[Yorkieluv]

Here's part of an article I found online written by a vet called Ron Himes:
The two most common signs of bladder stones are blood in the urine and painful urination. Blood in the urine or hematuria occurs when stones irritate the bladder’s sensitive lining causing bleeding. The inflamed bladder lining is quite painful as are the small sand-like stones that pass out with the urine. Dogs with bladder stones attempt to urinate much too frequently. They will squat and strain with no apparent success. The urine may be red or port wine in color. When they do urinate, the quantity of urine is small. In between urination these pets are restless. They walk with their loins down in a crouched position. Owners may misinterpret these signs and assume the pet is constipated. When I palpate the abdomen of these animals I can often feel small stones in the bladder grinding together like marbles. Large solitary stones in the bladder are hard for me to miss. If a veterinarian does not attend to this problem immediately, one of the stones may obstruct the urethra, the tube leading from the bladder to the penis or vagina. When this happens, urine backs up into the body causing uremia, depression and vomiting. The bladder stretches to several times it normal size and may even burst. It may take weeks after the problem is relieved for the bladder’s tone and size to return to normal. Blood taken from obstructed animals has elevated urea and creatinine and its ionic balance is disrupted. Despite these changes, dogs and cats with stones do not run high fevers. Analysis of the urine of these pets usually finds blood and white blood cells. Bacteria may also be present in the urine. Any urinary tract infection that reoccurs frequently should be checked carefully for the presence of bladder or kidney stones. These stones are porous and bacteria reside within them where antibiotics and the body’s immune system cannot easily reach them. That is why infections frequently reoccur.