Which statement best defines a stroke?

• A. Temporary interruption of blood flow to the brain that fully resolves in minutes.
• B. Permanent interruption of blood flow to the brain due to blockage or hemorrhage.
• C. An infection causing inflammation of brain tissue.
• D. A transient episode of neurological deficit that resolves within 24 hours.

Answer: (B)

Stroke is a sudden disruption of blood flow to a part of the brain that leads to brain tissue injury from ischemia or bleeding. The statement that best defines it is the one that describes this interruption as permanent, caused by a blockage or a hemorrhage. When blood flow is stopped or severely reduced and cannot be restored quickly, brain cells begin to die, producing focal neurologic deficits that can become permanent.

The other statements describe events that resemble a ministroke or transient events. A temporary interruption that resolves in minutes is characteristic of a transient ischemic attack, not a stroke. A transient deficit that resolves within 24 hours also points toward TIAs or other non-stroke conditions rather than an actual stroke. The idea of an infection causing brain inflammation is a different process altogether and does not define stroke.