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Head Injury

For further information, see CMDT Part 24-18: Head Injury

Key Features

  • Cognitive impairment tends to affect frontal and temporal lobe function, causing deficits in

    • Attention

    • Memory

    • Judgment

    • Executive function

  • Behavioral dysregulation, depression, and disinhibition can impair social functioning

  • Anosmia, presumably due to shearing of fibers from the nasal epithelium, is common

  • Severity ranges from concussion to severe traumatic brain injury (TBI)

    • Concussion is broadly defined as an alteration in mental status caused by trauma with or without loss of consciousness

    • The term "concussion" is often used synonymously with mild TBI

    • Grades of TBI are traditionally defined by the Glasgow Coma Scale (GCS) score measured 30 minutes after injury (Table 24–7)

  • Head trauma may cause cerebral injury through a variety of mechanisms (Table 24–8)

  • There appears to be an association between head trauma and the later development of neurodegenerative disease, such as

    • Alzheimer disease

    • Parkinson disease

    • Amyotrophic lateral sclerosis

  • Chronic traumatic encephalopathy

    • Defined as repetitive, mild head injury (often seen in athletes or military personnel)

    • Distinct pathologic entity associated with mood and cognitive changes

    • Characterized by the abnormal aggregation of tau or other proteins either focally or globally in the cerebral cortex

Table 24–7.Glasgow Coma Scale.1
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Table 24–7. Glasgow Coma Scale.1
Points Eye Opening Verbal Response Motor Response
1 None None None
2 To pain Vocal but not verbal Extension
3 To voice Verbal but not conversational Flexion
4 Spontaneous Conversational but disoriented Withdraws from pain
5 Spontaneous Oriented Localizes pain
6 Spontaneous Oriented Obeys commands

1GCS score indicating severity of traumatic brain injury: mild, 13–15; moderate, 9–12; severe, ≤ 8.

Reproduced, with permission, from Aminoff MJ et al. Clinical Neurology, 9th ed, McGraw-Hill Education, 2015; data from Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;304:81–84.

Table 24–8.Acute cerebral sequelae of head injury (listed in alphabetical order).
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Table 24–8. Acute cerebral sequelae of head injury (listed in alphabetical order).
Sequelae Clinical Features Pathology
Acute epidural hemorrhage Headache, confusion, somnolence, seizures, and focal deficits occur several hours after injury (lucid interval) and lead to coma, respiratory depression, and death unless treated by surgical evacuation. Tear in meningeal artery, vein, or dural sinus, leading to hematoma visible on CT scan.
Acute subdural hemorrhage Similar to epidural hemorrhage, but interval before onset of symptoms is longer. Neurosurgical consultation for consideration of evacuation. Hematoma from tear in veins from cortex to superior sagittal sinus or from cerebral laceration, visible on CT scan.
Cerebral contusion or laceration Loss of consciousness longer than with concussion. Focal neurologic deficits are often present. May lead to death or severe residual neurologic deficit.

Bruising on side of impact (coup injury) or contralaterally (contrecoup injury).

Vasogenic edema, multiple petechial hemorrhages, and mass effect. May have ...

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