CT Scan Decision in Pediatric Fall with Vomiting
Vomiting alone is an intermediate-risk factor that warrants consideration for CT imaging, but does not automatically require immediate CT scanning in children with otherwise normal examination findings.
Risk Stratification Based on Age and Clinical Features
The decision to obtain a CT scan depends critically on whether other high-risk or intermediate-risk features are present alongside vomiting:
High-Risk Features Requiring Immediate CT (regardless of vomiting):
For children ≥2 years:
- Glasgow Coma Scale (GCS) of 14 or other altered mental status (risk of clinically important traumatic brain injury ~4.3%) 1
- Signs of basilar skull fracture (risk ~4.3%) 1
For children <2 years:
Intermediate-Risk Features (Including Vomiting):
For children ≥2 years with GCS 15 and normal mental status:
- Vomiting 1
- Severe headache 1
- History of loss of consciousness 2
- Severe mechanism of injury 2
- Risk of clinically important injury: ~0.8% 2
For children <2 years with GCS 15 and normal mental status:
- Loss of consciousness >5 seconds 2
- Severe mechanism of injury 2
- Not acting normally per parent 2
- Nonfrontal scalp hematoma 2
- Risk of significant injury: ~0.9% 2
Clinical Decision Algorithm for Vomiting
If vomiting is the ONLY finding (isolated vomiting):
- The risk of clinically important traumatic brain injury is extremely low (0.3-0.6%) 3
- Observation without immediate CT is appropriate 3
- Consider extended emergency department observation, as every additional hour of observation decreases CT utilization without delaying diagnosis of significant injury 1
If vomiting occurs WITH other intermediate-risk factors:
- CT may be considered versus observation 2
- Factors favoring CT include: multiple risk factors present, parental preference for definitive imaging, worsening symptoms during observation, or young infants where assessment is challenging 2
If vomiting occurs WITH any high-risk features:
Evidence Supporting Conservative Approach to Isolated Vomiting
Research demonstrates that vomiting as the sole indication has a positive predictive value of only 3.7-4% for abnormal CT findings, with none requiring neurosurgical intervention 4. In a large cohort of nearly 20,000 children, isolated vomiting without other clinical decision rule predictors resulted in clinically important traumatic brain injury in only 0.3% and any CT-detected injury in 0.6% 3.
Critical Predictors That Increase Risk When Combined with Vomiting
When vomiting is present alongside other features, the following significantly increase risk of traumatic brain injury 3:
- Signs of skull fracture (odds ratio 80-113)
- Altered mental status (odds ratio 2.4)
- Headache (odds ratio 2.3-2.6)
- Acting abnormally per parent (odds ratio 1.8-1.9)
- Concern for non-accidental injury (odds ratio 6.8)
Imaging Technical Specifications
If CT is indicated:
- Perform non-contrast CT head using dedicated pediatric-specific, reduced-dose protocols following ALARA principles 1
- Use multiplanar and 3D-reconstructed images to increase sensitivity for fractures and small hemorrhages 2
- Never use skull radiographs, as they miss up to 50% of intracranial injuries 1, 2
Critical Pitfalls to Avoid
- Do not obtain CT in very low-risk patients who meet all PECARN criteria for safe discharge (GCS 15, normal mental status, no loss of consciousness, no severe mechanism, no severe headache, no basilar skull fracture signs), as this exposes them to unnecessary radiation 1, 2
- Do not delay CT when high-risk features are present, even if considering observation for isolated vomiting 1
- Do not apply these criteria to suspected child abuse cases—these children require CT or MRI regardless of clinical presentation 1
- Do not rely on presence or absence of skull fracture alone, as up to 50% of intracranial injuries occur without fracture 2