Expert: Jessica - 10/26/2010

Question
QUESTION: British shorthair, 8y male, hx of rt side ht enlargement w/ afib, age 2 on Dig since. Hind end weakness/withering, no dx.
nightly vomiting for last year, famotidine qd has helped.
last yr, urine dilute otherwise nl labs, this year increased drinking and urination x6 months, BUN 70, cr 3.6. Kidneys "hugely enlarged".
Also question of episodic weakness w/ refusal to eat, unclear which comes first, lasts for days seems to resolve on its own.  Given other hx and breed, likely cause of RF is FKD.  Given that, if untreated, what is likely prognosis.  I know this is terminal, but I am unclear on time line. I understand US may give dx, but is that likely to change treatment. Chemo would not be an option for this cat, fluids also iffy given heart hx. He is an extremely reluctant patient and trips to the vet are traumatic for us all, labeled fractious by vet.    Any help is appreciated.

ANSWER: Hi Sharon,

Sorry to hear about your kitty's conditions.  

It sounds to me as though all the ultrasound would do is determine what form of kidney failure your kitty has (Polycystic Kidney Disease tends to cause enlarged kidneys whereas Chronic Renal Failure usually shrinks the kidneys), or see if cancer is the issue.  The treatments for PKD and CRF are the same - a restricted diet, fluid therapy, and sometimes medications to help the cat feel better, as well as phosphate binders at times to prevent the cat from absorbing phosphorus from his food.  I think the only real reason to do an ultrasound would be if you were thinking about treating cancer, but his heart problems, as you know, would preclude many of the medications typically used, as well as the frequent anesthesia required to administer the chemo.  So in my opinion, no, a diagnosis would not change the course of treatment.  It would only provide you with an answer.

Any type of kidney disease is very unpredictable.  It affects each cat in a different manner, and survival time also depends on which stage your kitty is in when he is diagnosed.  There are four stages, and judging by his symptoms and blood test results, I would guess that your kitty is probably in Stage III renal failure (it’s not an exact science, so you can ask your vet for their opinion as well).  Diet is the most important factor to survival time, and in one study, cats diagnosed with Stage II renal failure who were fed a kidney friendly diet survived an average of 24 months, while those who ate a regular diet lived only 9.  Your kitty should probably be able to be on a kidney diet, as these are also reduced in sodium, but certainly check with your vet about this.  I have had cats diagnosed with end stage renal failure and given a couple weeks to live go on to live for 3 months, but I have also had those who have not survived more than a few days.  The longest survivor I had was a year and a half, diagnosed during Stage I, and he refused to eat any kidney diets.  He received no treatment whatsoever.  

So truly, it is very difficult to take a guess.  One thing is almost certain – if he can get on a kidney diet, he should feel better and survive longer.  If he refuses a kidney food, ask your vet about giving him a phosphate binder such as Alternagel or Epakitin.  Phosphorus, found in higher amounts in other cat foods, is the most dangerous ingredient to a kidney patient.

I hope he survives a good while yet!

Jessica



---------- FOLLOW-UP ----------

QUESTION: Thank you for this thoughtful answer.  Is there a kidney diet/food you recommend?

Answer
Your vet should carry an array of kidney diets, and the canned varieties are much more effective because they provide some extra moisture.  My cats really enjoy Royal Canin's LP Modified morsels in gravy, but this is the most expensive of the foods.  Second to this, they tend to prefer Purina Veterinary Diets NF, and then Hill's k/d.  Most of them are not so big on the regular Royal Canin's Modified LP formula.  This is a loaf type food that comes in a larger 6 oz. can.  Most of my patients have found this food too dense.  If your kitty is a dry food junky, each of these does come in a dry formula.

Good luck!