Feline Calcium Oxalate

Radiograph

The contour of these small to medium sized (usually 1 to 4 mm), radiodense stones can be smooth, irregular, spiked, or combinations. Even when small they are very radiodense.

General Information

Calcium oxalate (CaOx) is a common and difficult stone to prevent because factors responsible for formation are incompletely understood. It is accepted that crystal growth and possibly initial crystal formation are at least partly a reflection of urine supersaturation. Therefore, controlling risk factors promoting urine CaOx supersaturation (e.g. hypercalciuria, hyperoxaluria, hyperaciduria, hypocitraturia, and highly concentrated urine) should minimize urolith recurrence.

Diagnostic

• Serum calcium. Investigate causes for hypercalcemia, when present.

Medical

• Correct hypercalcemia based on cause (e.g. food change, prednisone, parathyroid removal, etc.). • Potassium citrate, if urine pH is consistently <6.5 (starting dose: 75mg/kg q12-24 hr). • Hydrochlorothiazide with highly recurrent stones (1mg/kg q12-24 hr).

Nutritional

• Mildly reduced protein/sodium foods that do not overly acidify urine (e.g. c/d multicare diets, others). If needed, feed canned therapeutic food or add water to achieve a urine specific gravity <1.030.

Monitoring

Urinalysis every 3 to 6 months to adjust pH to 6.5 to 8.0, and urine specific gravity to 1.030 and lower. Medical imaging every 6 to 12 months to detect recurrent stones when small to permit their removal without surgery.

Disclaimer

We advise reviewing manufacturer's literature regarding selected therapeutic foods to determine indications and contraindications. For pets with multiple health concerns,we suggest that the selection of diet should take into consideration all health needs of the pet.

Link to Full Recommendation PDF

Feline Calcium Oxalate
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