Xanthine calculi in the Lesch-Nyhan syndrome.

Urinary tract calculi composed primarily of xanthine are rare in adults and children. However, there is risk of xanthine calculi formation in children with hereditary xanthinuria and children on xanthine oxidase inhibitor therapy for hyperuricemia. We describe the clinical presentation and management of 2 children with the Lesch-Nyhan syndrome (a congenital disorder of purine metabolism) and xanthine calculi. Little information has been available to direct the urologic management of such patients. We have based a plan for management upon our clinical experience with these children, as well as upon in vitro dissolution studies of the calculi. We have had some clinical success using an alternating acid/base dissolution therapy developed in the laboratory.