Blood clots that temporarily block blood flow to the brain are the most common cause.
Blood clots that temporarily block blood flow to the brain are the most common cause of transient ischemic attacks (TIAs). Blood clots may develop for a variety of reasons. 1  A blood clot can form in an artery that supplies blood to the brain. Also, an artery that is partially blocked with plaque can reduce blood flow to the brain and cause symptoms. Rare causes of blood clots that can cause a TIA include: 1  Clumps of bacteria, tumor cells, or air bubbles that move through the bloodstream. 2  Conditions that cause blood cells to stick together. Causes of a transient ischaemic attack. Transient ischaemic attacks (TIAs) occur when one of the blood vessels that supply your brain with oxygen-rich blood becomes blocked. This interruption in the flow of blood to the brain means that the brain cannot carry out some of its normal functions properly, leading to symptoms such as slurred speech and weakness. Causes. A transient ischemic attack has the same origins as that of an ischemic stroke, the most common type of stroke. In an ischemic stroke, a clot blocks the blood supply to part of your brain. In a transient ischemic attack, unlike a stroke, the blockage is brief, and there is no permanent damage. A blood clot is the most common cause of a TIA. Blood clots can be the result of hardening of the arteries (atherosclerosis), heart attack, or abnormal heart rhythms. The clot can block blood flow to part of the brain. Brain cells are affected within seconds of the blockage. The underlying cause of a TIA often is a buildup of cholesterol-containing fatty deposits called plaques (atherosclerosis) in an artery or one of its branches that supplies oxygen and nutrients to your brain. Plaques can decrease the blood flow through an artery or lead to the development of a clot. 1 A transient ischemic attack (TIA) is a brief interruption of blood flow to part of the brain that causes temporary stroke-like symptoms. 2  The risks for TIA are the same as for heart attack, stroke, and peripheral artery disease, and include smoking, high blood pressure, high cholesterol, diabetes, and family history.
http://www.webmd.com/stroke/tc/transient-ischemic-attack-tia-cause http://www.webmd.com/stroke/tc/transient-ischemic-attack-tia-cause http://www.nhs.uk/Conditions/Transient-ischaemic-attack/Pages/Causes.aspx http://www.mayoclinic.org/diseases-conditions/transient-ischemic-attack/basics/causes/CON-20021291 http://www.cigna.com/healthwellness/hw/medical-topics/transient-ischemic-attack-hw226606 http://www.mayoclinic.org/diseases-conditions/transient-ischemic-attack/basics/causes/CON-20021291 http://www.medicinenet.com/transient_ischemic_attack_tia_mini-stroke/article.htm
what causes tias