Nephrolithiasis as an extra-intestinal presentation of pediatric inflammatory bowel disease unclassified.

Urolithiasis is quite rare in pediatric inflammatory bowel disease (IBD) compared with the incidence at 9-18% in adult cases. The diagnosis and treatment of pediatric IBD is challenging. Indeterminate colitis (IC), originally proposed as a subgroup of fulminant IBD, has also been used for patients when the diagnosis of either UC or CD cannot be made with certainty. Such patients should be diagnosed as having "IBD unclassified" based on evidence including mucosal biopsy samples. We report herewith a 9-year-old boy with isolated colitis that reached a diagnosis of IBD unclassified. Infliximab therapy led to a successful remission after the refractory course. However, urolithiases were impacted in the urethral valves and vesico-ureteral junction. Microhematuria was noticed from the onset of colitis. Renal calculi were detected on the X-ray films during the first line treatment. Transurethrally crushed stones consisted of calcium oxalate. Renal calculi are more closely associated with CD than ulcerative colitis in adult patients for the ileal involvement. The oxalate stones and treatment response indicated a CD-like pathophysiology. Nephrolithiasis might be a rare but noticeable extra-intestinal presentation of pediatric IBD. Infliximab therapy could be an option in pediatric refractory colitis to change the critical steroid dependency.