Ischemias Research Paper

TIAs are powerful forerunners of stroke. Approximately 10% of patients diagnosed as having a TIA have a stroke in the 90 days following the TIA diagnosis, with half of them having a stroke within 2 days of the TIA. TIAs are short-lived episodes of acute, focal, nonconvulsive neurologic dysfunction presumably caused by reversible ischemia to an area of the retina or brain. Onset of symptoms is sudden and often unprovoked, reaching maximum intensity almost immediately.
Completed Stroke
A completed stroke is the term applied to the temporal profile of the stroke syndrome in which the deficit is prolonged and often permanent, causing demonstrable parenchymatous changes.
Stroke in Evolution
Stroke in evolution, progressive stroke, or ingravescent stroke describes the temporal profile in which the neurologic deficit occurs in a stepwise or progressive fashion, culminating in a major deficit in the absence of treatment. Should the site of ischemia be the carotid arterial distribution, 24 hours without progression is usually enough time to establish that further

ETIOLOGY
Thrombosis
Lacunar stroke (small
The magnitude of flow reduction is a function of collateral blood flow and this depends on individual vascular anatomy and the site occlusion. A fall in cerebral blood flow to zero causes death of brain tissue within 4-10 min; values <20 mL/100 g tissue per min cause ischemia without infarction unless prolonged for several hours or days. If blood flow is restored prior to a significant amount of cell death, the patient may experience only transient symptoms, i.e., a TIA. Tissue surrounding the core region of infarction is ischemic but reversibly dysfunctional and is referred to as the ischemic penumbra. The ischemic penumbra will eventually infarct if no change in flow occurs, and hence saving the ischemic penumbra is the goal of revascularization