Crystals in Your Dog’s Urine

Crystals in Your Dog’s Urine

English: Struvite (magnesium ammonium phosphate) crystals found microscopically in a urinalysis of a dog with a bladder infection. Français : Cristaux de struvite dans l'urine d'un chien souffrant d'une infection de la vessie. Date13 January 2007 (scale added 2007-01-27) Source Own work Author Joel Mills

Struvite crystals found microscopically in a urinalysis of a dog with a bladder infection. Photo by Joel Mills.

Many people are surprised to learn that crystals are normally present in the urine of their dogs and cats. These struvite crystals, which are technically magnesium ammonium phosphate (MAP), are usually harmless as they typically dissolve and get flushed out during your pet’s urination.

However, certain bacteria can live within these crystals and may start to flourish given the right conditions.

Just like kidney stones in humans, these crystals can band together to form crystal-like stones in your pet’s kidneys, bladder, and urinary tract, which is diagnosed as urolithiasis, or struvite stones. This is why struvite stones are also known as triple phosphate stones, urease stones, and infectious stones.

Below you can discover possible causes, symptoms, and treatment options for struvite stones so you can both prevent and treat them for your dog.

When Struvites Cause Problems

Healthy pets have the ability to dissolve struvite crystals on their own. But elderly dogs and pets with health issues or poor immune systems are likely to see these harmless struvite crystals evolve into a more serious health condition.

Struvite stones are caused by several issues which can occur alone or concurrently, including:

Urine pH Levels

Think back to learning about the pH scale when you were in school. Here’s a refresher: a 7 on the pH scale is neutral; anything below 7 represents an acidic environment and any number above 7 is an alkaline environment.

Normal pH levels for dog and cat urine is between 6 and 6.5, which puts it closer to the acidic end of the scale.

Common substances on the pH scale.

Common substances on the pH scale.

When dogs eat meat in the wild, they have a well balanced acidic pH level since meat is more acidic in nature. By contrast, today’s commercial grain-laden pet foods favor less meat and as a result, the urine becomes more alkaline— which is not a good situation.

As urine loses its acidity, it’s less hostile to bacteria so the bacteria have the chance to thrive. The struvite crystals that would normally pass turn into dangerous magnesium ammonium phosphate hexahydrate or uroliths.

These uroliths are full of bacteria (usually proteus, staphylococcus, or klebsiella) that may have flourished due to concentrated or highly alkaline urine. Highly alkaline urine kills the beneficial bacteria population and allows the harmful bacteria to run rampant.

Besides proliferation, the unhealthy bacteria also produce the enzyme urease, which when combined with calcium phosphate, encapsulates the bacteria, thus protecting it and making it difficult to treat unless caught early.

Kidney stones successfully removed from an elderly dog, Cody. Data16 giugno 2008 Fonte JIM CONRAD'S NATURALIST NEWSLETTER. Written and issued at the woods edge near Natchez, Mississippi.

Struvite stones, also referred to as Kidney Stones, are more common in female dogs. Here are several that were successfully removed from an elderly dog. Photo by Jim Conrad.

Overuse of Antibiotics

When pets are brought to the vet because they’re feeling under the weather, an antibiotic is generally prescribed to rule out the possibility of an underlying infection before expensive tests are run.

However, you should limit your pet’s usage of antibiotics to only when it is absolutely necessary to do so. Using antibiotics kills off beneficial bacteria that your pet needs to keep the harmful bacteria in check. When your pet takes an unwarranted course of antibiotics, he will compromise his healthy bacteria and create super bacteria that are stronger and more resistant to treatment.

Bladder Inflammation (Cystitis)

Many issues can cause cystitis, which is an inflammation of the bladder and is also commonly referred to as a urinary tract infection (UTI). The most common cause is bacterial infection, but other root causes include tumors or bladder polyps, as well as abnormal or congenital anatomy issues.

It is possible to have inflammation without an infection (it is then called sterile cystitis).

When crystals or stones rub against the bladder wall, it opens the surface up to lesions that accept bacteria. You may notice the infection when you see pinkish blood in your dog’s urine, known as hematuria.

Steroid Therapy

High levels of steroids are a contributing factor in the process of struvite stone formation. These may include corticosteroids which increase the amount of calcium being excreted. Just keep in mind that this extra calcium may stop in the bladder or kidneys and begin the stone formation process instead of making their way totally out of the body.

Cushing’s Disease

Cushing’s Disease, which is characterized by frequent urinary tract infections, is a major contributor to the formation of stones thanks to the fact that UTIs are caused by trapped bacteria in the urinary tract. This bacteria may solidify into stones if not treated or well managed.

Diet and Inadequate Water Intake

Many veterinarians believe that struvite stones are caused by an improper diet.

As mentioned previously, a diet poor in proteins and rich in grains promotes alkalinity, which is the perfect breeding ground for bacteria to multiply, cause UTIs, and open the door for the formation of stones.

If your dog is plagued by frequent UTIs, or is at risk of developing struvite stones, try going low carb and grain and potato free to see if that helps the issue.

Make sure that your dog is drinking plenty of water. Like people, dogs may not drink the water that their bodies need to remain healthy. Plus, if your dog is not drinking enough and chowing on low-moisture dry food, he may be more susceptible to struvite stones.

The more urine is able to pass through your pet’s body, the more bacteria gets eliminated.

Some of the breed that get stones include

Some of the breeds that get struvite stones include Beagles, Cocker Spaniels, Lhasa Apsos, and Dachshunds.

Is My Dog At Risk?

Some breeds often plagued with struvite stones are:

  • Miniature Schnauzers
  • Cocker Spaniels
  • Dachshunds
  • Beagles
  • Shih Tzu
  • Bichon Frises
  • Miniature Poodles
  • Lhasa Apsos

You may start seeing struvite stone formation in dogs between the two and three-year age range, but the average age of getting struvites is at the six-year mark. There have been cases reported in dogs as old as 19 years of age.

Bladder struvite stones are the cause of over one third of urinary tract stones in dogs, and most often seen in middle-aged female dogs, and females who have been spayed.

Calcium oxalate stones are one of the most common and difficult to understand uroliths. While veterinarians still don’t know exactly what causes these stones, it is believed that they form as a result of high concentrations of calcium, citrates, or oxalates in the urine.

While struvite uroliths are found in female dogs, calcium oxalate stones are found in male dogs, are more prevalent in:

  • Schnauzers
  • Mini Poodles
  • Yorkshire Terriers
  • Bichon Frises
  • Shih Tzus
  • Lhasas

Keep in mind that as with any malady, stones may occur in any breed, and at any age.

Learn the Symptoms

Since this medical issue is centered around the bladder and kidneys, it is no small accident (no pun intended) that the symptoms all basically have to do with those organs.

Your pet may be leaking urine or urinating inside when they never did that before.


You may discover stones by running your hand over the area of your dog’s bladder and kidneys.

They may be straining to urinate outside, or squatting without producing a large enough result. It is this failure to fully empty the bladder that contributes to the problem: urine laced with bacteria doesn’t leave the body in full and the body tries to ward off the bacteria to no avail.

A fully blocked urine flow, which is the failure to produce any urine output, is a medical emergency. Your pet must be taken for emergency treatment immediately.

The same urgency is needed for blood in the urine which indicates a larger unresolved problem.

Your pet may be in pain from the infection, or from the sharp crystals or rugged stones irritating his bladder, kidneys, or urinary tract.

In an effort to instinctively flush the kidneys and bladder and reduce the burning pain associated with tainted urine, your dog may suffer from increased thirst and drink water constantly without seeming satisfied.

You may also accidentally discover the stones by running your hand over your pet’s bladder and kidneys. Your veterinarian would do the same by gently palpating (touching and examining) your pet.

Diagnosing the Issue

Let your vet know if you suspect a bladder or kidney issue. Your vet will want to take a sterile sample of your pet’s urine. This is wise as your vet will not only get a contaminant free sample, but she will process it timely, which is very important. Filling a jar of your pet’s urine from home is not the best option.

The urine may be tested via a urine strip which minimally registers blood and acidity. Your vet will may also create a urine culture and submit it to a sensitivity test to isolate and identify any bacteria. A complete urinalysis may be done to analyze glucose (sugar) levels, excessive protein, blood, ketones, and white blood cells to indicate an infection in progress.

Sometimes your vet may opt to send the urinalysis to a certified lab for an in-depth assessment.

X-rays and ultrasounds may be an option if the diagnosis is leaning towards a positive finding of the stones present.

Treatment Options

Do not assume to treat struvite stones in your pet on your own. You may begin treatment after you receive a diagnosis and instructions from your vet.

To counteract the alkaline pH levels of the urine, a low-carb, grain and potato free diet is a generally prescribed course of action.

Most grains and vegetables actually contain oxalates, as in the calcium oxalate that makes uroliths. Feed your dog foods with low phosphorous, magnesium, and protein levels which speed up the dissolution of the crystals.

A diet of 65–75% meat or dairy without artificial flavorings, sweeteners, or soy is a good rule of thumb during this recovery period. Your vet may have a diet formulated that she may recommend during this time as well. The restricted diet should be needed for several weeks to several months at most.

It should not be necessary to remain on a restricted diet indefinitely if the pet is properly monitored for steady pH levels. You can buy pH strips at the pharmacy to monitor your pet’s first urine stream in the morning (the strongest and most concentrated) for correct pH levels and the absence of blood. This non-invasive testing will stave off another urinary infection and further complications.

Hydration is key. Your vet may prescribe sodium chloride to stimulate thirst and to increase urination. Make sure to keep fresh bowls of clean cool water handy and in several rooms if that is what it takes to get your pet to drink more often.

Adding protein broths to the water may entice your pet to drink more since it’s flavored. Just boil and cool a broth of marrow or chicken bones to accomplish this. Never give your pet any of the bones! Place small amounts of the diluted broth out so that it may be tossed after 1–2 hours if not consumed. Refrigerate the portion not placed in the bowl.

Canned food may be used more during this period of recovery to introduce additional water content and moisture. You might even add some water to your dog’s food as well. Keep in mind that you will need to brush your pet’s teeth to make up for the loss of the teeth cleaning crunch of dry food.

As supplements, you might give your pet glucosamine and vitamin C to relax any inflammation of the bladder and kidneys. Cranberry extract creates a more acidic environment that the bacteria hate, and it prevents bacteria from attaching in the bladder and kidneys. Probiotics will introduce good bacteria that may be lacking in the urinary tract.

Your vet may need to medicate for pain and prescribe antibiotics after the findings of the urine culture and sensitivity test.

In advanced instances, the stones may be surgically removed rather than dissolved. The last thing you want is for an undissolved crystal to block the urine flow.

During treatment to dissolve the stones, the recuperation period may last anywhere from two weeks to seven months, depending on how early you caught the problem, how well your dog responds to treatment, and how quickly the uroliths are affected by the course of medications against it.

There will be plenty of time to roughhouse with your pet once they’re healed internally. They will let you know when they’re back to their old happy-go-lucky selves and ready for play.


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