A Case of Pediatric Yersinia pseudotuberculosis Infection Complicated by Acute Kidney Injury Successfully Treated With Prednisolone Without Renal Replacement Therapy.

Yersinia pseudotuberculosis (Y. pstb) infection causes bacterial gastroenteritis and may lead to complications, including acute kidney injury (AKI). We report a case of a previously healthy three-year-old boy presenting with prolonged fever, abdominal distention, generalized edema, and impaired renal function following gastroenteritis symptoms. Laboratory tests indicated severe inflammation and AKI, classified as renal failure by the pediatric-modified Risk, Injury, Failure, Loss, End-Stage Renal Disease (RIFLE) AKI classification system. Intravenous prednisolone rapidly improved clinical symptoms and renal function, eliminating the need for renal replacement therapy. Elevated serum anti-Y. pstb-derived mitogen (YPM) antibody titers confirmed the diagnosis. Pediatric AKI due to Y. pstb infection may involve immune-mediated mechanisms triggered by YPM. In this case, systemic glucocorticoid therapy effectively controlled the inflammatory response and restored renal function, without dialysis. Together with prior evidence that the YPM drives superantigenic immune activation in severe presentations, this case supports consideration of prednisolone as a dialysis-sparing option in select pediatric Y. pstb-associated AKI.