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Xanthinuria, Xanthine Stone Disease
Xanthinuria is a descriptive term for excess urinary excretion of the purine
base xanthine. Xanthine is a nitrogenous by-product of the metabolism of certain proteins. It is normally found in the muscles, liver, spleen, pancreas, and urine. It is broken down and degraded to uric acid by the enzyme xanthine dehydrogenase. When there is a deficiency of this enzyme, xanthine accumulates in the plasma and urine and causes disorders of blood vessels, muscles, kidneys, bladder stones and eventually kidney failure.
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Classic xanthinuria is one form of xanthinuria that is divided into 2 types based on the enzyme deficiency. Both types are inherited in an autosomal
recessive manner. |
- Classic xanthinuria type I is the result of a deficiency of
xanthine dehydrogenase enzyme.
- Type II xanthinuria is characterized by a deficiency of xanthine
dehydrogenase and a related enzyme, aldehyde oxidase.
The primary organs affected in xanthinuria are the kidney and, to a lesser extent, skeletal muscle and joints. Kidney complications are initiated by the formation of xanthine crystals in the tubules, leading to stone formation. Irritation of the tubular epithelium by xanthine crystals results in bloody urine (hematuria), whereas renal tissue deposits induce an inflammation of the kidneys. Urolithiasis (stones in the urinary tract) is the most common clinical manifestation of the xanthinuria. Further kidney complications include acute and chronic kidney failure and even end-stage kidney disease.
In dogs and cats, xanthinuria is an uncommon metabolic disorder clinically manifested as urolithiasis. Affected animals may have few or no clinical signs except for the formation of xanthine stones. The disease has been reported in Cavalier King Charles spaniels, Dachshunds, Himalayan cats.
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The bladder stones can be removed surgically, but the disease tends to recur. Since alkalinization (making more acidic) has little affect upon the
solubility of xanthine it adds little to the therapeutic regimen. High fluid intake is the key to therapy. Dehydration is to be avoided whenever possible. Low
purine diet is effective. Foods with high purine content such as liver, kidney, bacon, veal, venison, turkey should be avoided. There currently is no drug available that will reduce the risk of xanthine stone formation in these rare patients.
Adapted from:
1. Xanthinuria. eMedicine.
2. Xanthine urolithiasis in a cat: a case report and evaluation of a candidate gene for xanthine dehydrogenase. Journal of Feline Medicine & Surgery , Volume 9 , Issue 6, Pages 503 - 508S . Tsuchida, A . Kagi, H . Koyama, M . Tagawa
3. URIC ACID STONE DISEASE. Michael E. Moran
Go Pets America recommends seeking the advice of your local veterinarian for the most appropriate vaccination program and for the diagnosis and treatment of your pet's health problems. For vaccination requirements please contact your state and local licensing authorities.
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