What Types of Bladder Stones Are There, Part 2/2

What types of Bladder stones are there? First lets start with struvite!

Struvite bladder stones. What does that mean?

One of the more common urolith in the dog is composed of magnesium ammonium phosphate hexahydrate “struvite”.

How did my dog get them?

Struvite is a normal component of dog’s urine and will remain dissolved as long as the urine is acidic and is not too concentrated.  Female dogs tend to get these types of bladder infections and stones much more frequently than males, probably because their shorter, wider urethra makes it easier for bacteria to pass up the urethra into the bladder.

Other causes of alkaline urine such as certain kidney diseases, long-term use of diuretic drugs or antacids, and other conditions that cause elevated urine pH or elevated levels of urinary phosphorus or ammonia can also predispose a dog to the formation of struvite bladder stones.

How common are struvite bladder stones?

Bladder stones are somewhat common in dogs, and struvite stones are the most common; in clinical studies, up to 26% of all bladder stones were found to contain struvite. Together, struvite and calcium oxalate uroliths have been found to comprise over 85% of all uroliths submitted for laboratory analysis in a recent study.  Struvite uroliths were noted to be more common in female dogs and calcium oxalate uroliths in male dogs. Breeds most commonly diagnosed with struvite and calcium oxalate bladder stones included: shih tzu, miniature schnauzer, bichon frisé, lhasa apso, and Yorkshire terrier.

What causes calcium oxalate bladder stones to form?

Current research indicates that urine high in calcium, citrates, or oxalates and is acidic predisposes a pet to developing calcium oxalate urinary crystals and stones. Recent studies have shown diets that cause high urine acidity ( urine pH less than 6.5), may predispose dogs to develop this type of bladder stone.

There are likely other causes of calcium oxalate bladder stones. Over-usage of antibiotics may reduce numbers of the intestinal bacteria Oxalobacter formigenes whose sole nutrient is oxalate. In dogs with low populations of Oxalobacter, excess oxalate is secreted in the urine, increasing the likelihood that  calcium oxalate crystals and stones can form if the urine is highly concentrated or becomes acidic.

How did my dog develop cystine bladder stones?

Cystine bladder stones appear to be the result of a genetic abnormality that prevents a dog from reabsorbing cystine from the kidneys.  This condition is believed to be inherited in dogs and more often in males

How common are cystine bladder stones?

While bladder stones in general are somewhat common in dogs, cystine bladder stones are rare. Cystine uroliths were most commonly diagnosed in male dogs (98%) while only 2% of the dogs  diagnosed with cystine bladder stones were female.

How did my dog develope urate bladder stones?

One of the most common uroliths in Dalmatians is composed of urate crystals. Urate bladder stones are most commonly the result of a genetic abnormality that causes a defect in the metabolism of uric acid.

Other causes of urate bladder stones include liver diseases such as portosystemic shunts. In these situations, urate bladder stones may form if the urine is highly acidic or becomes extremely concentrated. If urate bladder stones or crystals are diagnosed in a dog that is not a Dalmatian, the dog should be tested for the presence of a liver shunt.

How common are urate bladder stones?

Urate stones constitute only about 5% of all bladder stones diagnosed, according to recent studies. Breeds most commonly diagnosed with urate bladder stones include Dalmatians, English bulldogs, and Black Russian terriers. In these breeds, genetic testing should be performed prior to breeding to reduce the occurrence of this condition. Urate bladder stones are more common in male Dalmatians (97%) than females (3%).

 

By |September 21st, 2017|

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