Definition An embolism is any material that travels through the bloodstream and then gets stuck in a blood vessel. When an embolism occurs in the veins that lead to the lungs, it is called a pulmonary or lung embolism.
What is going on in the body? A lung embolism can occur for many different reasons. The embolism travels through the bloodstream until it reaches a part of the lung circulation that is too narrow. The embolism then gets stuck in the blood vessel and keeps the blood from flowing beyond it. A lung embolism may be tiny and never noticed or it may be large enough to cause death.
What are the signs and symptoms of the condition? A pulmonary embolism may cause:
What are the causes and risks of the condition? A lung embolism may be caused by:
a blood clot known as a deep venous thrombosis from a vein in the legs or pelvis. These blood clots break off from the wall of the vein and travel to the lungs, and are the most common cause of pulmonary embolism.
fat, which usually comes from broken bones such as a hip fracture
air bubbles, which may occur in scuba divers who return to the surface too quickly or during medical procedures
a piece of tumour, which may occur in some cases of cancer that metatasises, or spreads through the body
foreign material, which sometimes occurs in people who abuse intravenous drugs
the amniotic fluid that surrounds a baby in the womb. This sometimes happens in pregnant women around the time of delivery.
What can be done to prevent the condition? Many cases cannot be prevented. Those who have or suspect a blood clot should get proper treatment. Medication to thin the blood or special stockings may be given to people who are bedridden or having surgery. This helps to prevent blood clots from forming. Scuba divers should follow proper procedure and not return to the surface too quickly. Intravenous drug abuse should be avoided.
How is the condition diagnosed? A person's history and a physical examination may make a doctor suspicious. Diagnostic tests may include:
What are the long-term effects of the condition? A lung embolism can cause death. Heart weakness or congestive heart failure and permanent lung damage can also occur.
What are the risks to others? This condition is not contagious and poses no risk to others.
What are the treatments for the condition? Oxygen and analgesics are given as needed. If a blood clot is the cause, a person will be given blood thinners, which are medications to thin the blood. For a large, life-threatening blood clot, "clot-dissolving" medications or surgery may be needed to eliminate the clot. Other medications and intravenous fluids may also be needed.
What are the side effects of the treatments? Blood-thinning and clot-dissolving medications may cause abnormal bleeding. In some rare cases, this can lead to death. All medications have possible side effects, such as allergic reactions and stomach upset. Surgery is high-risk in this setting and is usually reserved for life-threatening cases. All major surgery carries a risk of infection, bleeding, and even death.
What happens after treatment for the condition? What happens after treatment depends on what caused the embolism. For example, a woman who recovers from a fluid embolism during pregnancy is free to return to normal activities. No further treatment may be needed.
If the cause of an embolism is a blood clot, a person usually needs to take blood thinners, such as warfarin. Treatment usually lasts for several months. A person who has had more than one lung embolism may need to take blood thinners for life. If blood thinners cannot be tolerated for some reason, a person may need to undergo a special procedure. This procedure inserts a "filter" in a major vein leading back to the heart to stop an embolism from getting into the lungs.
How is the condition monitored? A person taking blood thinners needs to have blood tests, such as a prothrombin time or PT, done to make sure the medication is working properly. Any symptoms should be followed up by a doctor. Further monitoring may be needed in more serious cases. If a person is on blood thinners, it is important to watch for signs of bleeding. These include bloody stools, blood in the urine, and large bruising.
Author: Adam Brochert, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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