In other words, they have normal appetites, no vomiting, diarrhea, or lethargy generally occurs. Identical clinical signs can occur in dogs with urinary tract infections, and indeed many dogs with bladder stones have concurrent bacterial infections of their bladder. A bladder stone, or cystic calculus, is a mineralized concretion within the urinary bladder. They can range in size from the head of a pin to several centimeters in diameter. They may be single or multiple, I have seen dogs with as many as 50 individual stones present in the bladder.
Some stones have a smooth, polished-feeling surface, while others can be very rough and spiny.
Bladder stones are classified as to their mineral content. There are three main types of stones commonly encountered in dogs. Struvite stones are the most commonly found. Struvite stones occur in conjunction with bacterial infection of the bladder. The action of the bacteria causes urine to become alkaline, which allows the formation of the stones.