Rabbit renal problem

Question
I have a rescue rabbit.  She is a Florida about 6 years.  When I got her 5 years ago  she had urine burns up her back.  She can not lift he tail to urinate.  This has been an ongoing problem, but it had improved.  However for the past 2-3 months she seems to be peeing more and the problem has reoccurred.  She was X-rayed and found no blockages in her bladder however the bladder wall is thickened.  We also found that she has an abnormal curvature in her spine behind the front legs,  this doesn't seem to affect her movement but we wondered if that is the cause of her not being able th lift her tail. Urinalysis showed no infection however RBC's and increased protein (which I believe is normal for rabbits)  she also has calcium carbonate crystals.  I try to feed her a low calcium diet.  She eats mainly vegetables and timothy hay with about 1 tablespoon of oxbow timothy pellets.  Could the crystals in the urine be irritating her bladder and cause the RBC's and few Wbc's in her urine.  We use to have her on Potassium citrate and I have put her back on that to try to acidify the urine.  I don't know if that will help.  Is there anything else I should be trying.
Thank you
Debbie

Answer
Dear Debbie,

The spinal abnormality is a reasonable candidate for her being unable to properly lift her tail to urinate.  

If she is urinating and drinking excessively, then bloodwork to check her B.U.N. (Blood Urea Nitrogen) and creatinine would be in order, to see how well her kidneys are functioning.  Pairing this with a measurement of the urine specific gravity will give the most meaningful results, since high BUN and creatinine (and protein and RBCs and other values) also can be caused by dehydration.  If the SG of the urine is low and the kidney values are high, that's not good.

It's also normal for there to be (sometimes copious) calcium carbonate and even calcium oxalate crystals in the urine, and this usually is not changed by altering the diet.  As long as the urinary residue is white and powdery, it's not likely to cause a problem.  But if the residue becomes thick, like toothpaste, and a yellowish color, this can indicate  true bladder "sludge" that is often a flag for metabolic bone disease that will affect the renal system.

Be careful about too little calcium.  A rabbit with metabolic bone disease shouldn't be deprived of calcium, as this can speed osteoporosis, and usually does not affect the amount of sludge.

I've never used polycitra, but know people who swear by it.  Still, I would not assume from your description that your bunny has a serious problem.  SubQ fluids will correct slight dehydration, and a followup blood test after some fluid therapy will tell whether there really are any renal problems that might be brewing.  But it sounds as if the main problem is her posturing.  If she can't lift her tail, then even *normal* calcium crystals will be harder for her to void, and she might need occasional fluid therapy coupled with gentle bladder expression (jiggling the bladder in advance to suspend any calcium salts) to keep her bladder clear and comfortable.

I hope this helps.

Dana