Neurosurgery notes/Trauma/Head Trauma general/TBI classification/Severity of head injury

Severity of head injury

View Details
logo
Parent item
TBI classification
Severity
Fq ratio
Mortality
Intracranial injury/lesion
Post traumatic seizure/10 years
Overall
n/a
1%
2%
Mild 14–15
22
2.5%
7.1%
Same as general population
Moderate 9–13
1.5
(5-7% of all head injury)
15%
30%
5%
Severe ≤8
1.0
40%
Not specified
12%
  • GCS scale (see CRASH data for outcome base on GCS)
    • GCS 14–15 =mild (see concussion)
      • Numbers
        • Mortality: 2.5%
        • Easter 2015 Systematic review N=23,079 adults with minor head trauma (GCS 13-15 and appearing well on examination):
          • Prevalence of severe intracranial injury: 7.1%
          • Prevalence of injuries leading to death or requiring neurosurgical intervention: 0.9%
      • When to CT: Canadian CT Head Rule/New Orleans criteria for CT head
      • Recommendations for management based on CT head findings and GCS:
        • Abnormal CT head not requiring surgery or normal CT head but GCS < 15, seizures, or coagulopathy:
          • Inpatient observation for 24 h recommended due to risk of developing intracranial complications and need for repeat CT head before discharge.
        • Normal CT head and normal GCS with none or mild symptoms:
          • Observation at home by a responsible adult aware of signs requiring immediate medical assessment may be possible.
      • Further management on discharge includes:
        • Addressing post-concussion syndrome.
        • Assessing risk of second impact syndrome, especially in athletes, and contraindications to returning to contact sport.
        • Evaluating risk of post-traumatic epilepsy.
        • Considering the risk of chronic traumatic encephalopathy, particularly in individuals with multiple concussions.
    • GCS 9–13= moderate
      • Accounts for 5-7% of head injury attendances in the emergency department (22 mild: 1.5 moderate: 1 severe).
      • Affects young adults involved in traffic accidents, associated with alcohol or illicit drugs, and extracranial injuries.
      • Numbers
        • Approximately 30% chance of brain lesion (intra- or extra-axial).
        • About 30% chance of injuries progressing in volume or mass effect (new bleeding, rebleeding, edema).
        • Around 30% chance of neurological status deterioration or worsening.
        • Mortality: 15%.
        • 50% have cognitive sequelae
          • Only 20% recover without significant disability.
        • About 14% of patients with GCS 13 at admission have normal initial CT but develop abnormalities during hospitalization, especially diffuse cerebral edema.
      • Most "talk and die" patients (lucid interval)
        • Presenting with verbal GCS score ≥ 3, deteriorate and die due to potentially treatable head injury)
        • Part of moderate TBI category.
          • Although average GCS at admission: 14.
        • Morbidity and mortality in these patients might be reduced by early diagnosis and aggressive treatment of raised intracranial pressure (ICP).
        • Most frequently adult men.
        • Common mechanisms of trauma:
          • Falls,
          • Motor vehicle accidents,
          • Violence.
        • Most frequent intracranial injuries:
          • Acute subdural hematoma,
          • Diffuse cerebral edema,
          • Cerebral contusion.
      • Factors relating to death include:
        • Delays in diagnosis of lesion through CT scan.
        • Delays in transfer to specialized center.
        • Failure to identify risk factors for deterioration.
        • Inadequate prevention of secondary injury.
        • Inappropriate correction of underlying coagulopathy.
        • Loss of opportunity for definitive neurosurgical treatment.
    • GCS ≤8 = severe
  • Advantage
    • Most widely used
    • Best replicated scale employed for the assessment of head trauma.
  • Disadvantage
    • GCS is an ordinal scale that is non parametric (i.e., does not represent precise measurements of discrete quantities),
      • Each ‘score’ is qualitative and discontinuous
        • (i.e. a change from M2 to M3 is in no way related to a change from M4 to M5, let alone E3 to E4).
    • Non-linear scale,
    • Not an interval scale
      • Thus, performing mathematical manipulations (e.g. adding components, or calculating mean values), while often done, is not statistically sound.
    • GCS does not provide a granular classification for mild TBI, as it is not intended to capture more subtle changes such as ‘an alteration in brain function’.
      • Subtle and transient symptoms are reported, which may overlap with symptoms due to either post- traumatic stress disorders (PTSD) and/ or postconcussion syndromes.
  • It should be noted that especially early after injury the GCS may change over time, following resuscitation or as part of early recovery.
  • Accurate assessments of one or more of the components of the GCS may be confounded by prior alcohol or substance use, prehospital use of sedation, paralysis, and intubation