AUTHORS
Erica Bates, MD, Assistant Professor, Department of Emergency Medicine, Penn State College of Medicine, Penn State Hershey, Milton S. Hershey Medical Center
Matthew Turner, MD, Emergency Medicine Residency, Penn State College of Medicine, Penn State Hershey, Milton S. Hershey Medical Center
PEER REVIEWER
Steven M. Winograd, MD, FACEP, Attending Emergency Physician, Trinity Health, Albany, NY
EXECUTIVE SUMMARY
- Concussion and mild traumatic brain injury (mTBI) often are used interchangeably, but there is one potentially impactful difference.
- Concussion does not have structural brain damage visible on standard neuroimaging — computed tomography or magnetic resonance imaging.
- Mild TBI can have intracranial injury on conventional neuroimaging by some definitions.
- For seven to 10 days after the initial injury, the brain’s metabolism of glucose is impaired, explaining the leaning and behavioral impairments that occur during this phase after a concussion.
- Red flag symptoms after a concussion include loss of consciousness > 30 minutes, postural instability, hyperreflexia, cranial nerve palsies, and the fencing response.
- Headache is the most common symptom after a concussion, followed by neck pain and dizziness.
- During the first 24-48 hours after injury, relative rest is recommended; activities of daily living may be engaged as long as they cause only a mild and brief increase in symptoms.
- Reading and screen time should be minimized during the first 48 hours.
- The majority of patients have a swift and complete recovery from concussion, with complete recovery taking approximately two weeks for adults and four weeks for pediatric patients.
Introduction
The body of research regarding concussions has broadened dramatically in recent years. This expanded medical knowledge has led to changes in the recommended treatment of concussion. It is important for emergency medicine physicians to be well versed in the recognition and management of concussion in the emergency department (ED), as well as potential complications and long-term sequelae of this condition.
Definition
“Concussion” originates from the Latin concussus, meaning “to shake violently.”1 However, the exact definition of concussion is imprecise, is defined differently by various groups, and often overlaps with the definition of mild traumatic brain injury (mTBI) or minor head injury.2,3 The 2022 6th International Conference on Concussion in Sport formally defined concussion as a traumatic brain injury caused by a blow to the head, neck, or body that results in significant force being transmitted to the brain.4 While this term sometimes is used interchangeably with mTBI, no abnormalities will be present on standard brain imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI) scans, in concussion, while intracranial injury can be present in some definitions of mTBI.1,4
Even this definition for concussion is not definitive; the Conference noted that concussion covers a wide range of clinical signs and symptoms.4 In addition to this, the Conference’s definition is focused on sports or exercise-related injuries; however, concussion also may occur as a result of other trauma, whiplash injuries, or blast injuries.1,4 There is no evidence of any pathophysiological difference between sports-related concussion and concussion due to other etiologies.5 Patients in both groups display similar patterns of neuronal disruption.6 For the purposes of this article, we define concussion by the criteria shown in Table 1.
Table 1. Definition of Concussion |
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Epidemiology
Estimates of the number of annual concussions in the United States vary widely. Some sources estimate that of the 2.5 million visits to U.S. EDs for traumatic brain injuries (TBIs) each year, 75% are mTBIs.7 However, other sources estimate anywhere from 300,000 to 3.8 million sports-related concussions occur in the United States each year.5 The majority of concussions appear to occur in patients younger than the age of 19 years; approximately one in five children will sustain a TBI by the age of 16 years.8,9 Boys in collision and contact sports, such as American football, ice hockey, and lacrosse, are at a higher risk, especially when they are competing rather than practicing.8 Collegiate athletes in wrestling, ice hockey, and American football also are at an elevated risk.10 Female athletes also are at risk, and it is unclear if there are any significant differences between the sexes; studies have found approximately equivalent rates of concussion or slightly higher rates in females.10,11
The incidence of concussion appears to be increasing; a study from Ontario, Canada, from 2008 to 2016 found an annual incidence of 1.2% in the general population, the highest rate ever reported.12 However, it is possible that this increased incidence is simply due to improved recognition, diagnosis, and reporting.12
Sports-related concussions may be decreasing. High school athletics have seen significant decreases in reported concussions over the past several decades.13 Improvements in education and policy changes may be responsible for this; American football has had a 64% reduction in practice-sustained concussions as a result of a number of policy changes.4 Similarly, rugby players have displayed reduced concussion rates following improved warm-up and training strategies.4 Improved equipment also appears to play a role; adding mouth guards to ice hockey athletes reduced concussion rates by 28% in all age groups.4
Despite these improvements, the incidence of reported concussions in the adolescent age group has continued to increase.14 Other populations, such as U.S. service members, also have high reported incidences of concussion; more than 80% of the 327,299 TBI cases in the U.S. military from 2001 to 2016 were mTBI.15 Given the high rates of concussion sustained during military deployments, as well as increased reported concussions in the wider population, emergency physicians are likely to encounter patients with concussion frequently in their practice.14,15
Pathophysiology
Concussions are characterized by neurological symptoms of head injury in the absence of grossly visible damage to the brain, with no abnormalities evident on common imaging modalities such as CT scan.16 A full description of the neurometabolic cascade of concussion is outside the scope of this article, but in the acute phase following the injury, the axons of the brain appear to indiscriminately release glutamate, leading to a diffuse depression across the brain.16 To restore homeostasis, the ionic pumps of the membrane consume vast amounts of energy, generating free radicals and oxidative stress that may further impair the brain and make it more vulnerable to repeated injuries.16
For the next seven to 10 days after the initial injury, the brain’s metabolism of glucose is impaired, perhaps explaining learning and behavioral impairments that occur during this phase.16 Further complicating this pathology, axons may be damaged by the mechanical stretching involved in the injury. Diffuse inflammation may play a role as well.16
Clinical Presentation
There is no definitive objective test for concussion; diagnosis requires a history of blunt head trauma followed by a spectrum of neurologic symptoms that vary in severity and can be transient or prolonged.17 Both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have previously defined mTBI by a Glasgow Coma Scale (GCS) score of 13-15 within 30 minutes of the injury or on presentation to the ED, and at least one of the following symptoms: any loss of consciousness (LOC), any retrograde or anterograde amnesia, alteration in mental status (examples include “seeing stars,” confusion, a sensation of brain “fogginess,” disorientation, sensation of slowed thinking), or any neurological deficit (examples include weakness, sensory loss, and visual changes).5 (See Table 2.)
Table 2. Clinical Presentation of Concussion5 |
Glasgow Coma Scale (GCS) score of 13-15 on presentation to the emergency department or within 30 minutes of injury AND at least one of the following at any point after the injury:
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As discussed in the 2023 American College of Emergency Physicians (ACEP) Clinical Policy, there is debate about including patients with a GCS of 13 in the definition of mTBI.3 The CDC does not include assessing the GCS in their guidelines for acute concussion evaluation, and the Veterans Administration and Department of Defense do not recommend using the GCS to diagnose mTBI.18,19 To maintain consistency with the 2008 Clinical Policy, the 2023 ACEP Clinical Policy defined mTBI as “patients with blunt head injury with a GCS score of 14 or 15 (and improvement to GCS score of 15 at two hours postinjury if GCS score of 14) with or without a history of the following: LOC, amnesia, or disorientation.”3
Of these symptoms, loss of consciousness is one of the least likely, occurring in less than 10% of concussion patients.1 Anterograde or retrograde amnesia is significantly more common, occurring in approximately 30% to 50% of patients.17,20 The most common symptom is headache; however, it remains inconclusive whether the severity of the headache is tied to the severity of the TBI.21 Other common symptoms include nausea/vomiting, photophobia and phonophobia, emotional lability, mania, and alterations in sleep patterns.17 Up to 40% of pediatric patients will experience visual symptoms, including blurred and double vision, as well as reported ocular fatigue.22
It is important to note that many concussion symptoms can abate by the time a patient is evaluated in the ED. However, the absence of current symptoms should not be presumed to rule out concussion.3,5
Given the heterogeneity of the possible clinical presentations, physicians may find it helpful to classify patients into one of three categories based on the degree of confidence in the diagnosis: possible concussion, probable concussion, and definite concussion. Possible concussion refers to a patient whose symptoms could be explained by alternative etiologies, such as migraine or a viral infection. Probable concussion refers to patients where an acute concussion appears to be the most likely explanation for a patient’s symptoms after a known head trauma, even if they have other potential competing pathologies, such as cervical spine disorders, mood disorders, migraine headaches, and so on. Definite concussion is diagnosed when concussion is thought to be the only reasonable etiology for the patient’s symptoms.17
Evaluation
Early identification and treatment reduces the long-term sequelae of concussion.23,24 Because emergency physicians often are the only clinical providers encountered by concussed patients, it is particularly important that emergency physicians perform a thorough evaluation.7,18 Unfortunately, many patients with concussion do not receive formal evaluations by physicians; patients often do not present because they believe that their injuries are minor, because they are not seeking workers’ compensation for off-the-job injuries, or because physicians are less likely to evaluate for concussions in injuries that are not high-impact, such as motor vehicle collisions.23 In fact, the majority of potentially concussed patients who are seen at the ED do not have documentation of a thorough evaluation for concussion.7
Distracting injuries, especially in polytrauma, also may negatively affect concussion evaluations.5 One of the primary hypotheses for the increase in concussions among soldiers is that combat deaths have significantly decreased thanks to improvements in tourniquets, body armor, and hemorrhage control.15 Unfortunately, even the majority of patients at high risk for an mTBI who are seen at the ED do not have documentation of a concussion evaluation.7
A number of “sideline tools” exist that can be employed by both clinicians and non-licensed personnel. Meant for use on the sidelines of sporting events, tools such as the Sport Concussion Assessment Tool 5 (SCAT5) use several different methods to assess for concussion for up to five days postinjury.25 This questionnaire has been updated recently to the SCAT6, which takes 10-15 minutes to perform, and can be used up to seven days postinjury.26
The SCAT6 includes sections for immediate observable signs, an assessment of the GCS score, cervical spine assessment, a coordination and ocular/motor screen, and Maddocks questions for memory assessment, all of which can be performed immediately on the sidelines of an athletic event. The questionnaire includes further cognitive and coordination/balance screening that can be performed off the field in an environment with fewer distractions, such as a locker room.26 The Child SCAT6 can be used for pediatric patients aged 8 to 12 years.4
Similarly, the armed forces’ Military Acute Concussion Evaluation (MACE), designed for use by corpsmen and medics in combat environments, also is a potential screening tool, although it appears to have limited efficacy when used in civilian trauma populations.27,28 Other tools include the Concussion Symptom Severity Score (CSSS) and the modified Balance Error Scoring System (mBESS).29,30 Sideline assessments of balance also can be included; providers may be able to assess reaction time out in the field by simply dropping a stick or other weighted object and observing how long it takes the patient to catch it.30 However, it is important to note that these tools should be used as aids to inform the initial assessment and diagnosis — not as stand-alone diagnostic tools.26
In the ED setting, the Acute Concussion Evaluation (ACE) tool may be used and appears to be more effective than other tests, such as the SCAT5.31 The ACE includes a checklist of 22 symptoms that may be conducted in person or over the phone, as well as “red flag” symptoms and any risk factors for protracted recovery. Like the other tools meant for use in the field, the ACE is limited in its use as an aid, and it is best employed as a triage tool, not for diagnosis.32
In the ED, patients with a high index of suspicion for concussion should have a thorough history taken. Physicians should determine if the patient had any syncope that preceded the head injury, since this may indicate another underlying etiology. The patient and any witnesses present should be questioned regarding the events preceding the injury, the mechanism of the injury (including the type of force and the location on the head or body where the force was directed), and any immediate symptoms or postural changes after the injury.5 As with the ACE, patients should be assessed for any medical history that may prolong their recovery course, such as previous concussions, head injuries, or a history of migraines.31
As with all cases of trauma, patients should be assessed for their airway, breathing, and circulation. Afterward, the patient’s cervical spine should be cleared. If this is not possible, the patient’s cervical spine should be secured with a cervical collar to minimize the risk of spinal cord injury.25 Neck pain is one of the most common complaints following concussion, particularly in motor vehicle collisions, thus making it imperative that clearing patients for cervical spine injury is done properly and carefully.33
Afterward, a neurological exam should be performed on the patient. In the vast majority of concussion patients, neurological signs are subtle, and the neurologic exam largely is normal aside from mental status and difficulties with balance.25 Any significant neurologic symptoms may be concerning for a more severe injury, including loss of consciousness lasting longer than 30 minutes, a positive Romberg sign, postural instability, unequal or fixed pupils, ataxic gait, hyperreflexia, or presence of the Babinski reflex.25
Headache and ataxia in particular may indicate the possibility of an underlying posterior stroke.25 Cranial nerve palsies are particularly concerning. Any abnormalities to the third, fourth, and sixth cranial nerves are highly suggestive of a hemorrhage or other space-occupying lesion.34 Head imaging should be obtained in patients with an abnormal neurologic exam, signs or symptoms of skull fracture, significant mechanism of injury, or increased risk factors for intracranial hemorrhage, such as anticoagulation.
Balance should be assessed in a graduated manner, progressing from initial standing upright to the Romberg exam to gait assessment.5 Patients also may display the fencing response, first observed as a visual indicator of moderate TBI in 2009.20 In the fencing response, unconscious patients may display an unusual response where one arm extends while the other simultaneously flexes, mimicking the “en garde” fencing position.20 While the presence of a fencing response does not necessarily indicate that the patient’s TBI was severe, it appears to be associated with a more complex concussion.20
When possible, a screening ocular exam should be done, including evaluation for nystagmus and any abnormalities of saccades and smooth pursuits.31 Table 3 provides a list of concerning red flag symptoms physicians should beware of.
Table 3. Red Flag Symptoms in Concussion5,20,25,34 |
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Although it can be difficult in the ED setting, the patient’s cognitive status should be assessed as well. Physicians may employ tools such as the Mini-Mental State examination, or four to five rounds of serial subtraction exercises: serial 7s from 100 for adults, serial 3s from 100 for pediatric patients aged 14-18 years, and serial 1s from 10 for pediatric patients aged 7-14 years. Four or more errors are suggestive of impairment.5 Cognitive testing may be effectively used to track the patient’s progress over time.5
A 2017 study of 72 EDs found that only 68% of EDs assessed the emotional and behavioral symptoms of post-concussive patients. Given the mood disorders that often affect patient recovery, any symptoms should be reviewed and documented.35
Imaging
In all cases of head trauma, traumatic intracranial injury should be ruled out.5 Basic examinations should be performed quickly. GCS score should be assessed immediately; patients with a GCS score below 13 are at risk for severe injury. The patient’s head and cervical spine should be examined for evidence of basilar trauma, including raccoon eyes, cerebrospinal fluid (CSF) rhinorrhea, hemotympanum, Battle’s sign, cervical spine tenderness, or bruits that may indicate trauma to the carotid or vertebral arteries.5 It is important to note that, while unlikely, cerebral contusions and subdural and epidural hematomas can occur in up to 5% to 10% of concussions.5
To assess the need for CT scanning, physicians can use decision support tools such as the Canadian CT Head Rule, the Pediatric Emergency Care Applied Research Network (PECARN) rule, and New Orleans Criteria.5 While imaging modalities such as CT and MRI are not diagnostic for concussion, any patients with suspicion for an intracranial bleed should have a CT scan of their head done.4,5 In choosing to use or not to use neuroimaging, emergency physicians must weigh the likelihood of intracranial hemorrhage against the high healthcare costs and radiation exposure from CT scans for the individual patient.35
In the future, there may be a place for specialized imaging, such as positron emission tomography (PET) or magnetic resonance spectroscopy (MRS), but research in this field remains ongoing and has not yet reached the point of clinical application.6 Electroencephalography (EEG) is not indicated in the evaluation for concussion unless the physician suspects that a seizure disorder may have caused the injury.36
Laboratory Testing
In the vast majority of concussion cases, laboratory markers have no diagnostic utility in the clinical setting. However, this may change in the future. Recent research has focused on the use of potential serum biomarkers for assessment of TBI. The Food and Drug Administration (FDA) recently has approved the use of glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1, two serum biomarkers that indicate the presence of TBI.31 Other promising biomarkers include S100β, tau, neurofilament light protein (NFL), amyloid protein, brain-derived neurotrophic factor (BDNF), and creatinine kinase.6 S100β is particularly promising, given its association with an increased incidence of post-concussive symptoms, but it is limited in its clinical efficacy because it often is elevated in patients presenting with peripheral trauma or even vigorous exercise.6 Other potential biomarkers are similarly limited. More research ultimately is required before serum biomarkers can be used as reliable and objective measures of concussion.6
Acute Management
Headache is the most common post-concussive symptom, occurring in an estimated 70% of all cases.37 The spectrum of post-concussive headaches varies, ranging from a tension-type presentation to a migraine-type presentation.37 The migraine presentation, where the patient often will have a unilateral, pulsating headache that is exacerbated by physical activity and associated with nausea, vomiting, photophobia, and/or phonophobia, is the most concerning, because it is an indicator of a significantly prolonged recovery and clinical course.37 Potential migraine headaches may be evaluated via tools such as the Migraine Assessment Tool.37
Fortunately, post-concussive headache can be managed easily in the ED setting. Eighty-six percent of patients reported significant pain reduction, and 52% reported completed headache resolution, after a single intravenous (IV) dose of one or more of the following standard medications: ketorolac, prochlorperazine, chlorpromazine, metoclopramide, and ondansetron. A combination of IV metoclopramide and diphenhydramine appears to be particularly effective, with 95% of patients who receive this reporting complete headache relief within two hours.5 Patients may be discharged with a week-long course of nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen to reduce the risk of medication overuse headaches. Narcotics should not be prescribed. NSAIDs should be avoided before ruling out the possibility of intracranial hemorrhage.5 (See Table 4.)
Table 4. Acute Symptom Management in the Emergency Department |
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Headache |
Consider standard headache medications: intravenous ketorolac, metoclopramide, ondansetron, prochlorperazine Discharge with one week of nonsteroidal anti-inflammatory drugs and acetaminophen.5 |
Neck pain |
Rule out cervical spinal injury; pain control; early initiation of physical therapy, stretching38 |
Dizziness |
Spontaneous resolution in vast majority of cases; consider early referral to physical therapy39 |
Visual changes |
Refrain from prolonged reading or screen time for 24-48 hours34 |
Convulsions |
Antiepileptics and monitoring as needed; generally does not require treatment or imaging42 |
Neck pain is another frequent symptom following concussion.33 In the ED setting, it is important that providers determine whether the patient is experiencing cervicogenic symptoms, defined as a headache and/or dizziness that originates at the occiput or the neck. Patients complaining of neck pain with this presentation are significantly more likely to develop persistent post-concussive symptoms and are more likely to require long-term follow-up.38 In addition to this, patients presenting with acute neck pain are more likely to develop post-concussion sleep disturbances and may be more predisposed to future injury than patients without significant neck pain.38
In post-concussive patients with neck pain, once a cervical spine injury has been ruled out, early manual therapy through physical therapy, gentle stretching, light traction, and even vibration therapy should be initiated quickly, either by the ED provider or through a referral.38 Early initiation of physical therapy has been shown to significantly reduce the time to full recovery in these patients.38 If dizziness, neck pain, and headaches persist for longer than 10 days, the patient may be referred to a specialist for cervicovestibular rehabilitation.4
Dizziness occurs in up to 80% of sports-related concussion cases, particularly in the first few days after the injury.39 Fortunately, the vast majority of these patients will have spontaneous resolution of their symptoms within several days to weeks of the injury.40 While there are no uniform guidelines for physical therapy after a concussion, early referral to a physical therapist also appears to be helpful for the management of dizziness in the acute post-concussion stage.39 Vestibular rehabilitation therapy initiated within one to three days of the injury has been shown to be effective in the treatment of dizziness.41
A 2017 study of 41 patients that initiated physical therapy starting at 10 days post-concussion found that physical therapy significantly decreased the number of days required for both symptomatic recovery and full medical clearance.39 Physical therapy appears to be an effective treatment for patients experiencing persistent dizziness following concussion. In patients with both headache and dizziness, properly managing their headache symptoms also may improve their dizziness by allowing them to tolerate vestibular adaptation activities.39
Visual changes are common following concussion, particularly in convergence (tested by assessing the nearest point at the face that the patient can maintain binocular fusion). A near point of convergence (NPC) of greater than 5 cm strongly suggests acute concussion.34 Photophobia also is common in the acute post-concussive setting and resembles that experienced in migraines.34 In most patients, these symptoms will resolve spontaneously; in the acute setting, the patient should refrain from prolonged reading or screen time for the first 24-48 hours.34
Seizures may occur immediately following concussion, but are rare, occurring in approximately one in 70 patients. Seizures in the acute stage require neither further anti-epileptic treatment nor confer any increased long-term risk for seizures in the future.5 These seizures often are referred to as post-concussive convulsions; imaging studies typically are negative for any pathology, and any immediate/early seizures following the injury are poorly predictive for future seizures.42 A 2018 meta-analysis of eight studies of 130 athletes found that only 0.8% of patients displaying post-concussive convulsions received antiepileptic medications.43
Return-to-Learn/Return-to-Sport
There are a number of clinical time points that can be used to measure a patient’s recovery, from symptom resolution at rest to complete resolution of symptoms.4 In athletes and students who experienced sports-related concussions, the return-to-learn (RTL) phase of a concussion is defined as the point when the student can return to pre-injury learning activities with no need for increased academic support. Return-to-sports (RTS) is the transition back to full participation in sports with no concussion symptoms with maximum exertion/activity.4 While the guidelines for return to learning and return to sports are designed for students and athletes, they can be adapted to more general populations as well.18
Despite previous schools of thought, strict rest until the patient has complete resolution of their symptoms is not beneficial.4 However, the first 24-48 hours postinjury should be spent in a period of relative rest.4 During this period, patients may engage in activities of daily living (ADLs), so long as they only have a mild and brief increase in their symptoms during the ADL.4
The patient also should minimize their reading and screen time during this first 48 hours. If reading or screen time is necessary, the patient should start with five to 15 minutes at a time and gradually increase the duration.4,34 The only exception to this rule is in athletes, who should initiate ADLs such as walking immediately following the injury.4 Patients also may engage in light physical activity, as tolerated without exacerbating their concussion symptoms, during this period.4
Following an initial 48 hours of relative rest and gradual return to ADLs, the following days should be focused on a gradual stepwise approach to increasing cognitive load and physical activity. Each step in this pathway is symptom-limited; just as in the initial 48 hours, patients should experience only a mild and temporary exacerbation of their post-concussive symptoms to continue performing an activity.4 Early physical activity and aerobic exercise are beneficial in the early recovery phase but should be initiated carefully.44 Tables 5 and 6 demonstrate the timeline for RTL and RTS, respectively. RTL in student athletes can be expected to take approximately 10 days on average.44 While these tables were initially designed by the 6th International Conference on Concussion for students and athletes respectively, they can be adapted to other patient populations as well.4
Table 5. Return-to-Learn |
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Each step should be implemented gradually, limited only by mild and brief symptom exacerbations, defined as an increase of 2 points on the 0-10 point scale of symptoms for less than an hour.4 |
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Step 1. Initial relative rest of 24-48 hours |
Minimize reading and screen time; start at five to 15 minutes and proceed as tolerated. Driving restrictions for the first 48 hours5 |
Goal: Gradual return to ADLs |
Step 2. Resuming school/cognitive activities |
Homework, reading, cognitive activities outside of classroom/place of employment |
Goal: Increase tolerance to cognitive workload |
Step 3. Part-time school/employment |
Gradually introduce schoolwork/employment. May need partial school day/work day, greater access to breaks throughout day |
Goal: Increase academic activities |
Step 4. Full-time school/employment |
Progress in school/employment until patient can perform a full day’s activities with only mild symptom exacerbation |
Goal: Return to full pre-injury baseline |
ADLs: activities of daily living |
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Table 6. Return-to-Sport |
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Each step should be implemented gradually, taking a minimum of 24 hours, and limited by mild and brief symptom exacerbations, defined as an increase of 2 points on the 0-10 point scale of symptoms for less than an hour.4 |
||
Step 1. Initial relative rest of 24-48 hours |
Athletes should resume ADLs such as walking immediately after the injury. |
Goal: Gradual reintroduction of work and school |
Step 2A. Light aerobic exercise (up to 55% max HR) Step 2B. Moderate aerobic exercise (up to 70% max HR) |
Walking, stationary cycling, and light resistance training |
Goal: Increase heart rate |
Step 3. Individual sport-specific exercises |
Running, training drills. No activities with a risk of head impact. |
Goal: Increased movement and directional changes |
Steps 4-6 should be started after return-to-learn (Table 5) has been completed, with full resolution of cognitive symptoms, both before and after physical exertion. |
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Step 4. Non-contact training drills |
Passing drills, working in a team environment |
Goal: Resume usual intensity of exercise, coordination, and cognition associated with exercise |
Step 5. Full contact practice |
Normal training activities |
Goal: Allows full assessment of skills by coaching staff |
Step 6. Return to sport |
Normal game play |
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ADLs: activities of daily living; HR: heart rate |
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Repeat Concussions
The risk of a slower recovery, as well as the risk of chronic post-concussive symptoms, is significantly increased after a repeated concussion. Patients who have experienced multiple concussions have an increased risk of neurological, neurobehavioral, and psychiatric sequelae.45 Multiple concussions may have cumulative effects, including raising the risk of seizure.46,47 However, the data on this are mixed. A number of studies have found no significant changes in cognitive testing in high school football players with a history of multiple concussions, or in neuropsychological tests on pediatric patients with a history of multiple concussions.48,49
The most recent guidelines released by the 6th International Conference on Concussion concluded that the prevalence of cases of traumatic encephalopathy syndrome (TES) in former athletes and military veterans cannot be adequately determined at this time.4 Likewise, chronic traumatic encephalopathy (CTE) appears to be more associated with chronic and repetitive head trauma, rather than concussion or concussive symptoms.50
Despite these conflicting data, it does appear that a history of multiple sports-related concussions is associated with poorer cognitive health in retired athletes.51 More research on the long-term sequelae of multiple concussions is required. In the ED setting, we recommend that patients be provided with educational material to warn against the potential effects of multiple concussions.
Special Considerations in Certain Populations
Athletes/Soldiers
There appears to be a brief window of vulnerability after the initial injury where the patient is at a heightened risk of secondary injury.52 Athletes are at particular risk for repeated concussions because of their exposure to repetitive trauma as well as their tendency to underreport symptoms.6 While return-to-play protocols and conservative management of sports-related concussion have become much more prevalent in the sporting world since the 1990s, this remains a high-risk population for secondary injury.52
The second impact syndrome is especially concerning, when a patient suffers another head injury while still recovering from the symptoms of the first concussion. While rare, the second impact has been observed to cause significant neurological sequelae.53 The return-to-play model is specifically designed for athletes to avoid this potentially severe complication.4 Controversy over the precise definition of second impact still persists in the medical literature.54 However, it has been supported in animal models. Mice that have concussive injuries within three or five days of another concussive injury have significantly worse neurocognitive symptoms than mice that have had their injuries separated by seven days.16
Even more so than athletes, post-concussive soldiers often are returned to full duty status quickly after they sustain a mild TBI.55 Soldiers also are at significant risk for a repeat concussion; one study of soldiers participating in Operation Iraqi Freedom found that for 113 personnel who experienced multiple concussions, the median time between concussions was only 40 days.55 Twenty percent of repeated concussions occurred within two weeks, and 87% occurred within three months. For comparison, in college football players, one study found the incidence of repeated concussions is 4% at two weeks and 20% at three months.55
Pediatric Populations
Suspected concussions in young children should be managed differently than in adult patients.30 It appears that the impact force required to produce a concussion in children is significantly greater than that required in adult patients. This, along with young children’s reduced cervical musculature, relatively thin skulls, and neuroplasticity, suggests that children experience more significant TBIs than adults.30
TBI may reduce the natural process of brain myelination in children, ultimately increasing the duration of symptoms and required time for recovery. This can be seen in concussed high school athletes. Some sources estimate that they may take twice as long to recover from concussions as collegiate athletes.30 Of note, younger pediatric patients do not appear to have a longer recovery period than older pediatric patients. A 2019 study of 2,716 post-concussive patients across nine pediatric EDs found no significant difference in recovery time between children aged 5-7 years, 8-12 years, and 13-18 years.56
The majority of the data regarding concussions in pediatric patients have focused on patients older than 15 years of age.30 Patients aged from 5-15 years should have routine follow-up and specialized management that takes into account the significant amount of reading, language, physical, and cognitive development that takes place in this age range.30 Because of the wide range of developmental maturity that this age range encompasses, there are no generalizable tests that can be applied here; each patient should be followed closely and assessed on a case-by-case basis by their primary care provider.30 As a part of this process, pediatric patients may require specific accommodations to their academic workload and schedule as part of returning to school postinjury. These modifications will require a close collaboration between healthcare providers, teachers, and the patient’s family or caregivers.30
Children with any history of previous concussion are at an increased risk for prolonged symptoms and should be monitored closely postinjury.57 A 2019 retrospective cohort study of 536 pediatric patients aged 5-15 years estimated that approximately one in six children diagnosed with a concussion will develop a subsequent concussion within two years. In adolescents, the number is as high as one in five.58 These repetitive mTBIs may lead to long-term learning and neurological deficits. Pediatric patients with a pre-existing history of attention-deficit/hyperactivity disorder (ADHD), learning difficulties, psychiatric disorders, and mood disorders are at a higher risk of both repeat concussions and a prolonged recovery phase.58
ED physicians should be able to provide education to families regarding the future risks of concussion, as well as make recommendations to families on minimizing risks of future concussion in the child, through measures including limiting participation in contact sports.58 Pediatric patients with a history of multiple concussions should undergo an individualized assessment if they wish to continue sports.4
Patients on Antithrombotics
A 2020 multicenter study of 33,710 older adult patients taking some form of antiplatelet and/or anticoagulant therapy who experienced ground-level-falls (GLF) found that patients taking antithrombotics (ATs) had an inconsistent effect on the risk of TBI without a significantly increased risk in mortality.59 Further research is needed to determine if ATs actually increase the risk of traumatic intracranial bleeding, as current dogma holds. The researchers of this study noted that guidelines regarding the clinical approach to older adult patients taking ATs presenting with mTBI is inconsistent.59
Further complicating the issue, patients taking antithrombotic therapy who have an initial negative CT scan in the ED may be at risk of developing an intracranial bleed after discharge.60 This risk may be overblown; a study of 344 patients on AT therapy, presenting for mTBI and having two CT scans 48 hours apart found that only 1.4% of the patients who had a negative initial CT had a positive second CT scan. Of note, none of these patients had significant neurological symptoms or required neurosurgery.61 However, factors such as an international normalized ratio > 3 and increased patient age may increase the risk of a delayed intracranial bleed, but the data remain unclear.60
Ultimately, the decisions regarding the length of observation for patients taking AT therapy (in some cases, up to 48 hours) should be determined on a case-by-case basis, taking into consideration hospital and patient resources, ease of follow-up, and any comorbidities that the patient may have.60
Post-Concussion Syndrome
Post-concussion syndrome (PCS) covers a wide spectrum of physical, cognitive, and emotional symptoms that persist after a concussion. There is debate as to whether this term represents a specific syndrome or a constellation of independent symptoms. As a result, PCS is not formally defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) classification.62 PCS is heterogenous in nature and does not have a formal diagnostic criteria, making a definitive diagnosis difficult.63 Some researchers have even proposed that PCS symptoms may be affected by the “good old days” bias, in which patients display a tendency to underestimate their pre-concussion problems and overestimate their post-concussion symptoms.64
The majority of patients have a swift and complete recovery from concussion, with complete recovery taking approximately two weeks for adults and four weeks for pediatric patients.44 However, a number of post-concussive patients, ranging from 10% to 47% depending on the study in question, will develop symptoms consistent with PCS, with symptoms persisting at three months post-concussion.62 The most consistent predictor of a prolonged recovery from concussion is the severity of the patient’s initial symptoms.2 Pre-injury psychiatric history, life stressors, and acute post-traumatic stress related to the injury also appear to increase the risk of PCS.64 In the ED, physicians should consider the patient’s mental health as a significant factor in concussion recovery.64 Some patients may require referral to specialty care, often an interdisciplinary team involving physical medicine and rehabilitation, therapists, and a customized rehabilitation program.40
Post-Traumatic Headache
Post-traumatic headache (PTH) is the most common long-term sequela of concussion and is more likely to occur post-injury than in more severe TBIs.36 A prior history of migraine increases the risk of the patient developing PTH.36 Like other PCS symptoms, PTH has an extremely heterogenous presentation and remains poorly defined.65 Typical symptoms include tension-type and migraine-type headaches, as well as nausea, fatigue, irritability, and difficulty concentrating.65
There are few evidence-based studies or criteria on the pharmacologic treatment of PTH.66 Treatment often is challenging, requiring both abortive and prophylactic agents. One study of 100 PTH patients found that 87% of them were unsatisfied with their current treatment regimen.67,68 Exercise is a promising treatment for PTH, along with cognitive and behavioral treatments, which are particularly effective for those who sustained a concussion during a traumatic event, such as military personnel.65 In severe cases of PTH, surgical intervention via decompression and excision of peripheral nerves, such as the occipital and trigeminal nerves, may be warranted.69 The most successful treatments of PTH will require a multi-disciplinary approach and specialized care.
Post-Traumatic Epilepsy
Although the vast majority of seizures immediately following concussion spontaneously resolve and do not require further treatment, a minority of patients may develop post-traumatic epilepsy (PTE).42 PTE may develop following focal brain trauma, and accounts for approximately 20% of acquired epilepsies.42,70 However, the incidence of PTE increases with the severity of the TBI in question.70
In post-concussive patients, the incidence of PTE thus appears to be relatively low; a 2018 review of 130 athletes post-concussion found that only 6.9% of the athletes developed symptoms of PTE within 3.3 years of the event.42 Further research into this is warranted; another 2018 study of 330 post-concussion patients found that there was no increased risk of epilepsy for at least the first five to 10 years post-injury.71
Visual Disorders
Post-concussive patients may experience a wide range of chronic visual complaints. In up to one-third of post-concussive pediatric patients, these visual symptoms may persist for weeks or months after the initial injury.22 Between 25% and 33% of post-concussive pediatric patients may develop abnormal horizontal and vertical saccades; a significant proportion also will develop difficulty with smooth pursuit.22 Patients also may develop convergence insufficiency, which is the reduced ability to turn both eyes inward to focus on a near target. Convergence insufficiency typically presents with reading difficulties, diplopia, increased eye strain, and developing ocular fatigue or disinterest in reading.22
Likewise, in post-concussive accommodation insufficiency, patients develop reduced ability to change focus from a distant target to a near target. Accommodation insufficiency may present with a visual blurring sensation, headaches, fatigue, and further reading difficulties.22 The minority of these patients who have these symptoms persistently should be referred to specialty care.22 Some sources recommend that adult patients begin ophthalmic rehabilitation exercises if their visual symptoms persist for longer than two weeks after the injury; adolescents should begin this rehabilitation if their visual symptoms persist for longer than four weeks.34
Mood Disorders
Pre-injury psychiatric conditions appear to increase the risk of post-concussive syndrome. Measurements of pre-injury resilience and depression are predictive of anxiety and PCS post-injury.64 Psychiatric and psychological effects often follow sports-related concussion, where athletes develop fear of re-injury, fear of being perceived as weak, or a sense of isolation.64 The RTS algorithm may help restore confidence in this regard.4 In the acute post-concussive stage, pediatric patients also appear to have significantly higher rates of withdrawal, anxiety, depression, conduct problems, and aggression, although these effects seem to taper over time.64
In the longer term, concussions appear to increase the risk of mood disorders and substance use.72 Concussions appear to be a positive predictor of hazardous drinking, although more research is needed in this field.72 Additionally, a history of concussion is associated with an increased risk of clinical depression in former athletes.73 Ultimately, incorporating mental health services into early management of post-concussive patients appears to offer a protective effect and may be a helpful avenue of treatment.64
Sleep Disorders
Sleep-wake disturbances, which encompass excessive daytime fatigue and sleepiness and/or an increased need for sleep, insomnia, rapid eye movement (REM) sleep behavior disorder, and even obstructive sleep apnea, can become chronic after TBI as a result of a complex interaction of pain, anxiety, and mood disorders.74 High rates of pain appear to contribute to higher rates of anxiety and depression, which are associated with poorer sleep quality and increased likelihood of sleep disturbances.74
Patients experiencing these complications should be assessed with tools such as the Pittsburgh Sleep Quality Index (PSQI) and referred to specialty care. These patients also may be treated with routine treatments for sleep disturbance, including melatonin, light therapy, good sleep hygiene, and cognitive behavioral therapy.74 Patients with suspected obstructive sleep apnea should be referred for a sleep study.74
Cervicogenic Symptoms
As noted earlier, patients who initially present in the acute stage with cervicogenic symptoms are more likely to develop post-concussive symptoms.38 As many as 90% of persistent PCS patients may experience long-term neck pain, dizziness, and cervicogenic headaches.38 Females appear to be at a higher risk for developing these symptoms than males, possibly because of differences in neck strength in sports-related concussions.38 Early initiation of physical therapy and techniques such as light manual traction, vibration, and stretching may help alleviate these symptoms. If they last longer than 10 days, the patient may benefit from referral to cervicovestibular rehabilitation.4,75
Dizziness
Patients who experience dizziness for longer than three weeks post-concussion should have a work-up to evaluate for potential cervicogenic, peripheral, and central causes.40 The full evaluation and management of dizziness is outside the scope of this article. However, rehabilitation is effective in many cases, through both vestibular rehabilitation therapy and exercise therapy. The most extreme cases may require specialized care and surgical intervention.40
Conclusion
Concussion is a common and variable presentation in the ED for both adult and pediatric patients. Physicians should be well-versed in the recognition and treatment of this injury, as well as the potential complications that may result from it.
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The body of research regarding concussions has broadened dramatically in recent years. This expanded medical knowledge has led to changes in the recommended treatment of concussion. It is important for emergency medicine physicians to be well versed in the recognition and management of concussion in the emergency department, as well as potential complications and long-term sequelae of this condition.
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