Like humans, dogs can suffer from bladder stones. This is known as canine urolithiasis. In this condition, the urine can be either too acidic or too alkaline, which causes excessive amounts of tiny crystals to form in the urinary tract. Urolith formation can also occur when there is a high urine concentration of salts or urine retention; it can also be the focus of infection on which crystallization can occur. When left untreated, these crystals become enlarged and can form stones.
Stones are usually formed in the dog's bladder, but they can also form in the kidney or the urethra. Crystals cause urinary tract irritation and pain during urination. When too many crystals or a small stone becomes lodged in the dog's penis, they can painfully block the stream of urine and prevent the dog from urinating. While females may form crystals too, they easily pass because of their anatomy and do not cause a problem.
There are several types of stones, but the only way to determine what kind your dog suffers from is to retrieve a stone and have a laboratory analyze it. If the stones are very small they can be flushed from the bladder and forcefully expressed. The only other way to obtain a sample is to surgically open the bladder and remove the stones. Surgery is invasive but quickly removes the stones, while catheterization is less invasive but often less effective or not possible.
Struvite stones can form when there is a bladder infection or if the pH of the urine is consistently alkaline. The crystal form is composed of magnesium, ammonium, and phosphate. Struvite crystals can be found in normal urine and are not a problem unless they are present in very large amounts, cause discomfort, or form stones.
Some Dalmatians are prone to developing uric acid stones in the kidneys or bladder because of their unique uric acid metabolism. These dogs should eat a well-balanced, low-protein diet. They should avoid stress and purines (organic compounds contained in meat and especially organs), drink plenty of fresh water, and be taken outside to urinate once every three hours during waking hours.
Nearly 85 percent of patients with struvite bladder stones are females. Bichon Frises, Cocker Spaniels, Beagles, Miniature Schnauzers, Miniature Poodles, and English Cocker Spaniels are prone to forming these stones. Most dogs first develop them when they are around three years of age.
Oxalate stones need an acidic pH to form. Calcium oxalate stones cannot dissolve over time; diet change does not work as it does with struvite or uric acid bladder stones. After stones are removed either through surgery or catheterization, the focus is on lifelong prevention by maintaining a balanced pH and minimizing the amount of protein in the diet.
The breeds that are prone to developing calcium oxalate stones are Miniature Schnauzers, Lhasa Apsos, Yorkshire Terriers, Miniature Poodles, Shih Tzus, and Bichon Frises. Most cases of these stones develop in dogs between the ages of five and twelve years of age.
Attempting to dissolve existing stones is risky because they can become lodged in the urethra and cause a life-threatening urinary blockage. This is especially true in male dogs due to their anatomy. If you notice signs of a blockage, immediately contact your vet. Be on the lookout for increased frequency of urination, straining to urinate without producing any urine, reduced volume of urine, or blood in the urine.
Dogs with kidney disease need a diet that restricts the amount of protein, phosphorus, and sodium. A diet low in phosphorus may help slow the progression of kidney failure by reducing mineral deposits. Dogs with stones should not have additional vitamin C or excess salt in their diets.
Dietary management and prevention of urinary tract infections is key to helping your dog avoid urinary stones.