Concussion – Causes, Symptoms, Diagnosis, Treatment and Ongoing care



  • A complex pathophysiologic process affecting brain function, induced by traumatic biomechanical forces that generally resolves over 7–10 days.
  • Concussion severity can only be determined in retrospect.
  • System(s) affected: Cardiovascular; Endocrine/Metabolic; Nervous; Psychiatric
  • Synonym(s): Mild traumatic brain injury (TBI)

Pediatric Considerations

Children (ages 5–18) should not be allowed to return to training or play that same day and not until completely symptom-free. Resolution of symptoms and clinical findings often take longer in the pediatric athlete.


  • Predominant age: 12–24 years
  • Predominant sex: Male > Female
  • Usually related to accidents, sometimes sports related


  • 0.14–3.66 injuries/100 players each season at high school level
  • 0.5–3.0 injuries/1,000 athlete exposures at college level (1)
  • Average annual incidence 503:100,000.
  • ∼1.5 million cases of TBI in US annually, 85% of which are considered mild TBI.
  • ∼10% of TBIs are related to sports or cycling injuries.
  • Among the 5–14 age group, 26.4% of mild TBI is related to sports or cycling (2).

Risk Factors

Contact sports, particularly football, and history of recent concussion.

General Prevention

  • Educate athletes, coaches, parents, and officials on signs and symptoms of concussions.
  • Rule enforcement in sports (e.g., penalties for spearing or head-to-head contact)
  • Consideration of rule changes in sports to decrease dangerous plays
  • Current protective headgear for contact sports decreases facial injuries, but has not been shown to decrease the overall concussion risk.
  • Useful web site:


Concussion represents a functional brain injury rather than a structural brain injury. The neurobiologic cascade has been shown to include excitatory amino acid release, ionic flux, hyperglycolysis, and reduced cerebral blood flow.


  • Falls
  • Sports related
  • Motor vehicle accidents

Concussion, Traumatic brain injury, Epidural hematoma, Neurological Disorders, traumatic brain injury, cerebral blood flow, mild traumatic brain injury, protective headgear,



  • Cognitive symptoms:
    • Confusion
    • Post-traumatic amnesia (PTA)
    • Retrograde amnesia (RGA)
    • Loss of consciousness (LOC)
    • Disorientation
    • Feeling “in a fog,” “zoned out”
    • Inability to focus
    • Delayed verbal and motor responses
    • Slurred/incoherent speech
    • Excessive drowsiness
  • Somatic:
    • Headache
    • Fatigue
    • Disequilibrium, dizziness
    • Visual disturbances
    • Phonophobia
  • Affective:
    • Emotional lability
    • Irritability
  • Sleep Disturbance

Physical Exam

Variable and dependent on degree of injury:

  • ABCs if seen acutely
  • External evidence of major trauma
  • Focal neurologic signs and symptoms
  • Musculoskeletal: Evaluate for possible C-spine injury and stability.
  • Detailed neurologic exam including:
    • State of alertness
    • Orientation
    • 3- or 5-word recall at 5 minutes
    • Concentration/attention (serial 3s or 7s)
    • Cerebellar function and postural stability assessment

Diagnostic Tests & Interpretation

  • The sideline assessment of concussion (SAC) scale has been validated to drop from baseline after a concussion and return to baseline once symptoms clear.
  • Serial cognitive evaluations should be done by an experienced health care provider using the neurologic exam listed above or by using other assessment tools such as the sport concussion assessment tool (SCAT) (3)[C].
  • Computerized neurocognitive testing to date lacks sufficient evidence on validity, cost effectiveness, and improved management to warrant global usage (4)[B].
  • Current gold standard is evaluation and treatment by a trained physician. Until improved outcomes, validity, and cost-effectiveness of computerized testing are established, use should be limited to experimental situations or possibly in management of complex concussions.


Generally not necessary.


  • Structural neuroimaging is usually normal in the setting of concussion.
  • Consider MRI or CT with prolonged LOC, focal neurologic deficit, or overall worsening symptoms.
  • Role of functional MRI is largely experimental and unvalidated at this time.
  • Consider C-spine films.

Diagnostic Procedures/Surgery

Serial neurologic exams at least every 10–15 minutes until symptoms are clearing and patient is stabilizing or patient has been transported to hospital for further evaluation.

Differential Diagnosis

  • Concussion
  • Subdural hematoma
  • Epidural hematoma
  • Cerebral contusion
  • Facial or skull fracture



  • Ibuprofen or acetaminophen may be used as adjunct pain management for headache once structural brain injury ruled out.
  • Prolonged symptoms such as sleep disturbance or anxiety, may benefit from appropriate pharmacologic treatment for symptom relief.

Additional Treatment

General Measures

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  • Acute management depends on severity of injury. Most patients need only physical and cognitive rest, serial clinical evaluations to include neurologic checks, and a plan for follow-up evaluation (1)[C].
  • Prolonged LOC, abnormal neurologic exam, or deteriorating symptoms necessitate urgent or emergent referral to the hospital for further evaluation (1)[C].

Issues for Referral

  • Most concussions can be managed by primary care physicians using the standard guidelines for return to play; generally, referral to a specialist is not needed.
  • Patients with a complex or atypical concussion, or who have suffered recurrent concussions should be referred to a sports medicine physician or neurologist for management and clearance prior to returning to sports activities.

Surgery/Other Procedures

Generally not indicated, unless signs of more severe TBI present, with increased intracranial pressure or large bleed.

In-Patient Considerations

Initial Stabilization

  • ABCs take priority over head injury and concussion.
  • C-spine immobilization should be considered in all head trauma.

Admission Criteria

  • Progressive neurologic symptoms, including deterioration of mental status, seizures, and focal neurologic signs
  • No competent adult at home

Discharge Criteria

  • Improving mental status at or near baseline
  • Competent adult at home for patient observation (see Patient Monitoring)

Ongoing Care

Follow-Up Recommendations

  • Any athlete with a suspected concussion should be withheld that day from sports participation and not returned till a concussion has been ruled out or a diagnosed concussion has been appropriately treated as noted below (3).
  • Current recommendation on treatment involves an asymptomatic graduated return to play as follows (3)[C]:
    • Complete rest until symptom-free, including cognitive rest (e.g., video games, and potentially scholastic activities)
    • May then begin gradual reintroduction of activity as long as symptom free. Each step should be generally done 24 hours apart.
      • Light aerobic exercise
      • Sport-specific exercise
      • Noncontact training drills
      • Full contact training
      • Game play
  • If postconcussive symptoms occur (exertional headache, visual disturbance, or disequilibrium), decrease level of activity until again asymptomatic, and progress again in 24 hours.
  • High-risk athletes for more prolonged recovery include pediatric athletes, athletes with mood disorders, athletes with learning disabilities, and athletes with migraine headaches. These athletes should have a slower return to play progression and may require more intensive evaluation (formal neuropsychologic, balance, symptom testing).
  • Athletes with multiple concussions should have slower return to play and may benefit from sports medicine consultation or neurology referral.

Patient Monitoring

  • Written instructions regarding postconcussion management should be given to a competent adult describing signs to watch for and when to bring the patient back for further evaluation.
  • Have a follow-up plan prior to discharge to home, ideally to be seen within a few days.
  • Instruct patients and families regarding postconcussive symptoms, including the cognitive, somatic, and affective symptoms listed earlier.
  • Ensure adequate rest and symptom-free return to both school and sports-related activities.


As tolerated.


  • Delayed hematomas, including subdural hematomas, can present minutes to hours after initial injury, necessitating serial neurologic checks and close observation.
  • Postconcussion syndrome occurs when symptoms of concussion, such as headache, fatigue, memory changes, or emotional lability, are persistent and last >1–3 months.
  • Recurrent concussions can lead to second-impact syndrome or can occur with less and less impact force. Symptoms can persist longer than a 1st concussion, and progression to chronic cognitive and psychiatric symptoms is possible.
  • Second-impact syndrome describes an additional insult or injury to the brain after a concussion and before the brain has had adequate time to completely recover. A rare, but life-threatening, cerebral edema after repeated head injury can occur. The etiology is thought to be due to loss of regulation of either cerebral circulation or glucose metabolism in the concussed brain.
  • Chronic traumatic brain injury with chronic cognitive, mood, and potential Parkinson-type symptoms (5).


1. Concussion (mild traumatic brain injury) and the team physician: a consensus statement. Med Sci Sports Exerc. 2006;38:395–9.

2. Bazarian JJ, McClung J, Shah MN et al. Mild traumatic brain injury in the United States, 1998–2000. Brain Inj. 2005;19:85–91.

3. McCrory P, Meeuwisse W, Johnston K, et al. Consensus Statement on Concussion in Sport: the 3rd International Conference on Concussion in Sport held in Zurich, November 2008.Br J Sports Med 2009;42(Suppl 1):i76–90.

4. Randolph C, McCrea M, Barr W. Is neuropsychological testing useful in the management of sport-related concussion? J Athletic Train. 2005;40(3):136–51.

5. Guskiewicz KM, Marshall SW, Bailes J et al. Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery. 2005;57:.

Additional Reading

Halstead ME, Walter KD. Council on Sports Medicine and Fitness et al. American Academy of Pediatrics. Clinical report–sport-related concussion in children and adolescents. Pediatrics. 2010;126:597–615.

Mayers L. Return-to-play criteria after athletic concussion: a need for revision. Arch Neurol. 2008;65:1158–61.

See Also (Topic, Algorithm, Electronic Media Element)

Brain Injury, Traumatic; Brain Injury, Post Acute Care Issues; Postconcussive Syndrome; Seizure Disorders



  • 310.2 Postconcussion syndrome
  • 850.9 Concussion, unspecified


  • 110030002 Concussion injury of brain (disorder)
  • 40425004 Postconcussion syndrome (disorder)

Clinical Pearls

  • Most symptoms resolve completely within 7–10 days, but each person recovers at a different rate, and some symptoms may continue for weeks to months.
  • Some athletes notice worsening symptoms, such as headache or nausea, while concentrating. If symptoms worsen while in class, they should stay home from school until their symptoms clear.
  • Generally, patients who have been observed for at least 1–2 hours and are stable or improving do not need to be roused from sleep.
  • When symptom-free at rest, the athlete may begin a gradual ramp-up of activity over 3–5 days, as listed above. If symptoms recur during any level of play, the athlete should postpone further activity for at least another 24 hours.

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