Definition & Overview

A pulmonary embolism occurs when a blood vessel in the lung is blocked, usually by a blood clot that initially formed in the lower extremities and traveled towards the lungs. While majority of pulmonary embolisms involve the blockage of small vessels and are therefore not considered as fatal conditions, if the clot is large enough to block a major blood vessel, it can lead to the death of the patient. This is why pulmonary embolisms are considered as medical emergencies.

Although blood clots are the major causes of pulmonary embolism, other factors can also cause the condition. Fat that was loosened while undergoing orthopedic surgery, amniotic fluid, and air are some of the other causes of the condition.

Pulmonary embolism can sometimes display a variety of symptoms, such as shortness of breath, sudden chest pains, and coughing up pink foamy mucus. However, in some cases the symptoms can easily be missed and the condition misdiagnosed. For instance, the symptoms are also similar to those of a heart or anxiety attack. In order to avoid a misdiagnosis of the condition, doctors will need to collect information on the patient’s medical history, perform a physical exam and imaging tests such as a chest x-ray or MRI. An electrocardiogram (ECG) will also help rule out other conditions like a heart attack.


The majority of pulmonary embolism cases are caused by blood clots that initially formed in the legs. This condition is referred to as Deep Vein Thrombosis (DVT). A variety of factors can contribute to the formation of blood clots. These include, being stationary for a long period of time due to a stroke or long travel, leg trauma or injuries, heart disease, burns, and obesity. Cancer, pregnancy, hormone therapy, and oral contraceptives are also known to cause blood clots.

Key Symptoms

The symptoms of pulmonary embolism are similar to other conditions, such as heart and anxiety attacks. The most common symptoms are sudden coughing that can produce bloody sputum, breathlessness, chest pains under the breastbone or on either side of the chest, rapid breathing, rapid heart rate, leg pains in one or both legs, lightheadedness, fainting, anxiety, sweating, and low blood pressure. The patient can also experience wheezing, pelvis pain, swelling in the lower extremities, and have a weak pulse. However, not all pulmonary embolism cases display signs and symptoms.

Who to see and types of treatment available

If you notice any of the above symptoms, consider going to a hospital’s emergency department or calling a doctor or emergency services immediately. Other health professionals who are capable of diagnosing the condition are cardiologists, internists, pulmonologist, surgeon, or nurse.

In order to diagnose the condition accurately, a doctor will first need to obtain a complete medical history to find out if you have any history of blood clotting, DVT, or if you’ve undergone surgeries that are known to cause blood clots.

You will then undergo a physical exam. The doctor may focus on your lower extremities to look for signs of blood clotting. Other than a physical exam, you’ll likely also to undergo imaging tests, such as a chest x-ray to rule out other conditions. Chest x-rays will show if you have an enlarged heart or pneumonia. These conditions display similar symptoms.

Your doctor may also require you to undergo an electrocardiogram (ECG) to rule out a heart attack. A test that can confirm pulmonary embolism is an arterial blood gas analysis. This test involves checking your blood oxygen level. A sudden drop in blood oxygen suggests that there is a problem with the lungs and pulmonary embolism could be the culprit.

Once pulmonary embolism is suspected, you’ll likely need to undergo an MRI to view the blood clot in the legs or lungs, a pulmonary angiogram, Doppler ultrasound, or echocardiogram.

The goal of pulmonary embolism treatment is to first relieve the blood clot and prevent the condition from happening again. The initial treatment will be to supply oxygen either through a nasal cannula (a tube inserted into the nostrils), an oxygen mask, or a large tube inserted into the trachea (windpipe).

The patient will then be given blood-thinning medications orally or intravenously. These medications include Heparin, enoxaparin, and warfarin. In critical cases, the patient may be given medications called thrombolytic. These break up the clot blocking the artery. If the condition is life-threatening, the patient will need to have a catheter inserted into the pulmonary artery to suck out the clot, thereby immediately relieving the obstruction.

The patient will need to be monitored closely by a doctor, even when he or she has been discharged from the hospital. Patients will need to undergo blood tests every few days or on a weekly basis. If the levels are in the ideal range, tests can be scheduled every two to four weeks.

It is important to note that pulmonary embolisms can reoccur, so patients who have undergone treatment for the treatment need to be aware of the risk factors they need to avoid. These risk factors include, long periods of staying in the same position, wearing compression garments after a surgery, and avoiding anything that can cause blood clots. In some cases, the doctor may prescribe anticoagulant medications, especially if the patient has a high risk of developing blood clots. Some patients need to take anticoagulants for the rest of their lives.

If you have a history of DVT or already undergone treatment for pulmonary embolism, you should talk to your doctor before going on long trips. This way, you’ll be aware of your risks and know what to do to minimize the risk of the condition from reoccurring. Your doctor may prescribe medications that will prevent blood clots from forming during your travel. You can also take other precautions, such as walking around every hour when on a long flight, or stopping the car and going out for a short walk to stretch your muscles and get your blood flowing.


  • U.S. Department of Health and Human Services (2008). The Surgeon General's call to action to prevent deep vein thrombosis and pulmonary embolism.

  • Guyatt GH, et al. (2012). Executive summary: Antithrombotic therapy and prevention of thrombosis, 9th ed.—American College of Chest Physicians evidence-based clinical practice guidelines. Chest, 141(2, Suppl): 7S–47S.

  • Kearon C, et al. (2012). Antithrombotic therapy for VTE disease. Chest, 141(2, Suppl): e419S–e494S.

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