A pulmonary embolism is a blockage of an artery in the lungs. It is caused by a clot that travels through the bloodstream to the lungs. Once the clot is stuck in a lung artery, it blocks the blood from nourishing that lung. The tissues on the other side of the blockage may die if it doesn't receive enough blood from other sources. The lung may become damaged and stop working properly. In severe cases this can lead to death.
An embolism occurs when a clot moves through the bloodstream from the location where it was formed and becomes stuck in a blood vessel. An embolus, can be a blood clot, air bubble, or piece of fat, bone marrow, or tumor tissue.
The embolus in a
is usually a blood clot. A blood clot that forms and remains in a vein is called a thrombus. It most often starts in a vein in the legs or pelvis.
—a blood test to identify oxygen levels and other gases that are indicators of lung function
—a test that uses radiation to take a picture of structures inside the chest. A pulmonary embolism cannot be seen on the chest x-ray. But, if a part of the lung tissue dies, this can be seen on the x-ray.
Lung perfusion scan—a test that uses radioactive isotopes to measure breathing and circulation in all areas of the lungs. The presence of an embolus will show as a mismatch between ventilation of the portion of the lung and its blood perfusion.
CT scan of the chest
—a type of x-ray that uses a computer to make pictures of the inside of the chest. A spiral CT is a special type of CT scan that is able to make tri-dimensional pictures. It is also a very fast scan that can be completed in a very short period of time. It has become popular in diagnosing pulmonary embolism.
x-rays taken after a dye is injected into the blood vessels in the lungs. The test shows areas of blockage in the lungs. It provides a clear picture of blood flow through the arteries. But, this test is associated with relatively high risks.
(MRA)—Using this test to diagnose MRA is limited. But, it may be more useful in the future as the technology advances.
(ECG, EKG)—a test that records the heart's activity by measuring electrical currents through the heart muscle. In case of pulmonary embolism,
(rapid heart beat) is frequently seen, as well as several rhythm patterns. These results can help in the diagnosis.
—a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart. This test may be helpful in a small percentage of patients.
D-Dimer (a clot dissolving substance) blood test—Increased levels in the blood may suggest the presence of a clot. This test is nonspecific, though. A lot of conditions may cause the level to be elevated.
If you have a family history of blood clots and had a few instances of blood clots for no apparent reason, your doctor may order additional blood tests. The tests will look for possible inherited defects in your clotting system. The two most frequent genetic abnormalities that increase your risk of forming blood clots are:
Factor V Leiden mutation (seen in up to 40% of cases)
Increased factor VIII
Additional tests—to check blood flow or look for clots in the veins, especially in the legs
Treatment depends on the size and severity of the clot. Emergency treatment and hospitalization may be needed.
Thrombolytic medicine to dissolve clots, for example:
Streptokinase (Kabikinase, Streptase)
Tissue plasminogen activator
Anticoagulant medicine, called blood thinners (eg,
), to prevent more clots from forming
In some cases when the blockage is very large, a type of surgery called embolectomy may be done to remove it.
If you have a repeated problem with blood clots, surgery may be done to place a filter in the main vein that leads from the legs to the heart and lungs. This filter traps clots before they can reach the lungs.
If you are diagnosed with pulmonary embolism, follow your doctor's
Prevention of pulmonary embolism means preventing clots from forming.
You can help prevent clots with a healthful lifestyle:
Qaseem A, Snow V, Barry P, et al. Current diagnosis of venous thromboembolism in primary care: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians.
Ann Intern Med
Rosendaal FR. Venous thrombosis: a multicausal disease.
Rubini G, Niccoli A, Stabile A, et al. Acute pulmonary embolism: comparison and integration of perfusion lung scintigraphy with multislice spiral CT.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a