Bladder Stones in Dogs: The Characteristics of Urolithiasis

Bladder Stones in Dogs
Wyatt Robinson
Written by Wyatt Robinson

Urolithiasis, urinary calculi, urinary stones, kidney or bladder stones in dogs mean basically the same thing, namely the presence of small or large formations in their urinary systems. In more than 2 thirds of all cases, stones form in a dog’s bladder, but they can also appear in its kidney, ureter or urethra. Some dogs do not show any clinical signs, so their bladder stones are discovered incidentally after an ultrasound or a radiological examination or if their abdominal cavity is opened for other purposes.

However, a dog owner might observe the presence of blood in his or her dog’s urine, difficulty in urinating and recurrent urinary tract infections.

Fortunately, the struvite, which is a type of phosphate mineral, is radiopaque. This means that it can be seen on a regular radiograph. Sometimes, these stones are simply eliminated by dogs without showing any clinical signs. Any dog owner who notices the elimination of such stones should take his or her dog to the vet for further investigations. There might still be stones in the dog’s bladder or kidney, so they must be detected in a timely manner before they get larger.

Urolithiasis in dogs

Urolithiasis is a disease commonly found in dogs. It is defined by the formation of urinary concretions of minerals, organic or inorganic, called uroliths. They are formed by the aggregation of crystals from organic or inorganic substances excreted in urine. In most cases, urolithiasis is correlated with urinary infectious. Most predisposed to this disease are female dogs, but male dogs might also have it.

Crystalluria occurs in early stages, which are crystals found in urine and which may have different chemical natures. More specifically, they can be magnesium ammonium phosphate, calcium oxalate dehydrate, mono or calcium phosphate, cystine, ammonium urate and some rarely met crystals like calcium carbonate, tyrosine, bilirubin or crystals from certain medications. These might not make too much sense to you unless you are a chemist, but the composition of the stones is really important because it requires different treatments.

Canine urinary

Most commonly, uroliths are located in the bladder of dogs, but the worst phase of this disease is when uroliths appear in ureters or at urethra level. This affection can be fatal for older dogs because their urinary tracts might get blocked. In general, dogs and cats have slightly acidic urine. On the other hand, most salts are poorly soluble in alkaline solutions.

Therefore, if the urine is alkaline, then the danger of uroliths occurrence is higher. There are a number of bacteria in a dog’s bladder, which decompound urea in ammonia, substance which makes urine alkaline. Moreover, cellular debris is ideal for mineral salts to be deposited on. Because the blood salt concentration in some dog breeds is higher compared to other breeds, there are a few that are prone to developing bladder or kidney stones. These dog breeds are Dalmatian, Dachshund, Miniature Pinscher, Fox Terrier, Pekingese, Schnauzer and others.

If any specimen is dehydrated or insufficiently hydrated, then the risk of uroliths occurrence is higher. The concentration of salts from a dog’s urine is above normal levels when they start adhering to its urinary system. This is a type of disease that settles in mostly not because of genetic factors or environmental factors, but because of an imbalance found in a dog’s urinary system.

The occurrence of struvite

Usually, urinary calculi consist in several types of minerals. The most frequent ones are those that contain struvite or calcium oxalate. As said, it is essential to know the composition of the struvite because the therapeutic approach is different depending on their type. The only way you can find out the chemical composition of the stones that are located in your dog’s urinary system is to take them to a laboratory for an analysis. This test can discover other problems too, such as infections and some very small calculi that cannot be seen with the naked eye.

Measures to prevent Struvite Urolithiasis

In dogs, calculi that contain struvite occur almost always because of the changes in the bladder that take place during infections with Staphylococcus or Proteus. If both or any of these 2 germs are found in a dog’s urine, then the probability of having struvite is higher than having calculi made of oxalates.

Also, in order to form, struvite needs an alkaline pH, while oxalate needs an acid pH. Urine acidity or pH must be analyzed in order to give details about the nature of the stones. However, there are cases when calculi are mixed. That is a tricky situation that must be treated in completely different ways.

The formation of struvite

Struvite is the name given to crystals made of magnesium, ammonia and phosphorus. Struvite crystals are not normally found in urine, but appear constantly and in large quantities in case of bladder infections with Staph or Proteus. Crystals gather and grow like a snowball, turning into calculi or stones. The process of stone formation begins and continues in the presence of urea, a substance present in urine. When urine is infected with bacteria that use urea, the latter is decomposed into ammonia. Ammonia is toxic to the cells from the bladder wall, causing inflammation.

Proteins released in the inflammatory response form a matrix together with the struvite crystals, which is really the basis on which calculi are formed. This reaction takes place only in the presence of an alkaline pH and ammonia. Therefore, there are no stones in a dog’s urinary system if there isn’t a previous infection with bacteria. Cocker Spaniel is the only dog breed that makes an exception to this rule. It seems that specimens from this breed are genetically predisposed to the formation of struvite.

Signs of urolithiasis in dogs

The most common signs of urolithiasis in dogs are frequent and painful urination and the appearance of blood in urine, phenomenon called hematuria. Hematuria occurs because of lesions to the bladder and the urethral mucosa. The lining becomes swollen and painful when urine passes by, containing bladder stones or sand, which acts like genuine sandpapers.

Moreover, the symptoms of sand or stones in dogs are similar to those of man. Dogs affected by this will try to urinate, but they will be unable to eliminate more than a few drops. Most of the time they will be apathetic and in no mood to play. When they can’t even eliminate a few drops, dogs can become agitated.

Diagnsis and management of canine-struvite-urolithiasis

Often, the symptoms of this disease can be confused with constipation, so it is better to take your dog to the vet when you first notice one or more symptoms. Also, you can tell by the way its bladder feels if it has a problem or not. If your dog has not urinated for a long time, its bladder should be easy to feel when touched. In case you feel a big, hard formation, you should hurry to the vet because your dog might have its urinary system obstructed, fact which can lead to an irreversible dysfunction of its kidneys.

Stones that form at kidney level

Unlike bladder stones, kidney stones in dogs are rare. However, they are also dangerous because they can determine sporadic hematuria without presenting the classic signs of frequent urination. Stones that go from the kidneys down to the ureter and the bladder can affect a dog’s body for an extended period of time until they are eliminated from its body naturally or through surgery. The dog might get feverish and very agitated.

A dog’s kidneys are composed of thousands of functional units called nephrons, which filter blood, remove waste substances from the circuit and maintain the correct concentrations of fluid and minerals within the body. Some of these functional units disappear with age and are not replaced by others. A kidney disease includes any condition that results in the destruction of nephrons. An accelerated destruction of nephrons can be caused by a range of factors, among which are trauma, infections and cancer.

The treatment of urolithiasis in dogs

Kidney or bladder stones can be extracted surgically, removed by pushing them out with the help of a liquid column or dissolved by using special diets. The surgical method is by far the best and most widely used. Its advantage is that all stones are eliminated in one day.

Of course, like any surgery, this one also involves a few risks, such as those given by anesthesia, postoperative pain, the possibility of contamination with infected urine of the abdominal cavity and the possibility of leaving a few calculi in. In addition, some dogs are allergic to the thread used in veterinary clinics to close up wounds. However, these risks are considered minor and complications occur rarely.

Manage your dog's bladder stones

If the stones are small enough to traverse the urethra, the bladder of a dog can be pressed in order to eliminate them. This technique requires the palpation of the bladder, with firm movements so that the urine inside it becomes agitated and the stones are drawn into the movement. Next, thanks to the pressure, the dog should eliminate them through its urethra. This technique works if the dog has small stones.

In case they are numerous, the vet may repeat the process. Moreover, if the dog has both big and small stones, then this procedure is great in order to obtain a sample that can be analyzed in the laboratory. Discovering the composition of the calculi enables the vet to prescribe a treatment meant to dissolve the stones that are left in the body of the dog.

Diet has a very important role in treating bladder or kidney stones in quadrupeds too. A dog affected by such calculi should consume small amounts of protein to reduce the formation of ammonia in its urine. Phosphorus and magnesium consumption should also be low.

As for fluids, they should be consumed in large quantities. If the process of diuresis is stronger, the urine is more diluted and the stones are removed more easily. A dog should be kept under strict supervision and fed accordingly for 4 to 6 months depending on the gravity of its affection. Also, the vet might recommend a treatment with antibiotics.

A dog may require a treatment with antibiotics when the stones are located in its bladder because bacteria are encrusted on their surface and detach as the stones are dissolved. As for duration, it should take about 3 months for the stones to dissolve. During these 3 months, the dog’s diet should not be changed. When the radiological examination does not show any visible stones, you should know that your dog should eat the same for one more month.

The smallest stones that cannot be seen on a radiograph have to be dissolved as well. The frequency of going for radiological examinations is once per month. However, this treatment should not last for more than 6 months. If the dog in question has a narrow urethra, it will go through pain episodes when it will eliminate the stones. So, try to be ready to comfort your dog if it is a victim of this affection.

Dog radiological examinations

There are a few naturist options that can be used in the treatment of kidney stones. Some plants have diuretic, antiseptic, anti-inflammatory and antispasmodic effects on the urinary tract. For example, wild rose has an anti-inflammatory and diuretic effect, being able to dissolve kidney stones. Also, hibiscus is known to remove sand and small kidney stones and reduce inflammation.

Birch is very effective in removing water and excess uric acid from both dogs and human bodies. It is not advisable to use any of these plants before consulting the vet, but it is good to know about them and their properties. Besides these, there are countless naturist therapies that could make wonders if administered constantly.

The reoccurrence of stones

As soon as your dog is bladder or kidney stones free, you should focus on preventing their reoccurrence. Dogs that were already affected by urolithiasis are, in one way or the other, more predisposed to bladder infections, which means that there is a high probability for the calculi to form again.

For example, it only lasts 2 weeks for a stone to form as a consequence of a urinary infection. Prevention usually means special diet, regular examinations and other details that are established for every affected dog individually. In addition, there are meds meant to decrease the concentration of urea, thus discouraging the formation of calculi.

The risks of untreated urinary tract diseases

Untreated urinary tract disorders can lead to serious health problems, but also to increased discomfort for affected dogs. Infections of the bladder can reach the kidneys, where they can cause a number of complications that can endanger dogs’ lives. Bladder stones can lead to partial or complete obstruction of the urethra, which means that the affected dog is unable to urinate. This problem is a medical emergency and must be treated immediately.

Untreated kidney stones affect the dog’s entire urinary system and its bladder might crack, which can prove to be fatal. There are no affections that should ever be left untreated in both dogs and humans.

Dog in pain

Factors that may influence the possibility urinary system disease:

  • The age of a dog – the chances of kidney failure increase with age, doubling for pooches aged between 10 and 15 years
  • The breed of a dog — Kidney diseases are more common in certain dog breeds, which may also be predisposed to renal dysfunction. These dog breeds are Cocker Spaniel, Lasha Apso, Doberman Pinscher and Samoyed.
  • The living environment of a dog — certain common environmental chemicals, such as disinfectants based on phenol or paint are toxic for a dog’s kidney
  • The diet of a dog – The intake of phosphorus and protein of a dog should be carefully monitored because they encourage stone formation

Conclusions for urolithiasis in dogs

According to statistics, dogs aged between 2 and a half to 3 years old are the ones affected most by urolithiasis and everything it involves. As said, there are a few dog breeds that are predisposed to developing kidney or bladder stones.

Therefore, if you are the owner of a dog belonging to those breeds, then you should take it to the vet for a regular consultation and ask him or her for advices on how to prevent their occurrence if they aren’t causing problems already.

Canine urolitithasis

Also, if your dog is a female, then you must know than 85% of all dogs affected by bladder or kidney stones are females. The reason why this happens is because female dogs have shorter ureters, so they get infected more easily compared with male dogs. Infections are always those that appear before the formation of calculi.

Make sure your dog stays hydrated, consumes a regular amount of proteins for its characteristics and stays away from infections in order to prevent them from getting ill. Since you know how serious this affection might get, do not hesitate to investigate suspicious symptoms if you see any.

About the author
Wyatt Robinson
Wyatt Robinson

Wyatt Robinson had a great 25-years career as a veterinarian in United Kingdom. He used to be a member of British Veterinary Association and worked in 3 pet hospitals in London and Manchester. He is shining when he sees his pets healthy and full of energy and it is his duty to help other dog owners to keep their best friends full of life.