Struvite Crystals in Cats

Struvite crystals are one type of urinary blockage that pet cats can develop. Some male cats can develop blockages in their urethras (the tube through which urine travels out of the bladder) from the tiny crystals, or full-blown stones can develop in a cat's urinary tract.

How Struvite Crystals Form

Struvite stones are composed of magnesium, ammonium and phosphate. They are most likely to develop when a cat's urine is alkaline (more than 7.0 pH). Two dietary factors – urine pH level and the amount of water consumed daily – have the greatest impact on whether or not a cat will develop struvite stones.

These type of urinary stones used to be more common in felines, but cat food manufacturers began reformulating their diets to lower the magnesium levels. This helped decrease the number of cases of feline urinary stones. Review the magnesium levels in the food your cat currently eats, because a diet with a lower magnesium level may be available.

How to Treat Struvite Crystals

Your veterinarian will make treatment recommendations based on your cat's current condition and the severity of the struvite stones. Treatment options include surgery, bladder flushing, diet changes or a combination of all three.

In urgent situations, surgery may be required to remove a stone if it's blocking urine from leaving the cat's bladder. This surgery is required if your cat has developed large struvite stones. Some male cats may require a different type of surgery to resize their urethra if struvite crystals continue to be a problem.

During bladder flushing, a catheter in placed into your cat's bladder. Your vet flushes the bladder with a sterile saline solution to remove crystals and small stones. This procedure does not work to remove large stones from the bladder.

In milder cases of struvite stones, prescription diets can help dissolve the crystals before they develop into larger stones. These special diets help dilute the cat's urine and make it less alkaline. These diets should be used only on adult cats and under veterinary supervision. They are not designed for use with nursing females or kittens, and they do not require additional supplements of urinary acidifiers.

Along with feeding a special diet, you will need to monitor your cat's water intake to ensure she is drinking adequate amounts. If your cat's water intake doesn't increase, you may want to feed a canned food only diet, because canned foods contain higher water levels than dry food products.

How to Prevent Struvite Crystals

A few simple actions on your part can help decrease your cat's chances of developing (or redeveloping) struvite crystals. They include:

  • Keeping your cat at a healthy weight
  • Providing clean, fresh water at all times
  • Feeding a canned food only diet
  • Minimizing your cat’s stress level
  • Feeding your cat free-choice throughout the day instead of feeding one larger meal in the morning and one larger meal in the evening.