Canine Bladder Stones

These smooth whitish rocks were removed from the bladder of a very nice Rottweiler today.  Bladder urolithiasis (aka bladder stones) is a common condition seen in many practices.  A dog with urolithiasis will exhibit some or all of the following symptoms: frequent urination (often in unusual places), bloody urine, dribbling urine, straining, weakness, depression, loss of appetite, vomiting and pain. If your pet has any of these symptoms, you should contact your veterinarian immediately. In some cases without appropriate diagnosis and treatment, your dog could face a life threatening situation. Stones can block the urine flow, prevent elimination of poisonous wastes and cause death. It is important to know that not every dog with canine urolithiasis exhibits all of these symptoms.

The most common question a pet owner asks me is how do they get there and what can be done to prevent them. There is no single cause of canine urolithiasis. Yet, there are a number of important factors. 

• Age: Urolithiasis may appear in your dog when it is less than two months old, but most stones occur in dogs two to ten years of age.
• Sex: Urolithiasis appears to occur with equal frequency in adults of both sexes. However, because the urethra of the male is longer and narrower than the female's, urethral obstruction is more common in males.
• Breed: Small breeds, including the Welsh Corgi, Miniature Schnauzer, Pug, Lhasa Apso, Pekingese and Yorkshire Terrier are more commonly affected than are large breeds. The Beagle, Dachshund, Dalmatian, Bulldog, Basset Hounds, Cairn Terrier and Scottish Terrier are also susceptible.
• Confinement and Exercise: Infrequent urination, as a result of confinement, lack of regular exercise, or low water intake, contribute to the formation of crystals and uroliths.
• Diet: High levels of some minerals in the diet, such as magnesium, phosphorus, and sometimes calcium, have been directly linked to canine urinary bladder stone formation. A diet with excess protein can also contribute to stone formation.

Normal dog urine is slightly acidic and contains wastes from metabolism, including mineral salts and other compounds.  If the urine becomes exceptionally concentrated or if it becomes too alkaline, mineral crystals can precipitate and the beginnings of a stone is born.  Next comes a bladder infection, caused by bacteria, that produce an enzyme known as urease.  This enzyme breaks down urea present in the bladder and causes an excess production of ammonia, which in turn causes the urine to become more alkaline.  Ammonia in the urine also causes bladder inflammation.  Inflammation, bacteria and crystals continue to build on each other until a small grain of sand becomes a boulder.  

How does your veterinarian diagnose bladder stones?  They may perform some or all of these diagnostic tests: abdominal palpation, to feel stones present in the urinary bladder; urinalysis, to determine the types of crystals present; urine culture with antibiotic sensitivity, to determine if bacteria are present in the urinary tract and the appropriate antibiotic with which to treat these bacteria; and radiographic examination (possibly with contrast media), to see if stones are present and their location in the urinary tract and ultrasound. To evaluate how well your pet is responding to therapy, your veterinarian may periodically repeat some of these tests. Therefore, you will need to bring your pet in for rechecks as directed by your veterinarian.

How are bladder stones treated?   If the urinary tract is blocked, your veterinarian will have to correct the blockage and empty the dogs urinary bladder. Then, your dog will be further examined to determine the stone type and appropriate therapy. Your pet may need to stay at the hospital during this process. In the past, urinary bladder stones have been surgically removed and for some stones, surgery may be the only effective treatment. But for some stones, there is an alternative. In some cases, stones may be dissolved by feeding a special diet with reduced amounts of certain minerals and protein, or a special diet plus medication. If an infection is present, antibiotics are also necessary. Special diets work by reducing the mineral building blocks or urinary stones in the urine. These diets affect the urine pH and increase urination to help flush the urinary tract.

A pound of prevention is worth a ton of cure.  Of dogs treated for urolithiasis, 20 to 50 percent will have a recurrence of the problem and accompanying pain if preventive measures are not taken.  First of all I recommend that you feed a good quality balance dog food (Old Roy, does not qualify).  While top of the line dog foods may cost slightly more than 'generic' dog foods, in the long run your pet will be better for it.  Be sure your pet is has lots of fresh water, change the bowl daily.  Take your dog out frequently for 'potty' breaks, having to hold their urine for hours on end leads to more concentrated urine.  Provide your dogs with lots of good exercise, a trim and fit dog is healthier.  Limit or avoid human foods.  Dog foods are especially balanced for your pets needs.  The addition of human food not only adds unnecessary added calories, but can also alter your pet's urine pH, predisposing it to crystal formation.  If you have a pet that is over 5-6 years of age, consider allowing your veterinarian to perform a urine analysis annually as part of your pet's annual wellness visit.  This test may give your veterinarian a clue of impending problems.  Lastly, go outside with your dog when they go for a 'potty' break.  If you are not there, you will not be able to observe if your dog is having problems, such as blood in urine or difficulty in urinating.  You will want to be especially observant if you have one of the breeds of dogs that have a genetic tendency to stone formation.  

Parting advise, talk with your veterinarian about any concerns you have about your pet and it's health.  Veterinarians love to educate their clients and help you to make good sound decisions about your pet's health care.