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.

References:

1. Burstein B, Waterfield T, Umana E, Xie J, Kuppermann N. Prediction of Bacteremia and Bacterial Meningitis Among Febrile Infants Aged 28 Days or Younger. JAMA. 2025 Dec 8. doi: 10.1001/jama.2025.21454. Epub ahead of print. PMID: 41359314.
2. Searns JB, O'Leary ST. Moving the Field Forward to Safely Do Less With Febrile Neonates. JAMA. 2025 Dec 8. doi: 10.1001/jama.2025.23133. Epub ahead of print. PMID: 41359329.