Expert: Jessica - 10/4/2009

Question
Hello,
My cat Roxie is almost 2 years old and earlier this year she had crystals in her bladder and nearly died as a result.  She went on the special vet food and as a result had a terrible allergic reaction.  She is pretty bald, flaky skin, itchy all over.  She has been totally grain free for almost three months but still incredibly itchy.  I have kept a close eye on her since and now I notice that her urine has gone dark on occasion (not every time).  I am very very worried that she has crystals again but was wondering if it could be due to the itchiness or could just be an infection? She has had one since the crystals in April.  She is starting to get depressed but she is still eating and drinking and pooping fine.  She pees in the box 95% of the time.  (We have had trouble getting her to go back in the box since April as she was peeing pure blood.)  I can't get to the vet until Saturday but was hoping for some peace of mind that it may not be the crystals again.  She was in a lot of pain.
Thanks
Samantha and Roxie

Answer
Hi Samantha.  Dark urine can be caused by the presence of blood and bacteria.  These can occur with infection or with the presence of crystals.  

While urinary tract infections tend to be easier to treat than urinary crystals, they can carry serious consequences.  Bacteria can back up to the kidneys and cause a kidney infection, which may result in permanent kidney damage.  Long-standing UTI’s can cause protein loss and dramatic loss of muscle mass.  Also, because the presence of bacteria causes a high urinary pH, many cats develop struvite crystals in the bladder if a urinary tract infection goes untreated.  This is because struvite formation is encouraged when urinary pH is abnormally high.  In many ways, a urinary tract infection is more dangerous than urinary tract crystals in female cats (males tend to develop urinary obstructions, so this is untrue in their case).

Unfortunately, when crystals are the primary problem, a bacterial infection can result because crystals damage the protective lining of the bladder.  So if you have a urinalysis done, and it shows that there are both bacteria and struvite (as opposed to oxalate) urinary tract crystals, you can’t be entirely sure which problem is the underlying one and which is secondary.  Most vets will administer an antibiotic and recommend the special diets that you’ve tried, to cover all the bases.

Grain-free foods tend to have higher protein content, which usually leads to lower urinary pH when compared to regular foods.  This is good.  A low urinary pH helps prevent infection and the formation of struvite crystals, which are the most common kind.  Still, she may need extra help since she wasn’t able to tolerate the prescription foods.  You may want to talk to the vet about giving her a gel supplement called Methigel or Acidurin tablets.  These can lower urinary pH to help prevent infections and struvite crystals.  However, they can make problems worse for calcium oxalate crystal sufferers, so you want to check with your vet as to which type of crystals she had if you’re unsure.

Dark urine could also be caused by dehydration, so keep a close eye on her water bowl to make sure she’s drinking plenty.  Feeding her canned food would benefit her bladder health and can keep her more hydrated than dry food, so you may want to consider adding wet food (or more wet food) to her diet.  I would just be sure not to feed her a canned food with meat sources other than what’s in her dry food to prevent allergic reactions.  And if any chance arises to get her to the vet sooner than Saturday, I would take it.  

I hope all goes well!

Jessica