PECARN Pie - Risk Stratification of Febrile Infants 0-28 Days Old
Most febrile infants 0-28 days have viral illness, but the traditional default has been lumbar puncture, IV antibiotics, and admission because invasive bacterial infection remains high-stakes. New PECARN-based data suggest a well-appearing neonatal subgroup can safely avoid LP when low-risk labs are present. PECARN Low-Risk Febrile Neonates Traditional neonatal default: Routine LP, parenteral antibiotics, and admission have long been standard for febrile infants 0-28 days, even though only about 4% have invasive bacterial infection. PECARN low-risk profile: The low-risk group is defined by a negative urinalysis, ANC under 4000, and procalcitonin at or below 0.5, a simple lab combination that outperformed age alone. Meningitis miss rate: No cases of bacterial meningitis were missed among well-appearing infants meeting low-risk PECARN criteria, the key reassurance behind deferring LP in selected neonates. How many qualify: About 41% of febrile infants 28 days or younger met low-risk criteria, making this a meaningful practice question rather than a rare edge case. We get into the implementation nuance in the episode. Age versus biomarkers: Once inflammatory markers are included, chronological age adds little predictive value, pushing against the reflex that every infant in the first month needs identical management. Observation over intervention: For well-appearing low-risk neonates, the emerging strategy is admission for short observation without immediate LP or antibiotics, with important workflow details covered in the chapter. Guidelines and HSV Caveats AAP guideline tension: The 2021 AAP approach remained more conservative for the youngest infants, especially 0-21 days, while newer data support more selective management in the 22-28 day window. Canadian guideline shift: Canadian 2023 guidance already allows LP deferral in low-risk well-appearing infants 28 days and younger, showing this approach is moving from theory into policy. Real-world Montreal experience: Implementation across more than 2500 infants in Montreal reported zero missed invasive infections in the low-risk group, an external signal that the rule holds up outside derivation work. HSV phenotype warning: This analysis did not answer HSV meningitis risk, but invasive neonatal HSV is usually not the classic well-appearing low-grade febrile infant and is often accompanied by transaminitis.