Transient ischemic attack (TIA), commonly known as “mini-stroke,” is a series of symptoms that occur when the supply of blood and oxygen to local brain tissue is temporarily interrupted. Unlike a stroke, the symptoms of a TIA do not last more than 24 hours, usually less than 30 minutes, and resolve on their own. However, the risk of subsequent stroke is very high for any patient with TIA, so it is an early warning sign of stroke and should be taken seriously enough. Some doctors compare the relationship between TIA and stroke to that between angina pectoris and myocardial infarction, which is very appropriate. Once a TIA occurs, it is important to seek immediate medical attention. The risk factors for TIA and stroke are very similar to those for coronary heart disease, including hypertension, diabetes, hyperlipidemia, smoking, obesity, and family history. They are more common in men, three times more common than in women. The risk of TIA and stroke increases gradually with age after 45 years of age, with the highest risk in the 2 age groups of 70 and 80 years. The blood supply to the brain is the responsibility of 2 separate vascular systems: the carotid artery system and the vertebrobasilar system. Depending on the damaged blood supply system and brain tissue, the symptoms of TIA vary greatly. Symptoms of TIA associated with carotid artery disease include: loss of vision on one side; clumsiness or weakness of one limb; and speech impairment. Symptoms related to the vertebrobasilar system include: visual impairment in both eyes; vertigo; ataxia; diplopia; loss of consciousness or transient amnesia. The early symptoms of TIA and stroke are very similar and can only be differentiated by clinical examination or over time. Although the symptoms of TIA can return to full normal on their own, they should not be ignored. Because the risk of reoccurring TIA or having a stroke is very high in patients with TIA, about half of the patients with TIA will have a stroke within 1 year and 1/5 will have a stroke within 1 month, so once TIA is suspected, it is important to seek medical consultation to find the cause of it and to provide appropriate medical or surgical treatment to prevent future strokes. The doctor will make the diagnosis of TIA based on the history, physical examination and other ancillary tests, combined with the presence or absence of risk factors for stroke. The physical examination focuses on the cardiovascular system and the nervous system. The physical examination of the cardiovascular system includes looking for heart murmurs, irregular heart rhythms and the presence of carotid murmurs, which, if present, suggest the possible presence of carotid stenosis, the latter leading to the development of TIA. The neurological examination focuses on muscle strength (presence of muscle weakness on one side), speech, visual fields, coordination of movements and cerebral nerves (those controlling motor and sensory functions of the face and neck). An electrocardiogram, chest x-ray and brain scan (CT or MRI scan) are also required. Blood tests are also often required, but these are not very helpful in diagnosing or ruling out a TIA, but mainly to look for possible causes and to guide further treatment. Other tests that may be performed include cardiac ultrasound (to detect the presence of heart valve disease), carotid Doppler ultrasound (to assess the presence of carotid stenosis), magnetic resonance angiography or transcranial Doppler ultrasound (to detect the presence of intracranial artery stenosis). Once a TIA is identified, its etiology and prevention of recurrence need to be sought. After ruling out the absence of cerebral hemorrhage, some blood-thinning medications such as aspirin or similar may be given; some patients may need some anticoagulant medications such as warfarin. If carotid stenosis is found to be present, carotid endarterectomy may be required to remove the atherosclerotic plaque in the carotid artery. For patients who have not had a TIA, the key to prevention is to eliminate or minimize their underlying risk factors. For example, controlling hypertension, diabetes and hyperlipidemia through diet, physical exercise or medication; and quitting smoking. For patients who have had a TIA, prevention should focus on eliminating risk factors and other possible causes of stroke.