catch_head_injury_rule: CATCH Rule (Canadian Assessment of Tomography for Childhood...

In cliot: Clinical Indices and Outcomes Tools

CATCH Rule (Canadian Assessment of Tomography for Childhood Head Injury)

Description

Applies the CATCH Rule to determine the need for CT imaging in children with minor head injury. The rule stratifies patients into High Risk (need for neurological intervention) and Medium Risk (potential brain injury on CT).

Usage

catch_head_injury_rule(gcs_lt_15_2hr, suspected_open_skull_fx, worsening_headache,
                       irritability, basal_skull_fx_signs, large_boggy_hematoma,
                       dangerous_mechanism)

Arguments

gcs_lt_15_2hr	Numeric (0 or 1). GCS < 15 at 2 hours after injury. (High Risk Factor).
suspected_open_skull_fx	Numeric (0 or 1). Suspected open or depressed skull fracture. (High Risk Factor).
worsening_headache	Numeric (0 or 1). History of worsening headache. (High Risk Factor).
irritability	Numeric (0 or 1). Irritability on examination. (High Risk Factor).
basal_skull_fx_signs	Numeric (0 or 1). Any sign of basal skull fracture (e.g., raccoon eyes, Battle's sign, hemotympanum, otorrhea/rhinorrhea). (Medium Risk Factor).
large_boggy_hematoma	Numeric (0 or 1). Large, boggy hematoma of the scalp. (Medium Risk Factor).
dangerous_mechanism	Numeric (0 or 1). Dangerous mechanism of injury (e.g., MVA, fall from height >3ft or 5 stairs, bicycle w/o helmet). (Medium Risk Factor).

Value

A list containing:

Risk_Level	"High Risk", "Medium Risk", or "Low Risk".
Recommendation	Clinical guidance on CT imaging necessity.

References

Osmond MH, Klassen TP, Wells GA, et al. CATCH: a clinical decision rule for the use of computed tomography in children with minor head injury. CMAJ. 2010;182(4):341-348. doi:10.1503/cmaj.091423

Examples

# Example 1: High Risk
# GCS 14 at 2h (+1), Irritable (+1)
catch_head_injury_rule(1, 0, 0, 1, 0, 0, 0)

# Example 2: Medium Risk
# Normal GCS, but Dangerous Mechanism (Fall >3ft)
catch_head_injury_rule(0, 0, 0, 0, 0, 0, 1)

# Example 3: Low Risk
# No risk factors
catch_head_injury_rule(0, 0, 0, 0, 0, 0, 0)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.