Acute and Recurrent Pancreatitis in Children: Insights into Etiology and Clinical Course from a Retrospective Single-Center Study

Background/Objectives: Pediatric acute pancreatitis (AP) is increasingly recognized as a clinically significant disease, yet Central and Eastern European cohort data remain limited. Acute recurrent pancreatitis (ARP) affects a substantial proportion of these children and may reflect distinct underlying etiologies. This study aimed to characterize the etiological spectrum, disease severity, and hospitalization outcomes of AP and ARP in a pediatric tertiary referral population, and to identify early clinical predictors of severity. Methods: We retrospectively analyzed 63 children hospitalized between 2018 and 2025 with 77 documented episodes of AP. Diagnosis followed INSPPIRE criteria, and severity was graded using the 2017 NASPGHAN classification. Etiologies, clinical presentation, laboratory parameters, imaging findings, and hospitalization length were compared between AP and ARP groups, across severity and etiological complexity categories using appropriate non-parametric and permutation-based methods. Results: Genetic etiologies predominated in ARP (37.0%), whereas idiopathic and infectious causes were more common in first-episode AP (24.0% and 14.0%, respectively; overall p < 0.001). Severity distribution did not differ between AP and ARP, with mild disease accounting for the majority of episodes in both groups. Serum albumin was significantly lower in moderate/severe episodes (p = 0.030). Within the single-episode subgroup, etiological complexity emerged as a significant predictor of prolonged hospitalization, with complex multifactorial or systemic etiologies associated with markedly longer stays than idiopathic or single-factor disease (Welch ANOVA p = 0.007). Conclusions: In this Romanian pediatric cohort, genetic causes dominate ARP, while idiopathic and infectious etiologies characterize first-episode AP, supporting a stepwise approach in which comprehensive etiological work-up, including genetic testing, is prioritized after recurrence. The predominance of genetic causes in ARP should be interpreted with caution, as genetic testing was applied selectively, predominantly after recurrence. Recurrence status alone does not predict severity, whereas etiological complexity at first presentation and hypoalbuminemia represent practical, accessible early markers for clinically assessing more severe disease.