Calcium Oxalate Struvite Crystals In Cats

Struvite and calcium oxalate are the most common type of stones in cats.

Calcium oxalate struvite crystals in cats.

Struvite specifically is a material that is composed of magnesium ammonium and phosphate. The cornerstone of treatment is to increase water consumption to dilute the urine and promote urine specific gravity of less than 1 020 and urine ph of 6 8 7 5. How calcium oxalate crystals form. Struvite crystals develop in concentrated urine once the urine becomes supersaturated crystals aggregate to form stones.

Less common stones include ammonium biurate cystine and uric acid. Most calcium oxalate stones develop in cats between ages 5 and 14 years. Now a cat is just about equally likely to develop struvite or calcium oxalate bladder stones. Struvite crystals are microscopic crystals that are found in the urine of some cats.

35 of cats with calcium oxalate bladder stones have elevated blood calcium hypercalcemia. Once the stone is formed it increases in size over weeks or months. The crystals themselves can be perfectly normal but become problematic when they combine to form grit or stones of varying shapes and sizes. Cats with calcium oxalate bladder stones tend not to have crystals in their urine while those with struvite stones do tend to have struvite crystals in their urine.

Unfortunately this change isn t simply due to a decrease in the number of struvite stones. To reduce the incidence of struvite stone formation the cats were fed diets that had lower amounts of magnesium. A cat affected with struvite crystals calcium oxalate crystals or any other type of crystal will suffer from the same array of symptoms and are affected in the same way. Because struvite or magnesium ammonium phosphate crystals formed because of too much alkalinity in the feline diet commercial pet food manufacturers began acidifying their products.

Cats who have had calcium oxalate crystals are at increased risk of a recurrence. The very diets we use to dissolve struvite have put cats at increased risk for calcium oxalate stones. A generation ago struvite crystals and stones were commonly found in cats with urinary tract disease with calcium oxalate stones and crystals relatively rare. In the past most pets used to suffer from struvite stones.

Male domestic short haired medium haired and long haired cats appear to be 1 4 times more likely to develop a calcium oxalate urolith than a struvite urolith while both male and female purebred cats eg persian himalayan burmese ragdoll cats appear to be at risk.