Pulmonary Embolism: Causes, Symptoms, Diagnosis, Treatment, and Prevention

Pulmonary embolism is a condition characterized by a sudden blockage in the artery of the lungs, usually caused by a blood clot that breaks loose and travels through the bloodstream.

Pulmonary embolism can be life-threatening, especially if the clot is large or are many in number. This is because the clot will obstruct the blood flow to the lungs.

If diagnosed late or left untreated, the blockage can lead to death. However, immediate medical treatment decreases the odds of permanent lung damage.

Research says that about one-third of people with undiagnosed and untreated pulmonary embolism don’t survive. 

What Causes Pulmonary Embolism?

Blood clots can form due to a variety of factors, including:

  • Deep vein thrombosis: About 90% of cases of pulmonary embolism are caused by a thrombus or blood clot formed in the deep veins. 
  • Fat emboli: Fat emboli generally occur after fractures to the long bones of the lower body, specifically the femur (thighbone), tibia (shinbone), and pelvis.
  • Tumors: Cancer cells cause damage to the tissues in your body, which leads to swelling and triggers clotting. Tumors also produce chemicals that cause blood clots.
  • Sickle cell disease: When patients suffer an acute phase of the occlusive crisis, and the sickle-shaped cells become deposited, forming a clot.
  • Amniotic fluid: Amniotic fluid could also make its way to the lung and form emboli.
  • Endocarditis: Endocarditis can create lumps of blood and bacteria to develop in the blood vessels of the heart. These clumps, called vegetations, can break off and form a blood clot. Endocarditis is a rare cause of pulmonary embolism.

Who Is At Risk?

Certain factors that may put an individual at more risk of developing the condition include:

  • Cancer
  • Heart disease
  • Age over 60 years
  • Smoking
  • Obesity 
  • Prolonged immobility
  • Surgery
  • Pregnancy
  • Taking testosterone or estrogen
  • A family history of embolisms
  • Supplemental oxygen
  • Fractures of the leg or hips

What Are The Symptoms Of Pulmonary Embolism?

The symptoms of a pulmonary embolism depend upon the size of the clot and the location in the lungs where it has lodged. 

Shortness of breath is one of the most common symptoms of pulmonary embolism. This may be sudden or gradual.

Other common symptoms of pulmonary embolism include:

  • Cough
  • Chest pain
  • Rapid heartbeat
  • Chest pain that can extend to your shoulder, arms, jaw, or neck
  • Fever
  • Pain or swelling in the legs
  • Dizziness
  • Excessive sweating
  • Clammy or bluish discoloration of the skin
  • Spitting up blood
  • Restlessness
  • Fainting 

If you experience any one or more of these symptoms, especially shortness of breath, seek medical assistance immediately. 

How Is Pulmonary Embolism Diagnosed?

To confirm the diagnosis, your healthcare provider may order the following tests:

  • D-dimer blood test: To check for the levels of a clot-dissolving substance called D dimer in your blood; high levels of this substance may indicate an increased risk of blood clots.Blood tests can also measure the amount of oxygen and carbon dioxide in the blood. If a clot is present in a blood vessel in your lungs, it may reduce the concentration of oxygen in your blood. 
  • Chest X-ray: To view images of your lungs and heart and rule out the possibility of other conditions that mimic pulmonary embolism. 
  • Ultrasound: An ultrasound procedure called duplex ultrasonography to look for any blood clots in your thigh veins
  • Pulmonary angiography: To have a clear picture of the blood flow in the arteries to the lungs
  • Spiral CT scan: To view the cross-sectional images of your lungs and detect artery abnormalities.
  • Pulmonary Ventilation-perfusion scan (V/Q scan): To check which part of your lungs are getting adequate blood flow and airflow
  • MRI: This may be a great option if you’re pregnant or if your healthcare provider is concerned that other tests that use contrast might be unsafe for you.

Also Read: All You Need To Know About Chronic Obstructive Pulmonary Disease

How Is Pulmonary Embolism Treated?

Pulmonary embolism treatment is generally provided in a hospital so that your condition could be closely monitored. The length of your pulmonary embolism treatment and your hospital stay can vary depending upon the severity of the clot.

There are various treatment options available, including blood thinner (anticoagulant) medications, compression stockings, thrombolytic therapy, and sometimes surgery or non-invasive procedures to increase blood flow and minimize the odds of future blood clots.

Blood Thinner Medications

These medications prevent existing clots from expanding and new clots from forming while your body endeavors to break up the clots.

Anticoagulant medications include warfarin, heparin, low-molecular-weight heparin, and fondaparinux. 

  • Warfarin comes in the form of tablets and is taken orally (i.e., by mouth).
  • Heparin is a liquid medication, which is given either through an intravenous line that injects medication straight into the vein or by subcutaneous injections given in the hospital.
  • Low molecular weight heparin is administered beneath or under the skin (subcutaneously). It is given 1-2 times a day and can be taken at home.
  • Fondaparinux (Arixtra) is a new drug that is injected subcutaneously once a day.

Your healthcare specialist will let you know how to take anticoagulants correctly. Like with any medication, these medications need to be taken as prescribed for achieving the desired effect. 

The type of medication, how long to take it, and the follow-up care you’ll need depends on your diagnosis.

Make sure to keep all follow-up appointments scheduled with your healthcare provider and the laboratory so your response to the medications could be monitored carefully.

While taking anticoagulant medications, your follow-up will include certain blood tests, including:

  • PT-INR (The Prothrombin time (PT) / International Normalized Ratio (INR) test): It helps your doctor determine how fast your blood is clotting and if the dosage of your medication needs to be altered.This test is used to check your condition if you are taking Coumadin.
  • Activated partial thromboplastin (aPTT): It measures the time it takes for the blood to clot. This test is used to check your condition if you are taking heparin.
  • Anti-Xa or Heparin assay: It measures the level of low molecular-weight heparin in the blood. It is often not required to use this test unless you have kidney disease, are overweight, or are pregnant.

Other Alternatives For Pulmonary Embolism Treatment

Compression Stockings

Compression stockings constantly squeeze your legs, supporting your veins and leg muscles to move blood more efficiently. They provide a safe, straightforward and inexpensive way to keep blood from pooling during and after general surgery.

Talk to your doctor to know more about how to use compression stockings, for how long, and how to care for them. It is essential to launder them as instructed to prevent damaging them.


If your condition is life-threatening, or if other treatments fail to work, your healthcare provider may recommend:

  • Surgery to take off the embolus from the pulmonary artery.
  • A non-intrusive procedure in which a filter is placed inside the body’s largest vein (called vena cava filter), so clots can be entrapped before they enter the lungs.

Thrombolytic Therapy

Thrombolytic medications (clot dissolvers) such as tissue plasminogen activator (TPA) are used to dissolve the clot. It is always given in a hospital so your doctor can closely monitor you.

These medications are specially used if your blood pressure is low or if your condition is unstable due to pulmonary embolism. 

How To Prevent Pulmonary Embolism?

The best possible way to prevent pulmonary embolism is to reduce the risk of developing blood clots and deep vein thrombosis (DVT). Consider the following preventive measures:

  • Daily physical activity: If you remain inactive at your desk every day for an extended period, you should stand frequently, stretch yourself, and take occasional walking breaks.You can also flex and move your legs and feet while sitting at your desk. These small activities can increase and promote healthy blood circulation and prevent pulmonary embolism. 
  • Weight management: Being overweight or obese puts excess pressure on the veins in your legs, contributing to inadequate blood flow and the development of blood clots.Losing a few pounds can help prevent pulmonary embolism by lowering your blood pressure and improving blood flow.  
  • Mobility after surgery: People who are at significant risk for blood clots may be prescribed anticoagulants or blood-thinning drugs before and after any surgery.This minimizes the risk of blood clots forming during recovery when you might be lying in bed for prolonged periods of time.

    If you are having surgery, our doctors and nurses will encourage you to get up and walk and move around once they feel it’s safe to do so.

  • Travel precautions: Long plane and car rides can force you to sit in one position, but you must find the best ways to move as much as possible. Avoid sitting with your legs crossed for a long period.If you are on a flight, lift your knees and rotate your ankles to keep blood moving while you’re sitting. Whenever feasible, stand up and walk. If you’re traveling by car, take frequent breaks to stretch your legs and move around. 
  • Smoking cessation: Toxic chemicals found in cigarettes harm blood cells and blood vessels and make you more prone to deep vein thrombosis (DVT) and pulmonary embolism.Quitting smoking can help you prevent pulmonary embolism effectively.
  • Hormonal supplements: Oral contraceptives or hormone replacement therapy puts people at an elevated risk for blood clots and pulmonary embolism, especially if they are overweight or smoke.Talk to your doctor to determine whether these treatments are safe for you and also ask about any alternative treatments.


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Janet Fudge

Janet Fudge writes on general health topics for CheapMedicineShop.com. She holds a post-graduate diploma in Public Health with a major in epidemiology. During the outbreak of COVID-19, Janet actively volunteered in vaccination drives throughout the state of Iowa. She lives in Iowa with her husband and two children.