Chances are good you're here because your cat has just been given a diagnosis of CRF. And if you're anything like me, you're numb and in a panic all at the same time. Stay strong, and keep your chin up because your cat needs you. CRF is not a death sentence.
In my experience CRF is one of the most treatable conditions out there and with gentle methods i.e. no or minimal drugs and supportive treatments, a cat can enjoy an excellent quality of life for many years.

[Jules' darling boy Tuffy who she lost to CRF ]

The kidneys are an incredibly hard-working set of organs. They contain several thousand microscopic nephrons, which filter and reabsorb fluids in the body. Nephron damage and loss of kidney function can occur due to drugs e.g. Metacam at any time and particularly during surgery, infections, toxins, cardiac output causing decreased blood flow to the kidneys, and possibly as part of the aging process.

Progression of the disease depends on several things, including how much time the kidney has to compensate for nephron damage. Even with 25 percent of its original nephrons remaining i.e. by the time elevated BUN and creatinine (both waste products) are discovered on a blood test, a kidney can continue to function for many years.

Symptoms

Common early symptoms include nausea, poor appetite, dull coat, listlessness, increased thirst, and frequent urination. Sometimes the signs are very subtle and thus easy to miss.

Many of the symptoms of CRF can match those of diabetes and hyperthyroidism. One difference in the case of hyperthyroidism, cats are more likely to have a ravenous appetite, but with no weight gain. A CRF kitty will typically not have a huge or even the same appetite s/he did earlier on in their life.

At a later stage, things to watch out for include bad breath with or without mouth ulcers, hind leg weakness (usually due to potassium depletion/deficiency), high blood pressure (which can cause retinal detachment resulting in blindness), and anemia. In some cases, your vet might be able to feel that the kidneys are small and irregular, though in a smaller % of cases, there might be kidney enlargement.

Prolonged vomiting, and impaired ability of remaining nephrons can lead to metabolic acidosis which can be helped by Slippery Elm, and/or sodium bicarbonate (please be very cautious with this), and Potassium citrate if accompanied by hypokalemia.

Testing

Urine test

I'm a big fan of urinalysis (U/A) because it's non-invasive (no need for cystocentesis if one is not testing for bacterial infection), and can be a useful tool for not just early diagnosis of kidney insufficiency but also for monitoring progression of kidney failure to some extent.

A U/A will show among other things, whether there is excess protein being spilled in the urine, as well as specific gravity (USG) of the urine. In normal cats, there should never be protein in the urine. For raw-fed cats (who typically have more dilute urine anyway due to the high moisture content of meat), a USG of less than 1.03 or so (combined with clinical symptoms and/or blood values such as elevated BUN and Creatinine) becomes a warning sign because it signals decreased filtering ability of the kidneys.

I get U/As for my cats at least every six months because it's so easy to just drop off a sample at my vet's. For $20, I get a sense of my cats' liver, kidneys, and pancreas health, so it's well worth it, IMO. I'm even crazy enough to have purchased a hand-held refractometer for around $35 so in between full U/A from my cats' holistic vet, I can quickly and easily check USG at home for each of my cats on a monthly basis.

You might not be as big a nutter as yours truly, but if you can swing even once a year testing, please consider it. This is even more important after age 7 or 8, although it is not uncommon for cats as young as 2 years of age eating dry food to have failing kidneys. While we're on the subject, please pretty please do not feed your cat that horrible grain-based dehydrated junk, which is about as far removed from cat prey as can be. For a quick read (I promise!) on why, click here.

Blood/serum tests

When it comes to blood work, it only shows raised levels of Blood Urea Nitrogen (BUN) and Creatinine -- both of which are waste products excreted in the urine -- after at least 70-75% of the kidney function is lost. Rule of thumb - if your cat's BUN is higher than 33 or so, and Creatinine is higher than 1.8 - 2.0 Mg/Dl (varies, so please consult your lab's range), less than 25% of kidney function is left. Note: European and Commonwealth e.g. British and Canadian measurements are different so click here or if previous link is not working, then check Merck Vet Manual link here for conversions to US units.

It's best to do a SuperChem profile, which gives not only BUN and Creatinine, but also Phosphorus and Potassium which are important to monitor as well.

In addition, since cats with CRF can be prone to anemia, it's good to get a complete blood count (CBC) which looks at the numbers of white and red blood cells (RBCs). A lower than normal number of RBCs is significant because it often indicates a drop in erythropoiten, a hormone secreted by the kidneys that stimulates RBC production.


CRF Diet

The low-protein myth

In the past, it was believed that a low protein diet was essential in controlling CRF. The idea behind this was to supposedly cut down on the kidneys' load. However, studies done on dogs in renal failure, show that a low protein diet did not help said dogs. Since cats have an even higher protein requirement than dogs, it seems unlikely that they could thrive (or even properly exist) on low protein diets.

As an obligate carnivore, they need the nutrients only available from meat. My personal (and I like to think, informed) opinion is that cats with CRF should eat the same food that other healthy cats eat. Please check the references especially 9 and 10 for more arguments for feeding CRF cats a diet high in protein.

Cats are unique when it comes to diet. In all cats, their high protein requirement is due to high activity of hepatic enzymes which are responsible for ureagenesis i.e. the conversion of ammonia to urea in the liver. Cats do not have the ability to decrease the activity of these hepatic enzymes.

So it is dangerous to feed them a low protein diet as their bodies break down proteins via through the urea cycle on a continual basis regardless of the amount of protein fed. If cats do not get protein from diet, they will suffer from muscle wasting as their bodies will literally try to utilize protein internally.

Please do not deprive your cat of valuable protein (from real meat)! That said, only in very late stages of kidney failure, one can consider this purely for palliative relief from symptoms of uremia and azotemia.

There are several mouse studies all of which have found a positive relationship between protein and amount of "erythropoietic units" in spleen cells. Cats on a raw diet (at least 95% meat, including organs and bones) do not typically develop the muscle wasting or anemia commonly seen in cats with CRF because adequate protein amounts provide their body's basic building block not the least of which is RBC production.

The bottom line is that protein must come from an animal source, and must be of highest quality i.e. not primarily beaks, feathers, fur, claws, etc, just what comes with a whole bird/animal. The food should be digestible i.e. utilized by the cat's body so the kidneys do not have to process colors and preservatives such as dyes, BHA, BHT, etc.

If you cannot feed a raw diet, look for grainless canned foods that contain real meat. Examples of good brands – grain-free versions of Nature's Variety (Instinct), Merrick, Wellness, Natural Balance, EVO, etc. All of them contain real meat but not as much as a mouse/rat would have (mid-50%), all have low to mid Phosphorous levels, and Ca:Phos of 1.2:1 as well as moisture amounts equivalent to cat prey. Feed these better brands in rotation.

This is the same food one would give a non-CRF cat. Alas, the specialty foods fall short on many levels. For example, since meat is high in Phosphorous, far too many brands especially the ones that purportedly help CRF cats bring the amount down by adding grain and other filler in place of meat . This also has the effect of lopsided Calcium:Phosphorous ratios e.g. Hills K/D's is 1.7:1 (ideal for cats is 1.2 – 1.4:1) as well as of being rather unpalatable to cats (big shocker!).

What to feed

The best thing you can do for your CRF cat is to feed him/her a home-made diet from organic meat. For recipes, check the Keeping Cats Well-fed section. There is some evidence that one should keep a closer eye on Phosphorous in the diet, so one way to do this is to feed meats low in phosphorous, and/or swap out a small % of the meat with lightly cooked egg whites.

If your cat has elevated Phosphorous levels, look into eggshell powder which has been researched in Japan on human kidney failure patients, and shown to work as an Oral Phosphate Binder (OPB). More on this under treatments.

If a home-made diet is not possible, endeavor to reduce the load on your cat's kidneys by feeding commercial food with the least amount of fillers such as grains and other harmful ingredients like dyes and preservatives. Look for grain-less commercial wet foods such as Wellness, Nature's Variety, Natural Balance venison and pea, and Merrick (all except CA Roll and Southern Delight).


Treatments

Herbs

The only herb that has been studied and shown to help lower creatinine level is Stinging Nettle seed (not leaf, though if one cannot find seed, use the whole plant as a 2nd choice), as reported by herbalists David Winston, Alan Tillotson) and Johnathan Treasure. The amount and formulation would need to be customized for a kitty.

A chinese herbal formula for which there is some anecdotal support is Rehmannia 6 a.k.a. Six Flavor tea pills a.k.a. Liu Wei Di Huang Wan : 1-2 pills a day. Look for a brand that is GMP-certified.

For nausea, hyperacidity, and other symptoms of metabolic acidosis - Slippery Elm Bark (SEB): maintenance dose of 5cc (1 tsp) of slippery elm bark (SEB) gruel once a day. Many members have given up to 5 tsp a day if needed; it works as well as Pepcid AC without the horrid side-effects.

I make SEB like any tea infusion – add 1/4 tsp of the bulk powder to 2Tbsp of boiled water. It'll thicken as it sits. Powder from capsules isn't as strong, so if you are using that, add ½ tsp to 2 Tbsp of water.

Note: like other things high in mucilaginous fiber, SEB might inhibit absorption of other stuff given along with it, so give at least 30 – 60 minutes away from food to be on the safe side. Some cats actually like the taste of SEB slurry, and will lick it up when mixed with some treat e.g. yogurt or even alone.

If at all possible, use Marshmallow Root (MR) in place of SEB since they are similar in action and because SEB is endangered from over harvesting and Dutch Elm disease. Some cats do just as well on MR and for others nothing but SEB does the trick. Since there are so few safe options for cats, and SEB is one of those precious few, each of us has to decide if and when to use this herb.

Cautions

  • Do not use Uva Ursi, also known as Bearberry on a cat with CRF because it has a strong astringent effect, and in any case, is only indicated for short-term use in confirmed alkaline urine, like with a bout of cystitis.
  • Also do not give a CRF cat the herb Juniper Berries because it can irritate the kidneys.
  • Cats with CRF are prone to high blood pressure so stay away from Licorice and Horsetail as well.

Subcutaneous (subq) Fluids

In order of preference, on my list, we've had best results with Lactated Ringers solution. If a cat's Calcium levels are elevated (please confirm with an ionized calcium test), then one can switch to Normosol-R. Last choice, and the one that has caused problems for cats is saline solution (0.9% sodium chloride), yet many of our cats' vets have rx'ed this for some reason:(

If you need to educate yourself about types of solution, check this link. Subq fluids use the same solution as they list here for IV, just different delivery method: http://internationalwin.com/tech4.html
[Tasha who we lost in 1997 to ARF following surgery]

As they list in the above link, 0.9% sodium chloride has a much lower than ideal target pH (5.5) vs LRS and Normosol-R so the latter two are almost always better. The only exception would be if a cat for some unusual reason e.g. such severe vomiting for such a long period of time that the pH goes up, has metabolic alkalosis (in which case s/he needs immediate veterinary help).

Amount of fluids - As per Washington State Univ college of veterinary medicine, cats should get 5-10ml of subq daily per lb of body weight. I would be very careful going above this because we have had cats on my list develop fluids in the lungs. Many cats with undiagnosed heart disease can have complications from fluids. If you know your cat has heart disease, you can do what I did, and instead of subq, give fluids orally using a plastic syringe.

As an alternative to sub-Q fluids, I used either a 5cc pediatric syringe or an eye dropper to syringe spring water by mouth. Boo Boo was between 8 and 9 lbs so I aimed for 50-100mls total per day including what he got from raw food. He ate 3-4oz of raw mix per day, and since I syringed it into him, I was able to add 10ml of water per feeding.

The maximum he ever got - around 15cc (3 dropperfuls)- in one sitting was when he got just his herbal brews. Since cats aren't used to drinking much water I figured keep it a small amt like 1 or 2 5cc pediatric syringes. Boo Boo seemed to tolerate it very well, and always remained well-hydrated. If his heart hadn't given out first, I feel he could have lived on for years with a good quality of life with CRF.

Supplements

  • Potassium: Although a small % of cats with CRF can have elevated potassium (K) levels, they are generally more likely to have lower than normal blood potassium levels. It is possible for a cat to have normal potassium readings on a blood test, and still have low potassium levels in the tissues. So rather than wait till K level is down to 4 mEq/L, it's best to try and keep K around 4.5 - 5mEq/L through dietary choices or failing that, through supplementation.
  • The best choices for this are - potassium gluconate or potassium citrate @ 2 to 6mEq i.e 78mg - 234mg of elemental potassium, that is, between 468 mg and 1,404mg potassium gluconate/citrate (as stated on the label) daily
  • If your cat has metabolic acidosis, then Citrate is a better choice than Gluconate, but in early to mid-stage CRF, gluconate is a good choice. Avoid K Chloride which is indicated for metabolic alkalosis, as it can make your cat's problems worse.
  • Vitamins and trace minerals: Be aggressive with supplementation of water-soluble vitamins - C, and B-Complex as well as trace minerals. Be more cautious with fat-soluble vitamins such as A, D, E, and K which are stored in the liver.
  • Fish Body (not liver) Oils e.g. salmon, sardine, anchovy, or krill oil: 1-2 1,000mg softgels (depending on omega-3 in diet, adjust up/downward) with at least 180mg EPA and 120mg DHA e.g. Carlson's and Nordic Naturals brands. NOW brand krill oil is reasonably-priced and easy to squirt into food plus many cats actually like the taste.
  • L- taurine powder or capsule: 500 - 1,000mg NOW/Source Naturals/LEF brands
  • Coenzyme Q10 a.k.a. CoQ10: 30 - 60 mg e.g. Doctor's Best, NSI; get capsules so you can avoid plant-based oils (cats hate 'em anyway)
  • Glandulars or PMG products: Over the last 11 years, these products have been shown to greatly benefit our list cats with compromised kidneys. They have been helpful not only in keeping BUN and Creatinine levels in check, but other non-kidney glandulars can help with anemia as well. Use the ones marketed for humans e.g. Standard Process' Renatrophin and Renafood because they contain more meat and a lot fewer oddball ingredients than the "feline" formulas. These would have to be customized for your cat in terms of which type, exact amounts, and for how long.
  • Phosphate binder: Using aluminum as an oral phosphate binder (OPB) is not something I feel comfortable with. Medscape is replete with information on negative aspects of aluminum hydroxide e.g. just one of many examples: http://www.medscape.com/viewarticle/545034
  • "Of the commonly used phosphate binders, aluminum hydroxide is associated with aluminum toxicity and calcium carbonate is associated with hypercalcemia." 'Nuff said.
  • As a safer alternate OPB, I have been using eggshell powder (ESP) which is a natural source of calcium carbonate (e.g. Epakitin, which also contains chitosan). In the paper by Brown et al, linked and referenced below, Epakitin was found to not increase calcium levels (risk for CRF cats), in fact both PTH and Calcium decreased, as did serum Phosphorous level.
  • I prefer ESP which has the added benefit of being cheap, and easy to prepare at home. I have used ESP as an OPB to good effect. I use Dr. Nagode's guidelines (FWIW, his are for aluminum binders, not ESP) where a 5kg/11lb would need 300-500mg (~ 1/7 - 1/4 tsp) of ESP per day if Phosphorous level is between 6 and 8mg/dl, increasing ESP with higher Phosphorous levels even up to twice those amounts as Phos gets in the 7-8 range In comparison Brown et al, gave 1g twice a day for cats weighing under 5kg.
  • Probiotics: There is limited research support for a formula - Azodyl - containing the following strains of beneficial bacteria - Streptococcus thermophilus, Lactobacillus acidophilus, and Bifiodobacterium longum. The former 2 are in yogurt, but to get high enough numbers, one can get a product such as Source Naturals Life Flora. One can even mix 1/8 or 1/16 tsp of this powder into yogurt or another treat your cat likes.
  • Psyllium husk and/or cooked squash/pumpkin: There are no cat studies on psyllium, and as far as we know at this point, it is less fermentable than pumpkin or rice bran both of which are moderately fermentable, hence ideal for cats as these fiber feed gut bacteria. Probiotics together with fermentable fiber (which functions as a pre-biotic) trap some of the nitrogen, and instead of it being processed by the kidneys (BUN), it is excreted via stool thus keeping it from building up in the system.

All the cats I have helped now have lowered BUN and Creatinine levels from doing all of the above plus a homeopathic remedy that fits the kitty's total symptom picture. A customized raw diet with some tweaks e.g. fiber source, type of meat, ESP, etc. also play a huge role in keeping cats with kidney failure in good shape.

If you'd like help with a health, diet, or behavioral issue, click here for a consult.


Notes and References

  1. Coenzyme Q10 Good for People with Kidney Failure
  2. In this study, CoQ10 lowered serum creatinine by 29% and blood urea nitrogen by 9%:
    Singh RB, Khanna HK, Niaz MA, "Randomized, Double-Blind Placebo-Controlled Trial of Coenzyme Q10 in Chronic Renal Failure: Discovery of a New Role, J Nutr Environ Med, 2000;10:281-288.36843
  3. Herb of the Season: Stinging Nettle (Urtica dioica) By David Winston, AHG
    These researchers found that "Diets replete in protein were not associated with increased severity of glomerular or nonglomerular renal lesions, increased proteinuria, or decreased GFR. Diets replete in calories were not associated with increased severity of glomerular lesions, but were associated with mild increase of nonglomerular lesions. Factors other than protein and calorie intake must be considered potential causes of progression of renal failure in cats. Results raise questions about the practice of restricting quantity of protein in the diet of cats with chronic renal failure, with the intention of ameliorating development of further renal damage."
  4. Finco DR, Brown SA, et al Protein and calorie effects on progression of induced chronic renal failure in cats, American Journal of Veterinary Research, 1998, 59(5): 575–582
  5. Finco DR, Brown SA, Barsanti JA. "Divergent views on dietary management of renal failure: The Georgia experience". Proc 16th Ann ACVIM Forum 1998; 32-33.
    I could not find a link to this paper online, but do have a hard copy of it. Dr. Finco et al found that feeding cats with CRF diets "replete in protein" did not accelerate renal failure as measured by serum creatinine/BUN, nor did it have any other negative effects such as uremia and/or azotemia.
    In this great literature review, the authors underscore that not only does reduced protein not help, it can hurt. To wit: "Disadvantages to reduced protein intake include reduced kidney function as measured by GFR and renal plasma flow, possibility of a negative nitrogen balance, and the promotion of acatabolic state in the presence of proteinuria."
  6. Bovee, Kenneth C. DVM, MMedSc,"Mythology of Protein Restriction for Dogs with Reduced Renal Function", Practicing Veterinarian Vol. 21, 11 (K), Nov 1999
    This study showed higher EPA levels and lower AA levels might have a renal-protective effect:
  7. Plantinga EA, Hovernier R, Beynen AC, Qualitative risk assessment of chronic renal failure development in healthy, female cats as based on the content of eicosapentaenoic acid in adipose tissue and that of arachidonic acid in plasma cholesteryl esters., Vet Res Commun. 2005 May;29(4):281-6.
    Study showing diets hi in EPA (omega-3) good predictor of survival time:
  8. Plantinga EA, Everts H, Kastelein AM, Beynen AC. Retrospective study of the survival of cats with acquired chronic renal insufficiency offered different commercial diets, Vet Rec. 2005 Aug 13;157(7):185-7
    A fantastic article that should be a must-read for vets and caregivers alike; cogent arguments for not restricting protein. Alas, this is no longer available, but I do have this quote from it when I posted it to my forum -- "There is no evidence to believe that low protein diets are beneficial to all patients with renal azotemia (increased BUN and creatinine with isosthenuric urine specific gravity) and in fact this practice may be harmful to some patients."
  9. Nutritional Management of Dogs and Cats with Chronic Renal Failure - Dr. Tina Kalkstein
    In this study, cats fed a high-protein (51.7% protein) diet had higher HCT values, weighed more, and had lower K levels (reversed with supplementation); begs the question why they fed only 0.3% K to cats with CRF when daily requirement is supposed to be 0.6% (ahem!):
  10. Adams LG, Polzin DJ, Osborne CA, O'Brien TD., Effects of dietary protein and calorie restriction in clinically normal cats and in cats with surgically induced chronic renal failure, Am J Vet Res. 1993 Oct;54(10):1653-62.
  11. Tomohide Koizumi, Kazuya Murakami, Haruyuki Nakayama, Tomomi Kuwahara, and Yoshinari Ohnish Role of dietary phosphorus in the progression of renal failure, Biochemical and Biophysical Research Communications, Volume 295, Issue 4, 26 July 2002, Pages 917-921
  12. Sunvold G.D., Vickers R.J., Reinhart G.A. Effect of Fermentable Fiber Blends on Nitrogen Repartitioning in the Feline, North American Veterinary Conference, Orlando, Florida, USA, January 19, 2000
  13. Brown, Scott A., VMD, PhD, Marjorie Rickertsen, BS, Suzanne Sheldon, DVM, Effects of an Intestinal Phosphorus Binder on Serum Phosphorus and Parathyroid Hormone Concentration in Cats With Reduced Renal Function, Intern J Appl Res Vet Med Vol. 6, No. 3, 2008.