Brain Injury, Traumatic



  • Traumatic brain injury (TBI) is defined as an alteration in brain function or other evidence of brain pathology, caused by an external force.
  • System(s) affected: neurologic; psychiatric; cardiovascular; endocrine/metabolic; gastrointestinal; pulmonary
  • Synonym(s): head injury, concussion



  • Sixty-nine million individuals worldwide are estimated to sustain a TBI each year.
  • 801,700 ED visits and 326,600 hospitalizations per year in the United States
  • 61,000 deaths per year; ~30% of all injury-related deaths
  • Incidence in males twice that of females


  • Predominant age: 0 to 4 years, 15 to 19 years, and >65 years
  • Predominant gender: male > female (2:1)

Etiology and Pathophysiology

  • Centers for Disease Control and Prevention (CDC) TBI data in 2017, mechanism of injury of hospitalized patients (male vs. female percentage)
    • Unintentional falls (35.6 vs. 23.9)
    • Motor vehicle crashes (22.5 vs. 10.8)
    • Unintentionally being struck by or against an object (2.3 vs. 0.9)
    • Intentional self-harm (0.8 vs. 0.3)
    • Assault (7.5 vs. 1.7)
    • Children 0 to 17 years
      • Falls (7.7)
      • Motor vehicle crashes (6.8)
  • Contact sports account for 45% of TBI emergency room visits for children related to sports and recreation.
  • Primary insult: direct mechanical damage
  • Secondary insult: actuation of complex cellular and molecular cascades that promote cerebral edema, ischemia, and apoptotic cell death

Risk Factors

Alcohol and drug use, prior/recurrent head injury, contact sports, seizure disorder, ADHD, male sex

Geriatric Considerations
Subdural hematomas are common after a fall or blow in elderly; symptoms may be subtle and not present until days after trauma. Many elderly patients are on antiplatelet or anticoagulation therapy.

General Prevention

  • Safety education and fall prevention
  • Seat belts; bicycle and motorcycle helmets
  • Protective headgear for contact sports

Pediatric Considerations
Child abuse: Consider if dropped or fell <4 feet (e.g., off bed, couch), suspicious history, significant injury present, or any retinal hemorrhages.

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