Transient Ischemic Attack - Mini-Stroke
Transient ischemic attack (TIA) is a mini-stroke caused by temporary interruption of blood supply to brain cells, resulting in a sudden, brief decrease in brain function. If the symptoms resolve completely in less than 24 hours, this is called a TIA or mini stroke. If the symptoms do not resolve, the event is called a stroke.
Symptoms vary with the area of the brain affected and may include:
If the blood flow is decreased for a sufficient period, brain cells in the area die (infarct), causing permanent damage to that area of the brain or even death.
The loss of blood circulation to the brain can be caused by the following:
In a TIA, the blood supply is only temporarily blocked. For example, a blood clot may dissolve and allow blood to flow normally again.
Atherosclerosis ("hardening of the arteries") is a condition where fatty deposits occur on the inner lining of the arteries, which dramatically increases the risk for both TIAs and stroke. Atherosclerotic plaque is formed when damage occurs to the lining of an artery. Platelets clump around the area of injury as a normal part of the clotting and healing process.
Cholesterol and other fats also collect at this site, forming a mass within the lining of the artery. A clot (thrombus) may form at the site of the plaque, triggered by irregular blood flow in this location, and the thrombus may then block blood vessels in the brain.
Pieces of plaque or clots can also break off and travel through the bloodstream from distant locations, forming an embolus that can block the small arteries, causing TIAs.
About one-third of the people diagnosed with TIA will later have a stroke. About 80-90% of people who have a stroke caused by atherosclerosis had TIA episodes before their stroke. Approximately one-third of the people who have a TIA will have another TIA, while one-third will have only one TIA. The age of onset varies, but incidence rises dramatically after age 50. TIA is more common among men and black people.
Hypotension (low blood pressure) may precipitate symptoms in an individual with a pre-existing vascular lesion. Other risks for TIA include high blood pressure (hypertension), heart disease, migraine headaches, smoking, diabetes mellitus, and increasing age.
The treatment goal is to improve the arterial blood supply to the brain and prevent the development of a stroke.
Treatment of recent TIA (within the prior 48 hours) usually requires admission to the hospital for evaluation of the specific cause and determination of long-term treatment. Underlying disorders should be treated appropriately, including such disorders as hypertension, heart disease, diabetes, and blood disorders.
Treatment of symptoms of blood disorders may include phlebotomy, hydration, and treatment of the underlying (causative) blood disorder. Antihypertensive medications may be used to control high blood pressure. Medications to lower cholesterol may be useful in reducing high blood cholesterol levels.
With a TIA, some people have only a single episode, some have recurrent episodes, and some will have a stroke. A TIA needs to be treated as aggressively as a stroke would, as any given TIA could develop into a stroke.
Prevention of TIA includes controlling the risk factors:
TIA is a medical emergency. Call 911 or other local emergency number immediately. Do not ignore symptoms just because they resolve!
They may be a warning of an impending stroke. Even if symptoms resolve completely, it is important to call your healthcare provider or an emergency number and get immediate medical attention.