Every day, our dogs and cats urinate (hopefully where we want them to!) It’s a fact of life. When our pets urinate, they eliminate the end products of the metabolic activity occurring in their cells, as well as any other waste or toxins that are filtered out by the kidneys. The body is getting rid of this material in urine, so it’s totally useless, right?
Well, the sediments in your pets’ urine are useless to your pet’s body, but they can provide us important clues about your pet’s health! Urinalysis, testing that we perform on urine samples, can be used to gather information about the kidneys and bladder, as well as health indicators like glucose regulation and liver function.
Microscope image of struvite crystals found within the urine of a blocked cat.
Urinary Blockage
Occasionally, something goes wrong and a blockage prevents healthy urination. This happened to one of our feline patients recently. We placed a catheter to allow the cat to pass their urine, which would give us the opportunity to run a urinalysis. Upon microscopic examination, we discovered struvite crystals, pictured above. These crystals form within the bladders of pets that have the right conditions: it’s especially likely in pets that are infected with ammonia-producing organisms, within alkaline urine and in pets with a diet high in magnesium.
In cases where the stones are very small, urohydropropulsion is an option for treatment. In this technique, a urinary catheter is placed in an anesthetized patient, and a saline solution fills the bladder. Then the bladder is manually compressed to wash out the solution, taking the stones with it. This requires that the stones be small, as a urethra obstruction can be life threatening.
If large bladder stones form, surgery will be required to remove them. Minerals that had been dissolved in the urine can precipitate out of the solution and begin to form larger stones over time. If they do not pass into the urinary tract, they can continue to grow in the bladder for a long time. The stones pictured below were surgically removed from a small dog by Dr. Philippe Coudrai.
Two bladder stones that had been removed together from a small dog by Dr. Coudrai, next to a quarter for size comparison.
Bladder Stone Treatment
Bladder stone treatment can vary depending on the location and size of the stones. In many cases, the stones need to be removed surgically. The procedure is called a cystotomy. The surgeon makes an incision in the abdomen, exposing the bladder. The bladder is opened, the stones removed, urine collected for analysis, and finally the bladder is flushed with a sterile saline solution to remove any remaining residue in the bladder.
Since bladder infections can lead to stones, antibiotics may be used to kill harmful bacteria that create the environment in which stones grow. Those conditions can also be influenced by the pet’s diet, which may need to change to prevent future bladder stones. Specialty diets can be used temporarily to increase the acidity of the urine and lower the amount of certain minerals in the diet while treating bladder stones.
