Bladder Stones in Dogs
Types and How They Form

Bladder stones in dogs (also referred to as uroliths or calculi) are increasingly common, and can affect both male and female dogs of all breeds and all ages.

In many cases canine bladder stones may never cause any symptoms, and may only be detected by chance during a routine veterinarian examination.

In other cases, however, bladder stones in dogs can often cause excruciating pain and life threatening consequences. The most dangerous outcome is when a dog bladder stone becomes lodged in its urethra, preventing the dog from passing urine. This can result in illnesses such as uremic poisoning, acute canine renal failure, hyperkalemia, or septicemia - which can prove to be fatal if not treated as a medical emergency.

In the following article, we give an overview of:

• How Canine Bladder Stones Form
• Types of Bladder Stones in Dogs
• Causes
• Symptoms
• Diagnosis
• Treatment

We will also examine in detail the role of dog food and diet for canine bladder stones. This includes prescription dog food or other vet recommended dog food, homemade dog food recipes, and natural supplements for the treatment and prevention of canine bladder stones.

How Canine Bladder Stones Form

A canine bladder stone forms when microscopic crystals accumulate and unite in the dog's urinary tract system.

Struvite crystals found microscopically in a urinalysis of a dog with a bladder infection.

A diagnosis of crystals in your dog's urine may be of concern if:

• Your dog has a history of urinary stones;
• Your dog presently has a urinary tract infection, or has a history of UTIs;
• Your dog is susceptible to other causes of canine bladder stones.

It is important to understand, however, that it is not uncommon for a healthy dog to be diagnosed with crystals, and these findings are considered perfectly normal and harmless.

Additionally, crystals may form in urine within 30 minutes after collection, creating a false positive, so it's important that testing is done promptly.

As per Narda Robinson, DO, DVM, "Dispelling Myths About CaOx Uroliths, Veterinary Practice News - "Individuals may excrete millions of urinary crystals daily without producing stones. Fluids flushing the urinary tract counter the supersaturation of stone-forming solutes. Ensuring regular intake of clean, fresh water serves as the primary prevention strategy."

According to Patricia Schenck & D.J. Chew from the book: Home-Prepared Dog and Cat Diets - ”The frequency of bladder stones in dogs is not high enough to justify dietary modification before a stone forms, and treatment of crystalluria is unnecessary in dogs that have never formed a urolith”.

Types of Bladder Stones in Dogs

The two most common types of canine bladder stones are Struvite and Calcium Oxalate Stones.

Struvite Bladder Stones in Dogs

Struvite urinary stones (comprised of struvite crystals - aka magnesium, ammonium, phosphate) are one of the most prevalent bladder stones in dogs.

Struvite stones removed from
a dog's urinary bladder.

Although these canine bladder stones can afflict all dogs, those at significantly greater risk appear to be smaller female dogs between four and eight years of age, who are prone to canine bladder infections.

Breeds of dogs most susceptible to forming struvite bladder stones appear to be mixed breeds, Miniature Schnauzers, Shih Tzus, Bichon Frise, Cocker Spaniels and Lhasa Apsos.

Calcium Oxalate (CaOx) Bladder Stones in Dogs

Calcium oxalate stones found in the
urinary bladder of a dog.
(Photos by Joel Mills (own work) via Wikipedia)

Calcium oxalate stones (comprised of calcium oxalate crystals - CaOx) are also very common in dogs and their occurence has been steadily increasing over the past several years.

Unlike struvite stones, calcium oxalate bladder stones occur significantly more frequently in male dogs, and do not appear to be associated with urinary tract infection in dogs.

Although CaOx dog bladder stones can affect all breeds, those most predisposed are Miniature Schnauzers, Lhasa Apsos, Yorkshire Terriers, Bichon Frise, Shih Tzus, and Miniature Poodles between two and ten years of age.

The Bichon Frise appears to be particularly prone to recurring oxalate bladder stones, and they often seem to have a recurrence within the first year after surgery.

Less Common Dog Bladder Stones

Other - far less common - bladder stones in dogs are:

• Urate Stones are found mainly in older male Dalmatians and to a lesser degree in English Bulldogs and Yorkshire Terriers.
• Cystine Stones form due to a genetic defect that causes excess cystine in the urine. Signs of cystine calculi typically do not appear before 3 to 5 years of age, and the recurence rate is high.
• Calcium Phosphate Stone, and
• Silica Stones.

Additionally, bladder stones in dogs can consist of a core of one or more minerals surrounded by outer layers of different ingredients. They also may not even be comprised of the same crystals that may have been identified in your dog's urinalysis.

The only way to determine the type of your dog's bladder stone is to analyze a sample that has either passed naturally or been removed via surgery.

Although much less common, a dog can also form stones and crystals in other parts of its urinary tract including the kidney or urethra. Kidney stones in dogs (nephroliths) generally do not cause significant disease but, in some circumstances, they can lead to pyelonephritis (a bacterial infection of the dog's upper urinary tract and kidney) and chronic renal failure in dogs.

CONTINUE:

• Canine Bladder Stones - Causes, Sytmptoms, Diagnosis and Treatment
• More on Bladder Stones in Dogs - Types and How They Form
• Canine Urinary Tract Infection - Causes, Symptoms and Treatment
• Dog Bladder Infection - At Home Prevention Tips for Dog Urinary Problems - Prevent and Avoid Recurrence (Coming Soon)
• Canine Bladder Stones Prevention - Prescription Dog Food, Homemade Dog Food Recipes, Natural Dog Supplements and Other Home Care Tips (Coming Soon)
• Canine Kidney Failure Symptoms - Renal Failure in Dogs and Renal Dog Food Diets
• Low Protein Dog Food - Unlike high protein dog food, reduced protein dog foods are usually only indicated as a treatment aid for various dog health problems