MDCalc

Canadian CT Head Injury/Trauma Rule

Rules out need for head CT in minor head trauma.

Apply only to patients presenting within 24 hours of injury with a Glasgow Coma Scale (GCS) score of 13-15 and at least one of the following:

  • Loss of consciousness.
  • Amnesia to the head injury event.
  • Witnessed disorientation.

Exclusion criteria:

  • Age <16 years.
  • Blood thinners.
  • Seizure after injury.

Exclusion Criteria: If any of the following are true, the CCHR does not apply

Age <16 years
Patient on blood thinners
Seizure after injury

High Risk Criteria: Rules out need for neurosurgical intervention

GCS <15 at 2 hours post-injury
Suspected open or depressed skull fracture
Any sign of basilar skull fracture?
Hemotympanum, raccoon eyes, Battle’s Sign, CSF oto-/rhinorrhea
≥2 episodes of vomiting
Age ≥65 years

Medium Risk Criteria: In addition to above, rules out “clinically important” brain injury (positive CT's that normally require admission)

Retrograde amnesia to the event ≥ 30 minutes
“Dangerous” mechanism?
Pedestrian struck by motor vehicle, occupant ejected from motor vehicle, or fall from >3 feet or >5 stairs.

Result:

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Advice
  • Consider obtaining a CT scan if any questions in the rule are answered affirmatively.
  • This rule can only be applied to patients with LOC/Amnesia or changes in mental status.
  • The original study did not include subjects <16 years of age.
Management
  • Remember to always discuss post-concussive symptoms and management with the patient, especially if discharging them without a head CT. Otherwise when they feel post-concussive symptoms they may worry a CT was necessary.
  • By educating them on the symptoms of injuries that require neurosurgical intervention vs. post-concussive symptoms, the patient can feel empowered and reassured.
Critical Actions

The Canadian CT Head Rules have been validated in multiple settings and have consistently demonstrated that they are 100% sensitive for detecting injuries that will require neurosurgery.

  • Depending on practice environment, it may not be considered acceptable to miss any intracranial injuries, regardless of whether they would have required intervention.
  • Providers may want to consider applying the New Orleans Criteria (NOC) for head trauma, as there has been at least one trial finding it to be more sensitive for detecting clinically significant intracranial injuries (99.4% vs 87.3%). Though this comes at the price of markedly decreased specificity (5.6% vs. 39.7%).
    • Furthermore, there are other trials in which the CCHR was found to be more sensitive than the NOC for detecting clinically important brain injuries.
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