Bladder Stones “Urolithiasis”

by Dr. Jim Sillers

Bladder stone formation is not a specific disease but the result of a group of underlying issues. Instead of going into a detailed explanation and description of these issues, I will discuss how I would treat one of my own dogs if it had bladder stones.

When one discusses bladder stones most individuals assume you are discussing kidney stones since kidney stones occur in humans. I assume people can get bladder stones, but I have never heard of a person having them. But I have heard that a person passing a kidney stone is one of the great joys a person experiences in life.

If you ever grew crystals when you were in early elementary school, you have a basic understanding how crystals form. While bladder stones are not the result of a super-saturated mixture that precipitates crystals as the mixture evaporates, in this simplistic explanation at least you get a visual of what happens.

The common clinical signs of a dog that has bladder stones are very similar to a dog having a bladder infection. They have a need for frequent urination and when they do urinate there is straining. A dog will urinate, walk a few feet, stop, and urinate again. This will be repeated over and over again. If you look closely you might notice some blood being passed in the urine. The blood might be passed only at the end of the stream of urine or after the dog starts straining. Blood can be passed with a dog having a bladder infection but I have noticed these dogs usually have reddish color urine as the blood is mixed evenly in the total urine.

In the old days when a dog was presented with the clinical signs mentioned above I assumed the dog had a bladder infection. If the dog was put on antibiotics for three to four weeks, that corrected 98% of the cases treated. Once the antibiotics were given, if within a couple of days the clinical signs returned, 98% of these cases had bladder stones.

Many times the bladder could be palpated and the stones could be felt in the bladder. A radiograph of the bladder would confirm the diagnosis.
Some bladder stones are composed of predominantly one mineral, in some the minerals are mixed together to form the stone, and in others the stones have one mineral for the core and a different mineral surrounding it. These stones are formed because the conditions required to form the initial stone have changed and a different mineral starts to precipitate out in the bladder. Trying to prevent the recurrence of the stones is complicated when one is dealing with more than one mineral composition because what prevents one mineral from precipitating can promote the precipitation of another.

All dogs with bladder stones are predisposed to a bacterial urinary tract infection and this bladder infection must be addressed as part of the treatment. In some cases a urine culture and sensitivity is needed to determine the drug of choice to treat the infection.

Depending on the composition of the stone, the shape of the stones can look very different. The first case I treated after starting practice 40 years ago was a Dachshund with perfectly shaped stones of different sizes. These pyramid shaped stones filled half of a shoe box and the owner could not understand how there could be so many stones when the dog only started having problems the previous day. I wondered now a dog could be still walking around with so many stones filling its abdomen.

The urinary system is designed to dispose of body wastes in liquid form. For some reason when conditions are just so, crystals are formed in the urine. These crystals can be seen during a microscopic examination of the dog’s urine. Depending on the mineral composition of the crystals, their appearances have different shapes.

When conditions in the body are such that they promote a super-saturation of one or more substances in the urine, these substances can precipitate forming the stones in the bladder. There are commercial diets that can be fed to a dog with bladder stones to dissolve the stones.

I had the best results treating a dog with bladder stones by surgically removing the stone from the bladder, having the stone analyzed to know its composition, and then making changes in the dog’s diet and PH of the dog’s urine to prevent their recurrence. I was seldom able to dissolve the stones using just the diet, but I have had success in using the diets to help prevent their recurrence.

Only you can decide which method to use in treating the condition, surgically versus diet alone. Initially, the diet may seem to be the cheapest way to remove the stones, but if it takes many months to dissolve the stones and considering the cost of repeated radiographs to monitor the progress, it might have been cheaper to have them surgically removed in the first place. Part of the prevention’s success is knowing the composition of the stones. The best way to make this determination is to actually have the stone in hand and send it for evaluation.

Diet modification and drug therapy usually will not eliminate all the underlying factors that are involved, causing the formation of the stones. Consequently one cannot expect to completely eliminate their recurrence. However, in some dogs the therapy will eliminate bladder stone recurrence, and in others it will at least delay their recurrence.

A dog that is let out only once or twice in a 24 hour period to urinate will have more concentrated urine than dogs that are let out more frequently. When trying to prevent bladder stones from forming in a dog that is predisposed to the condition, you need to keep the urine as diluted as possible. Feeding a moist food or wetting down a dry dog food will increase your dog’s liquid intake, which helps to keep the urine less concentrated. I always had the best results treating dogs with bladder stones when their owners were willing to let me run a urinalysis from time to time. This let me monitor the PH of the urine and check for the reappearance of crystals in the urine.

Until next time…..
Dr. Jim

Practical Tip: After a dog whelps some will have a vaginal discharge for several weeks. It usually has a dark tar-like color. Should this be a concern?    This issue is always a concern because one always worries about a dog coming down with pyometra. The first thing I do is check to see if the discharge has an odor. An odor would indicate an infection. If there is no odor to the discharge, the next question asked is if there have been any changes in the dog’s appetite or water consumption. If that is normal I would just observe the bitch as probability says everything is okay.

CREDIT: Reprinted from the Shih Tzu Bulletin, 4th Quarter, 2010