Concussions: A Review of Physiological Changes and Long-Term Sequelae.

A concussion is a type of mild traumatic brain injury (mTBI). It is prevalent among athletes across a wide variety of sports. The exact mechanism of a concussion is unknown, but it is currently accepted that the acceleration and deceleration of the brain is the insult causing disturbances in activity. The most common symptoms of concussions include but are not limited to dizziness, nausea, vomiting, and headaches. With repetitive concussive injuries, athletes can experience permanent changes such as chronic traumatic encephalopathy (gradual degeneration of brain tissue), which can lead to personality changes and memory deficits. This literature review aims to provide insight into concussions and the evaluation of physiological changes and long-term sequelae. A comprehensive literature search was performed from April 2012 to April 2022 using PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online) and Embase databases. Nineteen articles were finally included in the literature review. The review shows that neuroimaging results demonstrated significant changes in the brain structure and function including alternations in the thalamus, hippocampus, corpus callosum, and the white matter, which can extend beyond the symptom amelioration. In addition, other approaches include brain metabolism, cerebral blood flow, and glucose utilization. Additional techniques include the evaluation of fatigue levels and the alterations in biomarkers, specifically IL-6. These approaches have demonstrated that consequences of concussions, including alternations in brain structure and function, can extend beyond an athlete's report of symptom resolution, and should be taken into consideration for return to play. The physiological changes present after a concussion have the potential to develop into long-term complications such as academic difficulty, cognitive decline, gut microbiome changes, gait changes, and increased risk of lower extremity injury. The findings in the literature review determine that is important to immediately address the symptoms of concussions to expedite treatment and prevent deleterious changes to the brain.