Canadian CT Head Rule: Minor Head Injury Evaluation

The Canadian CT Head Rule: Evaluating Minor Head Trauma

Published in 2001 by Dr. Ian Stiell, the Canadian CT Head Rule (CCHR) is a globally recognized clinical decision aid. It was developed to help emergency physicians accurately determine which patients with minor head trauma require urgent head computed tomography (CT) imaging. The primary objective of this rule is to identify, with near 100% sensitivity, lesions that require neurosurgical intervention, while simultaneously reducing unnecessary exposure to ionizing radiation and optimizing hospital resource flow.

To whom does this rule apply (Inclusion Criteria)?

For this clinical algorithm to be valid, the patient must strictly meet the following basic conditions:

• Have suffered a blunt (non-penetrating) head trauma resulting in witnessed loss of consciousness, a definite period of amnesia, or witnessed disorientation/confusion.
• Present with a Glasgow Coma Scale (GCS) score between 13 and 15 at the time of initial ED evaluation.
• Be at least 16 years of age and present no major exclusion criteria (such as known bleeding disorders, use of oral anticoagulants, post-traumatic seizures, or obvious penetrating skull injury).

Global Risk Interpretation

Present Factor	Risk Level	Clinical Action
None	Low Risk	Imaging not justified. Discharge with head injury instructions.
Medium Risk (≥ 1)	Moderate Risk	Head CT scan recommended. Observation.
High Risk (≥ 1)	High Risk	Urgent Head CT. Likely neurosurgical consultation.

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References:

1. Stiell IG, et al. The Canadian CT Head Rule for patients with minor head injury. The Lancet. 2001. [PubMed - NIH]
2. Smits M, et al. Predicting intracranial traumatic findings on computed tomography in patients with minor head injury: the CHIP prediction rule. Ann Intern Med. 2007. [PubMed - NIH]