Types of embolism

There are three types of embolism, which are briefly described below.

Cerebral embolisms are caused when a foreign body – usually a blood clot – blocks the blood supply to the brain. They are the leading cause of stroke.

Pulmonary embolisms occur when a foreign body blocks the artery that transports blood to the lungs. Many cases are caused by a clot – formed as the result of a condition called deep vein thrombosis (DVT) – travelling from a leg to the lungs. 

Amniotic fluid embolisms occur very rarely. They are caused by amniotic fluid – the fluid that surrounds and protects a baby inside the womb – leaking out of the womb into the mother's blood vessels during labour, blocking the vessels. The mother may then develop breathing problems, a drop in blood pressure and loss of consciousness.




  • stroke, where the supply of blood to the brain is interrupted or completely cut off
  • pulmonary embolism, where the blood supply to the lungs is cut off

Embolisms are a common health problem, and are a major cause of disability and death in the UK and across the world. For example, in England each year it's estimated there are 41,000 pulmonary embolisms and 120,000 strokes caused by embolisms.

What causes an embolism?


Blood clots


Certain health conditions – such as obesity, heart disease, cancer or pregnancy – can cause blood clots to form even where there's no bleeding. A clot can travel in the bloodstream before being deposited in an organ or limb.






See air embolism for more information.


In people who have extensive atherosclerosis (narrowed arteries due to a build-up of cholesterol), small pieces of cholesterol can sometimes break away from the side of a blood vessel, resulting in an embolism.

Increased risk

Things that can increase your risk of an embolism include:

Treating embolisms

How an embolism is treated will depend on:

  • what caused the blockage
  • the size of the blockage
  • where in the body the blockage is




Read more about treating air embolisms.



  • stopping smoking, if you smoke
  • exercising for a minimum of 150 minutes a week 

Page last reviewed: 22/01/2013

Next review due: 22/01/2015


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