Hypoxic-ischemic enterocolitis in extremely low birth weight infants: diagnostic insights from a pilot study

Hypoxic-ischemic enterocolitis (HIEnt) in extremely low birth weight (ELBW) infants represents a significant clinical challenge, frequently occurring in the first week and remaining undetected because of its non-specific presentation. Timely and accurate diagnosis is crucial for improving the poor outcomes associated with this condition. The aim of this pilot study was to evaluate early diagnostic tools and characterize HIEnt in a cohort of ELBW infants during the first week of life, with the goal of identifying promising markers for future large-scale studies. In this prospective, single-center pilot study, 23 ELBW infants (< 1000 g) born from July 2023 to February 2024 were enrolled. Clinical, perinatal, and neonatal variables, along with serum biomarkers (sodium, platelets, bicarbonate, and intestinal fatty acid-binding protein [I-FABP]), were systematically collected on days 2, 4, and 6. HIEnt was diagnosed according to modified Bell's criteria. Three infants (13%) were diagnosed with HIEnt. HIEnt cases exhibited significantly lower birth weight (mean 568.33 g vs. 818.00 g; p = 0.03) and a higher incidence of abnormal antenatal Doppler findings (100% vs. 20%; p = 0.02) compared to non-HIEnt infants. Platelet counts were lower in the HIEnt group on day 4 (p = 0.06), and initiation of diet was significantly delayed (mean 14.5 days vs. 3.59 days; p = 0.04). Serum I-FABP levels did not demonstrate significant differences or consistent temporal trends, and common clinical symptoms did not distinguish between groups.

Prenatal risk factors, low birth weight, feeding intolerance, and decreased platelet levels may serve as early indicators of HIEnt in ELBW infants, underscoring the condition's distinct pathophysiological origins. These findings underscore the need for integrated, multimodal diagnostic strategies and support the pursuit of larger, multicenter validation studies to improve the detection of HIEnt and outcomes in this vulnerable population.

• Hypoxic-Ischemic Enterocolitis (HIEnt) in extremely low birth weight (ELBW) infants is a distinct and severe condition manifesting within the first week of life. It is frequently underdiagnosed due to non-specific clinical signs and the limited sensitivity of existing diagnostic tools.

• This pilot study identifies significant predictors and diagnostic tools, including lower birth weight, abnormal antenatal Doppler findings, early platelet decline, and feeding intolerance, as potential early indicators of HIEnt in ELBW infants during the first week of life, underscoring the need for multimodal diagnostic strategies.