What occurs when an athlete who has sustained a previous concussion is returned to play prior to resolution of symptoms and then receives another head injury?

Definitions and Epidemiology

Concussion/mTBI is a purely clinical diagnosis. Characteristics include a history of altered neurologic function due to an external force transmitted to and through the brain, often leading to transient changes in the level of alertness or orientation. Concussion/mTBI may occur in a diverse range of circumstances. Common examples include blunt nonpenetrating head trauma from community events such as falls or assault, acceleration and deceleration forces from whiplash in traffic collisions, body checking in contact or collision sports, or blast injury among military personnel. Based on clinical features ascertained at time of injury (sometimes specified as within 30 minutes from index event), a diagnosis of concussion/mTBI can be distinguished from moderate and severe TBI in several ways using the current system of injury stratification. There is usually a transiently altered level of alertness or orientation, no or only brief (0 to 30 minutes) loss of consciousness, peri- or post-traumatic amnesia lasting less than 24 hours, the onset of neurologic or other symptom immediately or within 1 to 2 days, and a Glasgow Coma Scale (GCS) score of 13 to 15. In 2015, the Department of Defense (DoD) published a memorandum indicating that the GCS should not be used in diagnoses of TBI.

Concussion/mTBI is a global health problem. In the United States alone, there may be at least 2.5 million TBI-related emergency department encounters annually, and this is likely an underestimate due to unrecognized concussive injury, patient or clinician misappropriation of symptoms to alternative diagnoses, or under-reporting.1 The majority (80 to 90% or more) of all head injuries are classified as concussion/mTBI. Traffic and other community accidents may occur indiscriminately, but there are several groups at particular risk for sustaining head injury, including athletes, older adults (from falls), military personnel, and individuals with a prior history of TBI. Different mechanisms of injury may instigate distinct pathophysiologic sequelae, such as with blast exposure. There may also be unique patient or population level attributes that affect acute and subacute periods (e.g., physical resilience in athletes, cognitive vulnerability in older adults). Nonetheless, current injury classifications and subsequent management strategies are applied broadly to identify and treat concussion/mTBI since there is a paucity of evidence at this time to promote significantly differing management strategies solely based on the mechanism of injury.6 Patient-level characteristics should always be taken into consideration as with any complex medical condition.

Commonly utilized postinjury epochs include the immediate period (week 1), the acute period (weeks 1 to 6), the postacute or subacute period (weeks 7 to 12), and the chronic period thereafter. Many individuals recover briskly after concussion/mTBI within hours to days (typically 1 to 2 weeks), though symptoms may dissipate over several weeks in others. A frequently used benchmark for complete symptom resolution is 3 months, although some individuals remain symptomatic for weeks or even months afterward.

The majority of individuals with a history of concussion/mTBI can still expect a full recovery even if symptoms persist after 3 months. However, at least 10 to 25 percent of those with a history of concussion/mTBI may have a protracted symptom burden extending well beyond the traditionally quoted time periods noted above.7 In this setting it may become challenging to disentangle unmasked or exacerbated premorbid conditions such as mood, headache, or sleep disorders from those persisting after injury. An additional complicating factor is that many of these same comorbid conditions may place an individual at risk for a protracted recovery course perhaps due to as-yet undefined pathophysiologic or psychosocial vulnerabilities. Moreover, neuroendocrine dysfunction is an under-recognized consequence of concussion/mTBI and, like impaired sleep, can accentuate symptom burden.

Initial Evaluation and Diagnosis

The clinical syndrome produced by a concussion may take several hours to develop (McCrory et al., 2017). Given that, it is important to recognize that the role of the medical provider at a sporting event or practice is to triage for safety and screen for emergent neurological injury rather than to diagnose concussion per se. The likelihood of concussion is best clarified over the days following the injury. During this time, if concussion is suspected, the patient should not be allowed to participate in any activity involving the risk of impact.

If, after an biomechanical insult, a patient is unconscious or unresponsive, safety concerns should immediately be addressed. A focused physical examination is important to exclude other critical diagnoses, including cervical spine injury. Transfer to the emergency room (ER) should occur with any open injury, convulsive activity, altered mental status, persistent Glasgow Coma Scale (GCS) score less than 15, or focal neurological deficit. After an emergent situation has been ruled out, the evaluation for concussion begins, with screening for specific signs and symptoms (Table 61.1).

Previously, concussion was both diagnosed and then further graded based on the presence and duration of loss of consciousness as well as the presence of specific symptoms (i.e., disorientation/confusion). However, loss of consciousness occurs in less than 10% of concussions and does not predict the duration or severity of injury. More recently, previously used scales and grading systems have been abandoned in favor of more individualized approaches.

Symptoms from concussion may present directly after the traumatic force is applied or several hours later. In the acute setting, it is difficult to rely solely on the clinical evaluation, since the complexityof the brain creates significant variability in the type and severity of concussion presentations (Kutcher et al., 2013). Therefore meaningful diagnostic and management tools—including objective measures of eye movement, clinical reaction times, and balance as well as neurocognitive tests—may be helpful. Standardized assessment tools may provide a structure for the evaluation of concussion (Harmon et al., 2013). Graded symptom checklists may also be helpful. These tools can help to document the clinical presentation, can aid in diagnosis, and serve to document recovery.

Several assessment tools exist, including the Standardized Assessment of Concussion (SAC), the Standardized Concussion Assessment Tool (SCAT5;McCrory et al., 2017), and the Military Acute Concussion Evaluation (MACE;Coldren et al., 2010; Eckner et al., 2010; Kutcher et al., 2010). Most tools include aspects that track concussion symptoms, cognitive performance, and balance. It is important to note that some of these tools have not been standardized for use in children or adolescents. Cognitive evaluation usually includes the assessment of orientation, immediate memory, and delayed recall as well as concentration, learning, and attention. The physical examination usually includes assessments of speech fluency, cranial nerve examination, pronator drift, and gait.

Management of Concussion Complications

Headaches are among the most common symptoms of a concussion and often the symptom that bothers the athlete the most. In the acute period after injury, medications have some potential to mask important symptoms. For the first 1 to 2 hours after the injury, it is important to be able to accurately monitor the patient for a changing clinical picture, which could suggest that the head injury is not a concussion but rather an evolving epidural or subdural hematoma. For the first 24 hours, NSAIDs and aspirin should be avoided because they can thin the blood and potentially make an undiagnosed hematoma become a more significant bleed. Acetaminophen (Tylenol) is the preferred medication for headache in the first 24 hours. After the first day, it is safe to switch to ibuprofen (Motrin), which may have more benefit. If headaches are not improving after 3 to 5 days, it is advisable to switch to another medication that does not pose the risk of creating rebound headaches. Tricyclic antidepressants are a good choice and work very well. Nortriptyline (Pamelor)1 at a low dose (25 mg/d) is generally well tolerated in children as well as adults and may be stopped abruptly without withdrawal symptoms once the athlete is feeling well and ready to progress back to activities.

Sleep disturbances in athletes with concussion are also very common. Many will not sleep well the first night after injury and want to nap during the day. Other athletes may sleep much more than usual after initial injury. Although there are no clear studies proving the optimal amount of sleep, current trends are to try to return the athlete to normal sleep cycles and daily living as much as possible. An emphasis on sleep hygiene over the first few days is standard. If insomnia persists after 2 to 3 days, medications may be considered. Melatonin7 is available over the counter, has very few side effects, and is generally well tolerated. The next step would be amitriptyline (Elavil)1 at a low dose (10– 25 mg/d). This can be especially effective if the athlete has both headaches and poor sleep because it is more sedating than nortriptyline.

A concussion is expected to last no more than 14 days in an adult and less than 4 weeks in the pediatric population. Each individual physician will have a different comfort level treating concussion; however, it is reasonable to consider a referral to a specialty physician once an athlete has passed the normal expected recovery time and is not categorized as a “prolonged concussion.” Each city or region will have a different culture about who takes care of the prolonged concussions. Neurologists, sports medicine physicians, and physical medicine and rehabilitation physicians are all well equipped to take care of these athletes. Physical therapists, particularly those who specialize in vestibular rehabilitation, can be very helpful to patients with continued balance problems, concentration difficulties, and other visual symptoms. Last, neuropsychologists can be extremely helpful in difficult cases. Some athletes have complicated clinical histories prior to the injury. Attention-deficit/hyperactivity disorder, depression, anxiety, and chronic headaches can all make the clinical picture very confusing when the athlete is having symptoms such as concentration difficulties, mood swings, insomnia, or headaches that are not improving as expected. It is important to remember that many athletes would not rate their symptom severity score as all zeros at baseline, so expecting them to achieve this goal after injury is impractical. When this scenario is suspected, referral for neuropsychiatric testing can help to divide out which symptoms may be concussion related and which could be more chronic in nature.

KEY FACTS

Abstract

Concussion occurs in childhood across the age span from very young children to young adults, with each population having special considerations. Children may sustain a concussion from multiple different mechanisms of injury, not just sports participation, and an adequate clinical index of suspicion for the diagnosis of concussion in all settings where injury may occur is necessary. In addition, school is a primary vocation for children and concussion, with its associated cognitive, visual, and vestibular disturbances, may particularly impact their ability to fully participate in academics. Special consideration must be taken for academic adjustments and accommodations during the recovery from a concussion. Management goals include a full recovery and return to activity in school, sports, and life. For those with prolonged persistent concussion symptoms, there are emerging active therapeutic approaches that may be utilized in order to optimize the full return of children to the broad range of their life activities in a timely fashion.

Introduction

Concussion, or mild traumatic brain injury (mTBI), is a common, yet complex clinical entity. As concussion gains more attention within the medical, sport, military, and civilian populations, there has been a drive toward producing a common definition, diagnosis, and management approach. Currently, the diagnosis of concussion is clinical—based on history, symptoms, and examination. Early treatment centers on symptom management and reassurance is key as most concussions are self-limiting. This chapter provides a high-level overview of mTBI including the current working definitions, relevant epidemiology, and pathophysiology, as well as an evidence-based approach to acute diagnosis and management. Early mTBI will be covered over time, delineating the evaluation and management of mTBI in the minutes, hours, days, and weeks following concussion.

Military/Veterans

Concussions in the military are as ubiquitous as they are in the general population. Falls, motor vehicle accidents, and blunt trauma accidents are the most frequent etiology. However, assessing concussion in the combat theater is a special challenge. Injuries from blast-related events are common and span the range of polytrauma injuries to concussion. Similar to sports-related contexts, military personnel who may sustain an altered mental status without additional injury may, as a result of training and culture, underreport their initial symptoms in order to return to duty as soon as possible. In-field assessment may be dangerous and unreliable since the environment may be full of potential distractions. Delayed assessment may thus miss acute sequelae. Screening measures have been adapted and applied to aid medics and other personnel to identify cognitively based acute concussion.11 Despite these challenges to accurate assessment, persistent postconcussive complaints from combat personnel follow similar PCS complaint explanations. Studies show that when psychological factors are accounted for, there is essentially no significant contribution of the actual concussion to PCS complaints. Thus, PCS has been attributed to psychological factors and not neurological sequelae.11,96 Concussion assessment in military veterans presents its own challenges. Many active duty military service personnel are referred for neuropsychological assessment over a self-reported history of concussion during deployment, often without any corroborating medical documentation. Similarly, when veterans are routinely screened for a personal history of TBI, and if the screen is positive, they are referred for a TBI second-level examination where clinicians are asked to determine if there has been a likely TBI incurred, often only based on self-report.97 These second-level examinations are usually clinical in nature and involve an interview and possibly the completion of self-report checklists covering neurobehavioral symptoms. If the second-level examination is positive, or if the patient continues to report neurobehavioral complaints, they are often referred for formal neuropsychological assessment.98 Another pathway that veterans receive neuropsychological assessment for a reported concussion history is through a referral to compensation and pension through the veteran's benefits administration (VBA).99

Sports Concussion

Concussions are mild traumatic brain injuries sustained as a result of direct blows to the head or forces transmitted through the head and neck. The CDC estimates that 1.6 to 3.8 million sports- and recreation-related traumatic brain injuries occur each year. They occur in all sports but are most common in contact and collision sports. Concussions can result in symptoms, physical signs, behavioral changes, cognitive impairment, and sleep disturbance (Box 39.8). These symptoms are typically caused by a functional disturbance of the brain rather than a true structural injury, although there may be structural injury on a cellular level that cannot be assessed with standard imaging. It is vital to recognize that concussions rarely result in a loss of consciousness. Concussion symptoms are generally transient, although chronic sequelae might occur.

Pathophysiologically, the concussed brain exhibits increased metabolic needs combined with decreased cerebral blood flow.17 This mismatch of “supply and demand” creates a state of tissue vulnerability. Second-impact syndrome is a rare and catastrophic outcome related to concussion that might be caused by this mismatch. This phenomenon is seen when a youth athlete receives a second impact before the symptoms of the first concussion have subsided. These rare injuries have been reported only in youth athletes and result in severe brain injury and even death from malignant cerebral swelling.

The most vital component of concussion care is the prompt recognition of the injury itself. Athletes, coaches, trainers, and family members should have some degree of education regarding the most common signs and symptoms. Many states mandate annual coaching education on concussion as part of their concussion laws. An athlete with a suspected concussion should be removed from play immediately and evaluated on the sideline. The Standardized Assessment of Concussion, Pocket Sport Concussion Assessment Tool 5, and Maddocks questions are commonly used sideline tools. They do not replace the value of a more thorough assessment to detect more subtle abnormalities.163 The current consensus is that athletes should not RTP on the same day as a concussion. In certain professional athletic settings, adult athletes can RTP on the same day once cleared by a health care provider.163

Imaging is initially reserved for situations in which an intracranial abnormality is suspected, including prolonged loss of consciousness, focal neurologic deficit, or progressive decline in neurologic status. In athletes with prolonged or severe symptoms, magnetic resonance imaging (MRI) can be used to evaluate for other intracranial abnormalities. Newer imaging protocols, such as functional and diffusion-weighted MRI, positron emission tomography, and diffusion tensor imaging, are emerging but are not yet part of current concussion management.

Neuropsychological (NP) testing is a useful component in the management of concussions. Cognitive and somatic symptoms typically improve in parallel but often completely resolve at different times. As such, NP testing can give added information that cannot be gained in a typical clinical setting. Neuropsychologists are best suited to interpret these data, but in situations where no neuropsychologist is available, other medical professionals can be trained to perform the interpretation.68 However, NP testing is only one component of concussion management, and the decision to RTP is ultimately a medical one.

In the first several days to weeks after an injury, athletes with concussions are managed with relative physical and mental rest. This includes limiting activities that require concentration and attention such as scholastic activity, video games, computer use, and text messaging. These activities often exacerbate the athlete’s symptoms and can prolong the final resolution of symptoms. Youth athletes might require individualized schoolwork adaptations and the cooperation of school administration (e.g., extended test-taking time, tutors, limited class schedules). Section 504 of the Americans with Disabilities Act, part of a federal law that protects students with disabilities, is often used to create plans to help concussed athletes continue to participate in school.

Data support that athletes with prolonged recoveries are safe to begin subthreshold exercise programs, which may speed recovery. The optimal timing and type of exercise are unclear, but exercise 1 to 2 weeks after the injury has proven safe in study protocols. Resistance and interval training has not yet been studied. Vestibular rehabilitation has been shown to aid athletes suffering from dizziness, vertigo, or impaired balance after concussion. Optimal timing and duration of these programs are not known.220 Prognosis after sports-related concussion is typically excellent, with 80% to 90% of athletes free of symptoms within 7 to 10 days.162 Children and adolescents are notable exceptions and may have a longer recovery time.163 RTP decisions can be challenging and must be made by practitioners familiar with concussion management. No athlete should RTP until all the symptoms of the concussion have resolved and the athlete has returned to their baseline. Once the athlete is asymptomatic at rest, a stepwise approach RTP protocol must be completed before competition is resumed (Table 39.6). The athlete will need a 24-hour symptom-free period before advancing to the next step in the protocol. No athlete should be returned to competition while still symptomatic.

Athletes with repeated concussions must be evaluated on an individual basis. These athletes may have a prolonged recovery and may have higher symptom severity.46,47,49,230 An increasing body of literature suggests concussions are an independent risk factor for long-term deficits in executive function and processing speed.47,100 The phenomenon of athletes suffering increasingly severe concussions with decreasing impact severity should raise significant concerns for the physician. These athletes might need to consider giving up contact sports and might not be cleared to participate.33

Chronic traumatic encephalopathy (CTE) is a disease thought to be caused due to repeated concussive or subconcussive blows to the head. Pathologically, CTE involves the deposition of tau protein and amyloid plaques within the brain.164 This pattern and the accompanying syndrome are distinct from other tauopathies and other neurodegenerative diseases. A formal consensus for neuropathologic diagnosis has been developed for CTE, although diagnosis cannot be confirmed in living persons.165 There have been cases reported in American football, martial arts, soccer, boxing, and wrestling, and it has mainly been confirmed in professional athletes, although confirmed cases have been seen as young as 17 years. CTE typically presents many years after the last report of head injury. The symptoms include mood changes, memory deficits, impulse control problems, confusion, and dementia. CTE remains an area of debate and an opportunity for further research.8 Despite the increasing numbers of confirmed cases of CTE, we cannot fully elucidate the threshold (i.e., number of head impacts or years of exposure) for development of CTE or potential intrinsic, individual vulnerability to the development of the condition. There does seem to be a dose response phenomenon involved in CTE, with more cases confirmed in former professional athletes and fewer complaints noted in former high school athletes as they age.58,170

Physiatrists have a unique expertise in brain injury, sports medicine, and the complexities of managing the expectations of multiple involved parties in the care of a concussed athlete. Concussion is increasingly recognized as a public health concern that can result in significant long-term deficits in a young, vulnerable patient population. The Zackery Lystedt Law was the first concussion management law, passed by the state of Washington in 2009. It requires that all youth athletes with suspected concussion must be removed from play, evaluated, and cleared by a medical professional before returning to play. All 50 states have concussion laws, and sports medicine physicians are responsible to practice in accordance with those laws.