Calcium oxalate prevention tools
Approximately 50% of dogs will have a recurrence of calcium oxalate calculi within 2-3 years. Some dogs can have recurrent calculi much more frequently. Small breed, male, older dogs are more prone to this type of calculi.
Increasing water intake
Increasing his water intake, if possible. Urine specific gravity should be collected in the morning and should be below 1.020 (ideally below 1.008)
We recommend purchasing a refractometer to monitor the urine specific gravity and adjust the amount of water added to the diet to reach the ideal urine specific gravity
You may purchase one on amazon.com: click here
Monitor calciuria via urine calcium:creatinine ratio and intervene with hydrochlorothiazide or alendronate, if increased.
a. Monitor calciuria and adjust therapy as needed.
Monitoring ionized calcium
Measuring ionized calcium to rule out ionized hypercalcemia. Measure PTH if ionized calcium is at the upper end of the normal range to help rule out primary hyperparathyroidism.
Vitamin D status and intestinal hyperabsorption of calcium
Most dogs with calcium oxalate calculi have hypercalciuria due to intestinal hyperabsorption. There is a subset of dogs with calcium oxalate calculi that have an increased 25D/24,25D ratio, which suggests decreased vitamin 25D inactivation. Therefore, it is important to measure vitamin D metabolites. It is possible that these dogs may benefit from a low vitamin D diet.
Hereditary calcium oxalate urolithiasis, type I (CaOxl) gene
Hereditary calcium oxalate urolithiasis, type I (CaOxl) gene testing should be considered in the following breeds: American Staffordshire Terrier, Border Collie, Boston Terrier, Bullmastiff, English Bulldog, Havanese, Pit Bull, Rotweiller, Staffordshire Bull Terrier. This is an autosomal recessive gene that exclusively expressed in the kidney and released in urine. It functions to regulate urinary calcium resorption, inhibit crystalization, contributes to blood pressure and immunity against urinary tract infections. This gene is present in 60-65% of English Bulldogs with calcium oxalate uroliths, but it is present in less than 1% of the general English Bulldog population.
Monitoring urine pH
Controlling his urine pH and maintaining between 7.0-7.5.
I recommend getting a urine pH meter or tape.
Measure urine pH while fasted and after eating twice daily for 2 weeks. Continue to monitor urine pH if possible.
Use potassium citrate depending on the baseline urine pH.
AVOID potassium citrate that has cranberry. Cranberry can theoretically increase urine oxalate excretion.
Modify dose as needed to maintain urine pH within the goal.
Using potassium citrate is very important in dogs that are positive for the CaOx1 gene mutation.
Feeding a stone prevention diet
Common diets include Hills C/D, Hills U/D, Royal Canin SO (high sodium).
Diets will increase the interval of stone recurrence when compared to regular dog food.