, such as a hip or knee replacement
You’re more likely to get blood clots if you:
Have a blood clot disorder that's passed along in families
Take certain medicines, such as birth control pills
Recently gave birth or had surgery
Are dehydrated (too little water or other fluids in your body), especially if you’re an older adult
Are sitting for a long period, such as on an airplane
What are the symptoms of DVT?
Half of people with DVT have no symptoms.
If the clot is in a deep leg vein, which is the most common place, then your calf or leg may be:
Tender to the touch
A blood clot can break off and travel to your lung. This is a life-threatening condition called pulmonary embolism Pulmonary Embolism (PE) A pulmonary embolism is a clump of material (usually a blood clot) that gets stuck while moving through your bloodstream and blocks a blood vessel in your lungs. A pulmonary embolism blocks... read more . If you have this, you may have:
Shortness of breath
A weak and dizzy feeling (from low blood pressure)
What are the complications of DVT?
There are 2 main complications of deep vein thrombosis:
Pulmonary embolism Pulmonary Embolism (PE) A pulmonary embolism is a clump of material (usually a blood clot) that gets stuck while moving through your bloodstream and blocks a blood vessel in your lungs. A pulmonary embolism blocks... read more : A piece of the clot breaks off and travels to your lungs
Chronic venous insufficiency Chronic Venous Insufficiency and Post-Thrombotic Syndrome Chronic venous insufficiency is damage to your leg veins that keeps your blood from flowing normally. Phlebitis is inflammation of one of your veins. It's often caused by a blood clot in your... read more : The clot permanently damages your vein
A pulmonary embolism Pulmonary Embolism (PE) A pulmonary embolism is a clump of material (usually a blood clot) that gets stuck while moving through your bloodstream and blocks a blood vessel in your lungs. A pulmonary embolism blocks... read more may cause:
Shortness of breath
Weakness and dizziness
Chronic venous insufficiency keeps blood from flowing smoothly through the damaged vein. It can cause permanent swelling and discomfort to your leg or arm.
How can doctors tell if I have DVT?
Doctors look for a clot with tests such as:
A blood test to measure a substance released from blood clots
How do doctors treat DVT?
Treatment usually includes:
Blood-thinning medicines to prevent more clotting
If blood-thinning medicines don't work or you can't take them for some reason, doctors rarely may:
Put a clot-blocking filter in the main vein that leads to your heart—this can help prevent pulmonary embolism
Rarely, if you have a really big clot, doctors may give you clot-dissolving medicines in your vein. However, doctors don't do this often because clot-dissolving medicine can cause life-threatening bleeding.
Being physically active doesn’t raise the risk of pulmonary embolism and won’t make a blood clot more likely to break off.
How can I prevent DVT?
You can lower the chance of getting DVT if you:
Put your feet up when you're sitting, bend and straighten your ankles 10 times every half hour, and walk or stretch every 2 hours—this helps blood flow and lessens swelling of your legs
Take any blood-thinning medicine that your doctor prescribes
If you’re at higher risk, wear special tight stockings (compression stockings) during the day or use air-filled leg wrappings connected to a machine that squeezes your legs from time to time (intermittent pneumatic compression).