Healthcare & Clinical
CATCH Rule (Canadian Assessment of Tomography for Childhood Head Injury)
Evaluate Martin Osmond’s 7-item pediatric CATCH head CT rule (0–16 years, GCS 13–15) across 4 High-Risk neurosurgical intervention criteria and 3 Medium-Risk brain-injury-on-CT criteria.
Protect developing children from unnecessary cranial CT radiation while catching 100% of neurosurgical emergencies!
Martin Osmond et al. (2010, CMAJ) derived the Canadian Assessment of Tomography for Childhood Head Injury (CATCH) rule across 3,866 children aged 0 to 16 years presenting within 24 hours of blunt head trauma with GCS 13–15 and witnessed loss of consciousness, amnesia, disorientation, persistent vomiting (>= 2 episodes), or persistent irritability (< 2 yr).
CATCH stratifies cranial CT urgency into two validated tiers: (1) 4 High-Risk Factors for Neurological Intervention (100% sensitivity: GCS < 15 at 2 hours post-injury, suspected open or depressed skull fracture, history of worsening headache, or irritability on examination); and (2) 3 Medium-Risk Factors for Brain Injury on CT (98.1% combined sensitivity: any sign of basal skull fracture, large boggy scalp hematoma, or dangerous mechanism of injury [MVA, fall >= 3 ft / 5 stairs, or unhelmeted bicycle fall]). When all 7 CATCH factors are absent, cranial CT radiation can be safely avoided!
| CATCH Pediatric Tier (Ages 0–16, GCS 13–15) | Clinical Factors Checked | Pediatric Cranial CT Action |
|---|---|---|
| >= 1 High-Risk Factor (4 items) | 2h GCS<15, Open/Depressed Fx, Worsening HA, Irritable Exam | "Urgent Head CT (High Risk: Neurosurgical)" |
| 0 High-Risk, >= 1 Medium-Risk (3 items) | Basal Skull Fx, Large Boggy Hematoma, Dangerous Mech | "Head CT Indicated (Medium Risk: CT Lesion)" |
| 0 High-Risk and 0 Medium-Risk | All 7 CATCH Factors Negative | "No Head CT Required (CATCH Cleared)" |
Count of Positive High-Risk CATCH Neurosurgical Factors (0 to 4)
Tallies 2-hour GCS < 15 (B3 < 15) plus open/depressed fracture (B4), worsening headache (B5), and irritable exam (B6).
=IF(B3 < 15, 1, 0) + IF(B4 = 1, 1, 0) + IF(B5 = 1, 1, 0) + IF(B6 = 1, 1, 0)Complete Pediatric CATCH Cranial CT Triage Recommendation
Validates pediatric age 0–16 (B2) and GCS 13–15 (B3), then evaluates High-Risk before Medium-Risk (B7:B9).
=IF(OR(B2 < 0, B2 > 16, B3 < 13, B3 > 15), "Outside CATCH Pediatric GCS 13-15 Scope", IF((IF(B3 < 15, 1, 0) + SUM(B4:B6)) >= 1, "Urgent Head CT (High Risk: Neurosurgical)", IF(SUM(B7:B9) >= 1, "Head CT Indicated (Medium Risk: Brain Injury)", "No Head CT Required (CATCH Cleared)")))Try the example
Use the original values or change them to test your understanding.