So Your Dog Has Struvites

If your dog has struvite stones, he has a bladder infection. He doesn't need a special diet and he doesn't need his urinary pH adjusted. He needs his infection diagnosed and treated.

(To be perfectly accurate, there is a condition known as "sterile" or "metabolic" struvites that occurs very, very rarely in the dog. This condition isn't just a zebra, however; it's a unicorn. I'll say more about it later on.)

Why do dogs with urinary tract infections have struvite stones? Why do they so often have alkaline urine?

The urine becomes alkaline for the same reason the stones form: Because the urease-producing bacteria that usually cause canine UTIs produce magnesium, phosphate, and ammonium as waste products. The urine becomes super-saturated with these waste products. Add it all together, shake well, and you have struvite stones. It was once believed that the alkaline urine "caused" struvite stones, but that doesn't appear to be the case. Rather, it's now believed they are caused by the same thing, the bacterial waste products. In fact, sometimes struvite stones are called "triple phosphate" or "M.A.P" for "magnesium, ammonium, phosphate."

Should you acidify the urine of a dog with struvite stones to dissolve the crystals?

This is sort of like cutting the wire to the "check engine" light instead of fixing the engine. Diagnose and treat the bladder infection and the urinary pH will resolve naturally.

Won't acidifying the urine kill the bacteria?

That's a very common belief, expressed quite often on holistic email lists, but it's not true. While many bacteria don't like acid mediums, some do. More to the point, it's impossible to get bodily fluids and tissues acid enough to actually kill bacteria. There are bacteria that can live in vinegar (in fact, without some of them we wouldn't have vinegar). And as fast as you are acidifying the urine, the bacteria are in there alkalinizing it. The solution is to diagnose and treat the bladder infection. (Are you sensing a theme here?)

OK, how do you diagnose and treat a bladder infection?

To diagnose a bladder infection, you need to perform a test known as a urine culture. This should be done in combination with a sensitivity test to determine what antibiotics will be effective against the bacteria. It's helpful also to do a urinalysis, but you cannot diagnose a bladder infection, nor effectively treat it, with urinalysis alone.

A urine culture and sensitivity test will take about three days to run. If the dog has obvious symptoms, it's not unreasonable to begin antibiotic therapy before the results are known, as long as the urine sample is obtained before giving antibiotics. Antibiotics present in the urine will prevent bacteria from growing in the culture. Once the sensitivity results are in, if the chosen antibiotic was not appropriate, you can switch at that point.

Be absolutely sure to give your dog the entire prescribed course of antibiotics, as stopping the treatment too soon can create drug-resistant infections that are almost impossible to treat. If your dog has side effects from the antibiotics, even if the symptoms are gone, contact your vet instead of just stopping the drug.

But there were bacteria in the urinalysis, so why can't we just go ahead and treat without doing the culture and sensitivity?

A lot of vets do this, some because that's what they've always done and some because the clients won't pay for the extra testing. But this isn't a good idea for a number of reasons.

One, sometimes some other kind of debris is mistaken for bacteria. A properly obtained urine sample is less likely to have debris that is hard to differentiate.

Two, you can't tell what bacteria they are, so you have no real idea if you're choosing an effective antibiotic.

Three, if therapy fails, you won't really know what to do next. Was it the wrong antibiotic? Is this a new infection with a different organism? Is the problem something other than an infection?

Four, a culture done before, and again after, treatment gives you a yardstick to measure the success of your therapy.

My dog's urine culture was negative, but he has struvite stones. Does he have "sterile struvites"?

He might. He might also have an infection with a bacteria that doesn't grow in the culture that was used, or he might be infected with a bacteria that grows in tissue rather than urine. You can request a special, separate culture for mycoplasma/ureaplasma. If that, too, is negative, you can consider doing a biopsy of the bladder wall. However, at that point, many vets will instead put the dog on a trial of a drug effective against mycoplasma/ureaplasma, as a bladder wall biopsy is a very invasive test.

But yes, your dog might in fact have sterile struvites, in which case your vet's recommendation of a special diet and urinary acidification will be right on track. But those things are not appropriate for the vast, overwhelming majority of struvite stone cases, which are caused by infections that need to be diagnosed and treated.

My dog doesn't have struvite stones and he doesn't have a bladder infection, but he has struvite crystals. What should I do? Does he need a special diet?

If he has no symptoms and no stones and no infection, you don't need to do anything. Perfectly healthy dogs often have struvite crystals in their urine, and sometimes they will form due to the way the urine is handled. This finding is not significant.

Do I have to use antibiotics? Can't I treat the infection and stones with herbs and diet, even if acidifying the urine isn't enough?

There is no diet that will help treat a bladder infection, although of course proper nutrition will help a dog be more disease resistant in general. There are herbs that can help treat a bladder infection. Some of them are very potent, and are also powerful diuretics. Other, gentler herbs are also used in treating UTIs. Use them only as recommended by your qualified holistic vet, preceded and followed by a urine culture to make sure your treatment worked, just as you would do with antibiotic therapy. Don't cut corners and don't try to treat this on your own.

How can I dissolve the stones after I get the infection treated?

Most of the time, the stones will dissolve on their own once the infection is gone. If not, you can use urinary acidification or special diets temporarily to dissolve the stones. The commercial prescription diet S/D, formulated to dissolve struvites, is not intended for longterm feeding so should be discontinued when the stones are gone. Very rarely, surgery is necessary to remove the stones.

My dog gets infections over and over again. What causes that?

Your dog might not be getting infected over and over again; he might have one infection that is never fully eradicated. Doing a culture and sensitivity, then repeating the culture after treatment is finished, should clarify that situation.

However, some dogs have structural defects or other medical problems that cause them to suffer recurrent bladder infections. Other dogs have had surgical procedures such as a urethrostomy, which can make them more susceptible to bladder infections. Conditions such as Cushings also increase the incidence of bladder infections. Owners of dogs who suffer recurrent UTIs should ask their vet to refer them to an internal medicine specialist or veterinary college for an in-depth workup.

This article was written by Christie Keith and Nancy Campbell, RVT.