What is a thrombus?

A thrombus is less likely to occur in people who are mobile and who exercise regularly. (Photo: pixabay.com)

A thrombus is a blood clot in the vascular system (circulatory system). It stays attached to the site where it was formed and impedes blood flow. Under these circumstances, a person is said to be experiencing a thrombosis.

A thrombus is more likely to occur in people who are immobile, and who are genetically predisposed to blood clotting. A thrombus can also form if an artery, vein, or surrounding tissue is damaged.

Blood clots and thrombus types

A blood clot is usually a healthy physical response to injury. It quickly forms a plug that can reduce or even prevent bleeding.
A bit of blood clot that breaks free from the thrombus site and circulates in the bloodstream is called an embolus. An embolus moves through the vascular system until it eventually becomes lodged. An embolus is a dangerous and potentially fatal complication of thrombosis, especially if the embolus reaches the heart, lungs, or brain. When this happens, the person is said to be experiencing an embolism.

A thrombus is a problem because it impedes the function of a blood vessel. The effect of a thrombus on the body depends on its location. When a thrombus forms in an artery, such as in the heart or brain, it is called an arterial thrombosis. When a thrombus occurs in a vein, it is called a venous thrombosis. When this happens in the deep veins of the leg, it is called deep vein thrombosis (DVT).

Thrombus: its causes

Clotting is caused by chemical reactions between blood cells (platelets) and proteins (clotting factors). A healthy body regulates the clotting process as the body needs it.

The presence of any of the following factors are present can increase the risk of clot formation within a blood vessel:

•    tobacco smoking
•    high cholesterol
•    being obese or overweight
•    cancer
•    diabetes mellitus
•    stress
•    not exercising (sedentary lifestyle)

Some of these factors also increase the risk of atherosclerosis, a condition where the blood vessels become clogged with fatty plaque deposits. Atherosclerosis increases the risk of blood clots blocking the arteries, as well as the veins.

Symptoms of a thrombosis

Arterial and venous thrombosis can reduce or totally prevent blood flow. This can lead to severe and even life-threatening complications, depending on where the thrombus forms.

A thrombus does not usually cause any symptoms until it blocks or heavily restricts the flow of blood. Symptoms and complications of each type of thrombus are described below.

Symptoms of an arterial thrombosis

A thrombus in an artery can cause:
•    unstable angina, a type of chest pain
•    heart attack
•    ischemic stroke
•    peripheral arterial limb ischemia, where blood flow to the limbs is significantly reduced

These conditions all require prompt medical attention. People should seek emergency treatment if they experience any of the following symptoms:
•    chest pain
•    shortness of breath
•    the lower half of the face droops down on one side
•    sudden loss of strength in one arm or leg
•    a limb that has become cold, pale, and painful

Symptoms of a venous thrombosis

A thrombus in a vein, usually a deep vein in the leg, can cause the following symptoms:
•    pain, swelling, and tenderness, usually in the calf
•    an ache and warm sensation on the skin in the affected area
•    red skin, particularly at the back of the leg below the knee

People who experience any of these symptoms should see a doctor. A DVT can be a life-threatening condition; blood clots can break off and travel through the bloodstream before coming to block arteries higher up in the body.

Prevention measures

It is not always possible to prevent a thrombus from forming. However, there are steps that people can take to reduce their risk:
•    avoiding or quitting smoking tobacco products
•    maintaining a healthful weight
•    following a healthful diet
•    exercising regularly

It is particularly important for people to get up and move around whenever possible after a surgical procedure or during long-distance travel. Those who are known to be at an increased risk of developing a blood clot may also be given anticoagulant therapy, as well as medications to reduce blood pressure and cholesterol levels in the blood.


If a person gets the right treatment at the right time, then even potentially fatal medical emergencies associated with thrombosis can be successfully treated. Aftercare is of particular importance because complications can develop months or even years after the thrombus first formed, even after successful treatment.

Post-thrombotic syndrome is one of the potential complications of a DVT. This refers to the damage to surrounding tissue caused by the DVT formation, such as increase of pressure in the vein when blood flow is blocked, ulcerations, and pain. This can result in permanent damage, and under rare circumstances, the limb may even need to be removed.

Recovery depends on the location of the clot, as well as how much and for how long the blood flow was disrupted. The sooner the condition is dealt with, the less likely it is that long-term damage or complications will develop.

Author: Kanna Ingleson – 07/2017
Text abridged and adapted
With kind permission to publish from MNT
To read the complete article, please go to: Medical News Today

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