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This information was reviewed and approved by Chhaya Patel, MD (3/1/2021).

The word "embolism" comes from the Greek émbolos, meaning "stopper" or "plug."

A pulmonary embolism (PE) usually causes a blockage in the lung artery suddenly which halts normal blood flow to the lungs. It can cause significant difficulty breathing, lower the level of oxygen in the lungs and increase the blood pressure in the pulmonary arteries which is life threatening. Low oxygen can occur as well which can damage the lungs and other organs. Increased blood pressure in the lungs can make the right side of the heart work harder which can lead to heart failure.

A blood clot in an artery that supplies blood to the heart or brain may result in:

  • Heart attack

  • Stroke

  • Transient ischemic attack or mini-stroke

When blood clots occur in a vein in the legs or arms, symptoms may include:

  • Pain

  • Swelling

  • Warmth

  • Redness

If a clot forms in a vein in a leg or arm and then breaks off and travels to the lung, it causes a pulmonary embolus—a potentially life-threatening condition.

Symptoms of pulmonary embolism come on suddenly and are different depending on the size and location of the blood clot. 


Common symptoms of a blood clot in the lungs or pulmonary embolism include:

  • Sudden shortness of breath at rest or during activity

  • Rapid or irregular heartbeat

  • Rapid, shallow breathing

  • Pain in your chest, arm, should, back, neck or jaw that you can’t explain

  • Cough with or without bloody mucus

  • Abnormal amount of sweating 

  • Feeling lightheaded or passing out

  • Blue lips, nails or skin

  • Wheezing

  • Feeling anxious

  • Wheezing

  • Dizziness or fainting


Signs of Deep Vein Thrombosis (DVT)

Deep vein thrombosis or DVT is a blood clot that breaks off from the wall of a vein and travels to the lungs from a deep vein in the legs.

Signs you have DVT are: 

  • An arm or leg that feels warmer than normal and that is swollen

  • The skin on the affected arm or leg is discolored or red

  • Veins in the affected arm or leg are larger than normal

  • Pain in your leg when walking or standing

It is possible to have no symptoms when you have DVT.

Ask your doctor if you have an increased risk of developing PE and pay attention to the signs and symptoms.