What Is Pulmonary Embolism? Symptoms, Causes, Diagnosis, Treatment, and Prevention

A pulmonary embolism, or PE, is a blood clot that breaks off and travels from one part of the body to the lungs, where it blocks blood flow. Most commonly, the blood clot originates in the deep veins of the legs, though it is possible the clot can form in a vein in another part of the body.

A pulmonary embolism is serious, and can cause damage to the heart and lungs and even death. But if caught early, PE can be treated and is not often fatal, according to the Cleveland Clinic. There are also steps you can take to reduce the risk of blood clots and PE.

Since a PE can be life-threatening without prompt medical treatment, it’s important to be aware of symptoms. These can vary greatly, depending on the size and severity of the blood clot.

According to Mayo Clinic, common signs of pulmonary embolism include:

• Shortness of breath, even while resting and gets worse with physical activity
• Chest pain that feels sharp and worsens when you take a deep breath, cough, or bend over
• Fainting from a sudden drop in heart rate or blood pressure

With a pulmonary embolism, you may also experience:

• A fever
• Dizziness or lightheadedness
• Leg pain or swelling
• Fast or irregular heartbeat
• Coughing up blood
• Excessive sweating
• Skin that is clammy or discolored

Not everyone with a PE will have symptoms, but most people do, per the Cleveland Clinic. If you have symptoms of a pulmonary embolism, seek medical treatment right away.

A PE is caused by a blood clot that forms in the body that moves to an artery in the lungs where it stops blood flow. Blood clots typically form in the deep veins of the legs, a medical condition called deep vein thrombosis, or DVT.

Anyone can develop DVT that can lead to a PE, but it is more common in certain populations. According to Mayo Clinic, risk factors for pulmonary embolism include:

• A past history of blood clots
• A genetic risk of blood clots (your parent or sibling has had blood clots, for example)
• Extended periods of inactivity, most commonly bed rest after surgery
• Certain medical conditions, including heart disease, cancer, COVID-19, kidney disease, and blood clotting disorders
• Taking birth control pills
• Hormone replacement therapy
• Pregnancy
• Being overweight or obese
• Smoking tobacco
• Long trips in a car or on a plane

A PE can sometimes be difficult to diagnose because symptoms are similar to many other conditions, per Johns Hopkins Medicine.

To diagnose a pulmonary embolism, a healthcare provider will take a full medical history and complete a physical exam. If your doctor suspects PE, one or more of the following tests may be ordered:

• Blood Tests These may include a D Dimer test, which measures the levels of a clot-dissolving substance in the blood. Other blood tests can determine the amount of oxygen in your blood and check for inherited clotting disorders.
• Ultrasound In this noninvasive test, a wand-shaped device scanned over the skin uses sound waves to check veins for deep vein blood clots in the thighs, knees, calves, and arms.
• Chest X-Ray This will allow your doctor to view images of your heart and lungs. A PE may not be visible on a chest X-ray, but it can help rule out other health conditions.
• CT Pulmonary Angiography This produces 3D images of the arteries in the lungs and can detect changes like PE. A contrast, or dye-like substance, is injected into a vein so the arteries can be seen more clearly.
• Ventilation-Perfusion Scan (VQ scan) This alternative test is used when a medically vulnerable person needs to avoid the radiation or contrast from a CT scan. With a VQ scan, only a small amount of radioactive substance is injected into the vein, which tracks airflow to the lungs.
• Pulmonary Angiogram A catheter (a thin, flexible tube) is inserted into the groin up to the heart and pulmonary artery. Contrast is injected into the catheter so X-rays can be taken that provide images of the blood flow in the lung’s arteries. This is the most accurate way to diagnose a PE, according to Mayo Clinic, but because of potential side effects, is typically only done if a diagnosis can’t be made using other tests.

How long it takes to recover from a pulmonary embolism varies from person to person. Generally, most people will recover from a PE within several weeks to months without any significant complications, according to a paper published in the journal Circulation.

However, some symptoms may linger. According to one study of 101 people who experienced PE, 47 percent experienced shortness of breath and 25 percent had impaired quality of life at a six-month follow up.

Long-term complications, such as pulmonary hypertension can also occur, which may become chronic.

Prompt treatment of a pulmonary embolism is vital to prevent potentially fatal complications. Treating a PE focuses on keeping the blood clot from growing and preventing the formation of new clots.

Treatment typically takes place in a hospital and involves medication or surgery.

Medication

In most cases, a PE can be treated with anticoagulant medication, or blood thinners, which decrease the blood’s ability to clot. Your doctor may also prescribe thrombolytics, or medication that dissolves clots, if the clot isn’t dissolving on its own.

Surgery

If a PE is life-threatening, or if other treatments aren’t working, your doctor can remove the clot through surgery or by threading a catheter through the blood vessel to the site of the PE.

A pulmonary embolism can reduce blood flow to the lungs and cause low blood oxygen levels, which can lead to lung damage and damage to other organs. If a PE is not treated promptly, it can cause death. Approximately 25 percent of people with a PE die before they receive a diagnosis or treatment, according to the Centers for Disease Control and Prevention (CDC).

PE can also lead to pulmonary hypertension, characterized by shortness of breath and decreased ability to exercise. About 2 to 4 percent of people with PE have chronic pulmonary hypertension, according to the Circulation report.

If left untreated, PE can lead to heart failure.

Blood thinners that treat PE can have their own set of complications, including excessive bleeding. Per Johns Hopkins Medicine, signs of bleeding in the digestive system include blood in the stool, abdominal pain, and vomiting up blood, while signs of bleeding in the brain include severe headache, sudden change in vision, memory loss or confusion, and sudden loss of feeling or movement in the legs or arms. If you experience any of these symptoms, seek medical attention right away.

The best way to prevent a pulmonary embolism is to prevent blood clots in your deep veins. According to Mayo Clinic, preventive measures include:

• Blood Thinners These are typically prescribed post surgery and after a person has experienced a heart attack or stroke to prevent blood clots.
• Compression Stockings These improve blood flow in the legs. Talk to your doctor about what type of compression stockings to get and how to wear them.
• Elevating Legs if you are on bedrest or have limited mobility, such as after surgery, then elevating your legs is recommended.
• Returning to Physical Activity Do so as soon as you can following surgery.

Preventing Blood Clots While Traveling

The risk of DVT and PE while traveling is quite low, but long-haul flights do increase the risk.

If you’re at an increased risk of blood clots, talk to your doctor about steps you can take to stay safe during long-haul travel. These may include:

• Get up and walking around every hour on an airplane. On a road trip, stop every so often to get out of your car and walk around.
• Stay hydrated by drinking plenty of fluids, especially water. Avoid alcohol, which can lead to dehydration.
• Wear compression stockings, which can improve blood flow in your legs.
• Move your legs in your seat with circular ankle movements and toe raises every 15 to 30 minutes.

According to the CDC, as many as 900,000 people in the United States are affected by DVT or PE, though the precise number is not known.

Among people who have had blood clots, 33 percent will have a recurrence within 10 years.

The CDC estimates that between 60,000 to 100,000 Americans die from DVT or PE each year.

The most common cause of PE is a blood clot that forms in the deep veins of the legs, or DVT.

Certain medical conditions make blood clots more likely, including obesity, heart failure, and inflammatory bowel disease, per Mayo Clinic. Certain types of cancer, including those involving the stomach, brain, lungs, uterus, ovaries, and kidneys, also increase the risk of blood clots, according to the CDC. Cancers of the blood, including lymphoma and myeloma, also raise the risk. Additionally, elements of cancer treatment, such as prolonged hospitalization, chemotherapy, hormonal therapy, and surgery, increase the chances of blood clots.

Blood clots are also more common during pregnancy, childbirth, and up to three months postpartum. There are a number of reasons for this, including limited mobility and less blood flow to the legs during pregnancy. A woman’s blood also clots more easily during pregnancy to prevent excess blood loss during labor and delivery. According to the CDC, pregnant women are 5 times more likely to have a blood clot than women who aren’t pregnant.