Persistent post-concussion syndrome (PCS) is more common than many clinicians or patients might expect, affecting up to 22% of individuals who sustain a concussion. (1) Unlike the acute effects of traumatic brain injuries, PCS represents a chronic condition that persists for months, years or even decades after the initial trauma. These patients often face debilitating symptoms that impair their quality of life, yet the condition is often underdiagnosed or dismissed. As health care providers, it is crucial to address PCS holistically, recognizing its wide-ranging effects that go far beyond the brain.

Neurological Findings in Persistent Concussion Syndrome

Persistent PCS often presents with a constellation of neurological symptoms that can profoundly affect daily functioning. Visual convergence issues, for example, are common, leading to difficulty reading or focusing on close objects. (2)  Vestibular dysfunction, such as dizziness or balance problems, adds another layer of disability, frequently resulting in falls or reduced activity levels. (2) Cognitive difficulties like poor memory and concentration are hallmark features, often described by patients as “brain fog.” (3)  The emotional toll of these symptoms cannot be overlooked; many patients experience irritability, depression or chronic fatigue, compounding their struggles. These issues highlight the critical need for a comprehensive, multidisciplinary approach to care.

The Gut-Brain Connection in PCS

Emerging research underscores the role of gut health in chronic PCS. Traumatic brain injuries can induce systemic inflammation, disrupting the gut-brain axis. (4-8) This leads to increased intestinal permeability, or “leaky gut,” which perpetuates neuroinflammation and exacerbates symptoms. (9,10) Dysbiosis, or imbalances in gut microbiota, may further drive this process, contributing to cognitive impairment, mood disorders and systemic fatigue. (11) Addressing gut health through improving brain health, dietary interventions, specific probiotics and targeted supplementation can be a pivotal component in managing PCS effectively.

Hormonal Imbalances and Chronic PCS

The endocrine system often takes a hit in the aftermath of a concussion, particularly when the hypothalamic-pituitary axis (HPA) is disrupted. Dysregulation of sex hormones (like testosterone and estrogen), cortisol and thyroid hormones can manifest as chronic fatigue, poor stress tolerance and mood instability. (12- 15) Growth hormone deficiency is another common yet underappreciated sequela of concussion, associated with cognitive deficits and decreased quality of life. (15) These hormonal findings are likely attributed to how concussions specifically affect the anterior pituitary gland, where many of these hormones are released or regulated. Therefore, identifying and treating these hormonal imbalances via thorough hormone analysis and evidence-based interventions is critical in helping patients recover fully.

Conclusion

Persistent post-concussion syndrome is a multi-faceted condition that demands a broad clinical lens. From the brain to the gut to the endocrine system, its effects ripple through the body, leaving patients with a range of chronic, debilitating symptoms. This information should also inspire clinicians to consider previous mild traumatic brain injuries as a root cause of a patient’s chronic complaints.  By addressing the neurological, gastrointestinal, and hormonal dimensions of PCS, clinicians can provide more effective, individualized care. In doing so, we must appreciate how the brain interacts with other bodily systems and truly support recovery for the whole person.

Read more Doctor of Chiropractic – Illinois Student Blogs here.

References:

1. van der Vlegel M, Polinder S, Toet H, Panneman MJM, Haagsma JA. Prevalence of Post-Concussion-Like Symptoms in the General Injury Population and the Association with Health-Related Quality of Life, Health Care Use, and Return to Work. J Clin Med. 2021;10(4):806. Published 2021 Feb 17. doi:10.3390/jcm10040806
2. Master CL, Bacal D, Grady MF, et al. Vision and concussion: symptoms, signs, evaluation, and treatment. Pediatrics. 2022;150(2):e2021056047. doi:10.1542/peds.2021-056047.
3. McInnes K, Friesen CL, MacKenzie DE, Westwood DA, Boe SG. Correction: Mild Traumatic Brain Injury (mTBI) and chronic cognitive impairment: A scoping review. PLoS One. 2019;14(6):e0218423. Published 2019 Jun 11. doi:10.1371/journal.pone.0218423
4. Xu W, Yue S, Wang P, Wen B, Zhang X. Systemic inflammation in traumatic brain injury predicts poor cognitive function. Immun Inflamm Dis. 2022;10(3):e577. doi:10.1002/iid3.577
5. Witcher KG, Eiferman DS, Godbout JP. Priming the inflammatory pump of the CNS after traumatic brain injury. Trends Neurosci. 2015;38(10):609-620. doi:10.1016/j.tins.2015.08.002
6. Norden DM, Muccigrosso MM, Godbout JP. Microglial priming and enhanced reactivity to secondary insult in aging, and traumatic CNS injury, and neurodegenerative disease. Neuropharmacology. 2015;96(Pt A):29-41. doi:10.1016/j.neuropharm.2014.10.028
7. Hanscom M, Loane DJ, Shea-Donohue T. Brain-gut axis dysfunction in the pathogenesis of traumatic brain injury. J Clin Invest. 2021;131(12):e143777. doi:10.1172/JCI143777
8. Soriano S, Curry K, Sadrameli SS, et al. Alterations to the gut microbiome after sport-related concussion in a collegiate football players cohort: A pilot study. Brain Behav Immun Health. 2022;21:100438. Published 2022 Mar 1. doi:10.1016/j.bbih.2022.100438