If you've ever been through a blocked bladder episode with your male cat, it's something neither of you ever wants to repeat. While phosphate, or struvite, crystals can affect either feline sex, blockage is more common in males because of a smaller urethra. With diet, crystal prevention is a possibility.
Struvite crystals consist of magnesium, ammonium and phosphate. They're the most common type of crystal found in felines, tending to form in more alkaline urine. The Minnesota Urolith Center at the University of Minnesota School of Veterinary Medicine reports that, in 2008, of 394 urethral plugs submitted to the facility, 90 percent consisted of struvite and only 1 percent of calcium oxalate, the next most common form of crystal or stone. If you view these crystals under a microscope they resemble tiny, colorless prisms. These crystals can clump together, forming stones in your cat's kidneys, bladder or urethra. Crystal formation is actually more common in female cats, according to petMD. However, it's the males that more often suffer from possibly life-threatening consequences.
If Kitty is constantly in and out of the litter box, straining to pee, that's a veterinary red alert. He might lick his genitals, cry out in pain, or evacuate small amounts of urine outside the box. If he can't void his bladder at all, he'll die within a few days without treatment. Take him to the nearest veterinary emergency hospital immediately.
The only remedy for a male cat blockage is surgical removal of the stones. For female cats who aren't actually blocked, your vet can prescribe a diet that eventually dissolves the crystals, but this isn't recommended for male cats. That's because as stones still in the bladder begin dissolving, they are more likely to get stuck in the male's narrow urethra. Cystoscopy, which doesn't require actually opening up the bladder for stone removal, is also no good for males. The cystoscope, a long, thin instrument, can't fit easily into the male urethra.
Since struvites are present in the urine of many healthy cats, you can ask your vet to conduct a urinalysis on your male kitty. If these crystals are present, your vet might recommend putting your cat on a prescription diet to prevent them from forming. These diets are low in phosphorous and aid in acidifying urine. You'll take your cat to the vet periodically for urine testing. In general, feeding canned food over dry food might lead to fewer instances of crystal formation, because the high moisture content leads to more frequent urination and removal of minute crystals.
- Cornell University College of Veterinary Medicine: Urinary Crystals
- petMD: Urinary Tract Stones (Struvite) in Cats
- University of Minnesota College of Veterinary Medicine: Medical Management of Struvite Disease in Cats [PDF]
- VeterinaryPartner.com: Struvite Stones—Feline
- Merck Veterinary Manual: Urolithiasis in Small Animals
- Jupiterimages/Goodshoot/Getty Images