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Blood Clots

Also called: Hypercoagulability


What is a blood clot?

A blood clot is mass of blood that forms when platelets, proteins, and cells in the blood stick together. When you get hurt, your body forms a blood clot to stop the bleeding. After the bleeding stops and healing takes place, your body usually breaks down and removes the blood clot. But sometimes the blood clots form where they shouldn't, your body makes too many blood clots or abnormal blood clots, or the blood clots don't break down like they should. These blood clots can be dangerous and may cause other health problems.

Blood clots can form in, or travel to, the blood vessels in the limbs, lungs, brain, heart, and kidneys. The types of problems blood clots can cause will depend on where they are:

  • Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in the lower leg, thigh, or pelvis. It can block a vein and cause damage to your leg.
  • A pulmonary embolism can happen when a DVT breaks off and travels through the bloodstream to the lungs. It can damage your lungs and prevent your other organs from getting enough oxygen.
  • Cerebral venous sinus thrombosis (CVST) is a rare blood clot in the venous sinuses in your brain. Normally the venous sinuses drain blood from your brain. CVST blocks the blood from draining and can cause a hemorrhagic stroke.
  • Blood clots in other parts of the body can cause problems such as an ischemic stroke, a heart attack, kidney problems, kidney failure, and pregnancy-related problems.

Who is at risk for blood clots?

Certain factors can raise the risk of blood clots:

What are the symptoms of blood clots?

The symptoms for blood clots can be different, depending on where the blood clot is:

How are blood clots diagnosed?

Your health care provider may use many tools to diagnose blood clots:

  • A physical exam
  • A medical history
  • Blood tests, including a D-dimer test
  • Imaging tests, such as
    • Ultrasound
    • X-rays of the veins (venography) or blood vessels (angiography) that are taken after you get an injection of special dye. The dye shows up on the x-ray and allows the provider to see how the blood flows.
    • CT Scan

What are the treatments for blood clots?

Treatments for blood clots depend on where the blood clot is located and how severe it is. Treatments may include:

  • Blood thinners
  • Other medicines, including thrombolytics. Thrombolytics are medicines which dissolve blood clots. They are usually used where the blood clots are severe.
  • Surgery and other procedures to remove the blood clots

Can blood clots be prevented?

You may be able to help prevent blood clots by:

  • Moving around as soon as possible after having been confined to your bed, such as after surgery, illness, or injury
  • Getting up and moving around every few hours when you have to sit for long periods of time, for example if you are on a long flight or car trip
  • Regular physical activity
  • Not smoking
  • Staying at a healthy weight

Some people at high risk may need to take blood thinners to prevent blood clots.

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The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.