What Is Thrombosis? - Definition, Symptoms & Treatment

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  • 0:01 What Is Thrombosis?
  • 0:46 Causes of Thrombosis
  • 1:08 Symptoms of Thrombosis
  • 1:52 Risk Factors
  • 2:40 Treatment Options
  • 3:26 Lesson Summary
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Lesson Transcript
Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

Thrombosis is the formation of blood clots within a vessel. Complete this lesson to find out what causes thrombosis, what its symptoms are, and how the condition is treated.

What Is Thrombosis?

Right now, as you're sitting there reading this screen, blood is flowing throughout your body. Your veins carry this blood towards your heart to keep you alive. When something clogs them up, things can get pretty dangerous.

Thrombosis is the term used for the development of blood clots within deep veins in your body. It often occurs in the legs and, more specifically, is called deep vein thrombosis (DVT). It is most often caused by blood clotting disorders, but it can also happen if you stay sedentary for too long. Blood clots are dangerous because they can break apart, travel throughout the body, and cause blockages in the heart, brain, or lungs (leading to heart attack, stroke, or pulmonary embolism, respectively).

Causes of Thrombosis

Thrombosis is caused by blood clots forming in deep veins, most often in the legs. Blood clots can form whenever there is any condition that prevents blood from circulating or clotting normally. For example, they can happen to people who tend to lack physical movement after an accident, injury, surgery, or during bed rest.

Symptoms of Thrombosis

The two main symptoms of thrombosis are pain and swelling. The pain in the affected area (usually the leg) begins like a cramp and may intensify. Swelling occurs in the vicinity of the blood clot. In rare cases, there may be no symptoms at all.

The most serious symptoms may result from the formation of a pulmonary embolism, when arteries in the lungs become blocked by a blood clot. This can include sudden difficulty breathing, chest pain that gradually intensifies or gets worse when breathing in, dizziness, lightheadedness, increased heart rate, and coughing up blood. All symptoms require physician attention, but a pulmonary embolism requires immediate medical attention.

Risk Factors

There are certain variables that increase the probability of developing thrombosis. These include:

  • Inheriting a genetic blood-clotting disorder that causes the blood to clot more easily than normal
  • Extended periods of bed rest that prevent blood from circulating through the legs properly
  • Injury or surgery
  • Pregnancy and being overweight or obese, conditions which cause an increase in pressure in the lower body
  • Birth control pills or hormone therapy
  • Smoking
  • Cancer
  • Heart failure
  • Inflammatory bowel disease
  • Age
  • Sitting for extended periods of time (like flying or driving)

This list is not exhaustive but provides many of the commonly reported problems that often lead to thrombosis.

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