Head injury

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📊 Canadian CT Head Rule Calculator [show]

Canadian CT Head Rule

Canadian CT Head Rule

High Risk (for neurosurgical intervention)
Criteria	No	Yes
GCS <15 at 2 hours after injury	1
Suspected open or depressed skull fracture	1
Any sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea/rhinorrhea, Battle sign)	1
Vomiting ≥2 episodes	1
Age ≥65 years	1
Medium Risk (for brain injury on CT)
Amnesia before impact >30 min	1
Dangerous mechanism (pedestrian struck, occupant ejected, fall from ≥3 feet or ≥5 stairs)	1
High Risk Criteria	/ 5
Medium Risk Criteria	/ 2

Interpretation
All No	CT NOT required — Low risk for clinically important brain injury. Safe for discharge with head injury instructions.
Medium risk ≥1	CT recommended — Risk of brain injury on CT. Imaging indicated.
High risk ≥1	CT required — High risk for neurosurgical intervention. Urgent CT head.

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. PMID 11356436. 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. PMID 16189364. Inclusion criteria: GCS 13-15, age ≥16, injury within 24 hours, witnessed LOC/amnesia/disorientation.