Stroke is a brain injury caused by an interruption in blood flow. Brain tissue that does not get oxygen and nutrients from blood can die within minutes. The damage to the brain can cause a sudden loss in neurologic functions. The types of functions that are affected will depend on the part of the brain that is damaged.

Two blood flow problems that cause a stroke. Strokes may be hemorrhagic or ischemic.

  • A hemorrhagic stroke is caused by a ruptured blood vessel. It may be:
    • Intracerebral hemorrhage—bleeding in the brain
    • Subarachnoid hemorrhage —bleeding in the tissue around the brain
  • An ischemic stroke is caused by a blocked blood vessel.

nucleus fact sheet image
Copyright © Nucleus Medical Media, Inc.

A hemorrhagic stroke can occur because of abnormal blood vessels in the brain. These vessels are weaker than normal vessels and break open under pressure. The blood leaks out of the broken blood vessel and into the brain. This can lead to brain damage because blood flow is interrupted and the pooled blood can cause pressure on the brain.

Blood vessels may be weakened by:

Blood vessels damage can also be caused by trauma like a blow to the head or a car accident.