Summary Concussions are a subset of mild traumatic brain injury (mTBI) characterized by acute transient impairment of neurologic function secondary to an impulsive force transmitted to the head. Diagnosis is made by careful neurological evaluation of an athlete following head trauma with a focus on cognitive function. Treatment is immediate removal from play followed by cognitive and physical rest for 24-48 hours, and subsequent completion of a graduated return to play protocol. Epidemiology Incidence 1.6-3.8 million sports-related concussions per year increasing over the past decade, though possibly due to increased awareness substantial rise in youth athletes is concerning 5-9% of all sports injuries Demographics traumatic brain injury (TBI) is the leading cause of sport-related death American football associated with the majority of concussions occur in competition more often than practice Etiology Pathophysiology direct blow to the head, face, neck or elsewhere with force transmitted to the head complex neurometabolic cascade resulting in the typical signs and symptoms of a concussion abnormal neuronal ionic flux -- headache, photophobia, phonophobia altered release of neurotransmitters (glutamate) -- impaired cognition, amnesia, slowed reaction time energy depletion, in an effort to correct the above underlying biochemical imbalances -- vulnerable to second injury (second-hit phenomenon) may or may not experience loss of consciousness not required for diagnosis of concussion Risk factors sports with player-to-player contact football, wrestling, soccer, basketball at highest risk prior concussion 2-8x higher risk of sustaining another concussion female age < 18 years mood disorders, learning disorders, history of migraines mostly complicates diagnosis and recovery rather than predisposing to concussion Guidelines International Conference on Concussion in Sport meeting held every 4 years focuses on the prevention, diagnosis and management of sports-related concussion generates a consensus statement summarizing the updated practice guidelines consensus statement created at the first meeting in 2001 grading system for concussions removed in 2004 all classification systems removed in 2008 newer assessment tools and timing of return to play was the primary focus of the most recent meeting Presentation Symptoms somatic symptoms headache most common symptom present in 70% of concussed athletes types myofascial tension headache -- pain localized to posterior neck at base of skull post-traumatic headache -- pressure localized to forehead and/or top of head dizziness balance problems nausea and/or vomiting vision changes sensitivity to light (photophobia) or sound (phonophobia) cognitive symptoms feeling "in a fog" or slowed down difficulty concentrating forgetful emotional symptoms lability irritability sadness sleep disturbance change in amount of sleep (more or less) difficulty falling asleep, insomnia drowsiness Signs many sports have established "mandatory signs of concussion" presence of these visible signs dictates further evaluation and often removal from play note, the specific signs and subsequent recommended action differs between sports loss of consciousness occurs in only ~10% of cases lying motionless > 5 seconds slow to get up confusion or disorientation clutching the head amnesia vacant look motor incoordination ataxia Evaluation Sideline evaluation primary survey airway, breathing, circulation assess for spinal cord injury cervical collar and back board immobilization if needed in an altered patient, assume cervical spine injury until proven otherwise indications for transport to ER for advancing imaging deteriorating mental status increasingly restless, agitated or combative severe or worsening headache focal neurologic findings unequal pupils abnormal extraocular eye movements motor and/or sensory deficit neck pain or tenderness concerning for cervical spine injury bloody otorrhea, mastoid ecchymosis, blepharohematoma do not leave player alone after injury secondary survey -- evaluate cognitive function any athlete with symptoms or signs of a concussion should be removed from the playing field and undergo immediate cognitive evaluation by a licensed healthcare provider if no healthcare provider is avaliable, the athlete should be removed from play entirely and urgently referred to a physician sideline assessment tool that tests attention and memory SCAT5 is the most commonly used Sports Concussion Assessment Tool 5 (SCAT5) standardized neuropsychological test for evaluating concussions in athletes aged 13 years or older child SCAT5 can be used for younger athletes composed of two parts immediate on-field assessment office or off-field assessment immediate on-field assessment red flags observable signs witnessed or on video review Maddocks questions -- memory assessment Glasgow Coma Scale (GCS) cervical spine assessment off-field assessment should be done in a private, distraction-free area Standard Assessment of Concussion (SAC) test Balance Error Scoring System (BESS) test Imaging Advancing imaging usually unnecessary need for imaging is determined by the evaluating physician indications acute head trauma with deteriorating mental status increasingly combative, aggressive, restless focal neurologic deficit neck pain concerning for cervical spine injury history of subacute/chronic head trauma with persistent symptoms Computerized tomography (CT) head most commonly used in the acute setting findings normal in vast majority can identify fractures, intracranial hemorrhage, contusion, mass effect and herniation Magnetic resonance imaging (MRI) brain superior visualization of brain structures diffusion-weighted imaging (DWI) most sensitive to shear injury findings standard MRI normal in vast majority concussion is most often a functional rather than structural pathology functional MRI can show increased cerebrovascular reactivity in the acute post-concussive period Neuropsychological Assessment Tools Standard Assessment of Concussion (SAC) test evaluates orientation (ex. What month is it?) memory, immediate and delayed (ex. repeating 5 words over 3 trials and 1 trial at the conclusion of assessment concentration (ex. repeating string of 5 numbers backwards) Immediate Post-concussion Assessment and Cognitive Testing battery (ImPACT) a computer-based test that assesses verbal and visual memory, processing speed, reaction time, impulse control and presence of concussive symptoms comparison is made to baseline scores or historical controls useful tool in guiding treatment and return to play decisions Balance Error Scoring System (BESS) tests balance and postural stability by having the athlete perform 3 stances for 10 seconds each bipedal stance unipedal stance tandem stance Sensory Organization Test (SOT) assesses integrity of the entire balance system by testing the vestibular, visual and somatosensory systems, which are responsible for postural stability and maintenance of balance King-Devick (K-D) Test examines saccadic eye movements, language and concentration by having the athlete rapidly read numbers off a card from left to right for 3 successive tests Sports Concussion Assessment Tool 5 (SCAT5) reviewed under Sideline evaluation Treatment Nonoperative immediate removal from play, same day return to play is NOT indicated indications athletes of any age with signs/symptoms concerning for concussion (see above) if concerned at all, remove athlete from play! athletes with head trauma and no medical provider experienced in concussion evaluation present head trauma with history of concussion loss of consciousness amnesia positive exertional stress test symptoms lasting > 15 minutes cognitive and physical rest x24-48H, graduated return to play protocol indications acute concussion technique same day return to play is contraindicated in patients diagnosed with a concussion graduated return to play protocol highlighted in table below each step should take 24 hours, so an athlete should take one week to proceed through the full protocol and return to play Graduated Return to Play Protocol Stage Activity Goal 1. Symptom-limited activity Daily activities that do not provoke symptoms Gradual reintroduction of work/school activities 2. Light aerobic exercise Walking, swimming, or stationary cycling to maintain HR at <70% of maximum. No resistance training. Increase heart rate 3. Sport-specific exercise Running or skating drills. No head impact activities. Add movement 4. Non-contact training drills More complex training drills (i.e. passing drills). May start progressive resistance/strength training. Exercise, coordination, and improved cognition 5. Full contact practice Normal training activities. Restore confidence, assess functional skills 6. Return to play Normal game play Prevention Protective equipment head gear and helmets reduce impact forces to the brain helmet use is associated with decreased rates of head and neck injuries in certain sports youth hockey, alpine, equestrian, cycling and motor sports risk compensation use of protective equipment may paradoxically increase injury rates by enabling more dangerous playing techniques Rules changes beneficial when a clear cut mechanism is implicated in a particular sport upper limb-to-head contact banned in American football accounted for ~50% of concussions strict enforcement of red cards for high elbows in professional soccer Community education players, coaches, athletic trainers, referees and the general public focus on safe play, identification of concussion and appropriate graduated return to play minimizing premature return to play decreases risk of long-term complications Preparticipation concussion evaluation number of previous concussions, type and severity of symptoms, length of recovery mechanism of injury low-impact injury but with disproportionately high symptom severity can indicate an athlete who is particularly vulnerable to injury great opportunity for education and modification of high-risk behavior Future research energy-absorbing artifical turf fields genetic tests -- apolipoprotein E specific playing technique -- limited contact football, different tackling techniques Complications Second impact syndrome second head trauma before symptoms of a concussion have resolved catastrophic cerebral edema resulting from loss of autoregulation of the brain blood supply high rate of death and disability mortality rate ~50% associated with male gender, young age and American football Postconcussion syndrome persistent symptoms of a concussion (i.e. headache, confusion) > 10-14 days in adults > 4 weeks in children younger athletes at increased risk for prolonged return to sport return to play is contraindicated should undergo formal neuropsychiatric evaluation use of pharmacotherapy is controversial Intracranial hemorrhage subdrual hematoma most common epidural hematoma commonly have a lucid period before neurologic decline neurosurgical decompression and seizure prophylaxis indicated Chronic traumatic encephalopathy (CTE) progressive neurologic deterioration resulting from repetitive brain trauma symptoms behavior changes -- loss of impulse control, aggression, irritability mood changes -- depression, apathy, suicidal ideation cognitive impairment -- difficulty with executive functions (i.e. carrying out tasks), memory loss, dementia diagnosis postmortem neuropathologic examination of the brain cerebral atrophy enlarged ventricles diffuse senile plaques