CATCH Rule (CT for childhood minor head injury)
CATCH rule (Osmond 2010): CT of the head in a child with minor head injury is indicated if any high-risk factor (need for neurosurgery) or medium-risk factor (brain injury on CT) is present.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- GCS < 15 at 2 hours after injury
- Yes
Result: CT head indicated -- high-risk factor present (GCS < 15 at 2 hours after injury).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- High-risk
- GCS < 15 at 2 h, suspected open/depressed skull fracture, worsening headache, irritability -> predicts need for neurosurgical intervention.
- Medium-risk
- basal-skull-fracture signs, large boggy scalp hematoma, dangerous mechanism -> predicts brain injury on CT. Any factor -> CT indicated. The alternative to pecarn-head.
What you enter
- GCS < 15 at 2 hours after injury
- Suspected open or depressed skull fracture
- Worsening headache
- Irritability on examination
- Signs of basal skull fracture
- Large, boggy scalp hematoma
- Dangerous mechanism of injury
How this is calculated
Osmond MH, Klassen TP, Wells GA, et al (Pediatric Emergency Research Canada). CATCH: a clinical decision rule for the use of computed tomography in children with minor head injury. CMAJ. 2010;182(4):341-348. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.