Dysautonomia - A possible cause of post-concussion syndrome

1. Persistent headache

2. Dizziness

3. Loss of balance

4. Difficulty with concentration/brain fog

5. Nausea

6. Impaired or slow cognitive activity The symptoms are vague and non-specific. In medicine, there's a tendency and a desire to have a condition be linked to one very specific piece of anatomy. That way you can treat the diseased organ and cure the illness. The reality is that a head injury is likely disrupting multiple body parts simultaneously. The higher centers of the brain aren't the only things that get scrambled during a concussion. A concussion is likely damaging multiple areas in the brain along with the inner ear organs, the neck, the jaw, and the eyes. Since every head injury is unique in terms of velocity, direction, and magnitude, it means that each person's head injury is likely to impact their anatomy in individual ways. This is where you can have a lot of variation in how someone with post-concussion syndrome looks symptomatically. Another struggle is that different body parts can create similar symptoms. An injury to the neck can cause a feeling of vertigo just like an injury to an inner ear organ. An injury to the neck can also cause headaches symptoms just like the eyes or the vessels in the brain. Some doctors are looking at another potential cause of persistent concussive symptoms called dysautonomia.

Dysautonomia - A Fight Between 2 Super Systems Dysautonomia is a condition where the brain loses normal control of the internal organ systems of your body. Dysautonomia can show up in organs like the digestive system, bladder, glands, and pupils. Classically, these disorders show up in the cardiovascular system by affecting your heart rate and blood pressure. The most common disorders linked to dysautonomia are:

1. Multiple sclerosis

2. Fibromyalgia

3. Postural Orthostatic Tachycardia Syndrome (POTS) - an illness characterized by rapid heart beat to 150-200 bpm at rest

4. Neurocardiogenic syncope - a disorder characterized by unpredictable fainting attacks. When people have these disorders then the broken function of the nervous system causes people to feel dizzy, in a fog, extremely fatigued, light headed, and anxious. When you read those symptoms on paper (or screen) it doesn't sound like much, but the way those symptoms persist can drive someone mad. People don't just have a brain fog, they are scared and frustrated that their brain won't allow them to focus and accomplish a task. People don't just have fatigue, they have an inability to socialize and be effective at work and at home because of exhaustion. People don't just have dizziness, they are worried about driving and being in open spaces because their body is betraying them. People don't just have a rapid heart beat, they have fear and anxiety that this next attack could put them in the emergency room. Having dysautonomia whether it's an illness on it's own like POTS, or part of another illness like MS can make life much harder and depressing, because treatment for the illness is really limited.

Post-Concussion Syndrome and Dysautonomia Going back to post-concussion syndrome, we discussed how the illness can be extremely frustrating because doctors and scientists have had a hard time coming to a consensus as to where the symptoms are coming from. Some doctors and scientists are presenting an interesting theory that cases of post-concussion syndrome may be a manifestation of dysautonomia. One of the first studies to look at this phenomenon was done in 2016 on young patients with persistent concussion symptoms. The study involved a test called the head-upright table tilt test. You can check out the full study here: Orthostatic intolerance and autonomic dysfunction in youth with persistent postconcussive symptoms: a head-upright table tilt study This test is used to diagnose feinting conditions but is also a hallmark test for POTS. The study showed that 24 out of 34 PCS patients had findings on the test indicating a form of dysautonomia. 10 Patients had syncope while 14 patients had POTS. Even more interesting was that when the patients with POTS stopped having PCS symptoms, they also stopped having a reaction to the table tilt test when re-examined. Another 2016 study showed that patients who have a history of concussion show a decreased ability to modulate their heart rate and blood pressure at rest indicating a loss of autonomic control. This was happening in patients without any overt signs or symptoms of dysautonomia. Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury Then you also have a wide range of studies looking at how concussion can impact your heart rate variability which is an increasingly utilized biomarker for autonomic nervous system activity. HRV Studies A dysautonomic theory of post-concussion syndrome can also help explain some of the unusual symptoms that may arise after a head injury. While it's easy to understand how a PCS patient can have persistent headache and dizziness, there are a lot of people who will have a concussion or whiplash and start developing persistent gut issues and sensitivities to foods. Dysautonomia as a culprit helps to make better sense of this phenomenon.

What Does This Mean for Treatment? Dysautonomia is a condition that is not well recognized by many physicians and there aren't many choices for effective treatment options. In dysautonomia, the brain is having a terribly hard time making sense of its environment. There's some interesting work going on utilizing balance and vestibular exercises and graded cardiovascular exercise to help the brain recover from injury, but I'll cover that on another day. Today I want to talk about the veins in your neck. Dr. Michael Arata is an interventional radiology specialist in Southern California. I heard him speak at a conference in 2015 where he talked about the effect that the veins in your neck could have on your autonomic nervous system. It's been an interesting and controversial theory that has been tied to illnesses like multiple sclerosis where dysautonomia is a hallmark of the illness. When the large veins in the neck become narrowed or occluded, it can cause abnormal fluid movement in the brain leading to venous reflux, congestion, and neuroinflammation in the brain. Dr. Arata even published 2 studies that demonstrating that a procedure that uses a balloon to open these veins was able to create changes in the autonomic function of patients with multiple sclerosis including heart rate variability and blood pressure control. Transvascular autonomic modulation: a modified balloon angioplasty technique for the treatment of autonomic dysfunction in multiple sclerosis patients. Blood pressure normalization post-jugular venous balloon angioplasty But that wasn't the most interesting part of his presentation. During his talk, he talked about the concept of the atlas vertebra creating compression on these vascular structures. He even used an imaging technique called a venogram to show this happening in his patients: It's because of this phenomenon that Dr. Arata actually refers some of his patients for upper cervical correction so that they can influence this part of the autonomic nervous system. If dysautonomia is a primary symptom generator in PCS patients, then the impact from a potential neurovascular insult like an craniocervical displacement should be considered especially considering the mechanism of injury includes a blunt force to the head.

An Personalized Approach to Post-Concussion Syndrome Patients with post-concussion syndrome with signs of dysautonomia likely have multiple systems that must be addressed to regain normal functionality. In addition to dysfunction in multiple systems is the idea that each person will have a varying tolerance to different therapies. In truth, no single therapy is likely to fix someone with persistent post-concussive symptoms and dysautonomia. These patients need to improve their tolerance to exercise with gradual increased load (especially if they're an athlete). They also need vestibular rehabilitation so that their brain can move the head and eyes normally again. There's no disputing the necessity and usefulness of those treatment strategies. However, if we are concerned about the chronic effects of head injury and the ability to improve fluid movement through the brain, then we have to consider the impact that trauma has on the structural alignment of the neck and the neuroinflammatory consequences that these injuries can leave behind.