Xanthine stones can form if there is overproduction of xanthine and hypoxanthine due to a hereditary or acquired cause. Both chemicals are relatively insoluble, especially in an acid urine.


Conditions associated with xanthine stones:

(1) hereditary defect in xanthine oxidase (very rare autosomal defect)

(2) history of therapy with high doses of allopurinol

(3) Lesch-Nyhan syndrome (hereditary defect in purine metabolism)

(4) recent chemotherapy for malignant disease


Clinical findings:

(1) family history of stone disease (in the hereditary form)


Imaging studies:

(1) stones are radiolucent

(2) ultrasonography shows a stone with high density and a typical echo pattern


Laboratory findings:

(1) marked decrease in serum and urine uric acid

(2) elevated xanthine and/or hypoxanthine concentrations in the urine

(3) crystals in the urine, which may be confused with uric acid

(4) xanthine identified in stone analysis



(1) hydration all through the day and night to maintain a dilute urine

(2) ovo-lacto-vegetarian diet to increase the urine pH (alkalinize)

(3) reduced purine intake in diet


To read more or access our algorithms and calculators, please log in or register.