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Traumatic Brain Injury

Understanding the Concussion Symptoms You May Not Expect

Symptoms like sugar cravings and temperature shifts can be confusing.

On top of the well-known symptoms you may experience after a head injury—including short-term memory deficits, difficulty focusing and concentrating, fatigue, noise and light sensitivity, headaches, vomiting or nausea, vision problems, balance issues, emotional dysregulation, and sleeping disturbances—there are a host of other lesser known effects to brain and body functioning that can occur. These symptoms can continue for months or even years, despite the severity of the injury.

As a certified brain injury specialist and clinical psychologist specializing in treating car accident survivors, I see a large gap between brain injury research findings and the treatment of patients’ often extensive TBI fallout. Many of my patients report experiencing cravings for sugary foods, changes to blood pressure—including fainting spells or feeling lightheaded—difficulty regulating body temperature, noticing an increase in bouts of the flu or colds, or suffering from a constant runny nose.

Why Do These Lesser-Known Effects Occur?

Recent scientific studies on head injuries help to explain what is actually occurring in the brain and the body to cause these issues.

The brain’s main source of energy is glucose. After a head injury, the brain requires an increased amount of energy to assist in healing and maintaining the blood flow for neuronal connections—hence the cravings for sugar that some patients report.

However, if you have a TBI, there is a danger in consuming too many refined sugars, as they can increase the brain’s already existing inflammation. Stick to anti-inflammatory and antioxidant foods such as dark chocolate and fruit instead.

A study from UCLA reported that “the level of brain glucose use in people who suffer mild concussions is similar to that in comatose, severely brain-injured patients. Even mild head injuries result in major changes in the brain’s metabolism.” The study’s findings are further evidence that simply labeling a concussion or brain injury as “mild” does not mean that the symptoms experienced are any less debilitating than those from a more severe head injury. In fact, there are studies that suggest that recovery from an mTBI (mild traumatic brain injury) can be much more prolonged than recovery from a moderate or severe TBI.

We know that a head injury can cause dysfunction in the autonomic nervous system, which can result in high or low blood pressure, and may also result in POTS (postural orthostatic tachycardia syndrome). Many concussion patients experience lightheadedness, vertigo, or dizziness as a result of these blood pressure changes.

Nervous system dysfunction can also cause difficulties with regulating body temperature, causing the feeling of always being too cold or too hot. Temperature instability can occur due to metabolic changes in the brain as well as neuro-inflammation and/or injury to the hypothalamus, the structure in the brain that coordinates the activity of the nervous system and the pituitary gland.

The neuroinflammation that a brain injury leaves in its wake also compromises the immune system, leaving many patients more at risk for suffering colds and the flu more frequently. There are some interesting studies that suggest that some of the neurodegenerative effects from a head injury are caused by the body’s immune system response to the injury with postulations that the immune system attacks the brain after injury. More research in the area of immunology as it relates to brain trauma is needed.

To further complicate the symptom presentation picture after a head injury, experiencing a runny nose, headaches, clear fluid coming out of your ears, blurred or double vision, changes in hearing, neck pain, dizziness, vertigo, light sensitivity, nausea, vomiting, balance or gait problems may be attributed to a CSF (cerebrospinal fluid) leak. Some of the symptoms are often mistaken for recurring migraines, sinus infections, or allergies.

In my book on car accident recovery, I highlight the particular importance of ruling out a CSF leak. If a leak is suspected, it’s crucial to have your healthcare providers run imaging and diagnostic tests as the condition is treatable.

For TBI sufferers up against a healthcare system that tends to be overly focused on acute neurological care—along with the unfortunate reality that there is still a great deal we have yet to understand about the intricacies of healing the brain after trauma—it’s important that those treating concussions address all of the varied symptoms a patient may be experiencing.

I argue that neurorehabilitation after a brain injury needs to do much more to address lesser-known concussion effects and requires a holistic, interdisciplinary team approach that may include a neurologist, neuropsychologist or neuropsychiatrist, clinical psychologist, rehabilitation physician and nurses, pain management specialist, naturopath, dietician, neuroendocrinologist, physiotherapist, occupational therapist, speech and language therapist, social worker, case manager, and family and friends. With a more multi-dimensional, comprehensive team approach based on the sharing of research and knowledge amongst disciplines and an appreciation that no two brain injuries are the same, concussion patients could achieve greater recovery over a shorter time span.


Cleveland Clinic. “Cerebrospinal Fluid Leak.”, accessed January 12, 2023.

Eliza Marie Summers. “Feed Your Brain to Boost Recovery.” Brain Injury Hope Foundation, accessed January 2023.

Laura N. Verboon, Hiren C. Patel and Andrew D. Greenhalgh. “The Immune System’s Role in the Consequences of Mild Traumatic Brain Injury (Concussion).” Frontiers in Immunology, February 15, 2021.

Lea Farah. “Concussion and Sugar Cravings.” Concussion Home, accessed January 2023.

Dr. Jaycle Loewen. “Why Concussion Can Lead to Blood Pressure Changes and POTS.” Cognitive fx, May 24, 2022.

James F. Zender, PhD (2020). Recovering from Your Car Accident. The Complete Guide to Reclaiming Your Life. New York: Rowman & Littlefield.

Jeanne Paz. “Blocking an Immune System Molecule in Mice May Help Prevent Long-Term Disabilities After Traumatic Brain Injury.” The Conversation, December 14, 2021.

Ji-Woong Oh, So-Hyun Kim, and Kum Whang. “Traumatic Cerebrospinal Fluid Leak: Diagnosis and Management.” Korean Journal of Neurotrauma, October 31, 2017.

Ram Gowda, Matthew Jaffa and Neeraj Badjatia. “Thermoregulation in Brain Injury.” Handbook in Clinical Psychology, November 17, 2018.

Viktoriia Chaban, Gerard J.B. Clarke, Toril Skandsen, Rakibul Islam, Cathrine E. Einarsen, Anne Vik, Jan K. Damås, Tom E. Mollnes, Asta K. Håberg and Soeren E. Pischke. “Systemic Inflammation Persists the First Year after Mild Traumatic Brain Injury: Results from the Prospective Trondheim Mild Traumatic Brain Injury Study.” Journal of Neurotrauma, September 18, 2020.

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