Pulmonary embolus

Answer 1

Definition

A pulmonary embolus is a blockage of an artery in the lungs by fat, air, a blood clot, or tumor cells.

Alternative Names

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

Causes, incidence, and risk factors

A pulmonary embolus is most often caused by a blood clot in a vein, especially a vein in the leg or in the pelvis (hip area). The most common cause is a blood clot in one of the deep veins of the thighs. This type of clot is called a deep vein thrombosis(DVT).

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

Risk factors for a pulmonary embolus include:

• Burns
• Cancer
• Childbirth
• Family history of blood clots
• Fractures of the hips or femur
• Heart attack
• 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
• Stroke
• Surgery (especially orthopedic or neurological surgery)
• Use of Birth Control pills or estrogen therapy

People with certain clotting disorders may also have a higher risk.

Symptoms

• Chest pain
  • Under the breastbone or on one side
  • Especially sharp or stabbing
  • May also be described as a burning, aching, or dull, heavy sensation
  • May get worse with deep breathing, coughing, eating, bending, or stooping
  • You may bend over or hold his or her chest in response to the pain
• Cough
  • Begins suddenly
  • May cough up blood or blood-streaked sputum
• Rapid breathing
• Rapid heart rate
• Shortness of breath
  • May occur at rest or during activity
  • Starts suddenly

Other symptoms that may occur:

• Anxiety
• Bluish skin discoloration (cyanosis)
• Clammy skin
• Dizziness
• Leg pain in one or both legs
• Lightheadednessor fainting
• Low blood pressure
• Lump associated with a vein near the surface of the body, may be painful
• Nasal flaring
• Pelvis pain
• Sweating
• Swelling in the legs
• Weak or absent pulse
• Wheezing

Signs and tests

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
• Pulmonary angiogram

Other tests that may be done include:

• Chest CT scan
• Chest MRI scan
• D-dimer level
• Doppler ultrasound exam of an extremity
• ECG
• Echocardiogram
• Plethysmographyof the legs
• Venography of the legs

Treatment

Emergency treatment and a hospital stay are often necessary. The goal is to stabilize your cardiovascular system and to prevent new clots from forming. Oxygen therapy may be required to maintain normal oxygen levels.

In cases of severe, life-threatening pulmonary embolism, treatment may involve dissolving the clot and preventing new clots from forming.

Treatment to dissolve clots is called thrombolytic therapy. Clot-dissolving medications include:

• Streptokinase
• t-PA

Treatment to prevent clots is called anticoagulation therapy. Such drugs are commonly called blood thinners. The most commonly used clot-prevention medicines are heparin and warfarin (Coumadin). Fondaparinux (Arixtra) is a newer blood thinner used under special circumstances. Heparin or heparin-type drugs can be given intravenously (by IV, directly into a vein), or as injections under the skin. These are usually the first medications given, and are then transitioned over to warfarin given in pill form.

When you first start taking warfarin, you will need frequent lab tests to check the thickness of your blood. This will help your doctor properly adjust your dose.

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 central 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.

Expectations (prognosis)

It is difficult to predict how well a patient will do. Often, the outlook is related to what put the person at risk for pulmonary embolism (for example, cancer, major surgery, or trauma).

In cases of severe pulmonary embolism, where shock and heart failure occur, the Death Rate may be greater than 50%.

Complications

• Heart failure or shock
• Heart palpitations
• Pulmonary hypertension
• Severe breathing difficulty
• Severe bleeding (usually a complication of treatment)
• Sudden death

Calling your health care provider

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

Prevention

Preventing deep venous thrombosis (DVT) is very important, especially in people at high risk. To help prevent DVT, move your legs often or take a stroll during long plane trips, car trips, and other situations in which you are sitting or lying down for long periods of time. Walking and staying active as soon as possible after surgery or during a long-term medical illness can also reduce your risk.

Heparin therapy (low doses of heparin injected under the skin) may be prescribed for those on prolonged bedrest.

Sometimes patients in the hospital wear special soft boots that automatically (and gently) squeeze the calves periodically. This is called intermittent pneumatic compression. It helps keep blood moving and prevents blood clotting.

References

Anderson DR, Kahn SR, Rodger MA, et al. Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial.JAMA. 2007;298(23):2743-2753.

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.

Snow V, Qaseem A, Barry P, et al. Management of venous thromboembolism: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. 2007;146(3):204-210.

Tapson VF. Pulmonary embolism. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 99.

Answer 2

Definition

A pulmonary embolus is a blockage of an artery in the lungs by fat, air, a blood clot, or tumor cells.

Alternative Names

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

Causes, incidence, and risk factors

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

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

Risk factors for a pulmonary embolus include:

• Burns
• Cancer
• Childbirth
• Family history of blood clots
• Fractures of the hips or thigh bone
• Heart attack
• 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
• Stroke
• Surgery (especially orthopedic or neurological surgery)
• Use of birth control pills or estrogen therapy

People with certain clotting disorders may also have a higher risk.

Symptoms

• Chest pain
  • Under the breastbone or on one side
  • May feel sharp or stabbing
  • May also be described as a burning, aching, or dull, heavy sensation
  • May get worse with deep breathing, coughing, eating, or bending
  • You may bend over or hold your chest in response to the pain
• Sudden cough, possibly coughing up blood or bloody mucus
• Rapid breathing
• Rapid heart rate
• Shortness of breath that starts suddenly

Other symptoms that may occur:

• Anxiety
• Bluish skin discoloration (cyanosis)
• Clammy skin
• Dizziness
• Leg pain, redness, and swelling
• Lightheadednessor fainting
• Low blood pressure
• Sweating
• Wheezing

Signs 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:

• Chest CT scan
• D-dimer level
• Doppler ultrasound exam of the legs
• Echocardiogram

Treatment

A pulmonary embolus requires emergency treatment. You will have to stay in the hospital. You will receive oxygen.

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

• Streptokinase
• T-plasminogen activator (t-PA)

Blood thinners are given to prevent 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 usually tried first. They can be given through a vein (by IV) or by injection under the skin.

Warfarin is later given in pill form. 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.

Expectations (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.

Complications

• Heart failure or shock
• Heart palpitations
• Pulmonary hypertension
• Severe breathing difficulty
• Severe bleeding (usually a complication of treatment)
• Sudden death

Calling your health care provider

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

Anderson DR, Kahn SR, Rodger MA, et al. Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial.JAMA. 2007;298(23):2743-2753.

Kline JA, Courtney DM, Kabrhel C, et al. Prospective multicenter evaluation of the pulmonary embolism rule out criteria. J Thromb Haemost. 2008;6(5):772-780.

Lim W, Crowther MA, Ginsberg JS. Venous thromboembolism. In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier; 2008:chap 135.

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.

Snow V, Qaseem A, Barry P, et al. Management of venous thromboembolism: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. 2007;146(3):204-210.

Tapson VF. Pulmonary embolism. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 99.

Reviewed By

Review Date: 02/28/2011

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., Inc.