Abstract: FR-PO0726
Granulomatous Tubulointerstitial Nephritis in Pediatric Inflammatory Bowel Disease: A Case Report
Session Information
- Pediatric Nephrology: CKD, ESKD, and Glomerular Diseases
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pediatric Nephrology
- 1900 Pediatric Nephrology
Authors
- Trinh, Ashley, Children's National Hospital, Washington, District of Columbia, United States
- Kwon, Donghyang, Georgetown University Medical Center, Washington, District of Columbia, United States
- Kakajiwala, Aadil K., Children's National Hospital, Washington, District of Columbia, United States
Introduction
Tubulointerstitial nephritis (TIN) can be seen due to infectious etiologies, systemic inflammatory conditions, and drug hypersensitivity reactions. In patients with inflammatory bowel disease (IBD), TIN is thought to arise from immune-mediated mechanisms involving both humoral and cellular responses.
Case Description
A 16-year-old male presented for evaluation of elevated serum creatinine (2.21mg/dL). His history was notable for six months of postprandial emesis, abdominal pain, and persistent non-bloody diarrhea resulting in a 20-pound weight loss. On presentation, the patient was normotensive. His exam was significant for mild, diffuse abdominal pain and no evidence of edema. The ophthalmology evaluation was normal. Urinalysis revealed specific gravity of 1.008, +1 protein, +3 LE, and 66 WBCs. Stool studies were positive for C. difficile. Serum complements were unremarkbale (C3 140mg/dL, C4 37.9mg/dL). ANA, MPO, and anti-PR3 antibody were negative. A renal ultrasound demonstrated nonspecific, bilateral parenchymal echogenicity.
Endoscopy of the gastrointestinal tract revealed colitis and rectal cryptitis, consistent with ulcerative colitis. A native kidney biopsy was performed showed severe chronic granulomatous tubulointerstitial nephritis.
A comprehensive evaluation for various causes of TIN was negative. The granulomatous TIN was attributed to an extraintestinal manifestation of newly diagnosed ulcerative colitis. The patient was initiated on corticosteroid therapy, resulting in clinical improvement and a decline in serum creatinine on follow-up.
Discussion
TIN is recognized as a renal extraintestinal manifestation seen in IBD patients, though IgA nephropathy is the most frequently reported. In most cases, TIN in IBD is associated with hypersensitivity to medications such as mesalamine. However, this case highlights granulomatous TIN in a treatment-naïve patient, supporting the notion that TIN can be a direct manifestation of IBD itself rather than solely drug-induced.