In a 2-year-old who fell from a chair more than 72 hours ago and now has a unilateral periorbital hematoma on the side of impact without other neurological deficits, when should a brain CT scan be performed?

When to Consider Brain CT Scan in This Case

In this 2-year-old presenting more than 72 hours after a fall from a chair with only unilateral periorbital hematoma and no neurological deficits, a brain CT scan is generally NOT indicated unless new concerning symptoms develop during observation. 1, 2

Risk Stratification Using PECARN Criteria

The key to this decision is applying the validated PECARN clinical decision rules for children under 2 years of age 2:

This Child's Risk Category

Based on the presentation, this child appears to fall into either very low risk or intermediate risk:

Very Low Risk (if ALL of the following are true):

• GCS of 15
• No altered mental status
• No palpable skull fracture
• No loss of consciousness >5 seconds
• No severe mechanism of injury
• Acting normally per parents
• No nonfrontal scalp hematoma

Risk of clinically important TBI: <0.02% 2

Intermediate Risk (if GCS 15, normal mental status, no palpable skull fracture BUT):

• History of loss of consciousness >5 seconds, OR
• Severe mechanism of injury, OR
• Not acting normally per parent

Risk of clinically important TBI: ~0.9% 2

Critical Decision Points

The Periorbital Hematoma Location Matters

Nonfrontal scalp hematomas (including parietal and occipital) are PECARN risk factors for children <2 years 1, 2. However, periorbital hematoma specifically on the side of impact from a witnessed low-height fall (chair) is different from concerning scalp hematomas that suggest more severe injury patterns.

The 72-Hour Delay is Reassuring

Research shows that children presenting >24 hours after head injury with soft scalp hematomas who lack "red flags" have good outcomes without neuroimaging 3. All patients requiring neurosurgical intervention in one study presented within 24 hours 3.

Specific Recommendations

DO NOT obtain CT if:

• Child has remained neurologically normal for >72 hours
• No vomiting
• No altered mental status
• Acting normally per parents
• Fall from chair represents low-energy mechanism
• No clinical suspicion for skull fracture on palpation

CONSIDER CT if ANY of the following develop:

• New or worsening symptoms (vomiting, headache, lethargy)
• Change in mental status or behavior
• New neurological deficits
• Clinical deterioration during observation 4
• Parental concern about abnormal behavior 2

OBTAIN CT if:

• GCS <15
• Altered mental status
• Palpable skull fracture
• Signs of basilar skull fracture (though periorbital ecchymosis alone is not specific) 5

Common Pitfalls to Avoid

1. Don't assume periorbital ecchymosis = basilar skull fracture: While classically taught, periorbital ecchymosis can occur with various injuries including soft tissue trauma without fracture 5. The unilateral location matching the impact side suggests local soft tissue injury.

2. Don't ignore the mechanism: A fall from a chair is typically NOT considered a "severe mechanism of injury" in PECARN criteria, which refers to motor vehicle crashes, falls >3 feet (for children <2 years), or high-impact trauma 1.

3. Don't underestimate observation: The 72-hour asymptomatic period is highly reassuring. Clinically important traumatic brain injuries typically manifest within 24-48 hours 3.

4. Don't forget radiation risk: CT scans in young children carry lifetime cancer risk, with greatest risk to the youngest patients 1. This must be weighed against the very low probability of clinically important TBI in this scenario.

Practical Algorithm

For this specific patient:

1. Perform thorough neurological examination NOW (even though >72 hours post-injury)
2. Apply PECARN criteria systematically
3. If very low risk → No CT; provide return precautions
4. If intermediate risk → Consider observation vs. CT based on:
   • Parental preference
   • Reliability of follow-up
   • Ability to observe at home
   • Young age making assessment challenging 2

Given the >72-hour asymptomatic interval, observation with clear return precautions is more appropriate than immediate CT 3. Instruct parents to return immediately for vomiting, lethargy, worsening headache, seizures, or any behavioral changes.

The evidence strongly supports that children who remain asymptomatic >72 hours after minor head trauma have excellent outcomes without neuroimaging 3, and routine CT is not recommended for mild TBI in children 1.