Kidney and Bladder Stones in Pets
Mineral crystals can form stones in the urinary tract, causing pain, blockages, and infections. Diet plays a key role in prevention.
Uroliths (urinary stones) are mineral formations that develop in the kidneys, bladder, or urethra of dogs and cats. They cause pain, urinary obstruction, recurrent infections, and kidney damage. Some types of stones can be dissolved with diet; others require surgical removal. RVC diagnoses and manages urinary stones. Call +853 6677 6611.
Key Points
- Struvite and calcium oxalate are the most common stone types
- Male cats are at highest risk for life-threatening urethral obstruction
- Symptoms: straining, blood in urine, frequent small urinations, pain
- Some stones can be dissolved with prescription diets; others need surgery
- Diet modification prevents recurrence in many cases
- Recurrent stones require regular monitoring with X-rays or ultrasound
Types of Urinary Stones
Struvite (magnesium ammonium phosphate): most common in dogs; often associated with urinary tract infections (bacteria produce urease, creating alkaline urine that favors struvite formation). Can often be dissolved with prescription diets. Calcium oxalate: most common in cats; forms in acidic urine. Cannot be dissolved with diet — requires removal. Urate: seen in Dalmatians and pets with liver shunts. Cystine: hereditary in some breeds (Newfoundlands, English Bulldogs, Dachshunds). Calcium phosphate: often associated with metabolic disorders.
Symptoms and Complications
Symptoms: straining to urinate, frequent small urinations, blood in urine, pain when urinating, accidents, and licking the genital area. Complications: urinary obstruction (especially in male cats with small urethras) — a life-threatening emergency. Obstruction causes toxin buildup, electrolyte imbalances (fatal hyperkalemia), and bladder rupture. Recurrent UTIs: stones harbor bacteria. Chronic inflammation can lead to bladder wall thickening and dysfunction. Kidney stones (nephroliths) can damage kidney function over time.
Diagnosis
Diagnosis: urinalysis (pH, crystals, infection), urine culture (bacteria identification), blood tests (kidney function, calcium levels), and imaging. X-rays show radiopaque stones (struvite, calcium oxalate, calcium phosphate). Ultrasound shows all stone types including radiolucent ones (urate, cystine, some struvite). Stone analysis (sent to a lab) identifies the mineral composition — essential for choosing the right prevention strategy.
Treatment and Prevention
Struvite stones: dissolve with prescription diets that acidify urine and are low in magnesium (Hill's c/d, Royal Canin Urinary SO). May take 1-3 months. Calcium oxalate: surgical removal (cystotomy) or lithotripsy (shattering stones with ultrasound). Urate: low-purine diet (Hill's u/d) and allopurinol. Cystine: low-protein diet and penicillamine. Prevention: prescription diets formulated for the specific stone type, increased water intake (canned food, fountains, flavoring water), treating UTIs promptly, and regular monitoring with X-rays or ultrasound every 6-12 months.
When to See a Vet Immediately
- Straining to urinate with little or no urine produced
- Blood in urine
- Frequent small urinations with obvious discomfort
- Male cat unable to urinate (EMERGENCY)
- Recurrent urinary tract infections
- Known stones that need monitoring
How RVC Can Help
RVC provides diagnosis, surgical removal, and prevention plans for urinary stones. If your pet has urinary symptoms, call +853 6677 6611.
This article is for educational purposes only and does not replace professional veterinary advice. If your pet is showing any symptoms, please contact Royal Veterinary Center immediately at +853 6677 6611.