Bladder Stone and Mammary Tumor

Question
Hi Sandra,

We have an 18 month old unspayed female rat whom we brought in to see the vet for some mild sneezing.  During the exam the vet discovered a large bladder stone while palpating her abdomen which was verified on X ray.  She also discovered a mammary tumor.  

Our rat does not seem to be in any distress from the bladder stone at the moment, but after researching this and mammary tumors on your site and others, we are thinking we should go ahead and have this surgically taken care of, although it is a financial stretch.

I have some questions:

She is on antibiotics for the sneezing (Baytril and doxycyline), so I'm wondering if it really makes sense to pay the extra $143 for the Urine Culture and Sensitivity, since her being on antibiotics would upset the results?  Although some parts of the urinalysis seem important to analyzing why she has the stone?  The price for the surgery with the Urinalysis and C&S is $410 - $450, so if we skipped this, the price would go down significantly.

Would the vet be able to visualize threadworms if she has these during the surgery?  Or is there a separate lab test for this?  Or should we treat for this regardless?  This rat was a large pet store chain albino rat who recently lost her cagemate (who was always urinating on the shelving, etc...  these were our first rats, and we didn't realize this was perhaps not normal).  We adopted two female ratties from a breeder to keep her company after her cagemate died, so if the bladderstone resulted from a parasite, we'd want to know and have them treated, as well.  Do you know what the safest treatment for bladder threadworms is?  

Would it make any sense at all for us to consider spaying her at her age at the same time as the cystotomy and mammary tumor removal?

The vet quoted us an additional $168 if we wished to have the tumor biopsied.  I'm assuming this is probably unnecessary since most of these are benign...  What do you think?

I like this vet -  She is one of only two in our state listed on the rmca.org website, but she also treats a wide variety of wildlife and exotics so I know she can't be an expert on everything so I want to partner with her in this  (she has treated lots of rats, but has not encountered a bladderstone in one yet -- has seen them in hamsters and other rodents...  I shared what I found out with her about bladder threadworms and she seemed very receptive to this)...  She runs a wildlife rehab center for our state.

Thanks for your feedback.  

Answer
Hi

Wow, lots of things going on here. For starters, I would not bother spending money on having the urine tested, because as you stated, the prior use of antibiotics will give false test results. Its a waste of money. Second, the bladder thread worm. A common endoparasite among pet rats,bladder threadworms are easily treated with ivermectin. They can be passed on to other rats, so I would treat any cagemates. Clean the cage constantly, changing litter and bedding daily. Your vet can check for threadworm using the rats urine. It should not be expensive in the least.
Third, I would NOT spay. The ball is already rolling and once mammary tumors start to appear, at this age (she is more than likely already done with her estrus cycle and menses have ceased) hormone levels are higher now and this most likely triggered the growth or should I say, over growth of mammary tissue.  I have never seen a rat this age stop developing mammary tumors after a spay, but have seen some positive results in younger rats.  Spaying is very risky as it is,I wouldnt subject her to this on top of the other surgeries.
Biopsy? I wouldnt bother with that either. Chances are its benign and unless she had numerous tumors and the vet needed to know their origin in order to treat her chemically, using tamoxifen for malignant tumors or lupron for the benign growths, there is no real reason to know if its cancerous or not, which again, it probably isnt.