Concussion of the Brain
Concussion of the Brain, injury to the brain from a fall or a blow to the head, usually with loss of consciousness, the reason for which is not entirely understood. Increased pressure on the brain stem probably accounts for the slowing or temporary suspension of respiration and the reduced pulse rate that accompany a concussion; additional symptoms include pallor, sweating, and a drop in blood pressure . Dizziness, nausea, and a dull, restless feeling often follow a return to consciousness. Aftereffects such as headaches, dizziness, and nervousness may continue for several days, weeks, or even years after the initial injury. A concussion may temporarily or permanently damage nerve tissue , producing amnesia , irritability, and fatigue ; memory is often impaired. Recovery from a concussion is generally complete and prompt after less severe injuries.