Who knew that dogs could get urinary stones? Cats can as well, but there are usually other factors contributing.
There are different types of stones that can form in different conditions. The most common symptoms of urinary stones are: straining to urinate, blood in the urine, peeing more frequently than normal and having accidents in the house. These symptoms can also be caused by urinary tract infections, inflammation in the bladder or other issues – so it's important for a veterinarian to evaluate a urine sample to tell the difference.
Urinary stones most often form in the bladder, but they can form in the kidney as well. Urinary stones can usually be diagnosed by imaging (x-ray or ultrasound), but looking at the urine itself (running a urinalysis) can give clues too.
Urinary stones usually form if there is an excess of crystals in the urine, which can be diagnosed with a urinalysis. Sometimes the type of crystals match up with the type of stones in the bladder, but sometimes they don’t – and it’s even possible to have stones in the bladder and not find any crystals in the urine. There are different reasons for crystals to form, such as a genetic predisposition, urinary tract infection, or medications.
The two most common types of crystals that can form stones are struvite crystals and calcium oxylate crystals. There are many other types, but these are the types that are most frequently seen. Struvite crystals are frequently accompanied by a urinary tract infection and can often be dissolved by a special diet. When the urine is evaluated, there is often a high PH and rod type bacteria that contribute to struvite crystal formation. It is important to address an infection if it is present as well. Calcium oxylate crystals form under different circumstances and unfortunately cannot be dissolved with a diet change alone. If a calcium oxylate stone is present, surgery to remove it may be needed.
Bladder stones can become an emergency if they prevent a pet from urinating. When an animal can’t pee, the urine builds up and causes metabolic problems that can lead to death if untreated. If you see your pet straining to pee and nothing or very little is coming out, this is an emergency and your veterinarian should be contacted immediately. If not treated, pets can experience abdominal pain, and the bladder can even rupture. Depending on the situation and type of stone, surgery may be needed to correct the problem.
After stones have been resolved, with diet, surgery or both, usually a special long-term diet is needed to prevent their recurrence. Overall, it’s important to make sure your dog or cat can urinate normally, and if there is any difficulty or abnormality with their urine it is best to call your veterinarian as soon as possible for more information.
Dr. Sydney Routley is a 2012 graduate of the Western College of Veterinary Medicine. She was raised in Fort St. John and first started working at the North Peace Veterinary Clinic as a student back in 2004.