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Kidney Stones in Dogs: What You Need to Know

Posted May 26, 2015 in Dog Diseases & Conditions A-Z

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Kidney stones form in dogs for a few different reasons. The different causes ultimately predict which type of nephro (kidney) + lith (stone) is most likely to form. And the type of stone affects what treatments might help. Dogs with small kidney stones really may show no signs at all. Kidney stones may show up on x-rays of the belly that are being taken for unrelated reasons, as a so called “incidental finding.” For instance, they may be discovered when you think your pooch may have eaten something he shouldn’t have, like one of your favorite earrings. (Your vet found a stone, all right, but not the missing diamond you were seeking.) Since kidney stones don’t seem to cause dogs as much pain as they do for people, why worry about them at all?

Why are kidney stones in dogs important?
A kidney stone that allows normal urine flow out may be one that your vet watches closely, but ultimately leaves untreated. However, if the stone gets very large, or if little pieces break off and lodge in the ureter (the long narrow tube that connects each kidney to the urinary bladder) it becomes a ureterolith, and is likely very painful. Kidney colic, signaled by abdominal pain, discomfort and even vomiting, may result; the kidney may also swell and become damaged. If this should happen simultaneously to each kidney, and the blockage persists, your dog will likely become critically ill from the disrupted flow of urine. For these reasons, if you think your pet’s abdomen is painful, or his urinations change in any way, please contact your vet right away. A urinary obstruction is a life threatening emergency that must be treated!

Signs of kidney stones in dogs
The signs and symptoms of kidney stones could include:

Causes and types of kidney stones
Metabolic kidney stones, those stones formed due to some blood or urinary imbalance, are a bit more common in dogs than are stones caused by infection1. Female dogs outnumber males when it comes to stones2, and there are certain dogs and certain dog breeds that seem to be “stone formers.” They may form stones multiple times, despite ordinary precautions being taken to prevent them. Calcium oxalate is one of the most common types of kidney stones, and is common in the bladder, too.  

Stones that form in the bladder or kidney because of chronic bacterial infection are usually struvite. The stone components are magnesium, ammonium and phosphate.

Some dog breeds with an increased risk of kidney stones are listed here2:

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Celeste has more than 20 years of experience in the veterinary industry and is an Internal Medical Consultant as well as a valued member of IDEXX’s Pet Health Network team since 2015.