Stroke: Listen to the Warnings

Transient Ischemic Attack (TIA) and Cerebrovascular Accident (CVA)

Definition
Transient ischemic attack, TIA, or "mini" stroke is a temporary reduction of blood flow to part of the brain. Tissue death does not result and most symptoms resolve in an hour, with full resolution within 24 hours. TIA is a warning sign of an impending CVA (Medical, 2007).

Cerebrovascular accident, CVA, ischaemic stroke, or stroke occurs when the blood supply to the brain is compromised. Some areas of the brain suffer anoxia, a lack of oxygen to the cells, causing cell death and long term impairment or death of the body (Stroke, 2007).

Etiology
CVA
There are three main causes of stroke. The first is cerebral thrombosis, in which a clot forms within the brain and blocks a cerebral artery from perfusing the organ. Next is the cerebral embolism. This type of stroke occurs when a thrombus is formed in another part of the body and travels to the brain through the vasculature in an embolic stroke. Once there, the clot becomes lodged in an artery within the brain, causing blockage (Stroke, 2007). The final cause of stroke is cerebral hemorrhage. This happens when a blood vessel within the brain bursts, leaking blood freely into the brain, inducing further brain damage (Cerebral, 2007). Strokes can involve small or large sections of the brain (Stroke, 2007).

TIA
Transient ischemic strokes are caused by temporary blockages of cerebral arteries. This may be due to a clot that later shifts or dissolves. Another possible cause is hyper- or hypotension. Either condition can decrease blood flow to organs, as can diabetes. TIA's do not cause permanent damage, so residual effects are undetectable on MRI's and CT scans (NINDS, 2007).