What must we learn from the Zurich consensus statement?

– Written by Paul McCrory, Australia

Sport-related concussion is the most topical and contentious area of sports medicine today. No other condition in medicine attracts more column inches of newspaper copy, more electronic media stories and in the USA, is the only medical condition that has its management legislatively mandated. Over the past 15 years, numerous professional bodies have published treatment guidelines on this topic^1-5.

Commencing in 2001, the International Concussion in Sport Group (CISG) has held four consensus meetings that have established the key management concepts and global research agenda in the field⁶. The most recent conference was held in Zurich in November 2012. The consensus statement produced from this meeting was published in March 2013 and provides the most up to date knowledge on concussion in sport⁶. The CISG guidelines have influenced the clinical management of concussion in professional sports worldwide. This paper discusses the current best practice clinical management of concussion in light of the Zurich 2013 guidelines.

HOW IS CONCUSSION DEFINED IN 2014

Concussion is a subset of traumatic brain injury which is a broad term encompassing a spectrum of injuries to the brain resulting from trauma. Concussion is defined as a syndrome of neurological impairment that results from traumatic biomechanical forces directly or indirectly transmitted to the brain. Although the pathophysiology of concussion remains poorly understood, the current consensus is that it reflects a disturbance of brain function rather than a structural injury.

HOW COMMON IS CONCUSSION?

The incidence of concussion varies by sport. The approximate incidence of concussion by common participation sports is shown in Table 1.

WHAT ARE THE POTENTIAL COMPLICAT-IONS FOLLOWING CONCUSSION?

Concussion reflects a ‘functional’ injury of the brain rather than structural damage. Consequently, the changes are usually temporary and recover spontaneously if managed correctly. The recovery process however, is variable from person to person and injury to injury. While most cases of concussion recover uneventfully within 10 to 14 days of injury, complications or adverse outcomes may include:

• Impaired performance and increased injury risk on return to play.
• Acute, progressive diffuse cerebral swelling.
• Prolonged symptoms.
• Depression and other mental health issues.
• Cumulative cognitive deficits (chronic traumatic encephalopathy).

Risk factors for complications or adverse outcomes following concussion remain unclear. While there is a suggestion that genetic factors may play an important role, the current expert consensus is that premature return to play (and the subsequent risk of a second concussive injury before the athlete has fully recovered from the initial concussion) may predispose to poorer outcomes following a concussive injury.

The role of recurrent head trauma in the development of potential long-term complications such as chronic trauma encephalopathy and depression has received considerable press in both the scientific and lay press in recent years. Pathological case reports and cross sectional studies have suggested that retired NFL footballers, who have had recurrent head trauma during their careers, disproportionately suffer from cognitive impairment, depression and other mental health problems⁷. At this time, however, very little is known about what type, frequency or amount of trauma is necessary to induce the condition and more importantly why only a small number of athletes are at risk for chronic traumatic encephalopathy. Nevertheless, this concern should reinforce the need for conservative management strategies designed to ensure player safety.

MANAGING CONCUSSION SAFELY?

The key components of concussion management include:

1. Confirming the diagnosis (which includes differentiating concussion from other pathologies, in particular structural head injuries).
2. Determining when the player has recovered so that they can be safely returned to competition.

Confirming the diagnosis

The clinical history is most important in making a diagnosis of concussion. Common symptoms of concussion include headache, nausea, dizziness and balance problems, blurred vision or other visual disturbance, confusion, memory loss and a feeling of slowness or fatigue. While most symptoms appear rapidly following a concussive incident, some symptoms may be delayed or evolve over time. The diagnosis should be suspected in any player that presents with any of these symptoms following trauma to the head or neck. If video footage of the incident is available (from video camera, mobile phone camera etc), reviewing the footage may provide the clinician with important information.

Clinical features that are more specific to a diagnosis of concussion include: loss of consciousness, concussive convulsions, confusion and/or attentional deficit, memory disturbance and balance disturbance. These features however, may not be present in all cases. For example, loss of consciousness is seen in only 10 to 20% of cases of concussion. Questioning close relatives, especially parents or guardians in the case of children and adolescents, is often valuable. Any report that the individual ‘does not seem right’ or ‘is not themselves’ following trauma is strongly suggestive of a concussive injury.

The use of a graded symptom checklist is often helpful. The advantages of the symptom checklist are that it covers the range of symptoms commonly observed following concussion and provides a measure of symptom severity. The Zurich 2013 consensus statement includes a comprehensive Sport Concussion Assessment Tool (SCAT3) (see PDF) to facilitate medical assessment of athletes following a concussive injury. For non-medical personnel, the Concussion Recognition Tool (see PDF) provides sideline assessment advice.

Clinical features of concussion typically resolve within 10 to 14 days of injury and the possibility of structural head injury should be kept in mind in any case where symptoms persist beyond this time. Following an uncomplicated concussion, conventional imaging techniques such as skull X-ray, CT brain scan and MRI are typically normal.

Differentiating concussion from structural pathologies

It is not possible to rule out structural brain injury with certainty during a side-line assessment and for that reason this possibility must be considered in every case. Clinical features that may raise concerns of structural head injury and warrant urgent investigation include:

• The mechanism of injury e.g. high velocity impact.
• Immediate and/or prolonged loss of consciousness.
• Seizures.
• Vomiting (in adults).
• Focal neurological deficit.
• Any deterioration in clinical state such as worsening headache and/or deterioration in conscious state.
• Medical comorbidities e.g. clotting disorders.
• Situations where the neurological exam cannot be adequately performed (e.g. patient intoxicated).

In a concussed individual with any of these adverse warning signs, urgent neuroimaging is required to exclude intracranial haemorrhage or other pathology.

Estimating the severity of injury

Over the years, numerous concussion severity scales have been proposed. International scientific consensus has moved away from anecdotal severity grading systems (e.g. mild, moderate or severe or grade 1, 2 and 3 concussion) towards an objective measure of recovery following the injury using a combination of symptom checklist, physical examination and cognitive assessment.

Evaluation in the 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 examination should encompass:

• A medical assessment including a comprehensive history and detailed neurological examination including a thorough assessment of mental status, cognitive functioning, gait and balance.
• 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 video analysis, parents, coaches, teammates and eyewitnesses to the injury.
• A determination of the need for emergent neuroimaging in order to exclude a more severe brain injury involving a structural abnormality.
• Determination of the need for specialist referral.
• Provision of advice regarding recovery and return to play.

Determining when the player has recovered so that they can safely return to competition

The decision regarding the timing of return to play following a concussive injury is a difficult one to make. Expert consensus guidelines recommend that players should not be allowed to return to competition until they have recovered completely from their concussive injury. Currently, however, there is no single gold standard measure of brain disturbance and recovery following concussion. Instead, clinicians must rely on indirect measures to inform clinical judgment. In practical terms this involves a comprehensive clinical approach, including:

• A period of cognitive and physical rest to facilitate recovery.
• Monitoring for recovery of post-concussion symptoms and signs.
• Neuropsychological testing to estimate recovery of cognitive function.
• Graduated return to activity with monitoring for recurrence of symptoms.
• A final medical clearance before resuming full contact training and/or playing.

Period of cognitive and physical rest to facilitate recovery

Early rest is important to allow recovery following a concussive injury. Physical activity, physiological stress (e.g. altitude and flying) and cognitive loads (e.g. school work, videogames and computers) can all worsen symptoms and possibly delay recovery following concussion. Individuals should be advised to rest from these activities in the early stages (initial 24 to 48 hours) after a concussive injury, particularly while symptomatic. Similarly, the use of alcohol, opiate analgesics, anti-inflammatory medication, sedatives or recreational drugs can exacerbate symptoms following head trauma, delay recovery or mask deterioration and should also be avoided. Specific advice should also be given on cessation of activities that place the individual at risk of further injury (e.g. driving, operating heavy machinery).

Monitoring for recovery of post-concussion symptoms and signs

Monitoring of post-concussion sym-ptoms and signs can be facilitated by the use of the SCAT3.

Use of neuropsychological tests to estimate recovery of cognitive function

Cognitive deficits associated with concussion are typically subtle and may exist in a number of domains. Common deficits that follow concussion in sport include reduced attention and ability to process information, slowed reaction times and impaired memory. The use of neuropsychological tests in the manage-ment of concussion overcomes the reliance on subjective symptoms, which are known to be poorly recognised and variably reported. These tests allow detection of cognitive deficits, which have been observed to outlast symptoms in many cases of concussion. There are a number of levels of complexity of cognitive testing including formal neuropsychological testing, screening computerised cognitive test batteries and basic paper-and-pencil evaluation (i.e. SCAT3). Overall, it is important to remember that neuropsychological testing is only one component of assessment and therefore should not be the sole basis of management decisions.

Graduated return to activity

Following a concussive injury, players should be returned to play in a graduated fashion (Table 2) once clinical features have resolved and cognitive function returned to ‘normal’. When considering return to play, the athlete should be off all medications at the time of commencement of the rehabilitation phase and/or at the final medical assessment. Overall, a more conservative approach (i.e. longer time to return to sport) should be used in cases where there is any uncertainty about the player’s recovery (“if in doubt, sit them out”).

Progression through the rehabilitation programme should occur with at least 24 hours between stages. The player should be instructed that if any symptoms recur while progressing through their return to play programme that they should drop back to the previous asymptomatic level and try to progress again after a further 24 hour period has passed.

A final medical clearance before resuming full contact training and/or playing

A player who has suffered from a concussive injury must not be allowed to return to play before having a medical clearance. In accordance with current consensus guidelines, there is no mandatory period of time that a player must be withheld from play following a concussion. However, the minimum requirement is that a player must be symptom-free at rest and with exertion, have a normal neurological examination, returned to baseline of balance function and determined to have returned to baseline level of cognitive performance.

GAME-DAY EVALUATION AND TREATMENT

The management plan outlined above applies to concussive injuries being managed on game day. The main difference is that players diagnosed with concussion on game day should not be returned to play on the day of their injury.

With all concussive injuries, the critical game day management relates to the basic first aid principles, which apply when dealing with any unconscious player (i.e. airway, breathing, circulation). Care must be taken with the player’s cervical spine, which may have also been injured in the collision. When in doubt (e.g. unconscious or non-lucid athlete), the player should be removed from the field on a stretcher with appropriate cervical spine precautions and transported to an appropriate facility for formal assessment.

The key components of game day concussion management involve making an accurate diagnosis, differentiating concussion from structural pathologies and careful monitoring of the injured player.

The pocket Concussion Recognition Tool (see PDF) is an important practical instru-ment that can be utilised on-field or on the sideline to screen for concussion. For a more detailed assessment, the player should be moved to a quiet room, away from the field of play (e.g. change rooms, medical room etc) for a detailed neurological examination and use of the full SCAT3. The aim is to confirm the diagnosis of concussion and to differentiate between concussion and high-risk intracranial or cervical pathology.

A player with any of the following should be sent immediately to hospital for assessment:

• Loss of consciousness.
• Neck pain or spinal cord symptoms.
• Seizures.
• Neurological signs.
• Prolonged confusion (>15 minutes).
• Persistent vomiting or increasing headache post-injury.
• Deterioration of conscious state post-injury (e.g. increased drowsiness).
• Obvious skull fracture (Cerebrospinal fluid rhinorrhoea/otorrhoea) or facial trauma.
• Development of new symptoms.
• High risk patients (e.g. known bleeding disorders).
• Where there is difficulty with assess-ment or uncertain follow-up (e.g. no responsible adult supervision).

Overall, if there is any doubt, the player should be referred to hospital for urgent medical assessment.

Players who have a normal neurological examination, are improving following their injury and have a competent person looking after them may be discharged home. These players and their caregiver (parent, partner etc) should be given clear and practical instructions, particularly regarding abstinence from alcohol and driving, medication use, physical exertion and timing of medical follow-up. Players should not be discharged home alone and a player who has been concussed should not drive until fully recovered. The SCAT3 form has a patient head injury hand out which may be given to the responsible caregiver and contains a list of the clinical features to be concerned about and an emergency plan in the event of deterioration.

Players should be followed up early after a concussive injury (to monitor progress in the sub-acute stages of their injury) and for medical clearance before they return to full contact and collision training or game play.

Tools such as the SCAT3 facilitate regular re-assessment of concussed players and provide simple and practical advice for patient education (see attachment). It is important to note that abbreviated sideline evaluation tools are designed for rapid concussion evaluation. They are not meant to replace a more comprehensive cognitive assessment and should not be used as a stand-alone tool for the ongoing management of concussive injuries.

MANAGEMENT OF CONCUSSION IN CHILDREN

There is evidence that younger athletes take longer to recover following a concussive injury than adults and that return to play on the day of the injury leads to subsequent cognitive deterioration. Moreover, there are specific risks (e.g. diffuse cerebral swelling) related to head impact during childhood and adolescence. Consequently, a more conservative approach is recommended in all concussed footballers under 18 years of age, regardless of the level of competition in which they participate.

The diagnosis of concussion, monitoring concussive symptoms and physical and cognitive assessment must be modified in children because of physical, cognitive and language development. As such, a ‘childSCAT3’ has been developed for use in children ages 5 to 12 years. For children ages 13 to 17 years, the SCAT3 should be used. It will be noted that the childSCAT3 includes both a child-report and parent-report symptom scale. It is very important to include the parent/teacher/coach/guardian in assessing the child with concussion.

Once the diagnosis of concussion has been made, the priority in children is successful return to learning and return to school before considering return to play. Medical clearance is required before the child may return to school. In most instances, the child will only require 1 to 2 days off school, however in others, longer periods of rest will be required. Once the child’s symptoms are not exacerbated by reading or using the computer, he/she may return to school, but a careful plan will need to be developed for the parents and teachers that provide appropriate accommodations for the child, such as shorter school day, longer time to complete assignments, repeating instructions and frequent breaks (see page 4 of the childSCAT3). Only after successful return to school without worsening of symptoms may the child be allowed to commence return to sport. Medical clearance is required and a stepwise, supervised programme should be used (see page 4 childSCAT3).

Acknowledgements

The Florey Institute of Neuroscience and Mental Health acknowledges support from the Victorian Government, in particular the funding from the Operational Infrastructure Support Grant.

Paul McCrory M.B., B.S., Ph.D., F.R.A.C.P., F.A.C.S.P., F.F.S.E.M., F.A.C.S.M., Grad.Dip.Epid.Stats.

Neurologist & Sports Physician

The Florey Institute of Neuroscience and Mental Health

Melbourne Brain Centre – Austin Campus 

Heidelberg, Australia

Contact: paulmccr@bigpond.net.au

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Image via Clyde Orama