Struvite stones in the canine urinary bladder are intimately linked with urinary tract infections (UTI). The treatment of canine urinary tract infections which are complicated by the presence of bladder stones is two-fold. The infection must be controlled with an appropriate antibiotic and the struvite stones must be either dissolved or removed from the urinary bladder.
Treating Urinary Tract Infections in Dogs in the Presence of Struvite Stones
The bacteria which are infecting the urinary tract of the dog with struvite stones are found not only in the urinary tract and urine but also are embedded in the structure of the struvite stones themselves. Therefore, as long as the stones are present in the bladder, the bacteria causing the urinary tract infection will also be present.
Staphylococcus and Proteus are most frequently the bacteria that cause struvite stones to form in the bladder of a dog. Less commonly, Escherichia coli and ureaplasma organisms are involved.
Antibiotics are the mainstay of treating bacterial urinary tract infections. However, an appropriate antibiotic should be chosen based on the results of a urine culture and sensitivity, which identifies the bacteria present and provides information about which antibiotics are most likely to be effective in killing or controlling the infecting bacteria.
The chosen antibiotic must be continued until the infection in the bladder is resolved and the length of time it will take for this to occur will vary depending on how the struvite stones themselves are managed.
Methods of Managing Struvite Bladder Stones in Dogs
There are three options which may be considered to manage canine struvite stones. These options include:
- a special diet which is designed to dissolve the bladder stones
- surgical removal of the stones from the bladder
- urohydropropulsion
Dietary Dissolution of Struvite Stones
Before dissolution of a struvite stone is attempted, it is important to document that urinary tract infection is present and determine which bacteria are causing the infection. Struvite stones are one of several different types of bladder stones dogs can develop and treatment for other types of stones, particularly in relation to dietary needs, is different than with struvite stones.
Diets most commonly used to dissolve struvite stones lower the blood urea nitrogen, the urine specific gravity and the pH of the urine, all of which can be monitored to ascertain that the diet is performing its desired function. Examples of commercial diets formulated to aid in dissolving struvite stones include Hill's Prescription Diet Canine S/D® and Royal Canin SO®. If electing a home-made diet, consultation with an expert in canine nutrition is recommended.
The length of time necessary to dissolve the struvite bladder stones will vary depending on the individual dog but may range from several weeks to several months. These diets are restrictive diets and are not recommended to be fed long-term. In most instances, dissolution diets should be fed no longer than 6 months.
Surgical Removal of Canine Struvite Bladder Stones
Struvite bladder stones can be removed surgically, assuming that the patient is an acceptable surgical candidate. Surgical removal of these stones involves making an incision into the urinary bladder from which the stones are retrieved, a surgery referred to as a cystotomy.
Surgical removal of the stones is beneficial in that the stones are removed immediately so that recovery can begin immediately as well. The stones removed from the bladder should be analyzed for composition to confirm that they are truly struvite stones and no other mineral components or layers are present. Stones should also be cultured for bacteria after removal.
Complications with cystotomy and bladder stone removal are rare but can occur.
Urohydropropulsion in Treating Struvite Bladder Stones in the Dog
Urohydropropulsion is a technique in which sterile water is used to fill the urinary bladder. The bladder is then manipulated so that the contents of the bladder are agitated. A high pressure stream of urine is generated after manipulation and agitation to encourage the stones to pass through the urethra.
Urohydropropulsion only works if the stones are small enough to pass through the urethra. In cases where numerous stones are present, numerous attempts at urohydropropulsion may be necessary. Even if not successful in removing all of the stones from the bladder, this procedure is often useful in collecting a sample stone which can then be analyzed to determine its mineral content and confirm that dietary dissolution is possible.
Recurrence of Struvite Bladder Stones and Canine UTI
Following removal or dissolution of the stones, it is important to prevent their recurrence. Antibiotics must be continued until the infection is completely cleared. In the presence of urinary tract infection, struvite stones can reform within weeks. Adequate monitoring of urinalysis and urine cultures is necessary to prevent recurrence, particularly in dogs which are predisposed to bladder infections.
Generally, specialized diets are not needed once the struvite stones have been removed or dissolved. Prevention hinges on controlling bacterial infections of the urinary tract. The only exception are very rare individuals suffering metabolic disease that predisposes them to develop struvite stones.
Struvite bladder stones in dogs almost always form in the presence of urinary tract infections. While there are several means of getting rid of canine bladder stones, the most important part of treatment for struvite stones is controlling the infection which caused them to form.
Join the Conversation