Concussions

Other Names

• Mild TBI
• Mild Traumatic Brain Injury

Pathophysiology

• A concussion is a subset of mild traumatic brain injury (mild TBI) defined as a traumatically induced transient disturbance of brain function that involves a complex pathophysiological process.
• Characterized by a force delivered to the brain that causing motion of the brain inside the skull and stretches the neuronal cell membranes and axons
• This force leads to microstructural injury to the neurons that can affect neuronal metabolism, ionic balance, and neurotransmission.
• The mechanism of injury is typically an impulsive force from a blow to the body that causes motion of the brain inside the skull. This motion stretches the neuronal cell membranes and axons, causing microstructural damage.
• Causes a complex cascade of ionic, metabolic, and pathophysiological events that changes intracellular ion concentrations, the release of neurotransmitters, and cause mitochondrial dysfunction
• This leads to increased reactive oxygen species increased utilization of glucose, and a decrease in resting cerebral blood flow
• Inflammatory cell activation along with alteration of the blood-brain barrier, axonal degeneration, and altered neuroplasticity may occur more often in the chronic stages of concussion.

Types of Concussions

Causes

Risk factors for concussions include but are not limited to:

• Being in a motor vehicle accident
• Being in the military and engaged in combat
• Being a victim of physical abuse
• Having increased fall risk
• Having a previous concussion
• Females
• Engaging in sports
  • Sports with increased contact increase risk e.g.: Football, men’s ice hockey, women’s soccer
  • An athlete’s position may alter concussion risk

Female Collegiate Athletes 

• Ice hockey RR = 7.2
• Basketball 5.3
• Soccer 3.3
• Lacrosse 3.2
• Volleyball 2.8
• Softball 2.4

Male Collegiate Athletes

• Wrestling is #1 with RR of 7.9
• Ice Hockey 6.9
• Football 5.3
• Basketball 3.9
• Lacrosse 2.5
• Soccer 1.6
• Baseball 0.7
• Migraines
• Depression
• Anxiety
• History of multiple concussions/overlapping concussions
• Attention-deficit/hyperactivity disorder(ADHD)
• Learning disability
• Post-traumatic stress shortly after injury (~5 days)
• Young athletes
• Females historically are more symptomatic and take longer to recover than males
  • Learning disability and ADHD as risk factors have recently come into question as a risk factor 

• Intracranial injury
  • Epidural or subdural hematoma
• Heat illness
• Hypoglycemia
• Dehydration
• Syncope
• Cranial Nerve Injury
• Primary headache
  • Migraine, tension, cluster
• Psychiatric disorder
  • ADHD, Anxiety, Depression, Acute stress disorder, Post-traumatic stress disorder
• Overtraining syndrome
• Malingering

Concussion Danger Signs

• Based on clinical experience
  • Complicated by lack of validated objective tests and reliance on self-reported symptoms
  • Symptoms vary between patients and within patients with multiple concussions
• Common symptoms (may be unrecognized, delayed or unreported) 
• Affective/ emotional function
  • Irritability
  • Changes in mood
• Cognition
  • Confusion/ disoriented
  • Amnesia (retrograde or anterograde)
  • Mental fogginess
  • Poor concentration
  • Cognitive fatigue
• Somatic/ Physical
  • Headache (most common)
  • Dizziness
  • Decrease balance, unsteady gait
  • Visual changes
  • Neck pain
  • Fatigue
  • Vomiting
• Sleep
  • Drowsiness
  • Sleeping more or less than usual
  • Difficulty falling asleep
• Loss of consciousness (LOC) has been reported in mTBI cases. However, it is very uncommon; as less than 10% of the population experiences LOC
• If a patient has severe symptoms of one kind e.g. vestibular, it is recommended to refer that patient to a specialist for treatment.

Diagnosis

Preseason

• PPE (Pre-participation exam)
  • History of TBI, premorbid/comorbid conditions, risk factors
• Baseline neuropsychiatric testing done within some health systems and is required by many schools in the U.S.
  • Many availiable (SCAT5, Impact, Cogsport, etc)
    • Should include baseline symptom score, balance assessment
• Baseline sideline testing before the season and should be geared towards testing that is performed by the provider/health system
  • King-Devick, VOMS (Vestibular/ocular motor screening), etc.

Sideline assessment

• It is important to screen any athlete who may have a suspected head injury during a practice or game, as they are at risk for Second Impact Syndrome 
  • Loss of consciousness (LOC), impact seizure, tonic posturing, gross motor instability, confusion or amnesia, incoordination or balance problems, having a blank or vacant look, or repeated shaking of the head should always result in immediate removal from play and evaluation
  • Some of the above symptoms may indicate more severe injuries, therefore careful evaluations are important. Concerns for more serious head injury including prolonged LOC, severe or worsening headache, repeated emesis, declining mental status, focal neurological deficit or suspicion of significant cervical spine injury should trigger activation of the emergency action plan (EAP) 
• Brief history is needed followed by a cervical and neurologic examination
  • Many providers will move athletes to quiet environment and give them short rest before neuropsychiatric evaluation (SCAT 5, Child SCAT 5, King-Devick, VOMs, SAC, Balance Error Scoring System (BESS))
• The goal is to determine the probability athlete has sustained a concussion and remove the athlete if the provider feels this probability is high
  • Accurate diagnosis of a concussion is important because the risk of Second Impact Syndrome, a condition in which a patient sustains multiple concussions simultaneously. This condition can result is severe brain damage and death.
  • If an athlete is diagnosed with a concussion, they should be removed from sport until they complete the Return to Play protocol

Office assessment

• Comprehensive history and neurological examination
  • Should include mechanism of injury, sleep/wake disturbance, vestibular function (VOMS testing), ocular function (including fundoscopic exam), gait, balance, cervical spine exam
• Neuropsychiatric testing (Impact, Cogsport, SCAT5) may be performed and symptom checklist should be done
• Other pathologies such as cervicogenic pain, primary headache disorder, mood disorder should be ruled out if symptoms persist
• The Buffalo Concussion Physical Exam is a recommended tool for clinicians diagnosing mTBI in an office setting and includes:^[9]
  • Vital Signs
  • Neck/ Sub-occipital Region Exam
  • Head and Face exam
  • Cranial Nerve Testing
  • Fundoscopy
  • Pupil Reactivity
  • Visual Tracking
  • Smooth Pursuits
  • Repetitive Saccades
  • Vestibulo-occular Reflex (VOR) or Gaze Stability Test
  • Near Point of Convergence (NPC) and Accommodation
  • Tandem Gait with Eyes Open and Close, and Tandem Stance
• The Buffalo Concussion Treadmill Test (BCTT) is used to assess exercise intolerance in concussed patients ^[10]
  • The BCTT is a graded exercise test that allows clinicians to assess the level of exertion a patient can withstand in order to create a sub-threshold exercise program for the patient
    • Aerobic exercise has been shown to improve the prognosis of concussions

Treatment

• Most adults (more than 80%) will recover spontaneously within two weeks of the injury and the majority of children will recover within four weeks 
• A symptom checklist should be implemented at each follow-up visit
• Persistent headache, depression, and PTSD symptoms should be noted and have been shown to predict symptoms lasting >1 month ^[12]
• After acute onset, rest is generally prescribed for 24-48 hours
• Rest is followed by a gradual increase in physical and cognitive activity over the course of a few days
  • Ensure the patient stays below the symptom exacerbation threshold as to not worsen their concussion symptoms
• Emerging data suggest that both children and adults recover more quickly when subsymptom threshold exercise is performed and has been shown to be safe 
• Graded return to play protocol started once symptoms have subsided
• Despite the great interest, no proven pharmaceutical agents were shown to prevent or decrease symptoms in humans
  • Rodent studies have shown improvement with omega-3 fatty acids, B-vitamins, N-methyl-D-aspartate, vitamin D

Return to Sport

• Also known as Return to Play (RTP)
• Return to Play (RTP) is the protocol clinicians use to slowly acclimate athletes back to the sport after being removed due to a concussion
• RTP can be started once symptoms have resolved at rest (usually 24-48 hours)
  • Symptoms may be exacerbated during exercise
• Graded return to sport involves a gradual, stepwise progression into physical activity and sport-specific activities without a return of symptoms
  • Typically, this is a 5-day progression but can be modified based on an individual’s needs 
  • Each stage of the progression should be at least 24 hours without return of symptoms before progressing to the next stage
• The program should be supervised by a provider that is familiar with the athlete if possible
  • Individualized depending on the prior injury, age, level of play