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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: March 4, 2012.

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

Causes

Most of the time, a pulmonary embolus occurs when a blood clot from another part of the body breaks off and travels to the lungs and lodges in an artery. This kind of clot often starts in a vein in the leg or hip area. It is called a deep vein thrombosis (DVT).

You are more likely to have this problem if you have a history of blood clots yourself or you have a family history of blood clots. You may have a blood clotting disorder.

Other risk factors for a pulmonary embolus include:

  • Being ill in the hospital
  • Cancer (that is active)
  • Childbirth
  • Fractures of the hips or thigh bone
  • Heart attack or stroke
  • Heart surgery
  • Long-term bed rest or staying in one position for a long time, such as a long plane or car ride
  • Severe injury or burns
  • Smoking
  • Surgery (especially orthopedic or neurological surgery)
  • Use of birth control pills or estrogen therapy

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

Symptoms

Chest pain that:

  • Occurs under the breastbone or on one side
  • Most often feels sharp or stabbing
  • May be feel like a burning, aching, or dull, heavy sensation
  • Often gets worse with deep breathing
  • May cause you to bend over or hold your breath in response to the pain
  • Sudden cough, possibly coughing up blood or bloody mucus
  • Fast breathing
  • Fast heart rate
  • Shortness of breath that starts suddenly

Other symptoms may include:

  • Anxiety
  • Bluish skin color(cyanosis)
  • Clammy skin
  • Dizziness
  • Fainting
  • Leg pain, redness, or swelling
  • Lightheadedness
  • Low blood pressure
  • Sweating
  • Wheezing

Exams and Tests

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

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

  • Arterial blood gases
  • Pulse oximetry

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 emergency treatment. You may need to stay in the hospital. You will receive oxygen if your oxygen level is low.

In cases of severe, life-threatening pulmonary embolism, treatment may involve dissolving the clot. This is called thrombolytic therapy. Clot-dissolving medications include:

Blood thinners are given to prevent new clots. This is called anticoagulation therapy.

  • The most common blood thinners are heparin and warfarin (Coumadin).
  • Fondaparinux (Arixtra) is a newer blood thinner used under special circumstances.

Heparin or heparin-type drugs are almost always tried first. They can be given through a vein (by IV) or by injection under the skin.

Warfarin is usually start at the same time. It is a pill. When you first start taking warfarin, you will need frequent blood tests. This will help your doctor properly adjust your dose. You will likely need to take the warfarin for several months.

Patients who have reactions to heparin or related medications may need other medications.

Patients who cannot tolerate blood thinners or for whom they may be too risky may need a device called an inferior vena cava filter (IVC filter). This device is placed in the main vein in the belly area. 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.)

Death is possible in people with a severe pulmonary embolism.

Possible Complications

  • Coughing up blood
  • Heart failure or shock
  • Heart palpitations
  • Severe breathing difficulty
  • Severe bleeding (usually a complication of treatment)
  • Sudden death

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

Doctors may prescribe blood thinners 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 for 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 of time can also help prevent DVT. People at very high risk for blood clots may need heparin shots when they are on a flight that lasts longer than 4 hours.

Do not smoke. If you smoke, quit. Women who are taking estrogen must stop smoking. See: Smoking - tips on how to quit

References

  1.  
  2. Guyatt GH, Akl EA, Crowther M. et al. Executive Summary: AntithromboticTherapy 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]
  3. Righini M, Le Gal G, Aujesky D, et al. Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial. Lancet. 2008;371(9621):1343-1352. [PubMed: 18424324]
  4. Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI,eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 98.

Review Date: 3/4/2012.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.

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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.

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  • Blood thinners for the prevention of blood clots in children with central venous lines
    Over the last 10 years, the number of children found to have blood clots in their blood vessels, called veins, has become more common. As blood clots can either block these vessels and change their normal blood flow or shower pieces into other veins placed in important organs, serious health problems including death can occur. Venous clots are usually found in children with plastic tubes placed inside their blood vessels, called central lines, which are inserted to help or save the patient's life. However, these lines can also cause blood clots. We do not know if giving a medication to protect against blood clots, called an anticoagulant or low molecular weight heparin (LMWH), would protect against the clots. Therefore, we looked at all the research in children with central lines who received, or not, LMWH and only found one study with a total of 186 participants. This study did not have enough participants to show if this medication protects children with central lines from getting blood clots. The study also did not show that children on LMWH, at the doses given, experience too much bleeding because of its use. The included study did not report any additional adverse events. There were two deaths within the study in the standard care arm, and neither were due to a blood clot. Future studies looking at the role of this medication (LMWH) and if it protects children with central venous lines from getting blood clots are needed.
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    Respiratory system.
    Pulmonary embolus.

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