Transient ischemic attack (TIA) is a temporary dysfunction of the brain due to a shortage of blood and oxygen. A TIA lasts no longer than 24 hours. It is sometimes referred to as a mini-stroke.

TIA is a serious condition. It serves as a warning for a potential stroke.

Blood Supply to the Brain
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Blood and oxygen are carried to the brain through major blood vessels in the neck. The blood then passes through a series of blood vessels in the brain. A TIA occurs when the blood flow through the neck or brain vessels is reduced. The blood flow may be reduced by a narrowing or blockage of the blood vessels.

Narrowing of the blood vessels may occur with:

  • Build up of plaque in the blood vessels, called atherosclerosis
  • Vasculitis—inflammation of the blood vessels

Blood vessels can also become blocked or obstructed by a clot or clump that is floating in the blood. This may be caused by:

  • A piece of blood clot or plaque that has broken off of another location
  • Blood and blood-clotting disorders such as:
    • Severe anemia —too few red blood cells
    • Polycythemia —too many red blood cells
    • Hyperviscosity—abnormal thickening of the blood
  • Endocarditis —an infection of the lining of the heart