🧒 CATCH Pediatric Head CT Rule
UseWhen to use: children with minor head injury (GCS 13–15) plus LOC, amnesia, disorientation, vomiting, or irri…
StrataHigh-risk targets neurosurgical intervention; medium-risk targets CT-visible brain injury. Rule-negative is l…
LimitsWhen not to use: obvious major trauma, GCS ≤12, or pathways that mand… · Pitfall: applying CATCH to trivial bumps without derivation entry fea… · Local imaging capacity and radiation stewardship matter.
SourceOsmond MH, et al. CMAJ 2010 (CATCH)
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
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Methodology · worked example, guidelines & full notes
4 high + 3 medium (+ CATCH2 vomit≥4).
When to use
When to use: children with minor head injury (GCS 13–15) plus LOC, amnesia, disorientation, vomiting, or irritability — as in derivation.
How it works
High (any → CT): GCS <15 at 2 h; suspected open/depressed skull fx; worsening headache; irritability. Medium (CT vs observe): basal skull-fx signs; large boggy scalp hematoma; dangerous mechanism; CATCH2 adds ≥4 vomits.
Key points
- 4 high + 3 medium (+ CATCH2 vomit≥4).
- Any high → CT.
- Next: PECARN / CHALICE / neurosurgery.
References
- Osmond MH, et al. CMAJ 2010 (CATCH)
- CATCH2 refinement CMAJ 2018 (adds ≥4 vomits)
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| High: GCS < 15 at 2 h after injury | No (0) |
|---|---|
| High: Suspected open or depressed skull fracture | No (0) |
| High: History of worsening headache | No (0) |
| High: Irritability on examination | No (0) |
| Medium: Any sign of basal skull fracture | No (0) |
| Medium: Large boggy scalp hematoma | No (0) |
| Medium: Dangerous mechanism (MVC; fall ≥3 ft / 5 stairs; fall from bicycle without helmet) | No (0) |
| CATCH2 add-on: ≥ 4 discrete vomiting episodes | No (0) |
→CATCHRule-negative — low risk
- High-risk hits：0
- Medium-risk hits：0
| High: GCS < 15 at 2 h after injury | Yes — high risk |
|---|---|
| High: Suspected open or depressed skull fracture | Yes — high risk |
| High: History of worsening headache | Yes — high risk |
| High: Irritability on examination | Yes — high risk |
| Medium: Any sign of basal skull fracture | Yes — medium risk |
| Medium: Large boggy scalp hematoma | Yes — medium risk |
| Medium: Dangerous mechanism (MVC; fall ≥3 ft / 5 stairs; fall from bicycle without helmet) | Yes — medium risk |
| CATCH2 add-on: ≥ 4 discrete vomiting episodes | Yes — CATCH2 medium |
→CATCHHigh risk — CT recommended
- High-risk hits：4
- Medium-risk hits：4
- CATCH2 vomit≥4：Yes
Verification & sources · governance
FAQ
Frequently asked questions
- Does CATCH Pediatric Head CT Rule upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is CATCH Pediatric Head CT Rule calculated in practice? Can you show a worked example?
- Inputs: High: GCS < 15 at 2 h after injury No (0), High: Suspected open or depressed skull fracture No (0), High: History of worsening headache No (0), High: Irritability on examination No (0), Medium: Any sign of basal skull fracture No (0), Medium: Large boggy scalp hematoma No (0), Medium: Dangerous mechanism (MVC; fall ≥3 ft / 5 stairs; fall from bicycle without helmet) No (0), CATCH2 add-on: ≥ 4 discrete vomiting episodes No (0) → Result: CATCH Rule-negative — low risk（High-risk hits: 0, Medium-risk hits: 0） Inputs: High: GCS < 15 at 2 h after injury Yes — high risk, High: Suspected open or depressed skull fracture Yes — high risk, High: History of worsening headache Yes — high risk, High: Irritability on examination Yes — high risk, Medium: Any sign of basal skull fracture Yes — medium risk, Medium: Large boggy scalp hematoma Yes — medium risk, Medium: Dangerous mechanism (MVC; fall ≥3 ft / 5 stairs; fall from bicycle without helmet) Yes — medium risk, CATCH2 add-on: ≥ 4 discrete vomiting episodes Yes — CATCH2 medium → Result: CATCH High risk — CT recommended（High-risk hits: 4, Medium-risk hits: 4, CATCH2 vomit≥4: Yes）