Urinary Stones And Crystals

by Vickie Halstead RN, CVNS, CCRN, CEN

Bladder stones (uroliths) plague almost all breeds of dogs, but are more prevalent in some breeds including Bichons, being the #4 disease for the breed. Stones develop due to an excess of some mineral that solidifies in the bladder, rarely in the kidneys. These stones must be dissolved or removed, may pass out with the urine via the urethra, may lodge in the urethra, or may remain in the bladder. Stones can recur at a rate of about 30-50% if vigilant preventive measures are not followed. The presence of crystals in the urine upon examination is a precursor to developing stones. Crystals and/or stones irritate the lining of the urinary tract, causing pain and blood in the urine and possibly obstruction of urine flow. The most common signs are frequent urination, straining with urination, and licking the genital area. There are several types of stones determined by their composition. The most common type of stones found in Bichons are Struvite and Calcium Oxalate.

For additional information, read the articles on our web site www.bichonhealth.org on urinary stones under the heading Kidneys/Bladder, where you will also find the Powerpoint slides from a presentation in May of 2010 at the Bichon national specialty by Dr. Jessica Clemens.

If your Bichon is diagnosed with bladder stones, you must discern from your veterinarian which type of stone your dog has in order to properly treat and prevent future stones. Either type of stone can be visualized on an x-ray. If a stone is removed or is passed, it can be analyzed to determine its consistency. The presence of crystals in the urine is a precursor to developing stones, allowing actions to prevent formation of stones. However, you need to know which type of crystals is present to determine the proper treatment.

In the past the BFCA health committee has encouraged breeders to test the urine prior to breeding because it reflects the status of several organs of the body-diabetes, kidney disease, liver disease, dehydration, bladder infection, and blood caused by stones. Not only do the presence of struvite or oxalate crystals indicate that stones may develop, but the presence of urate crystals in the urine provides early detection of liver shunt, a genetic disease that is prevalent in Bichons. When your veterinarian evaluates a urine specimen from your dog, ask for the routine urinalysis plus the urine sediment evaluation for detection of struvite, oxalate and urate crystals.

To obtain a urine sample that will provide accurate testing, collect it in a clean and dry container and deliver to the veterinarian immediately if possible. If not, refrigerate the sample but do not freeze. Collect urine by using a pie plate or soup ladle as the dog urinates. If a sterile sample is needed, your veterinarian can use a small needle to obtain the specimen by accessing the bladder through the abdominal wall, or use a catheter.

Struvite stones/crystals are not considered to be hereditary, are usually caused by bladder infections, and are more common in females. However, the high incidence of these stones in some breeds of dogs, including Bichons, suggests a familial tendency, meaning that some breeds have a genetic predisposition to developing urinary tract infections. Signs of bladder infection include urinating more often with accidents in the house, pain with urination, blood in the urine (red or pink tinged) and the urine has a strong odor.

The urine needs to be acidic (pH < 7.0) to prevent struvite stones from developing, to dissolve existing stones, to eradicate crystals, and to fight the growth of bacteria. Your vet will put your dog on a special diet to help acidify the urine. Also, giving Vitamin C supplements will help acidify the urine and prevent bladder infections. I recommend 1000 mg. per day divided in 2 doses with meals, but start gradually to prevent diarrhea. You can find Vitamin C crystals (powdered) at health food stores or online. Another theory is to give the amino acid DL Methionine, which is contained in supplements that help reduce the pH of the urine and may also prevent yellow nitrogen burns to the grass from urine. In addition, some dog food companies make multivitamin supplements that can alter the pH of the urine. Lastly, adding apple cider vinegar to drinking water helps to acidify the urine and treat early bladder infections.

A bladder infection is the cause of the struvite crystals or stones, so the infection must be treated aggressively with the correct antibiotic. If your veterinarian analyzes a urine sample and finds no signs of infection, then further testing is needed to find the bladder infection, which does exist. This is accomplished by obtaining a sterile sample via a guided needle into the bladder through the wall of the abdomen that can be done without sedation. This sample is sent out to a laboratory that will do a culture to find out what bacteria are present, and a sensitivity to determine which antibiotic will kill the particular bacteria present in the urine. The results will be available in 3-4 days. If the bladder infection is not cured, the crystals will return or persist, and eventually develop into stones. The urine and surface of a stone may be sterile after a short run of antibiotics, however bacteria may reside below the surface of the stone if the incorrect antibiotic is prescribed.

To prevent future bladder infections, which can also lead to kidney damage and struvite stones or crystals:

  1. Keep the vulva or penis clean and clear of hair, and don’t allow your dog to urinate in dirty areas.
  2. Allow the dog plenty of opportunities to urinate. Holding urine for long periods stimulates the growth of bacteria and struvite.
  3. Encourage fluid intake by keeping fresh water (not softened) available at all times and feed a moist food (> 80% moisture) or the raw diet. Adequate hydration will help flush crystals and bacteria out of the kidneys and bladder.
  4. Give Vitamin C 1000 mg per day, which improves immunity and makes urine acidic. Start with 250 mg. per day, gradually increasing the dose to prevent diarrhea. There is a product that is a combination of cranberry and Vitamin C that is available online.
  5. Provide an optimal diet of either raw or home cooked foods with supplements that include a multiple vitamin, fish oil, cranberry juice capsules, and probiotics to support the immune system.
  6. Add apple cider vinegar 1 tbsp. to each gallon of drinking water if you see any early signs of possible bladder infection.
  7. Some dogs respond to ½ tsp. of D-Mannose daily, a simple sugar that helps fight urinary tract infections and can be found online.

In most cases Vitamin C, apple cider vinegar added to drinking water, vigorous treatment of the bladder infection with the correct antibiotic, optimal hydration, and temporarily a prescription diet (makes the urine more acid and pulls more fluid through the kidneys) will dissolve struvite stones preventing the need for surgery. In my experience, once struvite stones/crystals are resolved there is no need to stay on the presciption diet, but you must continue the Vitamin C, keep the dog well hydrated and strive to prevent bladder infections. Do not give Vitamin C to dogs with calcium oxalate stones.

Calcium oxalate stones/crystals are more common in males and are hereditary, so please alert your breeder. However, the diet and water provided can contribute to the development of these stones, i.e. a diet high in calcium, inadequate intake of water, and giving water from garden hoses or softened water from the faucet. The genetic cause of calcium oxalate stones is a lack of an enzyme to process oxalates, which are the product of metabolizing some foods and are produced by the liver. Oxalates do not circulate freely in the body, so they have to combine with other ions in the blood such as sodium or calcium to prevent excretion out of the body via the urine. If the calcium level is high, the oxalate will combine with the calcium, forming an insoluble crystal that can grow into a stone. If the crystals develop into stones that are too large to pass they may need to be removed surgically, since they cannot be dissolved. Reduced serum vitamin B6 concentrations may prove to be a risk factor for development of Calcium oxalate urinary stones.

To prevent recurrence of calcium oxalate stones, a special diet and Potassium Citrate prescribed by your vet is needed to keep the urine alkaline (pH > 7.0), as well as avoiding Vitamin C that will acidify the urine. Your vet will put your dog on a special diet to maintain alkaline urine and add moisture to the diet. In addition, calcium supplements and several foods must be avoided: salmon, bologna, sardines, dairy products, spinach, broccoli, beans, tofu, asparagus, celery, corn, tomatoes, green peppers, green beans, squash, berries sweet potatoes, oranges, apples, peaches, pears, pineapples, citrus peel, nuts, wheat germ (see this article on our web site bichonhealth.org/HealthInfo/UrinaryStones.htm). Serum levels of vitamin B6 should be monitored to determine if supplementation is needed. Ongoing research at the University of Minnesota reflects that recurrence is more prevalent in Bichons with high urine and/or blood calcium levels. Your veterinarian may consider the drug Hydrochlorothiazide if the stones are highly recurrent without high calcium levels.

Combinations of struvite and calcium oxalate stones have been found in some Bichons. First the dog develops a small calcium oxalate stone, which then becomes encased with struvite during a bladder infection. In this case the infection must be treated, and then use treatment for calcium oxalate stones since that is the origin of the stone.

Water:  What your dog drinks can play a part in developing either type of stone. Optimal water is reverse-osmosis filtered hard water. Avoid water from the garden hose or softened water from the sink faucet–it contains salt and can contribute toward calcium oxalate stones. Assuring that your dog drinks adequate volumes of water is key to prevention and treatment of bladder stones. Place water bowls in several strategic areas of your home. Keep the water fresh and cool to improve the taste. Ceramic bowls keep the water cooler longer. Also, provide a high moisture diet (>80% moisture). Add water to each meal.

Diets:  Most vets prescribe Hills CD diets for dogs with stones, but in my opinion there are better alternatives. We have received reports of Bichons with reactions to this food, and the ingredients are poor. Solid Gold has a good food for struvite stones called Berry Balance, and Royal Canin makes a food called Urinary SO with better ingredients than Hills. I strongly recommend a holistic veterinarian to treat a dog with stones. Some recommend a Chinese herb and Saw Palmetto to help pass the stones. Also, research supports giving lemon juice and pedialyte daily to reduce calcium oxalate stone formation.

To find a holistic veterinarian:  www.ahvma.org/Widgets/FindVet.html

Websites with good information on calcium oxalate stones and diet changes:
Read this detailed article about struvite stones from the stone expert, Dr. Osborne: