Urinary stones can be a painful and sometimes serious problem for our dogs.
Urolithiasis is the medical term for stones in any part of the urinary tract. They are hard masses of varying sizes, made up of minerals from the urine.
Treatment depends on the type of stone (what minerals it is made up of) and where it is.
Even once treated, affected dogs may be prone to getting stones again. Feeding a prescription urinary food recommended by your vet is usually the best way to help prevent this painful problem.
What are urinary stones and what are the signs?
A dog’s urinary tract like ours consists of two kidneys that make urine from water and their body’s waste; the ureters that transport urine from the kidneys to the bladder; and the urethra through which urine leaves the body.
Urinary stones develop when the minerals in concentrated urine form crystals that link together, increase in size and form stones. The signs a dog with urolithiasis will show depends on where the stones are.
Most urinary stones are found in the bladder or urethra. Signs of bladder stones include:
Blood in the wee
Straining to pass urine
Passing small amounts of pee more often
Wee accidents in a previously house trained pup
If stones block the ureter this will mean your dog is unable to pass urine and it can quickly turn into an emergency. If your dog is trying to pass urine but unable to do so you must contact your vet straight away.
Dogs with stones in their ureters or kidneys may not show obvious signs, or the signs may come and go. Sometimes there is blood in the urine but often the first symptoms are that the kidneys are not functioning properly.
We can see most urinary stones on an X-ray or abdominal ultrasound. Your vet will also want to run urine tests, and urine is often sent to a specialist laboratory for analysis and culture for bacteria.
The most suitable treatment for your pup will depend on the type of stone(s), their size and location.
Nutritional dissolution- this is feeding a special food that is designed to help certain types of stones dissolve. This doesn’t work for all types of stone, and is slow.
Surgical removal of the stones may be necessary.
Lithotripsy – a procedure that uses focused ultrasonic energy to break up the stones. This is available in some specialist centres.
The stones are named according to their mineral composition. Read on for more information about the most common stones our dogs can get.
Struvite are one of the most common type of stones in dogs.
On their own low numbers of struvite crystals in urine may not be a problem.
Struvite stones usually form in urine that’s been infected with bacteria.
Female dogs and some breeds including Shih Tzus, Miniature Schnauzers, Labradors and Dachshunds appear to be at higherrisk of struvite stones.
They can be dissolved using a special prescription diet and antibiotic treatment is often required.
Your vet will carefully monitor your dog as the stones dissolve with repeat urine samples and x-rays.
Calcium Oxalate Stones
These form when the urine is supersaturated with calcium and oxalate.
They are more common in male dogs.
Calcium oxalate stones can form in sterile urine and aren’t usually associated with urinary tract infections.
They cannot be dissolved using special foods but dietary therapy and increasing water intake are important to help prevent the stones from reforming.
Urate stones form because of increased amounts of urates and uric acid in the urine.
Dalmations and bulldogs are predisposed to getting this type of stone.
Liver disease can also cause urate stones- in particular dogs with portosystemic shunts (a bit of blood vessel that diverts the blood supply to the liver).
Diets are available to dissolve urate stones in some cases, but they are not suitable in many dogs.
There are medications available to help dissolve urate stones and prevent recurrence.
Once treated, unfortunately these pesky stones can be prone to coming back. Increase your dog’s water intake as much as possible, and taking your vet’s advice on prescription diets will really help to prevent this.