Transient Ischemic Attack (TIA) Causes

Brain cells require oxygen to function. If the blood supply is lost, then oxygen supply is lost, and the brain cells stop working. The blood supply to brain cells can be lost in a few different ways.

• Blood clots can form in one of the tiny arteries of the brain (thrombosis). This is usually preceded by gradual narrowing of the blood vessel with fatty build-up called plaque. Atherosclerosis (atheroma=deposits of cholesterol and fatty tissue + sclerosis+narrowing) of the brain arteries is the same as the narrowing that occurs in heart arteries preceding a heart attack. A blood clot can form if the plaque ruptures, leading to further blockage of the artery.
  
  
• Blood clots can float downstream from the heart and get caught in a tiny blood vessel (embolus). Atrial fibrillation (A fib) is the most common reason for an embolus. In atrial fibrillation, the upper chambers of the heart jiggle and don't beat in a coordinated fashion. This allows blood to become stagnant and form small clots. These clots can embolize to any organ in the body, but the brain is a common target.
  
  
• Debris can occlude the blood vessels. This debris often breaks off from carotid arteries that are narrowed by atherosclerotic disease as described above.
  
  
• Blood vessels can burst and cause bleeding within the brain tissue. An intracerebral hemorrhage (intra=within + cerebral= of the brain + hemorrhage=bleeding) is often caused by high blood pressure which can cause a small blood vessel to leak blood.