It can be hard to make the connection sometimes. Maybe it’s a persistent headache that simply won’t go away. Maybe it’s feeling excessively hot or cold. Maybe it’s dizziness when standing up, or extreme fatigue. If you’ve experienced a traumatic brain injury (TBI) a few days, weeks or months ago, you wouldn’t necessarily relate those symptoms to that past head injury. But when patients don’t seem to fully recover after even mild TBIs, they can experience autonomic nervous system (ANS) dysfunction. That’s why it is important to understand the connection between the autonomic dysfunction (which is also called dysautonomia) and concussions.
What is the ANS?
The ANS is the part of the nervous system that helps regulate the involuntary actions of internal organs, including the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, as well as sweat, salivary, and digestive glands. It works seemingly automatically, supplying functions that occur without us even being conscious of any effort or control. The ANS receives information about the body and what’s happening in our environment and then helps our internal organs respond as needed.
Functions controlled by the ANS include:
- Heart rate
- Breathing rate
- Blood pressure
- Body temperature
- Digestion
- Production of bodily fluids like sweat, saliva, tears
- Urination and Defecation
- Metabolism
“Autonomic functions are ones we don’t consciously think about,” explains concussion specialist Dr. Vincent Schaller, M.D., DABFM, CIC, founder of Mid-Atlantic Concussion Alliance, president and medical director of MAC Alliance. “While disruption to the ANS can result from disorders like diabetes and Parkinson’s disease, we know that autonomic neuropathy, also called dysautonomia, can also be affected by blows to the head.”
Post-Concussive Issues Can Include Trouble With Bodily Function Regulation
There’s a fine balance between the two parts that make up the ANS, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Both systems work in conjunction, in critical (and often opposite) ways to help regulate our bodily functions.
“While the sympathetic nervous system increases blood pressure, for instance, the parasympathetic system decreases it,” continues Dr. Schaller. Interestingly, the composition of the ANS results in a sort of yin and yang situation, where, despite opposite effects on the same organs, both systems are working at the same time in what’s known as the autonomic tone, which is a balance between the two systems depending on what the body needs.
ANS: The Sympathetic Nervous System (SNS): Fight or Flight
The sympathetic nervous system (SNS) part of the ANS is most commonly associated with what we call our “fight or flight” response, preparing us for stressful emergency situations. When your hair stands on end, for instance, or your palms sweat in uncomfortable situations, the functions are unconsciously occurring because of the efforts of your sympathetic nervous system. At the same time, the SNS is causing the body to release stored energy and increase heart rate, it is slowing body processes we don’t need during emergencies, such as urination or digestion.
ANS: The Parasympathetic Nervous System (PNS): Rest and Digest
Functioning in a seemingly opposite way, the parasympathetic nervous system (PNS) relates to what some call “rest and digest” actions, which may be a bit of an oversimplification. A common way of describing PNS is that helps with the slowing down of body processes during more normal situations, such as helping the body relax and stimulating digestion. We associate the PNS with energy conservation and the release of elimination of waste products.
ANS Dysfunction After Concussion
A 2019 article examining autonomic dysfunction following TBI published by researchers from University of Cincinnati and reported in the Journal of Neurosurgery noted that “it is likely that brain injury alters the fine balance between the sympathetic and parasympathetic arms of the autonomic nervous system, resulting in an imbalance of the homeostatic mechanisms that maintain normal organ system function and their interactions with each other.”
“Changes we note in the body following brain injuries can range from very mild to more severe, depending on what parts of the ANS have been affected,” says Dr. Schaller. They include:
- Hyperhidrosis (sweating excessively)
- Lowering or increase of blood pressure
- Immune system issues
- Balance issues
- Worsening headaches or migraines
- Heart palpitations or irregular heartbeat
- Insomnia
- Incontinence or other urinary problems
- Abnormal bloating, loss of appetite and other digestive issues
- Light, cold and/or heat sensitivity
- Dizziness
“Any new research on ANS is important when it comes to concussions,” says Dr. Schaller. “There’s a critical balance between these two systems and changes in this equilibrium means individuals must subsequently take the right steps after a head injury.”
Proper Dysautonomia Diagnosis and Treatment is Critical to Recovery
Even mild TBIs can impact the ANS. But the problematic issues you may notice as a result of ANS disruption won’t be picked up on regular imaging like CAT scans or MRIs. They can only be properly diagnosed and treated by specialists who understand how the brain relates to the body.
TBI specialists like Mid-Atlantic Concussion (MAC) Alliance help ensure that patients, caregivers, athletic trainers and other certified brain health professionals are aware of this dysfunction. They know that proper diagnosis, treatment, support and follow-up is imperative following head injuries that can disrupt various internal body processes.
Do You Have Lingering Dysautonomia Symptoms After a Concussion?
MAC Alliance works with healthcare affiliates, schools and individual patients to expertly diagnosis, evaluate and treat brain injuries. We often help post-concussive patients experiencing autonomic dysfunction or irregularities. We also team up with other types of brain health specialists, physicians and athletic coaches in neurocognitive (thinking and reasoning) and vestibular (balance) screening, diagnosis and treatment therapies to help address problematic symptoms. And we utilize today’s best diagnostic and treatment tools to address unresolved symptoms in post-concussion patients.
September 17th is National Concussion Awareness Day
Special Note: we observe National Concussion Awareness Day this month, founded in 2016 by then high school student Brooke Mills. Brooke was injured in gym class and suffered with post-concussion syndrome. The volunteer program she helped create is meant to increase concussion awareness “through education, support of research initiatives and charitable programs while giving hope to those affected by mild traumatic brain injury.”
On Lessen the Impact, Brooke and other students share their personal concussion experiences and the often baffling and long-haul (and sometimes traumatic) symptoms they experienced post- concussion. They stress how “not every injury is visible” along with the need for proper diagnosis, treatment and support for concussion patients “on the complicated thing that is a brain injury.”
—Reporting by Faith R. Foyil
