How common are struvite bladder stones?
Bladder stones are somewhat common in dogs, and struvite stones are the most common. In clinical studies, up to 26% of all bladder stones were found to contain struvite. Together, struvite and calcium oxalate uroliths have been found to comprise over 85% of all uroliths. Based on the results of tens of thousands of stone analyses, it has been found that the number of struvite bladder stones has been declining in dogs while the number of calcium oxalate stones has been increasing. Struvite uroliths were noted to be more common in female dogs, while calcium oxalate uroliths are more common in male dogs. Breeds most commonly diagnosed with struvite and calcium oxalate bladder stones include Shih Tzu, Miniature Schnauzer, Bichon Frise, Lhasa Apso, and Yorkshire Terrier.
What are the signs of struvite bladder stones?
The signs of bladder stones are very similar to those of an uncomplicated bladder infection or cystitis. The most common signs that a dog has bladder stones are hematuria (blood in the urine) and dysuria (straining to urinate). Hematuria occurs because the stones rub against the bladder wall, irritating and damaging the tissue and causing bleeding. Dysuria may result from inflammation and swelling of the bladder walls or the urethra, from muscle spasms, or from a physical obstruction to urine flow. Veterinarians assume that the condition is painful, because people with bladder stones experience pain, and because many clients remark about how much better and more active their dog becomes following surgical removal of bladder stones. (Struvite crystals via Wikimedia Commons / Joel Mills (CC BY-SA 3.0.)
Large stones may act almost like a valve or stopcock, causing an intermittent or partial obstruction at the neck of the bladder, the point where the bladder attaches to the urethra. Small stones may flow with the urine into the urethra where they can become lodged and cause an obstruction. If an obstruction occurs, the bladder cannot be emptied fully; if the obstruction is complete, the dog will be unable to urinate at all. If the obstruction is not relieved, the bladder may rupture. A complete obstruction is potentially life threatening and requires immediate emergency treatment.
Signs of Bladder Stones in Dogs
Dogs with bladder stones may display signs associated with a lower urinary tract disease, or they might not show any signs at all. Signs that your dog may have a bladder stone include:
Vets can identify most bladder stones in dogs through an X-ray or abdominal ultrasound. Your vet will likely also want to submit urine for analysis and culture for bacteria. Because tumors and infections may cause the same clinical signs as bladder stones, its important to follow all your vets testing recommendations.