A
transient ischemic attack (
TIA) is a transient episode of neurologic dysfunction caused by
ischemia (loss of blood flow) – either focal brain,
spinal cord, or
retinal – without acute
infarction (tissue death). TIAs have the same underlying cause as
strokes: a disruption of
cerebral blood flow (CBF), and are often referred to as
mini-strokes or
mega-strokes. Symptoms caused by a TIA resolve in 24 hours or less . TIAs cause the same
symptoms associated with stroke, such as
contralateral paralysis (opposite side of body from affected brain hemisphere) or sudden weakness or numbness. A TIA may cause sudden dimming or loss of vision (
amaurosis fugax),
aphasia, slurred speech (
dysarthria) and mental confusion. But unlike a stroke, the symptoms of a TIA can resolve within a few minutes or within 24 hours. Brain injury may still occur in a TIA lasting only a few minutes. Having a TIA is a risk factor for eventually having a stroke or a
silent stroke.