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Consensus Statement on Concussion in Sport—the 4th International Conference on Concussion in Sport Held in Zurich, November 2012

2013; Lippincott Williams & Wilkins; Volume: 23; Issue: 2 Linguagem: Inglês

10.1097/jsm.0b013e31828b67cf

1536-3724

Paul McCrory, Willem Meeuwisse, Mark Aubry, Bob Cantu, Jiří Dvořák, Ruben J. Echemendía, Lars Engebretsen, Karen Johnston, Jeffrey S. Kutcher, Martin Raftery, Allen K. Sills,

Traumatic Brain Injury and Neurovascular Disturbances

Preamble This paper is a revision and update of the recommendations developed following the 1st (Vienna 2001), 2nd (Prague 2004) and 3rd (Zurich 2008) International Consensus Conference on Concussion in Sport and is based on the deliberations at the 4thInternational Conference On Concussion In Sport held in Zurich, November 2012.1–3 The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the "background" section. This document is developed for use by physicians and health care professionals primarily who are involved in the care of injured athletes, whether at the recreational, elite, or professional level. While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving and therefore management and return to play decisions remain in the realm of clinical judgment on an individualized basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document, the Concussion Recognition Tool (CRT), the Sport Concussion Assessment Tool version 3 (SCAT3), and/or the Child-SCAT3 card and neither is subject to any restriction, provided it is not altered in any way or converted to a digital format. The authors' request that the document and/or the accompanying tools be distributed in their full and complete format. This consensus paper is broken into a number of sections: (a) A summary of concussion and its management, with updates from the previous meetings. (b) Background information about the consensus meeting process. (c) A summary of the specific consensus questions discussed at this meeting. (d) The Consensus paper should be read in conjunction with the SCAT3 assessment tool, the Child-SCAT3 and the Concussion Recognition Tool (designed for lay use). SECTION 1: SPORT CONCUSSION AND ITS MANAGEMENT The Zurich 2012 document examines sport concussion and management issues raised in the previous Vienna 2001, Prague 2004, and Zurich 2008 documents and applies the consensus questions from Section 3 to these areas.1–3 Definition of Concussion Panel discussion regarding the definition of concussion and its separation from mild traumatic brain injury (mTBI) was held. There was acknowledgement by the Concussion in Sport Group (CISG) that although the terms mild traumatic brain injury (mTBI) and concussion are often used interchangeably in the sporting context and particularly in the US literature, others use the term to refer to different injury constructs. Concussion is the historical term representing low velocity injuries that cause brain "shaking" resulting in clinical symptoms and which are not necessarily related to a pathological injury. Concussion is a subset of TBI and the term concussion will be used in this document. It was also noted that the term commotio cerebri is often used in European and other countries. Minor revisions were made to the definition of concussion and it is defined as follows: Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces. Several common features that incorporate clinical, pathologic and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury include: Concussion may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an "impulsive" force transmitted to the head. Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. However in some cases, symptoms and signs may evolve over a number of minutes to hours. Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury and, as such, no abnormality is seen on standard structural neuroimaging studies. Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course. However, it is important to note that in some cases symptoms may be prolonged. Recovery of Concussion The majority (80%-90%) of concussions resolve in a short (7-10 day) period, although the recovery time frame may be longer in children and adolescents.2 Symptoms and Signs of Acute Concussion The diagnosis of acute concussion usually involves the assessment of a range of domains including clinical symptoms, physical signs, cognitive impairment, neurobehavioral features, and sleep disturbance. Furthermore, a detailed concussion history is an important part of the evaluation both in the injured athlete and when conducting a preparticipation examination. The detailed clinical assessment of concussion is outlined in the SCAT3 and Child-SCAT3 forms, which is an appendix to this document. The suspected diagnosis of concussion can include 1 or more of the following clinical domains: (a) Symptoms - somatic (eg, headache), cognitive (eg, feeling like in a fog) and/or emotional symptoms (eg, lability) (b) Physical signs (eg, loss of consciousness, amnesia) (c) Behavioural changes (eg, irritability) (d) Cognitive impairment (eg, slowed reaction times) (e) Sleep disturbance (eg, insomnia) If any 1 or more of these components is present, a concussion should be suspected and the appropriate management strategy instituted. On-Field or Sideline Evaluation of Acute Concussion When a player shows ANY features of a concussion: (a) The player should be evaluated by a physician or other licensed healthcare provider onsite using standard emergency management principles and particular attention should be given to excluding a cervical spine injury. (b) The appropriate disposition of the player must be determined by the treating healthcare provider in a timely manner. If no healthcare provider is available, the player should be safely removed from practice or play and urgent referral to a physician arranged. (c) Once the first aid issues are addressed, then an assessment of the concussive injury should be made using the SCAT3 or other sideline assessment tools. (d) The player should not be left alone following the injury and serial monitoring for deterioration is essential over the initial few hours following injury. (e) A player with diagnosed concussion should not be allowed to return to play on the day of injury. Sufficient time for assessment and adequate facilities should be provided for the appropriate medical assessment both on and off the field for all injured athletes. In some sports, this may require rule change to allow an appropriate off-field medical assessment to occur without affecting the flow of the game or unduly penalizing the injured player's team. The final determination regarding concussion diagnosis and/or fitness to play is a medical decision based on clinical judgment. Sideline evaluation of cognitive function is an essential component in the assessment of this injury. Brief neuropsychological test batteries that assess attention and memory function have been shown to be practical and effective. Such tests include the SCAT3, which incorporates the Maddocks questions4,5 and the Standardized Assessment of Concussion (SAC).6–8 It is worth noting that standard orientation questions (eg, time, place, person) have been shown to be unreliable in the sporting situation when compared with memory assessment.5,9 It is recognized, however, that abbreviated testing paradigms are designed for rapid concussion screening on the sidelines and are not meant to replace comprehensive neuropsychological testing which should ideally be performed by trained neuropsychologists that are sensitive to subtle deficits that may exist beyond the acute episode; nor should they be used as a stand-alone tool for the ongoing management of sports concussions. It should also be recognized that the appearance of symptoms or cognitive deficit might be delayed several hours following a concussive episode and that concussion should be seen as an evolving injury in the acute stage. Evaluation in Emergency Room or Office by Medical Personnel An athlete with concussion may be evaluated in the emergency room or doctor's office as a point of first contact following injury or may have been referred from another care provider. In addition to the points outlined above, the key features of this exam should encompass: (a) A medical assessment including a comprehensive history and detailed neurological examination including a thorough assessment of mental status, cognitive functioning, gait, and balance. (b) A determination of the clinical status of the patient, including whether there has been improvement or deterioration since the time of injury. This may involve seeking additional information from parents, coaches, teammates, and eyewitness to the injury. (c) A determination of the need for emergent neuroimaging in order to exclude a more severe brain injury involving a structural abnormality In large part, these points above are included in the SCAT3 assessment. Concussion Investigations A range of additional investigations may be utilized to assist in the diagnosis and/or exclusion of injury. Conventional structural neuroimaging is typically normal in concussive injury. Given that caveat, the following suggestions are made: Brain CT (or where available MR brain scan) contributes little to concussion evaluation but should be employed whenever suspicion of an intra-cerebral or structural lesion (eg, skull fracture) exists. Examples of such situations may include prolonged disturbance of conscious state, focal neurological deficit, or worsening symptoms. Other imaging modalities such as fMRI demonstrate activation patterns that correlate with symptom severity and recovery in concussion.10–14 Whilst not part of routine assessment at the present time, they nevertheless provide additional insight to pathophysiological mechanisms. Alternative imaging technologies (eg, positron emission tomography, diffusion tensor imaging, magnetic resonance spectroscopy, functional connectivity), while demonstrating some compelling findings, are still at early stages of development and cannot be recommended other than in a research setting. Published studies, using both sophisticated force plate technology, as well as those using less sophisticated clinical balance tests (eg, Balance Error Scoring System [BESS]), have identified acute postural stability deficits lasting approximately 72 hours following sport-related concussion. It appears that postural stability testing provides a useful tool for objectively assessing the motor domain of neurologic functioning, and should be considered a reliable and valid addition to the assessment of athletes suffering from concussion, particularly where symptoms or signs indicate a balance component.15–21 The significance of Apolipoprotein (Apo) E4, ApoE promotor gene, Tau polymerase, and other genetic markers in the management of sports concussion risk or injury outcome is unclear at this time.22,23 Evidence from human and animal studies in more severe traumatic brain injury demonstrate induction of a variety of genetic and cytokine factors such as: insulin-like growth factor-1 (IGF-1), IGF binding protein-2, Fibroblast growth factor, Cu-Zn superoxide dismutase, superoxide dismutase -1 (SOD-1), nerve growth factor, glial fibrillary acidic protein (GFAP), and S-100. How such factors are affected in sporting concussion is not known at this stage.24–31 In addition, biochemical serum and cerebral spinal fluid biomarkers of brain injury [including S-100, neuron specific enolase (NSE), myelin basic protein (MBP), GFAP, tau, etc] have been proposed as means by which cellular damage may be detected if present.32–38 There is currently insufficient evidence, however, to justify the routine use of these biomarkers clinically. Different electrophysiological recording techniques (eg, evoked response potential [ERP], cortical magnetic stimulation, and electroencephalography) have demonstrated reproducible abnormalities in the postconcussive state; however not all studies reliably differentiated concussed athletes from controls.39–45 The clinical significance of these changes remains to be established. Neuropsychological Assessment The application of neuropsychological (NP) testing in concussion has been shown to be of clinical value and contributes significant information in concussion evaluation.46–51 Although in most cases cognitive recovery largely overlaps with the time course of symptom recovery, it has been demonstrated that cognitive recovery may occasionally precede or more commonly follow clinical symptom resolution, suggesting that the assessment of cognitive function should be an important component in the overall assessment of concussion and in particular, any return to play protocol.52,53 It must be emphasized however, that NP assessment should not be the sole basis of management decisions. Rather, it should be seen as an aid to the clinical decision-making process in conjunction with a range of assessments of different clinical domains and investigational results. It is recommended that all athletes should have a clinical neurological assessment (including assessment of their cognitive function) as part of their overall management. This will normally be done by the treating physician often in conjunction with computerized NP screening tools. Formal NP testing is not required for all athletes, however when this is considered necessary then it should ideally be performed by a trained neuropsychologist. Although neuropsychologists are in the best position to interpret NP tests by virtue of their background and training, the ultimate return to play decision should remain a medical one in which a multidisciplinary approach, when possible, has been taken. In the absence of NP and other (eg, formal balance assessment) testing, a more conservative return to play approach may be appropriate. Neuropsychological testing may be used to assist return to play decisions and is typically performed when an athlete is clinically asymptomatic, however NP assessment may add important information in the early stages following injury.54,55 There may be particular situations where testing is performed early to assist in determining aspects of management eg, return to school in a pediatric athlete. This will normally be best determined in consultation with a trained neuropsychologist.56,57 Baseline NP testing was considered by the panel and was not felt to be required as a mandatory aspect of every assessment however may be helpful or add useful information to the overall interpretation of these tests. It also provides an additional educative opportunity for the physician to discuss the significance of this injury with the athlete. At present, there is insufficient evidence to recommend the widespread routine use of baseline NP testing. Concussion Management The cornerstone of concussion management is physical and cognitive rest until the acute symptoms resolve and then a graded program of exertion prior to medical clearance and return to play. The current published evidence evaluating the effect of rest following a sport-related concussion is sparse. An initial period of rest in the acute symptomatic period following injury (24-48 hours) may be of benefit. Further research to evaluate the long-term outcome of rest, and the optimal amount and type of rest, is needed. In the absence of evidence-based recommendations, a sensible approach involves the gradual return to school and social activities (prior to contact sports) in a manner that does not result in a significant exacerbation of symptoms. Low-level exercise for those who are slow to recover may be of benefit, although the optimal timing following injury for initiation of this treatment is currently unknown. As described above, the majority of injuries will recover spontaneously over several days. In these situations, it is expected that an athlete will proceed progressively through a stepwise return to play strategy.58 Graduated Return to Play Protocol Return to play (RTP) protocol following a concussion follows a stepwise process as outlined in Table 1.TABLE 1: Graduated Return to Play ProtocolWith this stepwise progression, the athlete should continue to proceed to the next level if asymptomatic at the current level. Generally, each step should take 24 hours so that an athlete would take approximately 1 week to proceed through the full rehabilitation protocol once they are asymptomatic at rest and with provocative exercise. If any postconcussion symptoms occur while in the stepwise program then the patient should drop back to the previous asymptomatic level and try to progress again after a further 24-hour period of rest has passed. Same Day RTP It was unanimously agreed that no return to play on the day of concussive injury should occur. There are data demonstrating that at the collegiate and high school level, athletes allowed to RTP on the same day may demonstrate NP deficits postinjury that may not be evident on the sidelines and are more likely to have delayed onset of symptoms.59–65 The 'Difficult' or Persistently Symptomatic Concussion Patient Persistent symptoms (>10 days) are generally reported in 10%-15% of concussions. In general, symptoms are not specific to concussion and it is important to consider other pathologies. Cases of concussion in sport where clinical recovery falls outside the expected window (ie, 10 days) should be managed in a multidisciplinary manner by health care providers with experience in sports-related concussion. Psychological Management and Mental Health Issues Psychological approaches may have potential application in this injury, particularly with the modifiers listed below.66,67 Physicians are also encouraged to evaluate the concussed athlete for affective symptoms such as depression and anxiety, as these symptoms are common in all forms of traumatic brain injury.58 The Role of Pharmacological Therapy Pharmacological therapy in sports concussion may be applied in 2 distinct situations. The first of these situations is the management of specific and/or prolonged symptoms (eg, sleep disturbance, anxiety, etc). The second situation is where drug therapy is used to modify the underlying pathophysiology of the condition with the aim of shortening the duration of the concussion symptoms.68 In broad terms, this approach to management should be only considered by clinicians experienced in concussion management. An important consideration in RTP is that concussed athletes should not only be symptom free, but also should not be taking any pharmacological agents/medications that may mask or modify the symptoms of concussion. Where antidepressant therapy may be commenced during the management of a concussion, the decision to return to play while still on such medication must be considered carefully by the treating clinician. The Role of Preparticipation Concussion Evaluation Recognizing the importance of a concussion history, and appreciating the fact that many athletes will not recognize all the concussions they may have suffered in the past, a detailed concussion history is of value.69–72 Such a history may preidentify athletes that fit into a high-risk category and provides an opportunity for the health care provider to educate the athlete in regard to the significance of concussive injury. A structured concussion history should include specific questions as to previous symptoms of a concussion and length of recovery, not just the perceived number of past concussions. It is also worth noting that dependence upon the recall of concussive injuries by teammates or coaches has been demonstrated to be unreliable.69 The clinical history should also include information about all previous head, face, or cervical spine injuries, as these may also have clinical relevance. It is worth emphasizing that in the setting of maxillofacial and cervical spine injuries, coexistent concussive injuries may be missed unless specifically assessed. Questions pertaining to disproportionate impact versus symptom severity matching may alert the clinician to a progressively increasing vulnerability to injury. As part of the clinical history it is advised that details regarding protective equipment employed at time of injury be sought, both for recent and remote injuries. There is an additional and often unrecognized benefit of the preparticipation examination insofar as the evaluation allows for an educative opportunity with the player concerned as well as consideration of modification of playing behavior if required. Modifying Factors in Concussion Management A range of 'modifying' factors may influence the investigation and management of concussion and, in some cases, may predict the potential for prolonged or persistent symptoms. However, in some cases, the evidence for their efficacy is limited. These modifiers would be important to consider in a detailed concussion history and are outlined in Table 2.TABLE 2: Concussion ModifiersFemale Gender The role of female gender as a possible modifier in the management of concussion was discussed at length by the panel. There was not unanimous agreement that the current published research evidence is conclusive enough for this to be included as a modifying factor, although it was accepted that gender may be a risk factor for injury and/or influence injury severity.73–75 The Significance of Loss of Consciousness (LOC) In the overall management of moderate to severe traumatic brain injury, duration of LOC is an acknowledged predictor of outcome.76 Whilst published findings in concussion describe LOC associated with specific early cognitive deficits, it has not been noted as a measure of injury severity.77,78 Consensus discussion determined that prolonged (>1 minute duration) LOC would be considered as a factor that may modify management. The Significance of Amnesia and Other Symptoms There is renewed interest in the role of posttraumatic amnesia and its role as a surrogate measure of injury severity.64,79,80 Published evidence suggests that the nature, burden, and duration of the clinical postconcussive symptoms may be more important than the presence or duration of amnesia alone.77,81,82 Further it must be noted that retrograde amnesia varies with the time of measurement postinjury and hence is poorly reflective of injury severity.83,84 Motor and Convulsive Phenomena A variety of immediate motor phenomena (eg, tonic posturing) or convulsive movements may accompany a concussion. Although dramatic, these clinical features are generally benign and require no specific management beyond the standard treatment of the underlying concussive injury.85,86 Depression Mental health issues (such as depression) have been reported as a consequence of all levels of traumatic brain injury including sport-related concussion. Neuroimaging studies using fMRI suggest that a depressed mood following concussion may reflect an underlying pathophysiological abnormality consistent with a limbic-frontal model of depression.34,87–97 While such mental health issues may be multifactorial in nature, it is recommended that the treating physician consider these issues in the management of concussed patients. SPECIAL POPULATIONS The Child and Adolescent Athlete The evaluation and management recommendations contained herein can be applied to children and adolescents down to the age of 13 years. Below that age, children report concussion symptoms different from adults and would require age-appropriate symptom checklists as a component of assessment. An additional consideration in assessing the child or adolescent athlete with a concussion is that the clinical evaluation by the healthcare professional may need to include both patient and parent input, and possibly teacher and school input when appropriate.98–104 A Child-SCAT3 has been developed to assess concussion (see Appendix II) for subjects aged 5 to 12 years. The decision to use NP testing is broadly the same as the adult assessment paradigm although there are some differences. Timing of testing may differ in order to assist planning in school and home management. If cognitive testing is performed then it must be developmentally sensitive until late teen years due to the ongoing cognitive maturation that occurs during this period which, in turn, makes the utility of comparison to either the person's own baseline performance or to population norms limited.20 In this age group it is more important to consider the use of trained paediatric neuropsychologists to interpret assessment data, particularly in children with learning disorders and/or ADHD who may need more sophisticated assessment strategies.56,57,98 It was agreed by the panel that no return to sport or activity should occur before the child/adolescent athlete has managed to return to school successfully. In addition, the concept of 'cognitive rest' was highlighted with special reference to a child's need to limit exertion with activities of daily living that may exacerbate symptoms. School attendance and activities may also need to be modified to avoid provocation of symptoms. Children should not be returned to sport until clinically completely symptom free, which may require a longer time frame than for adults. Because of the different physiological response and longer recovery after concussion and specific risks (eg, diffuse cerebral swelling) related to head impact during childhood and adolescence, a more conservative return to play approach is recommended. It is appropriate to extend the amount of time of asymptomatic rest and/or the length of the graded exertion in children and adolescents. It is not appropriate for a child or adolescent athlete with concussion to RTP on the same day as the injury regardless of the level of athletic performance. Concussion modifiers apply even more to this population than adults and may mandate more cautious RTP advice. Elite Versus Nonelite Athletes All athletes, regardless of level of participation, should be managed using the same treatment and return to play paradigm. The available resources and expertise in concussion evaluation are of more importance in determining management than a separation between elite and nonelite athlete management. Although formal NP testing may be beyond the resources of many sports or individuals, it is recommended that in all organized high-risk sports, consideration be given to having this cognitive evaluation, regardless of the age or level of performance. Chronic Traumatic Encephalopathy (CTE) Clinicians need to be mindful of the potential for long-term problems in the management of all athletes. However, it was agreed that CTE represents a distinct tauopathy with an unknown incidence in athletic populations. It was further agreed that a cause and effect relationship has not yet been demonstrated between CTE and concussions or exposure to contact sports.105–114 At present, the interpretation of causation in the modern CTE case studies should proceed cautiously. It was also recognized that it is important to address the fears of parents/athletes from media pressure related to the possibility of CTE. INJURY PREVENTION Protective Equipment—Mouthguards and Helmets There is no good clinical evidence that currently available protective equipment will prevent concussion, although mouthguards have a definite role in preventing dental and oro-facial injury. Biomechanical studies have shown a reduction in impact forces to the brain with the use of headgear and helmets, but these findings have not been translated to show a reduction in concussion incidence. For skiing and snowboarding there are a number of studies to suggest that helmets provide protection against head and facial injury and hence should be recommended for participants in alpine sports.115–118 In specific sports such as cycling, motor, and equestrian sports, protective helmets may prevent other forms of head injury (eg, skull fracture) that are related to falling on hard surfaces and may be an important injury prevention issue for those sports.118–130 Rule Change Consideration of rule changes to reduce the head injury incidence or severity may be appropriate where a clear-cut mechanism is implicated in a particular sport. An example of this is in football (soccer) where research studies demonstrated that upper limb to head contact in heading contests accounted for approximately 50% of concussions.131 As noted earlier, rule changes also may be needed in some sports to allow an effective off-field medical assessment to occur without compromising the athlete's welfare, affecting the flow of the game or unduly penalizing the player's team. It is important to note that rule enforcement may be a critical aspect of modifying injury risk in these settings and referees play an important role in this regard. Risk Compensation An important consideration in the use of protective equipment is the concept of risk compensation.132 This is where the use of protective equipment results in behavioral change such as the adoption of more dangerous playing techniques, which can result in a paradoxical increase in injury rates. The degree to which this phenomena occurs is discussed in more detail in the review published in the BJSM supplement. This may be a particular concern in child and adolescent athletes where head injury rates are often higher than in adult athletes.133–135 Aggression Versus Violence in Sport The competitive/aggressive nature of sport that makes it fun to play and watch should not be discouraged. However, sporting