Just like humans, dogs can also get bladder stones. The stones (also known as calculi or uroliths) can be described as a collection of minerals that look like rocks and form within the urinary bladder. These stones may occur as collections of many small stones or a few larger stones. Some dogs with bladder stones may not present with any kind of symptoms until the stones are “accidentally” found, though there are other instances when dogs will show signs that may warrant a search for the bladder stones.

Primary Signs of Canine Bladder Stones

• Straining to urinate (Dysuria)
• Increase in urinating frequency (Pollakiuria)
• Bloody urine (Haematuria)

Bloody urine tends to occur due to the stones irritating and damaging the lining of the bladder, resulting in the bleeding. When your dog is straining to urinate or urinating more frequently, it is a result of the stones inflaming and irritating the walls of the bladder, causing swelling and pain.

Although rare, a life-threatening continuation of the formation of the stones in canines is the possibility of partial of complete obstruction of the dog’s urinary tract. This can often occur as the bladder stones attempt to move out of the bladder with the urine and they end up getting lodged in the urethra instead.

When an obstruction does occur, a canine tends to show signs of straining to urinate in addition to systemic signs that are associated with the inability to pass the urine. These signs include the lack of appetite, lethargy, and vomiting. If the dog is unable to empty the bladder, it can be painful and toxic products that are generally excreted during urination will build up within the bloodstream, resulting in kidney damage. In some cases, a blocked bladder results in the rupture of the bladder, causing urine to enter into the abdominal cavity. Therefore, it is crucial that dogs be seen by the veterinarian immediately if it is suspected that the canine has bladder stones.

Why Bladder Stones Form

There are many factors that are involved in how bladder stones form in canines. These can include the following:

• An increase or high levels of minerals like magnesium, phosphate, and calcium within the urine, which allows the super saturation and precipitation of crystals. The crystals then end up sticking together, allowing stones to form gradually—over time, they increase in size and number.
• Various types of bladder stones can form in alkaline or acidic urine. Therefore, it is important to maintain a neutral pH.
• The pH of the urine can be altered by bacterial infections in the bladder, which can encourage the formation of crystals.
• Abnormal metabolism of certain minerals can result in bladder stones, though some breeds are more susceptible to this than others, such as Dalmatians.

Bladder Stone Growth

The growth of bladder stones can occur within several weeks or several months. It depends on the amount of crystal material that is present in the bladder and the extent of infection that is present in the bladder. While it can take months for a larger stone to grow, there is evidence that sizable stones can form in just two weeks.

Bladder Stone Diagnosis

The symptoms of bladder stones are very similar to those of a bladder infection. Generally, canines that have a bladder infection will not have bladder stones. For that reason, veterinarians cannot conclude that a canine has a bladder stone based on these clinical signs. Some stones can be felt with the fingers through an examination of the abdominal wall. However, failure to feel them doesn’t completely rule the presence of stones out. This is because some bladder stones are simple too small to be felt this way or the bladder could be too firm to allow them to be felt.

Generally, bladder stones can be seen on X-rays or an ultrasound. If the veterinarian suspects your dog has bladder stones, then one—if not, both—of these procedures will likely be recommended. They should be performed on canines that have unusual pain when the vet feels and pushes on the bladder, canines that have recurrent blood in the urine and straining when urinating, or canines that have recurring bacterial infections in the bladder.

It is important to keep in mind that there are some bladder stones that will not appear on X-rays, and these are known to be radiolucent. This simply means that the stone’s mineral composition makes it so that they don’t reflect the X-ray beam. Luckily, these stones can show up on an ultrasound or through a radiographic contrasts study, which occurs after a special dye or contrast material is placed within the bladder.

Bladder Stone Treatment

Essentially, there are two primary treatments for canine bladder stones. The most effective of the treatments is for the bladder stones to be removed surgically, which requires opening the bladder up through an incision in the abdomen. After a two to four day recovery period, most dogs improve quickly. The bloody urine generally persists for several days following the surgical procedure before it finally resolves. For dogs that have other health concerns, surgery may not be recommended. However, canines with urethral obstruction do require surgical intervention as soon as possible in order to minimize any other potential complications.

The second treatment is to try to dissolve the bladder stones with a particular diet, but this only works with certain types of stones. This process can avoid surgery and is the best choice for some dogs. However, it does have its drawbacks, including:

• This method of treatment does not work for all types of bladder stones. Therefore, to determine if this course of action is appropriate, a stone analysis must be performed. In all cases, this may not be possible.
• This process can be slow. In fact, it can take several months for a large stone to fully dissolve, which means that the dog will continue to have the symptoms of the bladder stone (bloody urine, trouble urinating, frequent urination, etc.) throughout that time. In addition, during this period, there is a high risk of urethral obstruction.
• This process requires a special diet, and not all dogs are willing to eat this special diet. If the canine does not eat this diet exclusively, then the course of treatment won’t be effective.

Prevention of Future Bladder Stones

If you want to prevent or minimize the recurrence of bladder stones in the future, then it is imperative that you and your veterinarian be familiar with why and how the bladder stones formed in the first place and what type of mineral content the stones are. In some instances, a stone analysis and further investigation may be necessary—this is particularly true if the dog has had several bouts of infection as there will be a need to look for an underlying cause like diabetes.

Generally, though, your canine’s diet is the first place to look. As soon as the bladder stones have been dissolved or surgically removed, most stones can be prevented by sticking to a prescription diet. By altering your dog’s diet, you can reduce the concentration of minerals that may be causing an issue and alter the urine pH, which creates a less favorable environment for bacteria to grow.

The most important thing is to ensure that your dog goes to the veterinarian for regular checkups to make sure that bladder stones are not trying to form again. Usually, this will require urine analysis, occasional ultrasounds/X-Rays, etc. on a periodic basis.

For more information on bladder stones and dogs or if you suspect that your dog may have bladder stones, reach out to Huntsville Veterinary Specialists & Emergency.