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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Pulmonary embolus

Venous thromboembolism; Lung blood clot; Blood clot - lung; Embolus; Tumor embolus; Embolism - pulmonary

Last reviewed: February 13, 2014.

A pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.

Causes

A pulmonary embolus is most often caused by a blood clot in a vein. The most common blood clot is one in a deep vein of the thigh or in the pelvis (hip area). This type of clot is called a deep vein thrombosis (DVT). The blood clot breaks off and travels to the lungs.

Less common causes include air bubbles, fat droplets, amniotic fluid, or clumps of parasites or tumor cells.

You are more likely to get this condition if you or your family have a history of blood clots or certain clotting disorders. A pulmonary embolus may occur:

  • After childbirth
  • After heart attack, heart surgery, or stroke
  • After severe injuries, burns, or fractures of the hips or thigh bone
  • After surgery, most commonly bone, joint, or brain surgery
  • During or after a long plane or car ride
  • If you have cancer
  • If you take birth control pills or estrogen therapy
  • Long-term bed rest or staying in one position for a long time

Symptoms

Main symptoms include chest pain that may be any of the following:

  • Under the breastbone or on one side
  • Sharp or stabbing
  • Burning, aching, or dull, heavy sensation
  • Usually gets worse with deep breathing
  • You may bend over or hold your chest in response to the pain

Other symptoms may include:

  • Bluish skin (cyanosis)
  • Dizziness, lightheadedness, or fainting
  • Fast breathing or wheezing
  • Fast heart rate
  • Feeling anxious
  • Leg pain, redness, or swelling
  • Low blood pressure
  • Sudden cough, possibly coughing up blood or bloody mucus
  • Shortness of breath that starts suddenly
  • Sweating, clammy skin

Exams and Tests

The health care provider will perform a physical exam and ask about your symptoms and medical history.

The following lab tests may be done to see how well your lungs are working:

The following imaging tests can help determine where the blood clot is located:

Other tests that may be done include:

Treatment

A pulmonary embolus requires treatment right away. You may need to stay in the hospital:

  • You will receive medicines to thin the blood (to make it less likely your blood will form more clots).
  • In cases of severe, life-threatening pulmonary embolism, treatment may involve dissolving the clot. This is called thrombolytic therapy. You will receive medicines to dissolve the clot.

Whether or not you need to stay in the hospital, you will likely need to take medicines at home to thin the blood:

  • You may be given pills to take or you may need to give yourself injections.
  • For some medicines, you will need blood tests to monitor your dosage.
  • How long you need to take these medicines depends mostly on the cause and size of your blood clot.
  • Your health care provider will talk to you about the risk of bleeding problems when you take these medicines.

If you cannot take blood thinners, your doctor may suggest surgery to place a device called an inferior vena cava filter (IVC filter). This device is placed in the main vein in your belly. It keeps large clots from traveling into the blood vessels of the lungs. Sometimes a temporary filter can be placed and removed later.

Outlook (Prognosis)

How well a person recovers from a pulmonary embolus can be hard to predict. It often depends on:

  • What caused the problem in the first place (for example, cancer, major surgery, or an injury)
  • The size of the blood clot in the lungs
  • If the blood clot dissolves over time

Some people can develop long-term heart and lung problems.

Death is possible in people with a severe pulmonary embolism.

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of pulmonary embolus.

Prevention

Blood thinners may be prescribed to help prevent DVT in people at high risk, or those who are undergoing high-risk surgery.

If you had a DVT, your doctor will prescribe pressure stockings. Wear them as instructed. They will improve blood flow in your legs and reduce your risk of blood clots.

Moving your legs often during long plane trips, car trips, and other situations in which you are sitting or lying down for long periods can also help prevent DVT. People at very high risk of blood clots may need shots of a blood thinner called heparin when they take a flight that lasts longer than 4 hours.

Do not smoke. If you smoke, quit. Women who are taking estrogen must stop smoking.

References

  1. Guyatt GH, Akl EA, Crowther M, et al. Executive summary: antithrombotic therapy and prevention of thrombosis, 9th ed. American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2012;141(2suppl):7s-47s. [PMC free article: PMC3278060] [PubMed: 22315257]
  2. Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 98.

Review Date: 2/13/2014.

Reviewed by: Allen J. Blaivas, DO, Clinical Assistant Professor of Medicine UMDNJ-NJMS, Attending Physician in the Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Veteran Affairs, VA New Jersey Health Care System, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

What works?

  • Duration of treatment with oral anticoagulants for the treatment and prevention of recurrence of deep vein thrombosis and pulmonary embolismDuration of treatment with oral anticoagulants for the treatment and prevention of recurrence of deep vein thrombosis and pulmonary embolism
    Venous thromboembolism (VTE) occurs when a blood clot is formed in a deep vein or when it detaches itself and lodges in the lung vessels. These clots can be fatal if the blood flow to the heart is blocked. Vitamin K antagonists (VKA) are given to people who have experienced a VTE, to prevent recurrence. The major complication of this treatment is bleeding. The continuing risk of bleeding with drug use and uncertainty regarding the extent of the risk of recurrences makes it important to look at the proper duration of treatment with VKA for these patients. The review authors searched the literature and were able to combine data from eight randomized controlled clinical trials (2994 patients) comparing different durations of treatment with VKA in patients with a symptomatic VTE. Patients on prolonged treatment had a more than five times lower risk of recurrences. On the other hand, they had an almost three times higher risk of bleeding complications. The prolonged use of vitamin K antagonists reduced the risk of recurrent clots as long as they were used but the benefit decreased over time and the risk of major bleeding remained.
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Figures

  • Lungs.
    Respiratory system.
    Pulmonary embolus.

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