A pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.
Venous thromboembolism; Lung blood clot; Blood clot - lung; Embolus; Tumor embolus; Embolism - pulmonary
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)
- 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
- 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.
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:
- Bluish skin color(cyanosis)
- Clammy skin
- Leg pain, redness, or swelling
- Low blood pressure
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:
- Chest x-ray
- CT angiogram of the chest
- Pulmonary ventilation/perfusion scan, also called a V/Q scan
- Pulmonary angiogram
Other tests that may be done include:
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:
- Tissue plasminogen activator (t-PA)
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.
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.
- Coughing up blood
- Heart failure or shock
- Heart palpitations
- Pulmonary hypertension
- 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.
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
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.
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.
Weitz JI. Pulmonary embolism. In: Goldman L, Schafer AI,eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 98.
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.