Concussion Series Part 3
what is concussion?
We used to think that concussion was a “coup, countrecoup” injury where the brain “bounced” back and forward in the brain leading to bruising.
HERE’S WHAT THE EVIDENCE ACTUALLY TELLS US:
Concussion is a white matter injury that occurs due to shearing.
The brain is made of different layers like in this picture. These layers are different densities, which means that they accelerate at different speeds.
When a force is placed on the head or neck (the force does not need to be a direct blow to the head) these layers SHEAR over each other, causing stretching of the brain cells.
There are 2 phases to concussion:
1 // EXCITATORY PHASE
Neurons are stretched, which results in leaking of (K+) chemicals out of the cell causing many action potentials or what we call an “ELECTRICAL STORM”, a different chemical (Ca-) leaks into the cell, overloading it and decreasing the production of ATP (energy) leaving the patient in an ENERGY CRISIS
And causing immediate and evolving symptoms
2// SPREADING DEPRESSION
After 2 hours, the body starts to notice and experience the resulting significant loss of ATP, and symptoms can worsen. This ATP store starts to recover after 15 hours, but only after day 5 is the difference in energy production no longer “significant”
During this time, blood flow to the brain is also reduced, to counter this, blood is taken from other parts of the body to ensure stability of blood flow to the brain.