NEPHROLITHIASIS IN CHILDHOOD INFLAMMATORY BOWEL DISEASE

Abstract

Nephrolithiasis is an infrequent complication of inflammatory bowel disease (IBD) in children. Five patients have been managed at our institution since 1978. Their mean age at stone passage was 12.2 years and mean duration of active IBD was 33 months. The majority had ulcerative colitis, passed calcium phosphate stones, and developed nephrolithiasis during an acute exacerbation of IBD. Only one patient had a previous intestinal resection; no patient had a history of urinary tract infections. We have initiated a prospective evaluation of urinary crystalloid excretion in all newly diagnosed cases of IBD. Twenty-four hour urine determinations at diagnosis in 6 patients were within the normal range for calcium (mean = 151 mg), uric acid (338 mg) and oxalate (24 mg). One month after the initiation of therapy, there was an elevation in mean urinary calcium (222 mg) and uric acid (630 mg) excretion in 4 children receiving daily prednisone and salicylazosulfapyridine (SASP). These differences were not observed in 2 patients receiving SASP alone (calcium, 142 mg; uric acid, 374 mg). The effect of prednisone on calcium excretion is well described but its role in uric acid excretion is poorly understood. Further attention must be paid to the urinary excretion of various crystalline species throughout the course of IBD to prevent the complication of nephrolithiasis.