Xanthine crystalluria
Xanthine may precipitate in acidic urine in an amorphous form especially in dogs and cats which were given allopurinol. Amorphous xanthine crystals resemble to amorphous urate crystals (Fig. 64-66). The detection of xanthine crystals allows to presume an excessive dose of allopurinol related to the amount of purine predecessor in the food. Xanthine crystalluria in humans has been described in accordance to a hereditary xanthinuria.
Fig. 64)
Microphotographic picture from amorphous xanthine crystals in the urine sediment of a two-and-a-half-year-old castrated male shorthair cat whom allopurinol had been orally given to dissolve bladder calculus of ammonium urate.
Fig. 65)
Microphotographic picture from xanthine crystals in the urine sediment from the male cat from fig. 64
Fig. 66)
Scanning electron microscope picture from xanthine crystals in the urine sediment from the male cat from fig. 64.
Fig. 67)
Microphotographic picture from unidentified bundles of right-angle crystals in the urine sediment of an adult female Beagle. The appearance suggests it’s calcium hydrogen phosphate dihydrate (Brushite).
