Dog Cystinuria and Bladder Stone Management

Cystinuria is a genetic disorder causing cystine bladder stones in dogs that requires both medical and dietary management to prevent recurrence.

Key Facts

Cystinuria is caused by defective renal tubular transport of cystine and other amino acids, causing urinary supersaturation
Newfoundlands, Mastiffs, and mixed-breed dogs have known cystinuria genetic variants
Cystine stones form in the kidney and bladder and can cause urinary obstruction, a potentially fatal emergency
Stones are radiolucent on standard x-rays - ultrasound or contrast imaging is required for diagnosis
Hydration therapy (wet food, water fountains) dilutes urine and reduces stone formation risk
2-MPG (tiopronin) reduces cystine concentration and is used preventively in predisposed dogs
Genetic testing is available for known cystinuria mutations and can identify at-risk breeding animals

Welfare Considerations

Cystine stones cause recurrent painful episodes of urinary obstruction or dysuria. Dogs with urinary obstruction suffer acutely from inability to urinate and progressive uremia. Preventive management that reduces urine cystine concentration and promotes dilute urine is far kinder than repeated emergency obstructions and stone removal surgeries.

What You Can Do

Feed wet food and use water fountains to maximize water intake in predisposed breeds
Ask your vet about genetic testing if you own a breed with known cystinuria risk
Provide fresh water in multiple locations to encourage drinking throughout the day
Seek emergency care immediately for any dog straining without urinating - obstruction is time-critical
Discuss preventive tiopronin therapy with your vet for dogs with confirmed cystinuria