Transient ischemic attack causes

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The most common cause of a TIA is an embolus (a small blood clot) that occludes an artery in the brain. This most frequently arises from an atherosclerotic plaque in one of the carotid arteries (i.e. a number of major arteries in the head and neck) or from a thrombus (i.e. a blood clot) in the heart due to atrial fibrillation. Other reasons include excessive narrowing of large vessels due to an atherosclerotic plaque and increased blood viscosity due to some blood diseases. TIA is related with other medical conditions like hypertension, heart disease (especially atrial fibrillation), migraine, cigarette smoking, hypercholesterolemia, and diabetes mellitus.

The etiology of TIA may be divided in to following based on the pathophysiology involved:

• Caused by atherosclerosis of internal carotid artery at origin or intracranially
• Also called low flow TIA
• Lasts few minutes to hours
• May cause recurrent TIAs producing stereotyped symptoms based on the branches of vessel involved

• Caused by an embolic source from artery or heart
• Common causes of embolism include atrial fibrillation and ventricular thrombus
• Usually lasts hours

• Involves small penetrating intracerebral vessels
• Usually caused by atheroscerotic narrowing of small blood vessels or lipohyalanosis
• May invlove internal capsule, basal ganglia or thalamus

• Commonly cause symptoms due to cerebral ischemia or embolism
• Interruption of blood flow at the petrous portion of internal carotid artery or at the level of C1-C2 of vertebral artery as it enters foramen transversarium
• Symptoms may last from minutes to hours to days.
• May be detected by neurovascular imaging

Template:WH Template:WS