What You Should Know About Thromboembolism

Thromboembolism is the ungainly name given to the condition in which a blood clot that has formed inside a blood vessel (or inside the heart) subsequently breaks off, travels through the bloodstream, and plugs another blood vessel, causing organ damage.

Artwork showing a blood clot traveling through a vessel
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The word “thromboembolism” combines the words “thrombus” and “embolus.” A blood clot that forms inside the vascular system is called a thrombus. When it breaks off, travels through the bloodstream, and lodges elsewhere, that same blood clot is now referred to as an embolus. “Thromboembolism” combines the entire process into one word.

The Link Between DVT and Pulmonary Embolus

When doctors use the word thromboembolism, they are usually referring to the conditions deep venous thrombosis (DVT) and pulmonary embolus. The fact that these two conditions are so closely related accounts for the term “thromboembolism” being created in the first place.

In DVT, blood clots develop in the deep leg veins. DVT itself often causes severe symptoms, such as pain, swelling, and redness in the affected leg. DVT commonly occurs in people who have been sitting or otherwise immobilized for long periods of time. A long overseas flight where people are crammed into uncomfortable seats for many hours often becoming dehydrated at the same time is the most common example given.

However, the most frequent causes of DVT are related to underlying medical problems, such as recent surgery, cancer, bone fracture, stroke, paralysis or trauma. The risk of DVT also becomes elevated with heart disease, obesity, and in smokers.

While DVT is a problem all by itself, its major significance is that it often causes a pulmonary embolus. That is, part of the thrombus that has formed in the leg veins breaks loose and travels through the venous system, through the right side of the heart, and into the pulmonary artery where it lodges, and cuts off blood flow to a portion of the lungs.

While a small pulmonary embolus may not produce much in the way of symptoms, not uncommonly the embolus causes several symptoms which may include shortness of breath, chest pain, wheezing, cough, and bloody sputum. If the embolus is large enough it can produce death.

Generally, when doctors say “thromboembolism” they are referring to this complex problem of DVT and either an actual pulmonary embolus or the fear of an imminent pulmonary embolus. Because a pulmonary embolus is often a devastating condition when a DVT is suspected, doctors usually work hard to make a firm diagnosis and institute therapy right away with anticoagulant drugs.

Stroke Caused by Atrial Fibrillation

While “thromboembolism” almost always means DVT and pulmonary embolus to doctors, there is another kind of thromboembolism—namely a stroke caused by atrial fibrillation.

Atrial fibrillation is a common cardiac arrhythmia in which blood clots tend to form within the left atrium of the heart. (That is, there is a thrombus in the left atrium). All too often, a clot will embolize to the brain, producing a stroke. Preventing stroke is probably the most important aspect of treating a person with atrial fibrillation. This is, in fact, another example of thromboembolism that's important to be aware of.

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