“In various combinations and various severities, the resultant cellular dysfunction (of brain injury) defines the nature and extent of the primary injury, the outcome of which may not become apparent for several days or even weeks after injury.”
(Graham, Gennarelli, Greenfield’s Neuropathology, 1996, page 197.)
Cellular damage occurs predominantly to the axons.

NEXT: Shear and Delayed Effects.
The concussions that disable, are almost always more symptomatic at 24 hours, than at the 2-4 hour time frame when injured persons are evaluated in the emergency room. Brain injury symptoms escalate over the first 24 hours, because brain injury involves a cascade of events. It is critical that if you are still symptomatic the day after your injury, go back to the same Emergency Room, don’t wait for a doctors appointment. It is critical that the Emergency Room personnel see that the symptoms still persist or have gotten worse.