What Is Pulmonary Embolism
(Pulmonary Embolus)?
A pulmonary embolism is a sudden blockage in your pulmonary arteries, the blood
vessels that send blood to your lungs. It usually happens when a blood clot in the deep
veins in your leg breaks off and travels to your lungs.
A blood clot that travels to another part of your body is called an embolus. When an
embolus blocks a blood vessel it's called an embolism. When a pulmonary embolus
blocks blood flow to your lungs, it's called a pulmonary embolism.
Pulmonary Embolism Causes
The most common cause of a pulmonary embolism is a the breaking off of a blood clot
in your leg's deep veins, known as deep vein thrombosis (DVT). Other, rare causes of a
pulmonary embolism include:
Air bubbles
DVT in the upper body
Fat embolus, usually from a severely broken bone
Tumors
You are more likely to develop blood clots if you have risk factors such as:
Cancer
Family history of blood clots or clotting disorders
Heart disease
Health history of blood clots or clotting disorders
Long-term use of birth control pills or estrogen therapy
A pulmonary embolism is also more likely to develop after:
Childbirth
Heart attack or stroke
Long plane or car rides
Long-term bedrest
Severe injuries, burns or fractures
Surgery
Pulmonary Embolism Symptoms
You may not have any symptoms of a pulmonary embolism, depending on the size of
the clot and your overall health. As blood flow becomes more and more blocked, you
may experience symptoms such as:
Coughing, including a cough that produces bloody mucus
Dizziness
Heart palpitations, sensations of your heart racing or pounding
Leg pain or swelling
Sharp and sudden chest pain
Shortness of breath that worsens with exertion
Pulmonary Embolism Complications
A pulmonary embolism can be life-threatening without treatment. It can cause several
complications, including:
Cardiac arrest, when your heart suddenly stops beating
Cardiac arrhythmia, an irregular heart rhythm
Pleural effusion, fluid buildup in the membrane around your lungs (pleura
Pulmonary hypertension, high blood pressure in your lungs
Pulmonary infarction, when lung tissue dies
Rarely, people have multiple small pulmonary emboli that develop over time. This is
called chronic thromboembolic pulmonary hypertension (CTEPH).
Diagnosing a Pulmonary Embolism
To diagnose a pulmonary embolism, your doctor does a physical exam, asks about your
symptoms and orders one or more tests such as:
Blood tests to check if you have an increased risk of blood clotting
Chest X-rays to take pictures of your heart and lungs
CT pulmonary angiography, using X-rays and specialized computers to create
cross-sectional, 3D images of your lungs and pulmonary arteries
Doppler ultrasound, using sound waves to look for deep vein thrombosis in your
legs
Echocardiogram to view your heart's structures and blood vessels
Lab tests, such as pulse oximetry to measure oxygen levels in your blood or
arterial blood gas tests to measure the balance of oxygen and carbon dioxide
Pulmonary angiogram, using a small, hollow tube (catheter) and a contrast dye to
see how blood flows through the pulmonary arteries
Ventilation-perfusion (V/Q) scan, injecting a tracer into your veins to track blood
flow and compare it with air flow to check for pulmonary hypertension
