Struvite Crystals

[Laurie, Wally & Charlotte]

For the past six months, Charlotte's pH has been fluctuating and she has had a number of urine tests with some showing struvite crystals and some without. An x-ray was taken in December and revealed no bladder stones. Our vet concluded that Charlotte's pH just goes up and down, and without any stones this is Charlotte's "normal." About 10 days ago, she was showing physical signs of a UTI and was put on an antibiotic since we'd be traveling, but the urine evaluation did not find any bacteria. We have been flooding her food (Acana Grasslands) with water to dilute her urine, hoping that this will help keep the pH down. Next week, she'll have another x-ray done as well as a sterile urine culture. Here are my questions: If the x-ray shows no stone/s and the culture indicates no bacteria, but possibly struvite crystals again, should I change her food to one without starches (since starch alkalizes pH) and one without magnesium and calcium? Should I give her any supplements such as ascorbic acid, cranberries, d-mannose? Some of these are just for bacteria prevention if I understand it correctly. And if she doesn't have any bacteria in her urine, what would be the point? Help! How can I cross-post this with the Medical Group?

[Karen, Jasper and Jackdoodle]

You can copy and paste into a new discussion in the Health Group. 

The cranberry supplements also make the urine more acidic, which is what you want with struvite crystals. 

I think that if there is no infection present (i.e. no bacteria), no stones, and she has no symptoms, a diet change isn't necessary. The crystals in themselves mean nothing; that can be genetic and runs in I'd continue to encourage more fluid intake and maybe increase animal protein in her diet if possible. You aren't going to find any commercial food with no starch at all, but you can try to reduce starch or grain intake by only giving 100% animal protein treats & chews, too. 

[F, Calla & Luca]

I don’t think there is food without calcium and magnesium either nor do I think it would be a good idea for bone health. 

[Karen, Jasper and Jackdoodle]

I agree.

[Laurie, Wally & Charlotte]

Plus, if I understand it correctly, calcium oxalate crystals are different from struvite crystals, anyway. So if Charlotte's urine has struvite crystals, then having calcium in her diet would be irrelevant. Magnesium can cause struvite crystals, so that would theoretically be good to eliminate. However, if she isn't producing stones and it's just crystals in her urine, then maybe she can say on her current food with lots of added water. There are prescription diets without calcium and without magnesium. (I know someone who cannot take calcium supplements which are good for bone health, because her body produces kidney stones, so she sacrifices healthy ones for the decreased likelihood of kidney stones.)

[Karen, Jasper and Jackdoodle]

Yes, calcium oxalate crystals are completely different. For those, you need to make the urine more alkaline, so complete opposite nutritionally.

BUT...paradoxically, dairy products do tend to make the urine more alkaline. So, no cheese or dairy for Charlotte. 

 Dogs who are probe to calcium oxalate crystals/stones require potassium citrate supplements and need to avoid foods with high oxalate levels, like spinach and beets. 

[Laurie, Wally & Charlotte]

I thought that cranberry supplements are good for preventing the bacteria that can cause UTIs. I didn't realize that they would lower her pH. So, if there is no infection, is it true that the crystals cannot group together to form stones?

That's a good idea about reducing her starch intake by giving her treats without starches.

[Karen, Jasper and Jackdoodle]

It's my understanding that struvite stones form as a result of a bladder infection. 

This is a good explanation:

"Normal dog urine is slightly acidic and contains waste products from metabolism including dissolved mineral salts and other compounds. 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. If the urine becomes exceptionally concentrated or if it becomes alkaline, struvite crystals will precipitate or fall out of solution.

In dogs, struvite bladder stones usually form as a complication of a  bladder infection caused by bacteria that produce an enzyme known as urease.  This enzyme breaks down the urea that is normally present in the urine causing an excess production of ammonia; this ammonia production then causes the urine to become alkaline. Ammonia in the urine also causes bladder inflammation. Under these environmental conditions, struvite crystals will precipitate out of solution and collect around any cells or debris that may have formed in the bladder as a result of inflammation.  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. In some studies, up to 85% of dogs with struvite bladder stones were female."

[Leslie, Yogi & Maci Bear]

Yogi had a problem last summer with his urine and high ph. They didn’t find an infection though they did put him on an antibiotic for awhile. He had the struvite crystals.  We did check his urine 3 different times.  In the end we did decide to put him on cranberry supplement with his Vet’s input.