PECARN Pediatric Head Trauma Decision Calculator

Assess risk and guide CT use in children with minor head injury using the validated PECARN rule.

The PECARN Calculator helps clinicians and parents determine the risk of clinically important traumatic brain injury (ciTBI) in children with minor head trauma and guides the need for head CT. Based on age, symptoms, and injury mechanism, this tool provides evidence-based recommendations for safe, effective care.

Examples

Click an example to load it into the calculator.

Infant with Palpable Skull Fracture

high_risk

A 1-year-old with a palpable skull fracture after a fall.

Age (Years): 1

Age (Months): 2

Loss of Consciousness: no

Vomiting: no

Severe Headache: no

Severe Mechanism: yes

Palpable Skull Fracture: yes

Scalp Hematoma: yes

Altered Mental Status: no

Acting Abnormally: no

Post-Traumatic Seizure: no

Toddler with Scalp Hematoma

intermediate_risk

A 1-year-old with a non-frontal scalp hematoma after a minor fall.

Age (Years): 1

Age (Months): 8

Loss of Consciousness: no

Vomiting: no

Severe Headache: no

Severe Mechanism: no

Palpable Skull Fracture: no

Scalp Hematoma: yes

Altered Mental Status: no

Acting Abnormally: yes

Post-Traumatic Seizure: no

School-Age Child, No Risk Factors

low_risk

A 7-year-old with a minor bump, no symptoms or risk factors.

Age (Years): 7

Age (Months): 0

Loss of Consciousness: no

Vomiting: no

Severe Headache: no

Severe Mechanism: no

Palpable Skull Fracture: no

Scalp Hematoma: no

Altered Mental Status: no

Acting Abnormally: no

Post-Traumatic Seizure: no

Older Child with Vomiting

intermediate_risk

A 10-year-old with vomiting and severe mechanism of injury.

Age (Years): 10

Age (Months): 0

Loss of Consciousness: no

Vomiting: yes

Severe Headache: no

Severe Mechanism: yes

Palpable Skull Fracture: no

Scalp Hematoma: no

Altered Mental Status: no

Acting Abnormally: yes

Post-Traumatic Seizure: no

Other Titles
Understanding the PECARN Pediatric Head Trauma Decision Calculator: A Comprehensive Guide
Master the evidence-based approach to pediatric head injury risk assessment and CT decision-making.

What is the PECARN Pediatric Head Trauma Decision Calculator?

  • Core Concepts and Definitions
  • Why Use the PECARN Rule?
  • How the Calculator Works
The PECARN Pediatric Head Trauma Decision Calculator is a clinical tool designed to help healthcare providers assess the risk of clinically important traumatic brain injury (ciTBI) in children with minor head trauma. Developed by the Pediatric Emergency Care Applied Research Network (PECARN), this evidence-based rule guides clinicians in deciding when a head CT scan is necessary, reducing unnecessary radiation exposure while ensuring patient safety.
Why is the PECARN Rule Important?
Head injuries are common in children, but most do not result in serious brain injury. However, overuse of CT scans exposes children to unnecessary radiation, increasing long-term cancer risk. The PECARN rule provides a validated, systematic approach to identify children at very low risk for ciTBI, allowing safe observation without CT in most cases.
How Does the Calculator Work?
The calculator uses age, symptoms, and injury mechanism to stratify risk. It applies different criteria for children under 2 years and those 2 years or older, reflecting developmental differences. Based on the input, it categorizes risk as high, intermediate, or low, and provides clear recommendations for CT use or observation.

Key PECARN Rule Points:

  • Children <2 years: Palpable skull fracture or altered mental status = high risk
  • Children ≥2 years: Severe headache or altered mental status = high risk
  • Intermediate risk: Scalp hematoma, loss of consciousness, severe mechanism, acting abnormally, vomiting
  • Low risk: No risk factors present

Step-by-Step Guide to Using the PECARN Calculator

  • Collecting Accurate Patient Data
  • Inputting Symptoms and Mechanism
  • Interpreting Results and Recommendations
To use the PECARN Calculator effectively, start by collecting accurate patient data: age (in years and months), symptoms (loss of consciousness, vomiting, severe headache, altered mental status, acting abnormally, post-traumatic seizure), and mechanism of injury (severe or not). Enter each field carefully, as the risk assessment depends on precise information.
Inputting Symptoms and Mechanism
For each symptom and risk factor, select 'Yes' or 'No' based on clinical evaluation and caregiver report. Severe mechanism includes high-impact events such as motor vehicle crashes, falls from significant height, or being struck by a high-impact object. Palpable skull fracture and scalp hematoma are determined by physical exam.
Interpreting Results and Recommendations
The calculator will display the risk category (high, intermediate, low), estimated risk percentage, and a clear recommendation regarding CT use. High risk means immediate CT is recommended. Intermediate risk suggests considering CT or observation based on clinical judgment and family preference. Low risk means CT is not recommended, and observation is safe.

PECARN Calculator Workflow:

  • Step 1: Enter age, symptoms, and mechanism
  • Step 2: Review risk category and CT recommendation
  • Step 3: Discuss results with caregivers and plan management

Real-World Applications of the PECARN Calculator

  • Emergency Department Use
  • Primary Care and Urgent Care
  • Parental Guidance and Education
The PECARN Calculator is widely used in emergency departments to guide imaging decisions for children with head trauma. It helps reduce unnecessary CT scans, shortens ED stays, and improves patient safety. Primary care and urgent care providers can also use the tool to assess risk and determine when referral or observation is appropriate.
Parental Guidance and Education
Parents often worry about head injuries. The calculator provides a structured, evidence-based explanation of risk, helping clinicians communicate clearly and reduce anxiety. It supports shared decision-making and empowers families to participate in care decisions.
Research and Quality Improvement
Hospitals and researchers use the PECARN rule to monitor imaging rates, improve quality of care, and ensure adherence to best practices. The tool is validated in large, diverse populations and is recommended by major pediatric and emergency medicine organizations.

Clinical Scenarios:

  • ED: 2-year-old with vomiting and severe mechanism—intermediate risk, consider CT or observe
  • Primary care: 7-year-old, no symptoms—low risk, observe at home
  • Parental concern: 1-year-old with scalp hematoma—intermediate risk, discuss observation vs CT

Common Misconceptions and Correct Methods

  • Myths About Pediatric Head Injury
  • CT Overuse and Radiation Risk
  • Best Practices for Safe Care
A common misconception is that all head injuries require a CT scan. In reality, most children with minor head trauma do not need imaging. The PECARN rule helps avoid unnecessary radiation, which is especially important in children due to higher lifetime cancer risk.
CT Overuse and Its Risks
CT scans are valuable but should be used judiciously. Overuse leads to increased healthcare costs, longer ED stays, and unnecessary radiation exposure. The PECARN Calculator ensures CT is reserved for those at genuine risk, improving safety and efficiency.
Best Practices for Safe Care
Always use a structured approach to head injury assessment. Communicate clearly with families, document findings, and use observation when appropriate. Shared decision-making and evidence-based tools like PECARN improve outcomes and patient satisfaction.

Best Practice Tips:

  • Do not CT every child with a bump—use risk assessment
  • Educate families about signs of worsening injury
  • Observe low-risk children safely at home

Mathematical Derivation and Examples

  • PECARN Rule Logic
  • Risk Stratification by Age Group
  • Example Calculations
The PECARN rule is based on large, multicenter studies and uses a decision tree to stratify risk. For children <2 years, high risk is defined by palpable skull fracture or altered mental status. For children ≥2 years, high risk is defined by severe headache or altered mental status. Intermediate risk includes other symptoms and mechanisms. The calculator applies these rules to provide a clear, actionable result.
Example Calculations
Example 1: 1-year-old with palpable skull fracture—high risk, CT recommended. Example 2: 7-year-old, no symptoms—low risk, CT not recommended. Example 3: 10-year-old with vomiting and severe mechanism—intermediate risk, consider CT or observe.
Risk Percentages
High risk: >4% ciTBI, Intermediate risk: 0.9-1.0%, Low risk: <0.02%. These percentages are based on PECARN study data and guide clinical decision-making.

PECARN Rule in Action:

  • 1-year-old, palpable skull fracture: High risk, CT recommended
  • 1-year-old, scalp hematoma: Intermediate risk, consider CT or observe
  • 7-year-old, no symptoms: Low risk, CT not recommended
  • 10-year-old, vomiting and severe mechanism: Intermediate risk, consider CT or observe