Traumatic Brain Injuries & Concussions: Immune System Involved

By Dr. Shawn VanWinkle

Most people are aware that when someone suffers a concussion, it can lead to damage of nervous system tissue in the brain. Rarely considered or assessed are the effects of a concussion on the immune system in the brain. As we continue our Journey to Recovery from TBI’s and concussions, a discussion about the role of the immune system is warranted.

It is a natural process as we age for some neurons to die. When this happens, they need to be cleared out by the immune system. If this doesn’t occur in a timely manner, it will lead to inflammatory states in the brain. The immune system works very differently in the brain than it does in the body. When there is inflammation in the body, the immune system can use the lymphatic system to help rid the body of the waste. The brain is not able to do this. Instead, it uses cells called microglia to clean up the debris. The microglia recycle the debris from dying neurons and use it as building blocks and fuel for the brain.

The nervous system has a unique ability to control activity of microglia using “on” and “off” signals from nearby neurons. The more electrical activity there is from the neurons the more life is present in those cells. This results in an abundance of “off” signals being generated to help quiet the microglia. When the brain sustains a trauma, neurons that are damaged become unstable and less capable of conducting electrical activity, generating more “on” signals for the microglia. In addition, the brain also controls its own blood flow by communicating with the cardiovascular system to deliver blood to active areas. Damaged neurons are less capable of sending signals to get oxygen and glucose to them via the blood. When stimulation along with supply of oxygen and glucose are impaired, the ability of neurons to send off signals to the microglia are also compromised.

7 things that decrease “off” signals to microglia:

  • Lack of exercise
  • High caloric intake
  • Decreased thyroid hormone
  • Decreased CoQ10
  • Diabetes/Insulin resistance
  • Hypoglycemia
  • Respiratory disorders

When neurons do not recover from a sustained injury, a cascade of events unfolds, leading to a vicious cycle. When injured neurons die, they essentially turn on more microglia promoting more inflammation.  Neurons are not able to function optimally in inflammatory states. This leads to nearby neurons also becoming unstable, risking their health as well. The result is more injury to neurons, creating more inflammation leading to more damage to neurons. As this process unfolds, an even greater risk presents itself. As the microglia clean up the debris from the injury, they can potentially present tissue from the neurons as antigens to the immune system. When this happens, the immune system can start to make antibodies against brain tissue. If prolonged, this can result in neurological autoimmune disorders and irreversible brain damage.


Whenever someone sustains a brain injury, once they have been cleared medically from possible complicating factors, it is important for them to get plenty of rest in the beginning. The damaged neurons are unstable and too much activity can cause further damage. This also allows the immune system to go to work clearing out the debris from the neurons that didn’t make it without risking further cell death. During this time it is also helpful to reduce the amount of food you intake while still eating in a way that helps stabilize blood sugar (eating frequent small meals consisting of a balance of healthy carbohydrates, proteins and fats). The next step is to find someone trained in functional neurology that can help you slowly stimulate the unstable neurons without over stimulating them. This will help the surviving neurons recover a healthy state so they can appropriately send the signals they were designed to send. As the nervous system becomes more stable, it will become more capable of sending “off” signals to the microglia, promoting a balanced state of health between the nervous system and the immune system.

Copyright © 2014 Integrated Health Systems. All Rights Reserved. Dr. Shawn VanWinkle is an Associate Doctor at Integrated Health Systems. To learn more about how we can help you with your health goals visit our websites at and or email us at A free initial consultation can be scheduled by calling our office at 303-781-0126.