University of Oxford

Brain injury is a Process, Not an Event

“Brain injury is a process not an event.” A phrase that has guided my defense on the concussion as much as one. The author? Thomas Gennarelli, MD, I’m not sure the first time I said, but one of these places is said to be the Chapter of Trauma in the text of the famous neuropathology, Greenfield’s Neuropathology: Graham, Gennarelli, Greenfield’s Neuropathology, © 1996 Oxford University Press, page 209.) explained that also cite as follows:

“In various combinations and different degrees of severity, the resulting cell dysfunction (brain injuries), defines the nature and extent of the primary lesion, the result may not be evident for several days or even weeks after injury. (Graham, Gennarelli, Greenfield’s Neuropathology, 1996, page 197.)

The implications of that statement are really amazing compared to our normal rating for a person with brain injury. In my experience, a major concussion, these two primary evaluations. First, EMT personnel will be on the scene, asking a person basic questions like what do you remember the accident, where it hurts, they were unconscious. Then, assuming that taken by ambulance to hospital staff and emergency room doctor will ask questions like, as is almost always the three questions on the orientation of the Glasgow Coma Scale: do you know who you are, where are you and what day it is? If you put these three questions right, having a “perfect” Glasgow Coma Scale of 15 and probably sent home.

When there are still questions about the direction, a report by the uncertainty or loss of consciousness verified can get a longer evaluation and a CT scan. Mild concussion survivors are sent home three or four hours after injury. More symptomatic survivors may take a little longer for the CT scan to be read and evaluated. However, almost all survivors of concussion are released from the medical system for six hours after his accident. Big deal, improve brain injury not worse, right?

Not if you believe that Dr. Gennarelli’s published words. Greenfield says it takes 24 to 72 hours for typical axonal swelling that occurs. But to understand this issue fully, it is important to understand more about the neurons, the myelin sheath that protects them and traumatic defects in the cell that occurs at the time of trauma, something called mechanoporation. “Mechanoporation is the creation of a traumatic defect in the cell membrane that occurs as the lipid bilayer is temporarily separated from the protein more rigid inclusions, such as receptors or channels.”

Sounds pretty damn technical for a blog? What “mechanoporation” means that a defect is created in the insulation that protects the axon of potentially toxic chemical neurotransmitter that surround the axon. Each axon has small channels to allow just the right amount of these neurotransmitters in the axon, allowing it to transmit the electrical impulse along the axon. In the traumatic event, the axon is stretched so that the channels are open too wide and too neurochemical gets in the axon. The result is toxic, but can take up to 72 hours for the toxin to harm.

Follow us