Multicenter Insights into Pediatric Extreme Leukocytosis: A 5-Year Retrospective Study

Area of Science:

• Pediatric Emergency Medicine
• Clinical Pathology
• Infectious Disease

Background:

• Pediatric emergency department (PED) patients present with varying white blood cell (WBC) counts.
• Extreme leukocytosis (EL; WBC >25,000/µL) and moderate leukocytosis (ML; WBC 15,000 to 25,000/µL) are common findings.
• Understanding the clinical implications of EL versus ML is crucial for patient management.

Purpose of the Study:

• To compare clinical outcomes between pediatric patients with extreme leukocytosis (EL) and moderate leukocytosis (ML).
• To investigate the association of EL with infection and malignancy in a pediatric population.
• To analyze WBC trends and inflammatory markers in relation to leukocytosis severity.

Main Methods:

• Retrospective analysis of the MALRADI database, encompassing pediatric visits to Jerusalem hospitals and the TEREM urgent care network.
• Inclusion of 125,471 pediatric records, categorizing patients into EL (15.9%) and ML (84.1%) groups.
• Analysis of demographics, clinical data, laboratory results (CRP, ESR), culture positivity, and WBC trends.

Main Results:

• EL patients were younger, exhibited higher inflammatory markers (CRP, ESR), and had more frequent positive cultures compared to ML patients.
• A rapid decline in WBC count within 24 hours was noted in EL patients, contrasting with a slight increase in the ML group.
• Malignancy was rare (0.06%) in EL cases, strongly suggesting an infection-related etiology for EL in this cohort.

Conclusions:

• Extreme leukocytosis in pediatric patients is predominantly linked to infections requiring targeted monitoring.
• EL is rarely indicative of malignancy in the pediatric population.
• These findings underscore the clinical significance of EL, advocating for careful evaluation and monitoring in affected children.