Pulmonary Embolism


A pulmonary embolism is a blockage of an artery in the lungs. The embolism prevents blood and nourishment from getting to a specific area of the lungs. This may lead to the death of lung tissue in this area. Damage to the lungs may make it difficult for the lungs to work properly. In severe cases, a pulmonary embolism can lead to death.
Pathway of Pulmonary Embolism
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An embolism is caused by a lump of material, called an embolus, that is floating in the blood. The embolus is usually a blood clot, but can also be an air bubble, a piece of fat, bone marrow, or tumor tissue. The embolus travels from its original location and passes through larger blood vessels until it gets stuck in a smaller blood vessel. In this case, the embolus is trapped in an artery of the lungs.
A pulmonary embolism from a blood clot most often starts in a vein in the legs or pelvis.

Risk Factors

Factors that may increase your chance of a pulmonary embolism include:


The symptoms of a pulmonary embolism vary depending on the size and location of the blockage. The area of lung affected by the lack of blood will also affect the symptoms. Pulmonary embolism may cause:


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your doctor may order the following tests:
Imaging tests evaluate the lungs and surrounding structures. These may include:


Treatment depends on the size and severity of the clot. Emergency treatment and hospitalization may be needed.
Emergency treatment for shock may include IV fluids, medications, and oxygen therapy.
Treatment includes medication, and in some cases, surgery.


Medications called anticoagulants (blood thinners) are used to break up and control the clot. After the initial period, the blood thinner will be switched to a longer-acting anticoagulants.
Another type of medication may be needed to dissolve the clot. These are called thrombolytics. This type of medication is usually only used in people with a pulmonary embolism that is very large or is causing severe illness. Thrombolytics will not be used if you have a high risk of bleeding.


Surgery to remove the clot may be needed if the blockage is very large, not responding to treatment, or the person is in shock. The surgery is called an embolectomy.

Clot-Trapping Filter

Some people may have repeated problems with blood clots. Others cannot take anticoagulant medications. In these cases, a surgical procedure will be done to place a filter in the main vein of abdomen (vena cava). The filter will trap clots before they can travel to the lungs.


To help reduce your chance of a pulmonary embolism:
People at high risk of developing blood clots can do the following:


American Lung Association

American Society of Hematology


Health Canada

The Lung Association


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