Kidney Stones in Dogs - Symptoms, Causes and Treatment

Kidney stones in dogs are known as nephroliths. They are so-called because they are essentially the same as stones you would find in nature. Just as rocks are naturally occurring aggregations of minerals, so too are canine kidney stones. The difference is that the minerals accumulating do so within the genitourinary tract of the dog, not do to geographic rock formations.

The mineral from which kidney stones are made is usually calcium, in the form of the mineral salt calcium oxalate. They can also be made of mineral deposits from various sources, including magnesium ammonium phosphate (struvite), urate (a combination of carbon, oxygen, nitrogen and hydrogen) or cystine.

Depending where the mineral deposits originate, these stones are given different names:

• Kidneys: nephroliths
• Bladder: cystoliths
• Anywhere in urinary tract: uroliths

Each kidney stone can vary in size and shape, in part due to the shape of the mineral crystals of which they are made. All of these factors described above can influence the damage they will do to the urinary tract and the resultant symptoms in the dog.

Some of these kidney stones will be relatively small and may not even be noticed by the dog when they pass. It is only when they are sufficiently large will they be able to narrow the urinary tract or cause a blockage in the urethra. The larger the nephrolith, the more pain it is likely to cause. Although kidney stones are not as common as other types of urinary stones, they all cause similar problems.

The direct cause of kidney stones in dogs is the buildup of minerals we have already mentioned. However, there are certain factors which can predispose a dog to developing nephroliths. These include the following:

• Diet: a buildup of minerals is often a result of having too many of said minerals in a dog's diet. If we feed the dog food inappropriate for their age, health status or other factors, it can cause an imbalance and lead to urinary stone development.
  
  
• Hydration: having a sufficient water intake is essential for various processes, including the elimination of minerals in their diet. If a dog is dehydrated on a regular basis, it can lead to various urinary issues.
  
  
• Exercise: dogs need exercise to help their metabolic processes and other processes necessary for overall health. If a dog does not have sufficient exercise, but still eats a lot of food, they may not be able to metabolize properly and kidney stones can occur. At least one study has shown that lifestyle problems of the guardian can negatively impact the health of a dog an influence the development of uroliths^[1].
  
  
• Genetics: although it is not well understood, there is evidence of strong inherited component in the development of calcium oxalate urinary stones^[2]. This is evidenced in the fact that certain breeds are more prone to their development than others. These breeds include the Bichon Frise, Miniature Schnauzer and Shih Tzu.
  
  
• Obesity: although obesity is often causes by the other causes of kidney stones mentioned here, it is important to be particularly careful if our dog is overweight.

If your dog has any issues with the above, they may be prone to developing kidney stones. To help aid a diagnosis, it is important your look at kidney stones in dogs symptoms, information about which we provide in the following section.

Kidney stones in dogs will produce a series of symptoms that will serve as a signal they may have nephroliths. We will need to relay observations of these clinical signs to your veterinarian so they can make their diagnosis. While some of these symptoms will be due to the blockages caused by the stones, it is important to remember the stones can cause further problems such as perforations to the urinary tract or even kidney failure.

The most common kidney stones in dog symptoms are:

• Pain when urinating that will manifest itself in the dog taking greater effort to urinate. We may see the dog tries to pee often, but they do not succeed or they only pee a small amount. It is important we distinguish between a dog being unable to pee properly and a healthy dog marking with urine.
  
  
• Urinary incontinence caused by the distension which can occur in the bladder due to blockages.
  
  
• When there is a partial obstruction of the urethra, it can cause urine to spray when the dog urinates. This is like putting your finger over a water nozzle.
  
  
• Hematuria (blood in the urine) may be observed. It is normal for stones to cause micro-lesions in the urinary system which can result in bleeding. If the bleeding is in the urethra, it is possible we will see drops of blood in the dog's urine. In many cases, it may make the dog's urine darker, but we can only determine hematuria is present after testing.
  
  
• Crystals in the urine may appear. Since nephroliths are made from minerals, the crystals of the minerals may be seen in the dog's urine, especially when they reflect light.

As soon as we notice that our dog may be suffering from the presence of a kidney stone, we must take him to the vet. The first thing will be to get a urine sample to perform urinalysis. The vet usually provides us with a sterile cup for collection, just like the one used in human medicine. We must place the cup under the stream of urine to take the sample and take it to the clinic as soon as possible (it could be kept refrigerated for a few hours). Sometimes we can't pick it up and it will be the vet who has to extract it, either by pressing on the bladder or by pricking it directly.

A strip will be made from the urine sample that will allow us to know important data such as its density, its pH, the presence of blood or infection. When determining the existence of kidney stones in our dog, the most important diagnostic technique will be abdominal ultrasound or radiography. It will require shaving an area on their abdomen. Kidney stones will appear as white spots which vary in size.

The treatment of kidney stones in dogs will depend on the symptoms they trigger. As we have seen, both the size of the nephroliths and their placement in the urinary system must be taken into account. It is possible to treat kidney stones in dogs in the following ways:

• Diet and antibiotics: the objective is to undo the mineral buildups, favor their expulsion and avoid infections. Currently, there are dog food products specifically formulated for this purpose that can be often be found in your local pet store. A few weeks or a few months of feeding with these products is usually enough to solve the problem.
  
  
• Surgery: this is only necessary for the most serious cases. These are when there are large stones present that are unable to be easily expelled or that are causing great damage. This is the case if the kidney stone is causing perforation to any tissue, obstruction of the urinary tract or even damage to the dog's kidneys, especially if they influence kidney failure. Any kidneys stones that cannot be dissolved need to be removed.

Once the kidney stones have been treated, it is important we make steps to prevent them developing again. This is vital as recurrence rates of urinary stones in dogs can be as much as 57% within three years of their first development^[3]. This means we will need to ensure a proper diet, provide sufficient exercise and generally safeguard their health.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Kidney Stones in Dogs - Symptoms, Causes and Treatment, we recommend you visit our Other health problems category.