Bladder stones are solid mineral deposits that form inside the bladder of dogs and cats. The crystals form from multiple factors including a change in urine pH (pH = acidity and alkalinity in the urine), increased urine concentration and changes in the minerals when urine is being formed.
With time, the crystals keep forming and combine together causing them to form stones. The stones can range from 1-2 stones to hundreds of stones. Some stones can be small and “gritty” like whereas others can form to be over 2 inches around.
Types: The two most common types of stones we see are ones made up of calcium oxalate crystals and struvite crystals.
Symptoms: Straining to urinate, urinating smaller amounts more frequently, urine dribbling, urinating inside the house/outside of the litter box, vocalizing when trying to urinate and frequently licking penis/vulva. Urine may sometimes have a strong odour, blood or mucous present.
Diagnoses: To diagnose bladder stones, your veterinarian will perform a full physical exam. Large stones may be able to be felt with palpating the abdomen. A urine sample is sometimes requested to see if crystals are present, pH level and/or any indication of infection. Your veterinarian may recommend x-rays to confirm, but unfortunately are not always able to be seen.
If infection is present, it will need to be treated with a course of antibiotics. Depending on the type and size of the stone it may be able to be dissolved with a prescription food but surgical intervention is usually required, especially if the stone migrates and lodges in the urethra, causing a urethral blockage preventing the pet from urinating.
Before surgical intervention, your veterinarian may insert a urinary catheter into the urethra and sterile saline is injected into the catheter to try to propel the urethral stones into the bladder to allow for easier removal. The increased pressure of pushing additional fluid in the bladder, may allow for some small stones to pass easily and quickly out of the bladder into the urethra once the catheter is removed. If this does not work, surgical intervention is the only option and is where the doctor surgically opens the abdomen and bladder to physically remove the stones. Stitches and/or staples are then used to close the surgical site. This procedure is called a Cystotomy.