[Leukemoid reaction in extremely immature preterm infants]

Area of Science:

• Neonatalogy
• Hematology
• Pediatrics

Background:

• Leukemoid reactions, characterized by extremely high white blood cell counts, are uncommon in extremely immature preterm infants.
• The precise pathogenesis of non-malignant leukemoid reactions in this population requires further elucidation.
• Potential triggers include prenatal corticosteroids, chorioamnionitis, funisitis, and systemic infections.

Observation:

• A retrospective review screened infants with gestational age <26 weeks for leukocytosis between 2006-2007.
• One case presented with a leukocyte count of 229,300/microL at 48 hours of life, persisting for three weeks.
• No impairment of microcirculation or organ dysfunction was noted in this infant.

Findings:

• Extremely immature preterm infants can develop profound leukocytosis without apparent malignant causes.
• The observed leukocytosis did not lead to secondary complications like organ dysfunction or microcirculatory impairment.
• This case suggests non-malignant leukemoid reactions may have a different clinical significance in this specific patient group.

Implications:

• Standard interventions for hyperleukocytosis in malignant conditions may not be directly applicable to extremely preterm infants.
• Therapeutic decisions for leukemoid reactions in this population should be individualized and approached with caution.
• Further research is needed to understand the long-term outcomes and optimal management strategies for non-malignant leukemoid reactions in extremely preterm infants.