Early Markers Associated with Crohn's Disease in Emergency Department Patients with New-Onset Terminal Ileitis: An Exploratory Retrospective Cohort Study.

Background and Objectives: Terminal ileitis is a frequent radiologic finding in patients presenting to the emergency department with acute right lower quadrant pain, yet whether it represents an early manifestation of Crohn's disease remains challenging to predict. This study aimed to identify early clinical, laboratory, and imaging predictors of Crohn's disease in patients with newly identified radiologic terminal ileitis to improve early risk stratification. Materials and Methods: A retrospective cohort study evaluated adult patients presenting to the emergency department between 2010-2021 with radiologically confirmed terminal ileitis and no prior history of inflammatory bowel disease. Clinical data, laboratory markers, and imaging findings captured at presentation were analyzed. Patients were followed for 12 months for a subsequent Crohn's disease diagnosis. Results: Out of 68 included patients, 23 (33.8%) were diagnosed with Crohn's disease within one year. Multivariable logistic regression identified lower haemoglobin levels (OR 2.17 per 1 g/dL decrease, 95% CI 1.02-4.76, p = 0.044), elevated platelet counts (OR 1.03 per 103/µL, 95% CI 1.01-1.05, p = 0.002), and a composite radiologic finding of stenosis or proximal bowel distension (OR 28.5, 95% CI 2.35-345.6, p = 0.008) as independent predictors of a subsequent Crohn's disease diagnosis. Standalone platelet count (AUC = 0.897) and the platelet-to-hemoglobin ratio (AUC = 0.896) demonstrated excellent diagnostic discrimination. Conclusions: In this small retrospective cohort, approximately one-third of patients presenting with new-onset radiologic terminal ileitis were subsequently diagnosed with Crohn's disease within 12 months. Low hemoglobin, elevated platelet count, and radiologic evidence of stenosis or proximal bowel distension were independently associated with this diagnosis. These associations are hypothesis-generating and require external prospective validation before informing clinical decision-making.