[Febrile syndrome in children younger than 29 days]

Area of Science:

• Neonatal Medicine
• Pediatric Infectious Diseases
• Clinical Diagnostics

Background:

• Acute fever of unknown origin (FUO) in neonates (<29 days) is a significant concern due to the potential for serious bacterial infection (SBI).
• Prompt diagnosis and management are crucial for improving outcomes in febrile newborns.

Purpose of the Study:

• To investigate the clinical and laboratory characteristics of hospitalized neonates diagnosed with FUO.
• To assess the predictive value of laboratory markers for SBI in this population.

Main Methods:

• Retrospective study of 468 neonates (<29 days) hospitalized with FUO.
• Analysis of clinical records, including fever history, admission temperature, severity assessment, diagnoses, laboratory tests, and treatments.
• Classification of patients into severe (S) and non-severe (NS) groups based on discharge diagnosis.

Main Results:

• Urinary tract infection was the predominant diagnosis in the severe group (70.5%), while FUO was most common in the non-severe group (67.6%).
• Low concordance was observed between admission and discharge severity assessments.
• Leukocyte count, C-reactive protein (CRP), and neutrophil counts demonstrated low negative predictive values for ruling out SBI.

Conclusions:

• Despite most neonates presenting with mild initial severity, a significant proportion (24%) had SBI, underscoring the need for hospitalization and close observation.
• Routine laboratory tests like CRP and white blood cell counts are unreliable predictors of SBI in febrile newborns.
• The early administration of antibiotics for low-risk infants with FUO remains a debatable clinical decision.