Deep Vein Thrombosis (DVT)

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), 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. A blood clot in a shallow vein is called a superficial venous thrombosis.

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

• 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 cancer

• Have a blood clot disorder that's passed along in families

• Take certain medicines, such as birth control pills

• Smoke cigarettes

• 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

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:

• Swollen

• Painful

• Red

• Tender to the touch

• Warm

A blood clot can break off and travel to your lung. This is a life-threatening condition called pulmonary embolism. If you have this, you may have:

• Shortness of breath

• Chest pain

• A weak and dizzy feeling (from low blood pressure)

There are 2 main complications of deep vein thrombosis:

• Pulmonary embolism: A piece of the clot breaks off and travels to your lungs

• Chronic venous insufficiency: The clot permanently damages your vein

A pulmonary embolism may cause:

• Shortness of breath

• Chest pain

• Weakness and dizziness

• Death

Chronic venous insufficiency keeps blood from flowing smoothly through the damaged vein. It can cause permanent swelling and discomfort to your leg or arm.

Doctors look for a clot with tests such as:

• Ultrasound

• A blood test to measure a substance released from blood clots

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.

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).