Kidney pathology findings in pediatric patients with kidney injury and inflammatory bowel disease: A case series

Background Patients with inflammatory bowel disease (IBD) are at increased risk of renal pathologies such as IgA Nephropathy (IgAN) and tubulointerstitial nephritis (TIN). Data on renal abnormalities and treatments in pediatric IBD patients with kidney disease are limited. This study describes kidney pathology, treatments, and outcomes in pediatric IBD patients who underwent kidney biopsy at our centre. Methods We conducted a single-centre retrospective case series at a quaternary pediatric hospital in Toronto, Canada. Pediatric IBD patients who underwent kidney biopsy between June 2018 and February 2024 were included. Clinical data were extracted via chart review; biopsies were reviewed by a renal pathologist. Results Twelve patients were included; 11 had Crohn’s disease, and four were female. Biopsy findings included TIN (4), focal segmental glomerulosclerosis (FSGS) (1), IgAN (1), and acute tubular necrosis (1). Five biopsies (42%) showed normal or nonspecific findings. Biopsy indications included elevated creatinine (n = 10), nephrotic-range proteinuria (n = 1), and steroid-resistant nephrotic syndrome (SRNS) (n = 1). Kidney abnormalities appeared before IBD diagnosis (2), within one year (4), or 2–11 years post-diagnosis (6). TIN treatments included prednisone, stopping suspected triggers (e.g., ustekinumab, vedolizumab), and/or escalating IBD therapy. All TIN patients showed poor kidney function recovery. The IgAN patient recovered fully with steroids. The FSGS patient with SRNS responded to rituximab; IBD was independently treated with infliximab. Conclusion TIN was the most common renal finding but had poor treatment response. Many biopsies were non-diagnostic. Early kidney surveillance in pediatric IBD may aid in timely detection and management of renal disease.