What are the red flags to look for neurologically in a 6-month-old infant who fell 3 feet?

Neurological Red Flags After a Fall in a 6-Month-Old Infant

After a fall from 3 feet, a 6-month-old infant should be immediately evaluated for signs of traumatic brain injury, as infants this age are at high risk for clinically significant neurological complications even with seemingly minor trauma.

Immediate Neurological Assessment

Level of Consciousness

• Altered mental status: Any change from baseline behavior, including:
  • Excessive sleepiness or difficulty waking
  • Unusual irritability that cannot be consoled
  • Decreased responsiveness to parents or environment 1
  • Changes in feeding behavior or inability to suck/feed normally

Motor Function

• Asymmetric movements: Observe for:
  • One-sided weakness or decreased movement of limbs
  • Hand preference or asymmetry (particularly concerning at this age) 1, 2
  • Abnormal posturing or tone (increased or decreased)
  • Absence of age-appropriate motor skills that were previously present

Pupillary Response and Eye Movements

• Pupillary abnormalities:
  • Unequal pupil size
  • Sluggish or absent pupillary light response 1
  • Abnormal eye movements or fixed gaze

Vital Signs

• Vital sign abnormalities:
  • Irregular breathing patterns
  • Bradycardia or tachycardia
  • Hypertension (particularly with bradycardia, suggesting increased intracranial pressure)
  • Temperature instability 1

Specific Concerning Signs

Vomiting

• Vomiting patterns:
  • Projectile vomiting
  • Persistent vomiting (more than 2-3 episodes)
  • Vomiting that worsens over time rather than improves 3

Seizure Activity

• Seizure manifestations:
  • Rhythmic jerking movements
  • Eye deviation
  • Episodes of staring or unresponsiveness
  • Unusual posturing or stiffening 1, 2

Fontanelle Changes

• Fontanelle assessment:
  • Bulging anterior fontanelle (particularly when infant is calm)
  • Tense fontanelle that doesn't soften when upright 1

Timing of Symptoms

• Delayed deterioration: Monitor for 24-48 hours as symptoms may not appear immediately
• Progressive symptoms: Any worsening of symptoms over time is particularly concerning 1
• Persistent symptoms: Symptoms that don't resolve within expected timeframes

Imaging Considerations

The PECARN criteria suggest that infants younger than 3 months with minor head trauma remain at risk for traumatic brain injuries even when clinically stable 4. For a 6-month-old:

• Immediate neuroimaging indicated if:
  • Any abnormal neurological examination
  • Loss of consciousness
  • Palpable skull fracture or significant scalp hematoma
  • Altered mental status
  • Abnormal behavior according to parents 1, 4

Special Considerations for 6-Month-Olds

• Developmental context: At 6 months, infants should have head control, be developing trunk stability, and beginning to sit with support 2
• Baseline assessment: Any regression from previously achieved milestones is concerning
• Fall height significance: Falls from 3 feet (approximately 90 cm) have been associated with skull fractures in some cases 5

Follow-up Monitoring

• Home observation guidance (if discharged):
  • Wake infant every 2-3 hours during sleep periods for first 24 hours
  • Monitor for difficulty waking, confusion, or worsening symptoms
  • Return immediately if any deterioration occurs
• Developmental follow-up: Consider reassessment in 2-4 weeks to ensure normal developmental progression 1, 2

Common Pitfalls

• Underestimating risk: Infants under 12 months may have significant intracranial injury without obvious external signs 1
• Delayed presentation: Some neurological injuries may not manifest immediately after trauma
• Incomplete assessment: Focusing only on the head while missing potential associated injuries to neck or spine
• Inadequate history: Not obtaining detailed information about the mechanism of injury, which is crucial for risk assessment

Remember that falls are the most common cause of traumatic brain injury in young children, and infants have unique anatomical vulnerabilities including thin skull bones and relatively large heads compared to their bodies 6.