Nephrolithiasis in childhood inflammatory bowel disease.

Six children with inflammatory bowel disease and nephrolithiasis are reported. Their mean age at the passage of the first stone was 12.5 years and the mean duration of active inflammatory bowel disease was 34.5 months. Four had ulcerative colitis and two had Crohn's disease. In three patients, the onset of stone disease was associated with a flare in the bowel disease. Stone passage in four patients was accompanied by an increase in abdominal pain; three experienced gross hematuria. Stones from four of the patients were composed primarily of calcium phosphate; stones from the remaining patients contained uric acid and/or calcium oxalate. The pathogenesis of nephrolithiasis as it relates to inflammatory bowel disease is considered and an approach to therapy offered.