Definition and Overview
Transient ischemic attack (TIA) is a mild stroke caused by a brief interruption of blood flow to the brain. It causes stroke-like symptoms, such as vision problems and weakness of one side of the body. But unlike a full-blown stroke, TIA symptoms typically do not last longer than 24 hours nor cause noticeable or lasting effects because the body is able to resolve the blockage fast enough to prevent serious damage to brain tissue. Nevertheless, treatment is still required to prevent subsequent and potentially more damaging episodes of stroke. Based on statistics, one in three people who have had a TIA will develop a severe stroke within a year unless the condition is promptly diagnosed and the person’s risk factors are adequately managed.
Causes of Condition
Transient ischemic attack is caused by a brief loss of blood supply to the brain. Without the much-needed blood and oxygen supply, parts of the brain responsible for vision, balance, and coordination, among others, may be damaged and lose their ability to function normally. If the brain is able to regain blood supply in a matter of minutes, TIA symptoms can be reversed. Otherwise, a person will suffer from a severe stroke and its devastating consequences, which can include paralysis and permanent cognitive problems.
A stroke occurs when vessels that supply blood to the brain have become narrowed (atherosclerosis) or blocked by blood clots (thrombosis). Blood clots can either form inside the blood vessel or in different parts of the body and travel via the blood stream.
The risk of thrombosis and atherosclerosis can be increased by the following factors:
Cardiovascular disease - Heart conditions, including heart failure and congenital heart defects, can cause high blood pressure, which can damage and weaken the blood vessels that supply blood to the brain.
Diabetes and high cholesterol levels - Increase the risk of plaque buildup in the arteries.
Sickle cell disease - A genetic disorder that can increase the risk of blood clots.
Peripheral artery disease
Cigarette smoking and heavy drinking
Sedentary lifestyle and poor nutrition
A family or personal history of TIA or stroke
Advanced age - People aged 55 years and older are the most at risk of atherosclerosis as arteries generally become weaker with age.
Gender - TIA is slightly more common in men but is more severe in women. More than half of stroke deaths occur in women.
The symptoms of TIA are the same as those of a massive stroke. The only difference is that they immediately subside or disappear because the body is able to break the clot in the blood vessel and normal blood flow to the brain is restored before any serious damage occurs.
TIA symptoms include the sudden onset of:
Difficulty speaking or understanding others
Weakness, which mostly affects one side of the body
Vision problems, including temporary blindness in one or both eyes
Loss of coordination or balance
Sudden, severe headache
Fainting or an altered level of consciousness
An abnormal sense of smell or taste
Patients may experience some or all of the above symptoms depending on which part of their brain is affected.
To easily recognise the symptoms of stroke, a group of doctors has developed FAST, an acronym used to enhance responsiveness to stroke patients. FAST stands for:
Facial drooping - Does the person’s face droop when asked to smile?
Arm weakness - Does one arm drift downward when the person is asked to raise both arms?
Speech difficulties - Is the person unable to repeat a simple phrase or having difficulty speaking?
Time to call emergency services - If the answer to the three questions is yes, it means that the person is having a stroke and must be taken to an emergency room for evaluation and treatment.
Who to See and Types of Treatments Available
Treatment of transient ischemic attack focuses on identifying the cause of temporary loss of blood supply to the brain so measures can be taken to lower the risk of subsequent strokes. Diagnostic procedures and imaging tests commonly performed to visualise the arteries, the brain, and surrounding structures include:
Computed tomography (CT) scan of the brain
Magnetic resonance angiography
A thorough physical examination
Tests that check cholesterol, blood pressure, and amino acid homocysteine levels
Medications are usually the first line of defense in the prevention of subsequent strokes. These may include antiplatelet and anticoagulants drugs (prevent the formation of blood clots) as well as thrombolytic agents (dissolve existing blood clots). Antihypertensive medications, such as beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium channel blockers, are also prescribed if the problem is caused by high blood pressure.
If the carotid artery, or the blood vessel that supplies blood to the brain, has severely narrowed, medical procedures are performed to widen the artery. These procedures include carotid endarterectomy, which removes atherosclerotic plaques that have built up inside the artery and angioplasty with stenting, which uses a balloon-like device to open a clogged artery and a small wire tube (stent) to keep it open.
The prognosis for TIA patients heavily depends on how soon they receive treatment and how effectively their risk factors are controlled. When medical or surgical therapy is combined with a healthy lifestyle, patients have a better chance of preventing the occurrence of subsequent strokes.
Furie KL, Kasner SE, Adams RJ, Albers GW, Bush RL, Fagan SC, et al. Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke . 2011;42:227-276.
Daroff RB, et al. Ischemic cerebrovascular disease. In: Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. https://www.clinicalkey.com.
Furie KL, et al.Guidelines for the Prevention of Stroke in Patients With Stroke or Transient Ischemic Attack. Stroke. 2011;42: 227-276.