• Clinical science

Traumatic brain injury

Abstract

Traumatic brain injury (TBI), also referred to as head injury, is acute physical damage to the brain caused by an external impact. TBI is most frequently seen in young children, teenagers, and individuals above the age of 65. Motor vehicle accidents are the most common cause. Although the skull is often fractured in the process, acute cerebral damage can occur even if the skull remains intact. Clinical findings depend on the severity, type, and location of injury. Impaired consciousness is common in more severe TBI, whereas patients with mild TBI often only experience transient confusion, headaches, or nausea. Elevated intracranial pressure, hemorrhages, and seizures may occur rapidly after injury in severe cases, or develop as complications over the course of the illness. Skull fractures may cause immediate damage to sensory organs or cranial nerves, while also increasing the risk of infection. A noncontrast head CT is the diagnostic method of choice for detecting common pathologies such as fractures, midline shifts, or hemorrhages. Treatment is usually not required for mild TBI, although patients should be monitored for 24 hours to rule out complications. In most cases of more severe TBI, specific medical (e.g., reduction of intracranial pressure, prevention of seizures or infections) or surgical (e.g., decompressive craniectomy) measures are necessary.

Definition

  • Acute physical damage to the brain as a result of an external force

References:[1]

Epidemiology

  • Incidence: ∼ 800/100,000
  • Age: especially children 0–4 years, teenagers and young adults 15–24 years, and adults > 65 years
  • Sex: >

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

  1. Motor vehicle accidents (most common)
  2. Falls
  3. Contact sports (e.g., football)
  4. Gunshot wounds

References:[1][4]

Pathophysiology

Primary and secondary injury

  • Primary injury: acute physical injury that is dealt to the brain during the traumatic event
    • Acceleration-deceleration trauma
      • Coup injury: cerebral contusion on the side of an impact
      • Contrecoup: additional cerebral contusion on the opposite side of impact
    • Contact trauma: may involve fractures of the skull or superficial wounds (focal injury)
  • Secondary injury: pathologic changes induced by inadequate cerebral perfusion and/or inflammatory processes after primary injury

Consequences of injury

References:[5][6][7]

Clinical features

Clinical findings vary depending on the location, severity, and type of injury. In addition to the initial presentation, further symptoms may develop as lesions progress (e.g., intracranial hemorrhages).

General symptoms

Signs of basilar skull fracture

Possible traumatic brain injury must always be considered in a patient with a reduced level of consciousness (unless another cause is evident)!

Skull fractures, (worsening) neurological impairment, repeated vomiting, and seizures are indicative of more severe trauma or intracranial hemorrhage!

References:[7][8][9][10][11][12]

Diagnostics

General approach to TBI patients

Acute stabilization and measures of life support should always take precedence over diagnostic investigations!

  • Cranial CT (without contrast) if consciousness is impaired
  • Glasgow Coma Scale (GCS) for evaluation of consciousness
    • Assessment of neurological status and trauma severity in patients with traumatic brain injury (mostly used in acute cases)
    • Maximum score 15 points (full consciousness); minimum score 3 points (coma or death)
Points Eye opening Verbal response Motor response
6 Obeys commands
5 Appropriate words and oriented Localizes pain stimulus
4 Spontaneously Appropriate words but confused Withdraws from pain
3 To verbal command Inappropriate words Decorticate posture
2 To pain Incomprehensible sounds Decerebrate posture
1 No response No response No response
Mild head injury: GCS score 13–15 Moderate head injury: GCS score 9–12 Severe head injury: GCS score ≤ 8 (Indication for endotracheal intubation)
  • Additional investigations: exact description of injury mechanism with evaluation of injuries; full medical and neurological examination

Imaging

  • First-line: cranial CT (cCT) without contrast to look for the following:
  • CT angiography: to evaluate/localize vascular injury (e.g., CTA spot sign )
  • Intrathecal application of contrast agent: to evaluate/localize leakage of CSF
  • Survey x-ray: orbital region for orbital fractures; trunk and/or the extremities

References:[13][14][15][16][17][18]

Treatment

Mild TBI

  • Monitoring for 24 h
  • Temporary rest and symptomatic pharmacotherapy
  • No specific treatment, possibly symptomatic (e.g., pain management)
  • For athletes: Refrain from contact sports for a week, re-evaluate at that time
    • Observe for 6 hours in the ED for worsening
    • Following discharge → six stages of gradual recovery, each stage requiring at least 24 hours
      1. No activity
      2. Light aerobic exercise
      3. Sport-specific exercise
      4. Non-contact workouts
      5. Full-contact practice
      6. Return to full play

More severe TBI

  • Intensive care with general measures (e.g., fluid management, pain relief, blood pressure management); possibly advanced neuromonitoring
  • Intubation: if GCS score is 8 or lower
  • Monitoring of
    • ICP; , risk of elevated pressure (see ICP management)
    • Cerebral perfusion pressure (CPP)
    • Glucose blood levels (normoglycemic)
    • Body temperature (normothermic)
  • Prevention of
  • Surgical therapy
    • Superficial debridement, closure of the dura (if skull was fractured or penetrated)
    • Removal of hematomas (usually recommended if GCS ≤ 8)
    • Decompressive craniectomy

References:[9][16][19][20]

Complications

We list the most important complications. The selection is not exhaustive.

Prognosis

  • Mild TBI: usually self-limiting
  • Severe TBI: mortality rate as high as 30%

References:[9][16]

Special patient groups

When evaluating children and infants with TBI, a number of special issues must be observed.

  • Causes:
    • Falls (most common)
    • The possibility of child abuse must always be considered.
  • Clinical features: : esp. bulging anterior fontanelle (↑ ICP)
  • Diagnosis: identify patients with significant TBI but avoid unnecessary radiographic testing
    • CT recommended for signs of skull fractures, ↑ ICP, major neurologic symptoms (e.g., impaired consciousness, seizures), suspected child abuse
    • Consider CT: if less severe symptoms (e.g., changes in behavior, self-limited vomiting) are present.
  • Management
    • Inpatient observation indications
      • Skull fracture > 3 mm separation or depressed
      • Evidence of traumatic brain injury on imaging (e.g.., intracranial hemorrhage)
      • Signs of ↑ ICP (e.g., headache, altered mental status)
      • Signs of physical abuse
      • Caregivers who are unreliable or unable to return if neurological deficits develop within 24 hours after release.
    • Release and at-home observation for 24 hours
      • Patients without neurological deficits and non-depressed linear skull fracture < 3 mm separation
      • Requires a caregiver who can reliably recognize new clinical neurological deficits and return the patient to the hospital if such manifestations arise

References:[21]