Cool Case Friday! Bladder Stones.

Another Friday, another really cool case!!!!! So, today, any Modern Family fans out there?
If so, do you remember the episode where Phil has kidney stones? Remember how he was in excruciating pain, but Claire was more concerned about getting dressed up and doing her makeup because the firemen were on the way to their house along with the ambulance for Phil? A great episode!

Well……humans aren’t the only ones to get stones in their urinary tracts. Though it is a bit different for cats and dogs, we can believe the discomfort is equal. Dogs and cats can get “mineralization” in their kidneys, but it is not as common to form kidney stones, or to have those get stuck in the ureters (the connections from the kidneys to the urinary bladder). It can happen, but it is much more common to form bladder stones.

Meet Elouise (name changed for privacy). She is a middle aged spayed female cat who came to see me due to her owners seeing her urinate out of the litterbox.

Cats may urinate in inappropriate places for many reasons, but the most common is due to pain. Why, you may ask? Well, if every time she urinates in the litterbox and feels pain, it stands to reason that she may believe the litter box is actually causing the pain. Even though it hurts just as much to urinate on the carpet or in the sink, she has associated the litter box with discomfort. Some owners will just see this inappropriate urination, while others will see blood in their dog or cat’s urine.

Anyhow, Elouise had been urinating out of the litter box for a couple days and the owners were concerned. My first recommendation is always to check a urine sample for bacteria, white blood cells, red blood cells, and CRYSTALS. For most bladder infections, we Veterinarians may see all of these. We realize that all of these things are temporary due to the infection, and with an appropriate course of antibiotics, they will resolve.

 

Courtesy: ResearchGate

HOWEVER, when crystals are seen, and even sometimes when they are not, I always recommend an abdominal x-ray to look for bladder stones. Some owners decline x-rays in the beginning, which is fine, but if the bladder symptoms are not resolving on antibiotics, an x-ray becomes mandatory. Many times when crystals are seen, or if the urinary symptoms are not resolving, we find urinary stones in the bladder. OUCH!

Let’s take a side trip here……where do these stones come from? Many clients ask me if they are feeding the wrong food, offering the pet the wrong water (hard vs soft vs bottled), if it is the treats, etc. The answer to all of these questions is “NO.” Unfortunately this is due to your pet’s genetics. Some pets are just “mis-programmed” and do not break down their food correctly.

You could feed two sibling or two non-sibling cats/dogs the same diet, and one may develop bladder stones and the other may not. There are some breeds more prone to developing crystals, and then stones, than other breeds. So, how do stones start? As the food is broken down when we eat it, crystals will form in the urinary tract of some animals. If they drink enough water and urinate frequently enough, no symptoms may ever been seen. But for others, where the crystals sit in the bladder long enough, those crystals make friends with other crystals, and that’s when a stone forms. There are many different types of urinary crystals: struvite, oxalate, cystine, urate, ammonium biurate, bilirubin, and amorphous to name a few. All will form in different urinary “environments.” Some are very small, like pea gravel, others are huge and will take up most of the space in the bladder. Some are rough, some are smooth, some shed the crystals into the urine for easier diagnosis, and others never shed crystals. YIKES!

So, back to Elouise. As you remember, she came to me with a few day history of urinating out of the litter box. Her owners elected to start with the urinalysis. I found the standard red blood cells, white blood cells, bacteria, and also found struvite crystals. After discussing the options with the owner and recommending an abdominal x-ray, they elected to proceed with the x-ray at this same visit.

 

Good thing they did! While these aren’t the largest bladder stones, look how many there are. Poor kitty! Not only do these rub on the bladder wall causing pain and inflammation, but they are also what we call a “nidus for infection.” Anything present in the bladder that shouldn’t be there (stones) or any defect in the bladder wall, can attract bacteria. Once bacteria attaches to a structure or defect in the wall, it starts to replicate, leading to infection. For many pets with recurrent bladder infections, it is due to the bacteria constantly having something to attach to in the bladder, hence, the importance for x-rays!

Now that we have a diagnosis, what can we do to get Elouise back to her happy and playful self? The great news is that for some types of urinary stones, we can dissolve them with a specific diet. WOW! Wouldn’t you prefer that over surgery any day? If a stone is “purely” struvite in nature, there are some pretty cool pet foods - Hill’s s/d, Hill’s c/d, Royal Canin SO to name a few - that can dissolve stones in as little as 7 days.

Most take a couple weeks to a month to disappear, but it’s still pretty exciting. Now, that being said, this is much safer to do in female cats and dogs than in males. As we are dissolving these stones, you can imagine they are getting smaller and smaller until they can pass through the outflow tract (urethra) and out of the body. Females have a much wider urethra than males, and the concern is that a stone may get stuck on the way out of the male urethra, leading to a HUGE emergency! So, I often have a long talk with owners of male dogs with stones, that surgery is still our best option. For any stones other than purely struvite stone (some stones are mixed in their makeup….part struvite, part oxalate, etc), these foods will likely not solve the problem, and surgery will be necessary to remove the stones.

Luckily for Elouise, the food did the trick. You’ll notice in the one month recheck x-ray that the stones have completely disappeared. HOORAY! Her owners were thrilled and Elouise was a much happier kitty cat.

While these next two pictures are not from Elouise's bladder (remember we dissolved those stones), they are stones from other pets that I removed in surgery, and I thought it would be fun to throw them in.  Stones can range in size from tiny pea gravel to golf ball size. Sometimes these larger stones are easier to remove because you are just looking for one stone.

The pets with the gravel-type stones in their bladder are much more challenging during surgery.  I flush and flush, and search and search during those surgeries. And, I'm constantly asking myself, "Did I find all of them?" I ALWAYS take an intra-op x-ray prior to finishing surgery to make sure all of the stones are removed before waking up the pet. ALWAYS.

Now, you may think that is the end to this story, but for Elouise it is not. Remember how I said that her body had been “mis-programmed” and that is why she created these bladder stones to begin with? What is to stop her from making more in the future?

The other part of my discussion with these owners has to do with prevention. These pets need to be on a specific food the rest of their life to dissolve these crystals as they form, before they become stones. Two great options for this are Hill’s c/d or Royal Canin SO. Both are highly palatable. One of my cats was on this for many years of his life as he was a crystal-former as well. Other types of stones can behave differently and it’s important to speak with your own Veterinarian regarding your pet's specific diet. While less common, there are pets who will need multiple surgeries over the course of their life to remove recurrent bladder stones.

One final note……can an animal who had a struvite stone once have a different type of stone in the future? Unfortunately, yes. So, it’s important to check for stones at future visits if your pet is symptomatic.

Happy Friday. Hope you enjoyed these cool x-rays!