A concussion may result when the head strikes against an object or is struck by an object. Sometimes a concussion may cause a brain contusion (bruise). Concussions may produce unconsciousness or bleeding in or around the brain.
Review Date 11/13/2021
Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.