Despite advances in new knowledge and technologies, a minority of concussion sufferers will experience prolonged complications, including headaches, depression, and memory problems for reasons that are not fully understood. A few will experience more severely acute and/or chronic complications.
According to Barlow (2016), 1 in 7 children with a diagnosed mTBI will develop prolonged symptoms for 3 or more months after a concussion in a condition described as post-concussion syndrome (PCS). Criteria for the threshold of time for this diagnosis varies from one to three months, and sources differ on required number of symptoms. Studies have not explicitly defined what factors put some children at greatest risk for PCS; however, a recent study concluded that prolonged symptoms appear to be related to initial symptom severity, female gender, amnesia, and loss of consciousness (Fehr et al., 2019). Optimal management for prolonged symptoms should be directed by a multiprofessional team under guidance of an expert in concussion practice, and should offer needed psychological, physical, and cognitive therapies (McCrory et al., 2013).
Second Impact Syndrome
Unlike PCS, second impact syndrome is a rare but acute disorder that develops after a second impact while the brain is still recovering from the first. It should be noted that the first 10 days after a concussion appear to pose the period of greatest risk for being diagnosed with another concussion (AAN, 2013; Guskiewicz & Valovich-McLeod, 2011). Given the metabolic nature of an mTBI, a second impact can impede the brain's ability to restore its equilibrium, resulting in mental status changes followed by eventual loss of consciousness (McLendon, Kralik, Grayson, & Golomb, 2016). This condition has been observed primarily in adolescent male athletes and is often fatal, with those surviving frequently left with severe disabilities (Guskiewicz & Valovich-McLeod, 2011; McLendon et al., 2016). All reported cases occurred in athletes under age 20 years (Halstead & Walter, 2010; McLendon et al., 2016). According to McLendon and colleagues (2016), the second impact causing a concussion may be of decreased magnitude and does not have to be a head impact. Typically occurring 24 to 48 hours after the second impact, cerebral edema may develop due to the brain's inability to autoregulate cerebral pressure, leading to fatal herniation (McLendon et al., 2016).
Long-term Effects: Chronic Traumatic Encephalopathy (CTE)
Some evidence indicates that the effect of multiple concussions over time can increase the risk of chronic cognitive or neurobehavioral dysfunction (AAN, 2013; McCrory et al., 2017; Norton et al., 2013). This grave condition, known as chronic traumatic encephalopathy (CTE), has received considerable media attention in recent years that primarily focuses on sports figures who have developed depression and suicidal tendencies after years of play. Risk factors appear to include prior concussions and longer exposure to the sport beginning at an early age (AAN, 2013; McLendon et al., 2016). Marked by the gradual build up of tau, a type of brain protein deposit, CTE cannot be detected by MRI or imaging. Currently, the only way to diagnose abnormalities associated with CTE is through autopsy (Norton et al., 2013). Evidence of this condition has been found in deceased persons as young as age 18 years (Halstead & Walter, 2010; Norton et al., 2013). However, reasons why a few persons, but not most, develop this condition are not fully understood; therefore, more research on CTE is needed (McCrory et al., 2017).
A Troubling Finding
Evidence is emerging suggesting cognitive changes in players who have experienced repeated sub-concussive impacts or micro-trauma from activities, such as heading a soccer ball, without a clinically diagnosed concussion (Goldsmith & Ver Hage, 2011; Johnson & Syd, 2012; Talavage et al., 2014). A longitudinal assessment of football players (age 15 to 19 years) revealed that a subgroup of these players, who exhibited no clinical symptoms, were showing measurable neurocognitive impairments (Talavage et al., 2014). Furthermore, the Berlin Consensus Statement (McCrory et al., 2017) cited multiple studies, suggesting that subtle microscopic alterations may exist within nerves and brain cells of recovered patients without apparent symptoms; thus, some of these players who reported no symptoms (or were unaware they were experiencing them), may have suffered neurological injury.
Pediatr Nurs. 2019;45(5):235-243. © 2019 Jannetti Publications, Inc.