Xanthine Urinary Tract Stones in Dogs

Xanthine Urolithiasis is the condition in which excessive Xanthine may get deposited and cause xanthine uroliths (stones). While Xanthine is a natural by-product of purine metabolism and is normally converted to uric acid by enzyme Xanthine Oxidase and passed out of body through urine, it isalso the least soluble purine and its excessive amount may lead to Xanthine uroliths (stones). Damage to Xanrthine Oxidase enzyme results in xanthines in the blood (hyperxanthinemia) and xanthines spilling over into the urine (xanthinuria).  Xanthinuria can be congenital or acquired. 

Acquired Xanthinuria occurs in dogs that are being treated with drug allopurinol for urate urinary tract stones or leishmaniasis (a parasitic infestation). High protein diet in dogs that are on drug allopurinol also contributes towards the condition.

In naturally occurring xanthinuria, a familial or congenital defect in xanthine oxidase activity is likely.

There are many symptoms for this condition. 

May be asymptomatic

Mustard colored urine

Bladder stones:

Frequent urination (polyuria)

Difficulty urinating

Bloody urine (hematuria)

Stones in the urethra:

Frequent urination

Difficulty urinating

Bloody urine

Urethra may be blocked

Kidney stones (nephroliths):


Hydronephrosis – kidney is swollen with urine due to a blockedureter (the tube leading to the bladder from the kidney)

Kidney disease

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