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Monday, February 22, 2010

HEALTH BEAT: Management of Bichons with Urinary Stones

Management of Bichons with Urinary Stones

It has long been recognized that some Bichons Frises have a predisposition to formation of urinary stones (uroliths). This condition is known as urolithiasis. There are several types of stones that can form in the bladder, with struvite (also called magnesium triple phosphate or "infection" stones) and calcium oxalate being the most common in Bichons. The most important preventative for stone formation is free access to fresh water. For a dog predisposed to stone formation, there are other considerations as well. This article is intended to provide the pet owner with a better understanding of the prevention and treatment of urinary stones. Good veterinary treatment is the most reliable resource for the ongoing care of your dog. You may wish to copy this article for your veterinarian.

The Bichon Frise Club of America, Inc. sought input from Carl A Osborne DVM, PhD in preparing this material. Dr. Osborne, Professor at the College of Veterinary Medicine, University of Minnesota, is considered a leading authority on canine uroliths. We are grateful to him and to his team at the Minnesota Urolith Center for their assistance in making this information available. For more information, you and your veterinarian will be aided by the book "The ROCKet Science of Canine Uroliths". You will find details in the article below.

And now, please carefully read the following article, prepared by Dr. Osborne and his staff. At the end of the article, there are several paragraphs about Bichon health that need to be considered as a part of the total picture in treating Bichons with bladder infections and stones.

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BLADDER STONES IN THE BICHON FRISE

The Bichon Frise appears to be at increased risk for some types of bladder stones (or uroliths). In medical terminology, this condition is called urolithiasis (uro = Greek meaning urine, lith = Greek meaning stone, iasis = a process or condition).

What are uroliths?

Several different minerals can form stones within the urinary tract of dogs, including magnesium ammonium phosphate (struvite), calcium oxalate, ammonium urate, cystine, calcium phosphate and others. In uroliths, these minerals may occur singly or in combination.

Key Point: Knowledge of the mineral type(s) comprising the stones is recommended to determine the best treatment and preventative therapy.

Currently the two most common minerals found in uroliths formed by the Bichon are magnesium ammonium phosphate (struvite) and calcium oxalate. In the past decade, an increased occurrence of calcium oxalate urolithiasis has been recognized in several breeds of dogs and several breeds of cats. The causes associated with this increased occurrence of calcium oxalate uroliths are currently under investigation. To date, studies indicate that multiple genetic, environmental, dietary and drug related factors may be involved.

Of the uroliths submitted in 1998 to the Minnesota Urolith Center for analysis from the Bichon Frise breed, 51% were struvite, 37% were calcium oxalate and the remaining 22% were composed of other minerals. Calcium oxalate is more likely to form in males, struvite is more likely to form in females. In a recent survey of the Minnesota Urolith Center database, 10% of male Bichons formed struvite uroliths, 80% of male Bichons formed calcium oxalate uroliths. Conversely, 50% of female Bichons formed struvite uroliths, 36% of female Bichons formed calcium oxalate uroliths. These percentages refer to stones removed from Bichons and therefore they do not apply to all Bichons.

Key Point: Calcium oxalate uroliths are increasing in occurrence. Multiple factors are associated with this change in prevalence of mineral types in stones and studies are underway to identify risk factors.

Struvite uroliths

In dogs, struvite uroliths are primarily associated with a diagnosis of infections caused by urease producing bacteria. Although other factors may predispose a dog to struvite uroliths, bacterial infections with staphylococcus and other urease producing pathogens are clearly the most important. Once a diagnosis of struvite uroliths has been made, at least 3 therapeutic options are present.

    1. Medical and dietary dissolution of uroliths
    2. Non-surgical procedures for removal of uroliths
    3. Surgical removal of uroliths
  1. Medical and dietary dissolution consists of feeding a special diet, available from veterinarians, along with treatment with an appropriate antibiotic. Your veterinarian will perform a urine culture to determine which antibiotic will most likely be effective in treating the infection. These antibiotics should be administered until the stones are completely dissolved. The time required for medical dissolution is dependent on the number and size of the stones and compliance with dietary and antimicrobial treatment by the owner. Some have been dissolved within a few weeks, whereas others may require up to 2 months or more.
  2. Non-surgical procedures have been developed to remove stones small enough to pass through the urethra. Best results may be obtained from veterinarians who have experience with these techniques.
  3. Surgery consists of removal of uroliths from the urinary tract.

Once struvite uroliths are dissolved medically or removed surgically, prevention of the urinary tract infection will prevent recurrence. Prevention of urinary tract infections may require periodic urinalysis and urine culture. Periodic radiographs (i.e. x-rays) may also be indicated. Antibiotics and/or a diet designed to lower urine pH and restrict certain minerals may be recommended on the basis of these test results.

Key Point: If the infection can be eradicated, struvite uroliths will not form or recur even if secondary factors persist.

What about water sources?

In a case-controlled epidemiological study performed at the University of Minnesota,

the source of water ingested was not found to be a risk factor for formation of calcium oxalate

uroliths. However, the volume of water ingested usually plays a significant role.

By increasing water consumption, the urine concentration of urolith-inducing constituents

will be decreased or diluted.

We highly recommend feeding a canned diet and providing ready

access to fresh water at all times to increase water consumption and urine voiding.

Both of these goals decrease the risk factors for urolith formation.

What about pH testing?

Ask your veterinarian about testing urine pH at home. Struvite uroliths tend to occur in alkaline urine. Calcium uroliths are associated with acid urine.

What about collecting urine samples?

Urinalysis is an important part of preventative therapy. Because external factors such as temperature, delay in sample analysis, evaporation of the sample, contaminated collection container, contaminants from hair or skin, and other factors may affect the urine, urine samples should be collected (preferably by the veterinarian) and evaluated as soon as possible.

Samples may also be collected at the veterinary hospital by a procedure called "cystocentesis". A sterile needle is inserted into the bladder and a urine sample is withdrawn into a sterile syringe. This is the preferred method for collecting a urine sample for culture. Identification of crystalline material is best performed at the veterinary hospital.

Screening samples may be collected by the owner using a clean cup or container. These samples should be capped, labeled with the date and time collected, and taken promptly to your veterinarian for evaluation.

Key Point: For best results, fresh urine samples should be analyzed.

What about analysis of stones?

Any stones that are removed surgically or voided during urination should be evaluated by quantitative methods of analysis. Proper analysis of the uroliths is vital to successful treatment. Unfortunately most veterinary laboratories perform qualitative analysis which is a highly unreliable test.

Key Point: Have uroliths analyzed by quantitative analysis.

Veterinary laboratories qualified to perform quantitative analysis are:

Minnesota Urolith Center
Dr. Carl Osborne DVM, PhD, Director
Department of Small Animal Clinical Sciences
College of Veterinary Medicine
University of Minnesota
1352 Boyd Avenue
St. Paul, MN 55108
Lab Phone 612/625-4221

Urinary Stone Analysis Laboratory
Gerald V. Ling PhD, Director
College Of Veterinary Medicine
University of California-Davis
Davis, CA 95616
Lab Phone 530/752-3228

Where can my veterinarian get more information?

The Veterinary Clinics of North America – Small Animal Practice

"The ROCKet Science of Canine Urolithiasis"
Volume 29:1
January 1999
(Available from W. B. Saunders Publishing Company
Phone 800/654-2452)


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