An embolus is a blood clot, bit of tissue or tumor, gas bubble, or other foreign body that circulates in the blood stream until it becomes stuck in a blood vessel.
When a blood clot develops in an artery and remains in place, it is called a thrombosis. If all or part of the blockage breaks away and lodges in another part of the artery, it is called an embolism.
Blockage of an artery in this manner can be the result of a blood clot, fat cells, or an air bubble. When an embolus blocks the flow of blood in an artery, the tissues beyond the plug are deprived of normal blood flow and oxygen. This can cause severe damage and even death of the tissues involved.
Emboli can affect any part of the body. The most common sites are the legs and feet. When the brain is affected, it is called a stroke. When the heart is involved, it is called a heart attack or myocardial infarction (MI).
A common cause of embolus is when an artery whose lining has become thickened or damaged, usually with age, allows cholesterol to build up more easily than normal on the artery wall. If some of the cholesterol breaks off, it forms an embolus. Emboli also commonly form from blood clots in a heart that has been damaged from heart attack or when the heart contracts abnormally from atrial fibrillation.
Other known causes are fat cells that enter the blood after a major bone fracture, infected blood cells, cancer cells that enter the blood stream, and small gas bubbles.
Symptoms of an embolus can begin suddenly or build slowly over time, depending on the amount of blocked blood flow.
If the embolus is in an arm or leg, there will be muscle pain, numbness or tingling, pale skin color, lower temperature in the limb, and weakness or loss of muscle function. If it occurs in an internal organ, there is usually pain and/or loss of the organ's function.
The following tests can be used to confirm the presence of an arterial embolism:
Arterial embolism can be treated with medication or surgery, depending on the extent and location of the blockage.
Medication to dissolve the clot is usually given through a catheter directly into the affected artery. If the embolus was caused by a blood clot, medications that thin the blood will help reduce the risk of another embolism.
A surgeon can remove an embolus by making an incision in the artery above the blockage and, using a catheter inserted past the embolus, drag it out through the incision.
If the condition is severe, a surgeon may elect to bypass the blocked vessel by grafting a new vessel in its place.
An arterial embolism is serious and should be treated promptly to avoid permanent damage to the affected area. The outcome of any treatment depends on the location and seriousness of the embolism. New arterial emboli can form even after successful treatment of the first event.
Prevention may include diet changes to reduce cholesterol levels, medications to thin the blood, and practicing an active, healthy lifestyle.