Struvite: The Less Common Type of Kidney Stone

Struvite: The Less Common Type of Kidney Stone

The Struvites are a type of kidney stones. They are known as “Less Common” because they have been found only in some breeds such as Labradors, Golden Retrievers, German Shepherds and others. However, they do occur in other species like cats and humans too.

Kidney Stones – What Are They?

A kidney stone is a hard solid mass of crystals or mineral deposits inside your kidneys. These stones may be small (less than 1/4 inch) or large (more than 2 inches). Some forms of kidney stones are harmless while others cause problems if not treated properly. Kidney stones can damage the blood vessels that carry urine out of your body and into the toilet bowl where it needs to go. If these blood vessels become damaged, then the fluid level in your body will drop causing symptoms such as nausea, vomiting and diarrhea.

Types of Kidney Stones

There are two main types of kidney stones: calcium oxalate stones and struvite crystals. Calcium oxalate stones are formed when crystals from foods like spinach, kale or broccoli grow inside your kidneys. Struvite stones are formed when certain types of bacteria grow in your urine.

Struvite: The Less Common Kidney Stone

Struvite crystals are a type of kidney stone that is also known as a “infection” or “struvite” stone. They are actually not formed from normal urine due to an infection within the urinary tract. Normal urine does not contain enough minerals to grow into a stone. Struvite stones can be seen on a radiograph or x-ray and also by a urine culture.

Struvite stones are white, yellow or green in color.

What Are These Stones?

Struvite crystals grow in your dog’s bladder, ureters and kidneys if certain types of bacteria are present. These stones are usually seen in dogs that have recurring urinary tract infections. The stones are formed when these bacteria break down the urinary tract lining. These stones can also form when there is an excess of minerals in the urine.

Struvite Stones in Dogs

Struvite stones can form when some types of bacteria grow excessively in your dog’s urinary tract. These bacteria include: E. coli, Proteus, Klebsiella, Staphylococcus, Enterobacter and Pseudomonas. These bacteria are able to break down substances in the bladder into smaller substances that form stones.

These stones can then clump together and grow into larger masses that cannot pass out of the body by normal means.

Struvite stones are different from other types of stones such as calcium oxalate stones that form when certain foods are ingested such as spinach, beet greens, and chocolate.

How Are Struvite Stones Diagnosed?

These types of stones are confirmed by a urine culture. The bacteria that is seen in the culture will be determined after a urine analysis. A complete blood count may also be recommended since these can help identify if there is a bacterial infection present.

How Are Struvite Stones Treated?

Treatment for Struvite Stones

These stones can be treated in several ways such as: surgery, shock wave therapy and/or special diets. The type of treatment that is chosen depends on a variety of factors such as the size of the stones, their location, your dog’s age and overall health. If there are only a few stones then they may pass out of your dog’s body without any treatment. Surgical removal may also be an option.

What Is Shock Wave Therapy?

If your veterinarian recommends shock wave therapy, this procedure involves the use of sound waves to break up the stones so that they can be more easily passed by your dog. This procedure is usually done using an endoscope, an instrument that allows your veterinarian to see inside your pet’s inner organs. The sound waves are directed at the stones, breaking them up and passing them out in the urine. The procedure takes less than one hour to complete.

What Is a Special Diet?

Your dog’s diet may also be adjusted to help decrease the formation of additional stones in the future. It is usually recommended that your dog’s food be increased in fiber, decreased in protein and phosphorous and water intake should be increased. Your veterinarian can tell you which foods are best for your dog in this instance.

What Is the Prognosis For Your Dog?

The prognosis for dogs with stone problems is usually very good. The stones that form tend to be passed or eliminated from the body fairly easily as long as your dog receives proper treatment.

If your veterinarian has recommended surgery or another form of treatment, it is important that you adhere to the recommendations. If a stone should pass into your dog’s urethra and become lodged there, he can suffer from extreme pain as well as complications with his bladder and kidneys. This is an emergency situation that must be treated as soon as possible.

Learn more about Diseases of the Dog and Cat.

Sources & references used in this article:

Struvite stones by JS Rodman – Nephron, 1999 – karger.com

Treatment options in struvite stones by LP Wang, HY Wong, DP Griffith – Urologic Clinics of North America, 1997 – Elsevier

Renal struvite stones—pathogenesis, microbiology, and management strategies by R Flannigan, WH Choy, B Chew, D Lange – Nature reviews Urology, 2014 – nature.com

Absence of bacterial imprints on struvite-containing kidney stones: a structural investigation at the mesoscopic and atomic scale by D Bazin, G André, R Weil, G Matzen, V Emmanuel… – Urology, 2012 – Elsevier

Reduced glomerular filtration rate and hypercalciuria in primary struvite nephrolithiasis by C Kristensen, JH Parks, M Lindheimer, FL Coe – Kidney International, 1987 – Elsevier