Canadian CT Head Injury/Trauma Rule
Notes:
- Signs of basal skull fracture: hemotympanum, raccoon eyes, Battle's sign, CSF otorrhea/rhinorrhea
- Dangerous mechanism: pedestrian struck by vehicle, ejection from vehicle, fall from elevation ≥ 3 feet or 5 stairs
- This rule is only applicable to patients with GCS 13-15 with witnessed loss of consciousness, amnesia, or confusion
- Not applicable to patients with bleeding disorders, on anticoagulants, or with obvious open skull fracture
About the Canadian CT Head Rule
The Canadian CT Head Rule is a clinical decision rule used to determine which patients with minor head injury need CT scanning. It was developed to identify patients at risk for clinically important brain injury while reducing unnecessary imaging.
Clinical Significance
The Canadian CT Head Rule helps clinicians identify patients with minor head trauma who are at risk for neurosurgical intervention or clinically important brain injury, while potentially reducing unnecessary CT scans by up to 30-40%.
When to Use
Use this rule for patients with minor head injury who:
- Have a Glasgow Coma Scale (GCS) score of 13-15
- Had loss of consciousness, amnesia, or confusion
- Presented within 24 hours of the injury
- Are ≥ 16 years old
Limitations
- Not applicable to patients with GCS < 13
- Not validated in children under 16 years
- Not applicable to patients on anticoagulants or with bleeding disorders
- Not applicable to patients with seizure after injury
- Not applicable to patients with obvious open skull fracture
Evidence Base
The Canadian CT Head Rule was derived from a prospective cohort study of 3,121 patients with minor head injury and validated in a separate cohort of 2,707 patients. It has a sensitivity of 100% for detecting injuries requiring neurosurgical intervention and 87-100% for clinically important brain injuries.
References
- Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357(9266):1391-1396.
- Stiell IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA. 2005;294(12):1511-1518.
- Papa L, Stiell IG, Clement CM, et al. Performance of the Canadian CT Head Rule and the New Orleans Criteria for predicting any traumatic intracranial injury on computed tomography in a United States Level I trauma center. Acad Emerg Med. 2012;19(1):2-10.
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