Canadian CT Head Injury/Trauma Rule
Clears head injury without imaging
Jennifer Glen
Provided by
EVAL FoundationInstructions
For patients < 19 years, consider the PECARN Pediatric Head Injury/Trauma Algorithm.
If any of the following criteria apply, the Canadian CT Rule does not apply.
Head trauma complaints in the outpatient setting (emergency department, urgent care and primary care) are common. However, the majority of patients have minor head trauma that will not require specialized treatment or neurosurgical intervention. Yet, rates of CT imaging of the head have more than doubled starting in the early 1990s. The Canadian CT Head Rule (CCHR) is a well-validated clinical decision aid that assists clinicians in determining which minor head injury patients need head CT imaging. Thus, safely ruling out the presence of intracranial injuries that would require neurosurgical intervention or admission. In the validation trial (Stiell, 2005), the CCHR was 100% sensitive for both clinically important brain injuries and injuries that require neurosurgical intervention. Specificity was 76.3% for clinically important brain injuries and 50.6% for injuries that required neurosurgical intervention. It is 70% sensitive for clinically important brain injury in patients with alcohol intoxication (Easter, 2013). In most studies 7-10% of patients had positive CT's considered to be clinically important brain injuries, but < 2% required neurosurgical intervention. The rule excludes patients on blood thinners, > 16 years old and with seizure after injury.
Providers often consider applying the Canadian CT Head Rule (CCHR) for head trauma in addition to the New Orleans/Charity Rule (NOC). Both the CCHR and the NOC have demonstrated 100% sensitivity for ruling out intracranial injuries that would require neurosurgical intervention. One trial found the NOC more sensitive for detecting clinically significant intracranial injuries (99.4% versus 87.3%) but a decreased specificity (5.6% versus 39.7%) compared to the CCHR. The NOC is less complex than the CCHR but much less specific than the CCHR in all settings. The decrease in specificity can be attributed to the NOC's broad questions, such as "Any trauma above the clavicles."
.Summary
The Canadian CT Head Rule (CCHR) is a well-validated clinical decision aid that assists clinicians in determining which minor head injury patients need head CT imaging. The criteria allow clinicians to safely rule out the presence of clinically important traumatic brain injuries among adult head injury patients without the need for CT imaging. Consider the PECARN Pediatric Head Injury/Trauma Algorithm for patients < 19 years old.
Recommendations & Criteria
| Recommendation | Criteria | CCHR Findings |
| Exclusion criteria met: Not eligible for Scoring | Any of the following true
| |
| Consider CT: High risk | Any of the following true
| Cannot rule out need for imaging due to presence of one or more high risk criteria that may need neurosurgical intervention.
|
| Consider CT: Medium risk | Any of the following true
| Cannot rule out need for imaging due to presence of one or more medium risk criteria that may put the patient at risk for a "clinically important" brain injury defined as a positive CT that typically requires admission.
|
| CT Unnecessary | All criteria are false | The Canadian Head CT Rule suggests a head CT is not necessary.
|
¹Signs of basilar skull fracture
- Hemotympanum
- Racoon eyes
- Battle's sign
- CSF otorrhea or rhinorrhea
²Dangerous mechanism
- Pedestrian struck by motor vehicle
- Occupant ejected from motor vehicle
- Fall > 3 feet or > 5 stairs
Management Considerations
If CT is negative and patient is referred for outpatient follow-up, consider the following recommendations:
- Provide reassurance, education and strict return precautions.
- Discuss post-concussive symptoms and clinical course.
- Headache
- Balance problems or dizziness
- Sound and light sensitivity
- Feeling agitated or irritable
- Confusion, concentration or memory problems
- Discuss brain bleed symptoms. Go to the ED if you experience any of these symptoms:
- Drowsiness or inability to wake up
- Worsening headache
- Slurred speech, weakness, numbness, or decreased coordination
- Repeated vomiting or seizures
- Unusual behavior
- Follow-up with primary care, sports medicine or neurologist as indicated.
Provider Resources
.All questions & possible results
Exclusion CriteriaTitle not visible
Select all that apply
If any of the following criteria apply, the Canadian CT Rule does not apply.
Select all that apply:
- Age < 16 years
- Patient on blood thinners
- Seizure after injury
- None of the above apply
High Risk Criteria
Rules out need for neurosurgical intervention.
GCS <15 at 2 hours post-injury
Select one option:
- No
- Yes
Suspected open or depressed skull fracture
Select one option:
- No
- Yes
Any sign of basilar skull fracture?
- Hemotympanum
- Racoon eyes
- Battle's sign
- CSF otorrhea or rhinorrhea
Select one option:
- No
- Yes
≥ 2 episodes of vomiting
Select one option:
- No
- Yes
Age ≥ 65 years
Select one option:
- No
- Yes
Medium Risk Criteria
Rules out "clinically important" brain injury defined as positive CT's that normally require admission.
Retrograde amnesia to the event ≥ 30 minutes
Select one option:
- No
- Yes
"Dangerous" mechanism?
- Pedestrian struck by motor vehicle
- Occupant ejected from motor vehicle
- Fall > 3 feet or > 5 stairs
Select one option:
- No
- Yes
Possible results
Consider CT: High risk
Cannot rule out need for imaging due to presence of one or more high risk criteria that may need neurosurgical intervention.
- High risk means 5 out of 100 patients will need treatment by a neurosurgeon, but the risk could be higher or lower based on clinician judgement and patient risk factors.
If CT is negative and patient is referred for outpatient follow-up, consider the following recommendations:
- Provide reassurance, education and strict return precautions.
- Discuss post-concussive symptoms and clinical course.
- Headache
- Balance problems or dizziness
- Sound and light sensitivity
- Feeling agitated or irritable
- Confusion, concentration or memory problems
- Discuss brain bleed symptoms. Go to the ED if you experience any of these symptoms:
- Drowsiness or inability to wake up
- Worsening headache
- Slurred speech, weakness, numbness, or decreased coordination
- Repeated vomiting or seizures
- Unusual behavior
- Follow-up with primary care, sports medicine or neurologist as indicated.
Provider Resources
CT Unnecessary
The Canadian Head CT Rule suggests a head CT is not necessary.
- Sensitivity 83-100% for all intracranial findings
- Sensitivity 100% for findings requiring neurosurgical intervention
Management Considerations
- Provide reassurance, education and strict return precautions.
- Out of 100 patients who get a CT scan, 3 patients will have a minor injury that will heal on its own.
- Out of 100 patients who get a CT scan, 97 will have no head injury on CT.
- CDC patient handout: Mild Traumatic Brain Injury and Concussion
- Discuss post-concussive symptoms and clinical course.
- Headache
- Balance problems or dizziness
- Sound and light sensitivity
- Feeling agitated or irritable
- Confusion, concentration or memory problems
- Discuss brain bleed symptoms. Go to the ED if you experience any of these symptoms:
- Drowsiness or inability to wake up
- Worsening headache
- Slurred speech, weakness, numbness, or decreased coordination
- Repeated vomiting or seizures
- Unusual behavior
- Follow-up with primary care, sports medicine or neurologist as indicated.
Provider Resources
Consider CT: Medium risk
Cannot rule out need for imaging due to presence of one or more medium risk criteria that may put the patient at risk for a "clinically important" brain injury defined as a positive CT that typically requires admission.
If CT is negative and patient is referred for outpatient follow-up, consider the following recommendations:
- Provide reassurance, education and strict return precautions.
- Discuss post-concussive symptoms and clinical course.
- Headache
- Balance problems or dizziness
- Sound and light sensitivity
- Feeling agitated or irritable
- Confusion, concentration or memory problems
- Discuss brain bleed symptoms. Go to the ED if you experience any of these symptoms:
- Drowsiness or inability to wake up
- Worsening headache
- Slurred speech, weakness, numbness, or decreased coordination
- Repeated vomiting or seizures
- Unusual behavior
- Follow-up with primary care, sports medicine or neurologist as indicated.
Provider Resources
Literature
- The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001 May 5;357(9266):1391-6. — Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, Laupacis A, McKnight RD, Verbeek R, Brison R, Cass D, Eisenhauer ME, Greenberg G, Worthington J.
- Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA. 2005 Sep 28;294(12):1511-8. — Stiell IG, Clement CM, Rowe BH, Schull MJ, Brison R, Cass D, Eisenhauer MA, McKnight RD, Bandiera G, Holroyd B, Lee JS, Dreyer J, Worthington JR, Reardon M, Greenberg G, Lesiuk H, MacPhail I, Wells GA.
- A prospective cluster-randomized trial to implement the Canadian CT Head Rule in emergency departments. CMAJ. 2010 Oct 5;182(14):1527-32. — Stiell IG, Clement CM, Grimshaw JM, Brison RJ, Rowe BH, Lee JS, Shah A, Brehaut J, Holroyd BR, Schull MJ, McKnight RD, Eisenhauer MA, Dreyer J, Letovsky E, Rutledge T, Macphail I, Ross S, Perry JJ, Ip U, Lesiuk H, Bennett C, Wells GA.
- Clinical decision rules for adults with minor head injury: a systematic review. J Trauma. 2011 Jul;71(1):245-51. — Harnan SE, Pickering A, Pandor A, Goodacre SW.
- A Top-Five List for Emergency Medicine: A Pilot Project to Improve the Value of Emergency Care. JAMA Intern Med. 2014;174(4):509–515. — Schuur JD, Carney DP, Lyn ET, et al.
- Traumatic intracranial injury in intoxicated patients with minor head trauma. Acad Emerg Med. 2013 Aug;20(8):753-60. — Easter JS, Haukoos JS, Claud J, Wilbur L, Hagstrom MT, Cantrill S, Mestek M, Symonds D, Bakes K.
