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 9/23/2019
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Emeritus, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.