Q. My 10-year-old female cat was recently diagnosed with several small calcium oxalate stones in her bladder, but she is otherwise acting normal. My veterinarian noted that the recommended diet change has not dissolved/lessened these stones. How important is it to surgically remove five stones from the bladder of this asymptomatic kitty? I don’t want to stress her unnecessarily since she has already had diabetes-related skin issues and had an eye surgically removed when she was at the shelter where I adopted her.
A. Thanks for getting in touch, and I completely understand your concern for this kitty. Uroliths, or urinary tract stones, are a common feline condition that can potentially cause significant problems depending upon their location, composition, and other factors, including the presence of other diseases like chronic renal disease, diabetes, and/or urinary tract infections.
It is not surprising that these stones were not dissolved by dietary modification, as unlike the case with some forms of uroliths (like struvite and urate uroliths), which can often be dissolved medically and/or by changes in diet, this is not usually the case with calcium oxalate crystals.
For the sake of this discussion, I will assume that your cat only has stones in her urinary bladder, that there is no urinary tract infection, and that she has no other health issue aside from diabetes.
The decision regarding whether to surgically remove uroliths is multifactorial. There is some disagreement among veterinarians regarding best practices in this situation, but there is a good amount of evidence suggesting that conservative management involving leaving the stones in the bladder with careful monitoring and steps to minimize the likelihood of further stone formation and infection may be reasonable in many cases.
The fact that your cat has diabetes may predispose her to urinary tract infections (glucose in the urine of diabetics may create a more favorable environment for bacterial growth in the urinary tract), and there is some concern that the presence of stones may exacerbate this possibility, but this is a source of debate.
The major concern is that these stones may end up obstructing your cat’s urethra, making it difficult or even impossible for her to urinate, which is a potentially life-threatening medical emergency that must be dealt with immediately. While this is possible, and becomes more likely if more stones form or if they migrate, there is evidence to suggest that urethral obstruction may be more likely to occur after surgery to remove bladder stones in some cats.
If these stones do not change in size (and you must work with your veterinarian to make sure that the size of the bladder stones is monitored judiciously), and if he/she educates you about the signs of potential urethral obstruction/urinary tract infection (painful urination, inability to urinate, blood in the urine, urinating outside the litter box, frequent urination with small amounts of urine, frequent licking of the genital region, lethargy), it may be reasonable to adopt a conservative approach without surgically removing these uroliths.
Please continue to work closely with your veterinarian to assure best care, and best of luck with this kitty.