Retrospective evaluation of patients with hematochezia in the Neonatal Intensive Care Unit

Hematochezia in neonates is a significant clinical finding with various etiologies. This retrospective study analyzed the frequency, causes, and clinical outcomes of hematochezia in 89 neonates admitted to the NICU of Eskişehir Osmangazi University between 2019 and 2024. Patients were categorized into three groups: Sepsis-NEC (n=25), Non-IgE-Mediated Food Protein Allergy (non-IgE FPA) (n=18), and Idiopathic Transient Colitis (ITC) (n=46). The Sepsis-NEC group had the lowest birth weight (2065.4±733.1 g) and 5th-minute Apgar score (median 8, p=0.028), with the highest intrauterine growth restriction (IUGR) rate (48%). Absolute eosinophil count and percentage were significantly higher in the non-IgE FPA group. Although not statistically significant, urinary tract infection (UTI) was notably frequent in this group. While all Sepsis-NEC patients received antibiotics, usage rates in non-IgE FPA and ITC groups were 44.4% and 43.5%, respectively. Recent studies suggest a link between recurrent UTI, non-IgE FPA, and dysbiosis, which may explain the high UTI prevalence in the non-IgE FPA group. Diagnostic accuracy was highest in the Sepsis-NEC group (96%), compared to non-IgE FPA (61.1%) and ITC (64.4%). Patients with diagnostic discrepancies had lower gestational age, birth weight, and higher white blood cell counts at diagnosis. These findings highlight the impact of prematurity, birth weight, and inflammatory markers on the differential diagnosis of neonatal hematochezia. Optimizing diagnostic processes and understanding gut microbiota's role are essential for improved patient management. Key Words: Neonate, hematochezia, necrotizing enterocolitis, food protein allergy, isolated rectal bleeding