A brain stroke occurs when the blood supply to a part of the brain is disrupted, leading to the loss of brain function.
This disruption can be due to either ischemia (insufficient blood flow) or hemorrhage (bleeding).
When an area of the brain doesn't receive enough blood or is damaged by bleeding, it cannot function normally.
This can result in various impairments, such as motor deficits affecting one or more limbs on one side of the body, difficulties with speech comprehension or articulation (aphasia), or vision impairments affecting one side of the visual field.
Ischemic strokes, the most common type, are caused by blockages in blood vessels, either from a blood clot (thrombosis), a traveling clot (arterial embolism), or reduced blood flow to the brain (cerebral hypoperfusion).
Hemorrhagic strokes, conversely, are caused by the rupture of blood vessels in the brain, leading to bleeding directly into the brain tissue or into the fluid-filled space surrounding the brain (subarachnoid space).