Concussion is defined as a traumatically induced transient disturbance of brain function that involves a complex pathophysiologic process. It results from a direct blow to head, face or neck; or a blow elsewhere with impulsive forces transmitted to the head. With a concussion, there is rapid onset of short-lived neurologic impairment. This is an isolated functional injury without any structural disturbance and the impairment occurs at cellular level.
A recent report estimated 1.0 to 1.8 million Sports-Related Concussions (SRCs) per year in the age range of 0 to 18 years and a subset of about 400,000 SRCs in high school athletes. Determining actual sport or activity-based concussion rates is difficult. It is estimated that more than 50% of high school concussions are not even related to organized sports, and only 20% are related to organized school team sports. Between 2% and 15% of athletes participating in organized sports will suffer a concussion during a single season. Symptoms can be variable, ranging from physical (amnesia), somatic (headache), emotional (labile, irritable), or cognitive (feeling in a fog). Headache is the most common (85.2%).
Concussion is a clinical diagnosis! It is made through a combination of history and physical exam, including mental status, cognitive function, neck, cranial nerves, strength, balance, coordination, and gait. A neurologic exam is done to rule out more seriously pathology, such as intracranial bleed. If this is a concern, the athlete is immediately sent to the hospital and a head CT scan would be indicated. However, this is often unnecessary for a routine concussion.
Multiple tools are available to assist in sideline evaluation, including the SCAT 5 evaluation tool. (http://bjsm.bmj.com/content/47/5/259.full.pdf). An athlete is not permitted to return to sport the same day as a diagnosed concussion! This is due to a theoretical concern for more serious injury with repeated blow after concussion.
There is a need for more definitive and objective clinical tools for diagnosing concussion. This interest has led to a plethora of innovative technologies, but unfortunately, there is ongoing need for validation of these tools. The following technologies have yet to be prove sufficient research to establish their utility; sideline evaluation tools, helmet and non-helmet impact monitors, fluid biomarkers, genetic testing. Computer and neurocognitive testing have also become more prevalent in clinical management of concussion. Again, they are not the sole basis for a decision making and should be used only as part of a multifaceted approach. Treatment involves a combination of physical and cognitive rest until symptoms resolve, followed by a step-wise return-to-play protocol. The majority (80-90%) of concussions resolve within 7-10 days but recovery and outcomes are individualized.
Recent 2019 consensus guidelines endorse 24 to 48 hours of symptom-limited cognitive and physical rest followed by a gradual increase in activity, staying below symptom-exacerbation thresholds. Further research is needed to define the role of prescribed rest in recovery. “Return to learn” is the process of transitioning back to the classroom after a concussion through the use of individualized academic adjustments, as concussions can induce changes that may temporarily make learning difficult. School personnel should be informed of the injury and implement an initial school support plan.
“Post-Concussive Syndrome” is when symptoms do not resolve over 4 weeks. This occurs in less than 10% of concussions and is often confounded by ADHD, migraines, learning disabilities, etc.
“Chronic Traumatic Encephalopathy” (CTE) is a theorized distinct progressive neurological deterioration resulting from repetitive concussions. It was first described in 1920’s with boxing, “dementia pugilistica,” and can involve memory disturbances, behavioral/personality changes, parkinsonism symptoms, speech and gait abnormalities. Opponents contend that it is not a distinct clinical syndrome, stating that there are many confounding factors that could lead to similar neurologic deterioration. At this point, a definitive causal link between CTE and concussion or exposure to contact sport has yet to established.
The takeaways are as follows; remove athletes from sport immediately and have them evaluated by a health care professional, educate parents and ensure supervising adults know concussion signs/symptoms, teach best safety practices, and recommend parents consider carefully the potential risks and benefits of athletic participation.
Harmon KG,, et al. American Medical Society for Sports Medicine Position Statement on Concussion in Sport. Clin J Sport Med 2019; 29:87-100)