Bladder Stones in Dogs
Urinary stones, or uroliths, are exactly as the name suggests. These abnormal stones inside the bladder vary in size from small bits of gravel to large rocks that form anywhere in the urinary system. This includes the kidneys, bladder, and connecting tubes (ureters and urethra). They are not as common as other urinary conditions such as infections, but they can cause the same symptoms in dogs. If your dog has persistent symptoms of urinary infections, it’s certainly worth considering whether there is an underlying condition such as a bladder stone. Keep reading to learn more!
What is Urolithiasis?
Urolithiasis is an umbrella term for any condition in the urinary tract in which stones are present. The type of stone is named after its location. Thus, there are kidney stones (nephroliths), ureter stones (ureteroliths), bladder stones (cystoliths or cystic calculi), and stones in the urethra (urethroliths).
What Causes Bladder Stones?
Several different types of uroliths can develop in the urinary tract. They are all created from minerals that can form in the urine. Urine carries much of the waste products produced by the body and can consist of minerals like ammonium, magnesium, and calcium, to name a few.
In the right conditions, these elements collect to form crystals. Then the crystals assemble to form stones. The conditions that favor this depend on the urine pH and concentration, previous urinary infections, and the breed of the dog. For example, Dalmatians lack a certain enzyme that causes urate crystals and stones to form. And for other reasons that are less clear, Schnauzers, Poodles, Yorkshire Terriers, and Cocker Spaniels are all prone to developing different types of stones.
Symptoms of Bladder Stones in Dogs
The signs of urinary stones are very similar to other urinary diseases:
- Straining to urinate
- Increased thirst
- Increased frequency of urination
- Blood in the urine
- Urinating inappropriately (having urinary accidents inside the house)
- Urinary incontinence
Some stones in the kidneys cause no symptoms unless they begin to pass into the ureter, causing flank or abdominal pain.
In rare cases, urinary stones can cause a blockage of urination. This is a medical emergency. In this case, your dog will be straining repeatedly and unable to urinate. They will also seem incredibly uncomfortable and will quickly become ill and lethargic. If you suspect a urinary blockage you should contact your vet immediately.
How to Diagnose Bladder Stones in Dogs
If your dog has recurring signs of urinary infections or repetitions of any of the signs mentioned above, then stones should be ruled out by your vet. This is done via imaging of the urinary tract. X-rays are useful, but some stones will show-up well while others won’t. These other stones (not easily identified on x-ray) can be highlighted by ultrasound imaging or contrast x-ray studies of the bladder.
Treatment of Bladder Stones in Dogs
The treatment of your dog’s urinary stones will depend upon the type of stone that has formed. Some can be dissolved with a special diet. These diets change the pH and composition of the urine and can be very effective, though often take some time to work (about 6-10 weeks). Other stones will need to be removed surgically.
Lithotripsy is a treatment involving ultrasound waves that can shock and disrupt stones. It is uncommonly used in veterinary practice and not widely available but can be considered in some cases where surgery is contraindicated or the stones are contained within the kidneys.
Other options for urolith removal which are less invasive and ideal for small urolith retrieval include:
- Laser lithotripsy
- Extracorporeal shock wave lithotripsy (ESWL)
- Catheter-assisted retrieval
- Voiding urohydropropulsion
Surgical removal of nephroliths and ureteroliths can be more challenging compared to cystoliths and associated with higher rates of morbidity and mortality.
However, not all nephroliths and ureteroliths may require surgical intervention. Regular monitoring and medical treatment to promote urolith voiding and slow down the increase in size may be undertaken before surgery is considered.
To prevent a recurrence, dog owners must realize the importance of compliance in terms of management and prevention, as well as regular monitoring. But even with strict adherence to recommendations, rates of recurrence remain high for calcium oxalate uroliths.
Preventing Urinary Bladder Stones in Dogs
Prevention of stones or prevention of recurrence often involves a special diet to manipulate the pH and mineral content of the urine. The exact diet will be prescribed by a vet and will be determined by what stones have been diagnosed or suspected. In every case, ensuring your dog drinks enough water and urinates regularly is also very important.
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