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Bladder Stones in Dogs & Cats

vet holding black dog

Have you noticed your dog or cat straining to urinate or urinating more frequently than usual? Do they seem restless and constantly need to go out or use the litter box? These can be serious symptoms of a larger issue—and bladder stones could be the cause. Bladder stones in dogs and cats are uncomfortable and can lead to a blockage if not treated. At Petco, our full-service pet hospitals are equipped to help your pet. Read on to find out more about this relatively common condition. 

What are bladder stones?

Bladder stones are clusters of minerals, like calcium and phosphorus, that accumulate in the urinary bladder of dogs, cats and even other species like tortoises. They can range in size from small, sand-like stones to larger stones that can be as big as grapes or even larger. 

Signs of bladder stones in dogs and cats

Many pet parents don’t become aware that their dog or cat has bladder stones until they obstruct the urinary tract or cause discomfort or infection. They are sometimes spotted when a pet has an X-ray for an unrelated issue.  

Signs of bladder stones in dogs and cats can include the following: 

  • Urgent, frequent and painful urination 
  • Bloody urine 
  • Urinating in the home (or outside the litter box) 
  • Straining to urinate 
  • Restlessness 
  • Licking at prepuce or vulva

In emergency situations like a blockage, you may notice the following symptoms: 

  • Severe pain 
  • Vomiting 
  • Acute kidney failure 

The symptoms of bladder stones in dogs and cats are similar to bladder infections and other types of stones such as kidney stones. Consulting veterinary services as soon as possible can help get to the root of the problem. A blockage can be life-threatening.

Causes of bladder stones in dogs and cats

Bladder stones can occur when a dog’s or cat’s urine becomes oversaturated with minerals. One of the jobs of the kidneys is to filter minerals that are in the blood. If a higher than normal level of minerals ends up in the urine, whether due to a high level in the blood or other metabolic dysfunction, they can start to crystallize. When they irritate the bladder, mucus is produced and the clusters that are created form stones. However, it is important to note that it is possible for dogs and cats to have stones and not have crystals in their urine. 

Theories about why oversaturation of minerals occurs involve the functions of the kidneys and changes in the pH of the urine. Beyond that, what causes bladder stones in dogs and cats isn't exactly clear, but the following factors have been known to play a role. 

  • Genetics 
  • Diet and nutrition
  • Dehydration 
  • Frequency of urination 
  • Urinary tract infections 
  • Issues with metabolism 

When looking at the causes of bladder stones in dogs, diet is commonly recognized as one of the leading factors along with their daily water intake.  

Types of bladder stones in dogs and cats

The type of bladder stones a dog or cat develops depends on the minerals present in their urine, the pH level and other factors. Certain types of stones are more common than others.  

  • Struvite These stones are made up of ammonium and are the most common type of bladder stone in female dogs. Miniature Schnauzers, Miniature Poodles, Bichon Frises and Cocker Spaniels tend to be the most susceptible breeds.  
  • Calcium oxalate These stones are made up of calcium and are the most common in male dogs and cats.  
  • Ammonium urate These stones are made up of uric acid and can occur in dogs whose livers aren't properly cleaning the blood. They're most common in Dalmatians because the breed lacks a specific enzyme needed to clear uric acid from the blood.  
  • Cystine These stones can occur as the result of a genetic disorder and are common in male Dachshunds.  
  • Silicate These stones may be caused by foods that are high in silicates. They occur most often in Golden Retrievers, Labrador Retrievers and German Shepherds.  

Diagnosis of bladder stones

If you notice any symptoms of bladder stones in your dog or cat, take them to the vet as soon as possible. By the time your pet shows symptoms, they may be approaching an emergency.  

Your veterinarian will ask questions about your pet’s clinical symptoms and their history of urinary issues. They may palpate your pet's abdomen to feel for larger stonesy. They will likely use an abdominal X-ray as the first diagnostic tool because many stones can appear on an X-ray. Certain types of bladder stones in dogs and cats—like cystine and urate stones—and smaller stones, however, may not.  

If nothing appears on the X-ray but your vet still suspects bladder stones, the next step will usually be to take contrast X-rays or perform an ultrasound. These are more reliable and comprehensive ways to diagnose bladder stones.  

Treatment of bladder stones in dogs and cats

Treatment for your pet's bladder stones will depend on the size or the stones and if your pet is in danger of suffering a blockage. Here are six options you may be presented with when you bring your pet to your neighborhood Petco Pet Hospital.  

Diet for bladder stones in dogs and cats For smaller stones caught early, special diets may help. These diets can increase thirst, and the extra water dilutes the urine and helps dissolve the obstruction. Diets for bladder stones in dogs and cats are typically strict and include limits on treats and bones. Results may not be apparent for three to four months.

Hydropulsion For small stones, hydropulsion may be your vet's first recommendation. In this nonsurgical procedure, which is effective for female pets only, the bladder is filled with saline and squeezed to force out the stones.  

Urohydropropulsion Your vet may be able to put a catheter into the bladder and flush the stones out through a process called urohydropropulsion. This is most effective for removing small stones. While it's a nonsurgical option, your pet will need to be under general anesthesia.  

Cystotomy Cystotomy is the most common form of surgery for bladder stones in dogs and cats. Your vet will open the bladder and take out the stones. While it sounds complex, it's a relatively routine surgery for most vets, and your pet should recover quickly.  

Laparoscopy Laparoscopy isn't as common as cystotomy, so your veterinarian may or may not have the resources to offer this type of surgery. A small incision is made and a laparoscope is inserted to allow the surgeon to see inside the body in a minimally invasive way. They can then remove the stones and also examine the bladder.  

Ultrasonic dissolution Ultrasonic dissolution uses high-frequency ultrasound to break up the stones, which are then expelled from the bladder during urination. This is the most effective and immediate option for removing bladder stones in dogs and cats, but it's an advanced technique that isn’t commonly available.  

No matter which option you and your vet choose, it's important that your veterinarian analyze the stones to determine what minerals make up the obstruction. This can tell them about the causes of the bladder stones in your dog or cats and the treatment method they should use. 

Prognosis for Bladder Stones

How long a pet can live with bladder stones depends on the stones’ type and size. If there is no obstruction or infection, your dog or cat may feel fine and may be able to pass the stones naturally in their urine.  

Problems typically occur when there is an obstruction of the urethra. A partial obstruction can result in the symptoms of bladder stones in dogs and cats discussed above. A total obstruction—when your dog or cat cannot urinate at all—is a medical emergency because the bladder may rupture. Bladder stone obstructions are more common in male cats due to the diameter of their urethra, which is smaller than in females, and in male dogs due to the length of their urethra, which is longer than in females.

Once bladder stones are removed, symptoms will typically diminish as long as pet parents follow preventive measures like special diets and ensuring their pet stays hydrated. However, bladder stones still may recur, especially in certain breeds that are prone to them.  

Preventing Bladder Stones

When stones are removed during surgery, they are sent to a lab to be analyzed. Once your vet knows their composition, they can recommend medication or a special diet to help keep them from recurring. If you don't make an effort to remedy the causes of the bladder stones, they will likely recur.  

The most important thing you can do to prevent future bladder stones is to ensure your pet drinks enough water. Water dilutes the urine and can help prevent the buildup of compounds that commonly cause stones. You can have your pet's urine occasionally tested to determine if they're hydrating enough and confirman infection isn’t causing the stones. 

Poor diet and nutrition are two of the leading causes of bladder stones in dogs and cats. Diets with reduced amounts of certain minerals—like phosphorus and magnesium—and that are lower in protein are common solutions, although their effectiveness can depend on the type of stone. The right balance of calcium can be vital, as too much or too little calcium in the diet can contribute to the formation of stones.  

Because the causes, treatments and prevention of stones can vary greatly, you should follow the guidance of your veterinarian when it comes to bladder stones in dogs and cats. With the right plan, you can remedy any existing issues and prevent future occurrences. 

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Reviewed by Dr. Whitney Miller, DVM, MBA, DACVPM

As Petco’s Chief Veterinarian, Dr. Miller is the lead veterinary subject matter expert, overseeing the company’s standards of excellence in animal care and welfare, growth in pet services and much more. Dr. Miller leads Petco’s medical team, supporting over 200 full-service hospitals and mobile vaccination clinics operating in over 1,000 Petco Pet Care Centers nationwide