2. Definition
• Concussion is a complex pathophysiological process affecting the brain resulting in alteration of
brain function, that is induced by nonpenetrating biomechanical forces, without identifiable
abnormality in standard structural imaging.
• Results in a graded set of neurological symptoms that may or may not involve loss of
consciousness (LOC).
• Concussion can occur without a direct blow to the head, e.g. with violent shaking of the torso and
head.
3. Symptoms and Signs of Acute Concussion
• Concussion symptoms can present soon after an insult or in a delayed fashion.
• Symptom onset is usually rapid, short-lived and resolves spontaneously.
• The subject may not be aware that they have sustained a concussion.
• Manifestations may include transient deficits in balance, coordination,
memory/cognition, strength, or alertness.
● May result in neuropathological changes, but the acute clinical symptoms
largely reflect a functional disturbance rather than a structural injury.
● Resolution of the clinical and cognitive features typically follows a sequential
course.
• While most victims recover completely, effects of concussion can be serious, and
in some instances, may be lifelong.
4. • 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.
• The suspected diagnosis of concussion can include 1 or more of the following clinical
domains:
1.Symptoms: somatic (eg, headache), cognitive (eg, feeling like in a fog), and/or emotional
symptoms (eg, lability);
2.Physical signs (eg, loss of consciousness, amnesia);
3.Behavioral changes (eg, irritability);
4.Cognitive impairment (eg, slowed reaction times); and/or
5.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.
5. Concussion versus mTBI
• Concussion occurs in a subset of patient with mild traumatic brain injury
• It is considered “mild” because it is usually not life-threatening by itself.
• Concussion and mTBI are not interchangeable. Concussion may be
thought as a subcategory of mTBI on the less severe end of the brain
injury spectrum, though with similar clinical symptoms.
• A major difference between the two is that mTBI may demonstrate
abnormal structural imaging (such as cerebral hemorrhage/contusion) and
concussion, by definition, must have normal imaging studies.
• mTBI is part of an injury severity spectrum primarily based on GCS score.
TBI is evaluated 6 hours after injury and differentiated into mild, moderate
and severe.
Concussion is evaluated directly after the insult and based on a clinical
diagnosis aided by a multitude of standardized assessment tools.
6. Risk factors for concussion
• History of previous concussion increases risk for further concussion
• Being involved in an accident: bicyclist, pedestrian or motor vehicle collision
• Combat soldier
• Victim of physical abuse
• Falling (especially pediatrics or elderly)
• Males are diagnosed with sports-related concussion more than females (due to increased number
of male participation in sports studied) but females have a higher risk overall when compared to
males who play in the same sport (i.e., soccer and basketball)
• Participating in sports with high risk of concussion:
○ American football
○ Australian rugby
○ Ice hockey
○ Boxing
○ *Soccer is the highest risk for females
• (For contrast, sports with the lowest risk of concussion: baseball, softball, volleyball & gymnastics)
• BMI > 27 kg/m2 and less than 3 hours of training per week increase risk of sports-related
concussion
7. Approach
• Take a concussion specific symptom survey including inquiries about: H/A, N/V, light sensitivity,
tinnitus, feeling like being in a fog, sleep disturbances
• History of diagnoses that might have an impact on the assessment or on a current concussion
○ History of prior concussions
○ H/A history
○ ADD/HD
○ Learning disabilities
○ Medications (prescribed and other) that might affect alertness or cognition
• Perform a good general neurological exam
• Include a concussion specific neuro exam
○ Check orientation
○ Assess for amnesia and impaired verbal memory
○ Balance: Romberg test (look for significant sway or breaking stance), single leg stance
○ Eye movements: optokinetic nystagmus (OKN), smooth pursuit
○ Simultaneous task performance: e.g. snap fingers while walking
● Include assessment aides (“sideline tools”) as appropriate
9. Assessment aids
• There is no single validated assessment tool for diagnosis of concussion.
• It is primarily a clinical diagnosis that is ideally made by certified
healthcare providers who are familiar with the patient based on a detailed
history and physical examination and a continuum of evaluation from the
sideline to the clinic (diagnosis is ideally made within 24 hours of injury)
● Diagnosis may be aided by concussion assessment tools such as the
SCAT3, ImPACT™.
• ✖ No test has shown high validity on independent testing, and no test
should be used as the sole method of diagnosing concussion or for
determining suitability for return to play.
• Athletes have also learned to “game” some baseline tests to avoid removal
from play after possible concussion
10. SCAT3
• SCAT3 (Sports Concussion Assessment Tool – 3rd Edition): Derived from the 2012 Zurich
Conference.
• The SCAT has become the most commonly used standardized tool for sideline
assessment of sport concussion.
• The sensitivity and specificity of concussion assessment tools change over the course of
a concussion so a tool designed for sideline use (i.e. SCAT3) is not appropriate for office
use
○ SCAT3™ is a trademarked tool developed by the Concussion in Sports Group for use
only by medical professionals for assessing sports-related concussion
○ It can be found at http://bjsm.bmj.com/content/47/5/259.full.pdf
○ To be used in athletes of 13 years or older (for 12 and younger, use Child SCAT313)
○ Is a multimodal assessment tool with 8 sections that includes self-reported symptoms
and evaluation of functional domains such as cognition, memory, balance, gait and motor
skills
○ Takes 8–10 min to administer
○ A “normal” SCAT3 does not rule out concussion
○ It has not been validated
11. Other types of sports concussion assessment tools
• SAC (Standardized Assessment of Concussion: a neurocognitive
test that includes tests of immediate memory, delayed recall, serial
7’s, digit span
• ImPACT™ (Immediate Post-Concussion Assessment and Cognitive
Testing
• PCSS (Post-Concussive Symptom Scale)
• CSI (Concussion Symptom Inventory)
• BESS (Balance Error Scoring System): the subject stands in each of
various standardized positions for 20 seconds each, and the number
of errors are recorded (breaking stance, opening
eyes, taking hands off hip…).
• SOT (Sensory Organization Test)
• “Concussion Quick Check” app for mobile devices produced by the
AAN
12. On-site/sideline evaluation
• Any individual suspected of having a concussion (displaying ANY S&S of concussion) should be
removed from the activity (for athletes, stopped from playing) and assessed by a licensed
healthcare
provider trained in the evaluation and management of concussions with attention to excluding a
cervical spine injury.
• If no provider is available, return to the activity is not permitted and urgent referral to a physician
should be arranged.
• After ruling out emergency issues, the provider should perform a concussion assessment (may
employ standardized tools such as SCAT3™ or other methodologies).
• The patient should not be left alone, and serial evaluations for signs of deterioration should be
made over the following few hours.
13. Indications for imaging or other diagnostic testing
• Imaging in concussion is typically used to rule out more serious traumatic injuries.
Indications for CT or MRI imaging:
● Adults with or without LOC or amnesia
○ Focal neurologic deficit
○ GCS < 15
○ Severe headache
○ Coagulopathy
○ Vomiting
○ Age > 65 years old
○ Seizures
● Peds
○ LOC > 60 secs
○ Evidence of skull fracture
○ Focal neurologic deficit
14. Other imaging studies:
● Diffusion Tensor Imaging (DTI): used to quantify white matter tract
integrity throughout the brain
● Functional MRI (fMRI): consists of 2 types (task-based fMRI and
resting state fMRI) and is based on the blood oxygen level dependent
(BOLD) effect, in which specialized MRI sequences measure/detect
regions of increased oxygen rich blood flow to areas of upregulated
neuronal activity.
● Imaging studies that are currently used primarily in concussion
research: positron emission tomography (PET), single photon
emission CT (CT-SPECT), MR-spectroscopy (MRS).
Quantitative EEG (QEEG) is another research tool for concussion that
assesses brain activity, patterns of cortical activation and neuronal
networks. The concept is that post-concussion studies are compared
to baseline.
15. Acute pathophysiology
• Biomechanical force results in unregulated ionic (K+ efflux, Na+/Ca2 + influx) flux and unrestricted
hyperacute glutamate release from sublethal mechanoporation of lipid membranes at the cellular
level.
• This triggers voltage/ligand gated ion channels causing a cortical spreading depression-like
state that is thought to be the substrate behind immediate postconcussive symptoms.
• Subsequently, ATP-dependent ionic pumps are extensively upregulated to restore cellular
homeostasis causing widespread intracellular energy reserve depletion and an increase in ADP.
• Cells then pass into a state of impaired metabolism (energy crisis) that can last up to 7–10 days and
may be associated with alterations in CBF.
• This impaired metabolic state is associated with vulnerability to repeat injury as well as behavioral
and spatial learning impairments.
• Cells also undergo cytoskeletal damage, axonal dysfunction, and altered neurotransmission with
the as yet unproven impression that each of these pathologic processes correlate with a separate
symptomology
17. Post concussion syndrome (PCS)
• As with most concussion related pathologies, there are multiple
definitions of PCS.
• An amalgam of some definitions is as follows: Patients having ≥
3 symptoms including headache, fatigue, dizziness, irritability,
difficulty concentrating, memory difficulty, insomnia, and
intolerance to stress, emotion, or alcohol, and symptoms must
begin within 4 weeks of injury and remain for ≥ 1 month after
onset of symptoms.
• Occurs in 10%-15% of concussed individuals.
18. • In this retrospective
study, the following
conclusions were
reached
● > 80% of PCS
patients had at least 1
previous concussion
● average number of
previous concussions
was 3.4
● median duration of
PCS was 6 months
● 50% of patients were
< 18 years of age
● LOC does not
increase the risk for
PCS
19. Prevention of concussion
• The AAN guidelines conclude that protective headgear in
rugby is “highly probable” to decrease the incidence of
concussion.
• However, the AMSSM (American Medical Society for Sports
Medicine) hold that there is no clear evidence that soft or
hard helmets reduce the severity or incidence of
concussion (in football, lacrosse, hockey, soccer, and
rugby).
• Biomechanical studies have shown helmets reduced impact
forces on the brain but this has not translated into
concussion prevention.
20. Management of concussion and post-concussion syndrome Return to Play (RTP)
• No system of return to play (RTP) guidelines has been rigorously tested
and proven to be scientifically sound
● After sustaining a concussion, athletes should not return to play the
same day.
• Prohibited by some state laws.
• ✖ a symptomatic player should not return to competition.
● If there is any uncertainty: “When in doubt, sit them out”
21. Return to play(RTP)
• Evaluation should proceed in a stepwise fashion.
• A player needs to be completely asymptomatic both at rest and
with provocative exercise before full clearance is given.
• There is no standardized RTP protocol.
• Each player’s progression should be individualized.
• Generally, the athlete’s level of activity should be gradually
increased over 24-hour increments from light aerobic activity to
full contact practice.
22. • The athlete is evaluated after each progression.
• If postconcussive symptoms occur then the player is dropped back
to the previous asymptomatic level and then allowed another attempt
at progression after a 24-hour rest period.
• 80–90% of concussions resolve within 7–10 days.
• This recovery time may be longer for children or adolescents.
• The CDC endorses a graded 5-step return to play for athletes
• The athlete should move to the next step only if they have no new
symptoms. If symptoms return or new ones develop, then medical
attention should be sought and after clearance the player can return
to the previous step
24. Management of post-concussive syndrome
• Most symptoms from concussion resolve within 7–10 days and do not require
treatment.
• The most common exception to this is posttraumatic headache, the most
common subtype being acute
posttraumatic migraine.
● Psychological and neuropsychological involvement is often employed
● Pharmacologic treatment: there are no evidence-based studies of the utility of
medications for
post-concussive symptoms (aside from H/A)
● Intractable headaches: occurs in ≈ 15% of concussions
○ Expert neurology consultation is usually required for difficult-to-control
headaches
○ The first line drugs are OTC medications
○ Triptans are usually employed for nonresponders
○ Third line drugs include Ketorolac or DHE-45 (dihydroergotamine)
○ Steroids may be beneficial for some
○ Avoid: narcotics, butalbital/caffeine preparations (Fioricet, Esgic…), beta
blockers, and calcium channel blockers
25. Second impact syndrome (SIS)
• A rare condition described primarily in athletes who
sustain a second head injury while still symptomatic
from an earlier one.
• Classically, the athlete walks off the field under their
own power after the second injury, only to deteriorate to
coma within 1–5 minutes and then, due to vascular
engorgement, develops malignant cerebral edema that
is refractory to all treatment and progresses to
herniation.
• Mortality: 50–100%.
26. Chronic traumatic encephalopathy (CTE)
• There is limited evidence-based research involving the pathophysiology
and natural history of CTE.
• Thought to be a distinct neurodegenerative disease (tauopathy)
associated with repetitive brain
trauma, not limited to athletes with reported concussions, and can only be
diagnosed postmortem
with a pathology-confirmed analysis.
• Small studies have shown that there is a variable age of onset with
variable behavioral, mood, and cognitive deficits present at the time of
death (92% symptomatic at time of death).
27. References
• Greenberg Handbook of Neurosurgery 9th Ed
• Tator, Charles & Davis, Hannah. (2014). The Postconcussion Syndrome
in Sports and Recreation: Clinical Features and Demography in 138
Athletes. Neurosurgery. 75 Suppl 4. S106-S112.
10.1227/NEU.0000000000000484.
