What is Pulmonary Embolism?

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Pulmonary embolism is a blockage in an artery in the lungs. It occurs when a blood clot - usually from the legs (deep vein thrombosis) - breaks off, is carried through the bloodstream and lodges in the arteries in the lungs. This blocks the flow of blood through the heart, which may lead to death.


  • Chest pain (often sudden)
  • Shortness of breath
  • Sharp pain that worsens when taking a deep breath
  • Coughing up blood

Risk Factors

  • Age, especially over the age of 60
  • Presence of deep vein thrombosis or previous deep vein thrombosis
  • Certain inherited conditions, such as factor V Leiden
  • Previous pulmonary embolism
  • Recent treatment for cancer
  • Presence of a central venous catheter, a tube that is placed in a vein for some medical treatments
  • Sitting for long periods of time (for example in a car or on an airplane)
  • Pregnancy, including the six week period after pregnancy
  • Hormone therapy
  • Birth control pills
  • Obesity


Massive pulmonary embolism causes an overload of the heart and can cause a sudden collapse of the cardiovascular system, which can cause fainting or sudden death.


  • Oxygen is usually given - through a tube, through a mask or, in severe cases of low oxygen levels, through a ventilator
  • Medication
  • Blood thinners, such as heparin or warfarin
  • Blood pressure elevators
  • "Clot buster" medications (thrombolytics) for the most serious cases

For further information please consult following chapters of Layman's Handbook of Venous Disorders:

Chapter 2: Risk Factors for Venous Thrombosis

Chapter 3: Clotting disorders

Chapter 6: Clinical Presentation of Venous Thrombosis "Clots": Deep Venous Thrombosis and Pulmonary Embolus

Chapter 7: Medical Treatment of Deep Vein Thrombosis and Pulmonary Embolus

Chapter 9: Indications for Inferior Vena Cava Interruption