Friday, December 16, 2011

Kidney Failure in Dogs and Cats

Almost Everything You Need to Know About
Chronic Renal Failure
But Might Be Afraid to Ask

First - let's get some definitions down: 

Chronic: long term. 
: kidney. (we use them interchangeably)
Failure: the inability to perform a task adequately. 

Chronic renal failure (CRF), also called chronic kidney failure, refers to the situation where the kidneys have not been able to perform at least one of their many tasks adequately for some time (months to years). Many doctors opt for the term chronic renal insufficiency, as many cases can be treated successfully and can look forward to months or often years of quality life, while failure connotes negativity. In addition, at this time we do not usually do dialysis with pets, but there are some programs for kidney transplants available in cats.

Kidneys:  two bean-shaped organs present in our abdominal cavity that make urine and a whole lot more!  The kidneys are made of thousands of tiny filtration units called nephrons. Once a nephron is destroyed by a disease, it is not replaced; the number of nephrons we have has to last a lifetime (or at least quite a few need to last a lifetime-we do have extras).

Many people have no idea what our kidneys do for us beyond that they have something to do with urine production. In fact, the kidneys are involved in conservation of water, stimulating red blood cell production, regulating blood pressure, balancing salts, activating Vitamin D, and more. Any of these functions may be failing in the renal failure patient.

The kidneys remove toxic wastes from our bodies and when these substances cannot be adequately removed, we develop excess thirst, nausea, pain, weakness, appetite loss, intestinal bleeding, even seizures. Our goal in early stage patients is to postpone or even fully prevent the development of uremia. Our goal in later stage patients is to resolve the uremia and bring the patient back to an earlier stage of disease. 

If the pet is still making plenty of urine, how can there be kidney failure?
In chronic kidney failure, urine is usually produced in excessive quantities. What the kidneys are failing to do is conserve water and they fail to make concentrated urine. The body produces numerous toxins as it goes through its daily tasks. These toxins circulate to the kidneys where they are filtered out and urinated away. An efficient kidney can make highly-concentrated urine so that a large amount of toxin can be excreted in a relatively small amount of water.

When the kidneys fail, they lose their ability to concentrate urine and more water is required to excrete the same amount of toxin. This usually starts to happen when about 2/3 of the nephrons are no longer working.  The animal will begin to drink more and more to provide the failing kidneys with enough water. Eventually, the animal cannot drink enough and toxin levels begin to rise. At first owners might notice only that they are filling the water bowl more often, or the litter box is wetter, or that the dog has to go out more often or is having accidents.  Later the pet owner might notice weight loss, listlessness, nausea, constipation, and poor appetite.
Fortunately, we have many extra nephrons, so many extra that overall kidney function does not fall behind until we are down to about 1/4 of our original number of nephrons.

Nephrons can be destroyed quickly or slowly. Usually, by the time less than 1/4 of our original nephrons are left, whatever the inciting disease process was is long gone and there is no way to tell what happened. All we can do is make the kidney workload easier by making up for the kidney’s inadequate performance with medication or supplements. Hopefully, we can also slow the progression of the failure. Therapy is highly individual depending on which jobs the kidneys are having trouble doing.

Azotemia:  the condition where toxins have built up in the bloodstream and lab tests are definitely abnormal. It does not necessarily mean the patient is experiencing reduced life quality as a result of these abnormal lab findings. 

Uremia means that the patient is experiencing uremic poisoning. In other words, not only are the tests abnormal but the patient is feeling the effects of the toxic build up.

Therapy:  Our goal in treatment is to prevent, postpone, or resolve uremia. Resolving azotemia may not be realistic.  In most cases, by the time the diagnosis of kidney failure has been made, the initial disease that started the kidneys on their path to failure is long gone, leaving a progressive loss of function to march unrelentingly onward. Our goal is to stop that march, and get to a stage where the patient does not feel the consequences of the disease. We cannot make failed kidneys become normal again, but we may be able to re-balance our patient’s metabolism so that he or she feels as though we did. What makes a case hopeless or hopeful depends on the patient’s ability to respond to therapy nearly as much as it depends on the stage at which the condition is discovered.   See suggestions after each of the lab parameters we monitor.

Lessons in Lab Work:
Let’s begin with some of the relevant lab values that come up in the course of screening a pet’s kidney function. Your veterinarian may also recommend other tests besides these, such as urine sediment and/or culture if there is a chance that there is a urinary tract infection present as well.  It is helpful to familiarize yourself with these terms so you can understand what your veterinarian is monitoring:

Urine Specific Gravity:  One of the kidney’s most important jobs is the conservation of the body’s water. The kidney must excrete the toxic by-products created by the body’s metabolism but it will want to do so in the least amount of water possible. The healthy kidney is able to make very concentrated urine.

When we analyze a urine sample, one of the most important parameters is the specific gravity. This is a measure of how concentrated a urine sample is. Water has a specific gravity of 1.000. A dilute urine sample has a specific gravity less that 1.020.  A concentrated urine sample would have a specific gravity over 1.030 (dogs) or 1.040 (cats). A failing kidney by definition cannot make concentrated urine and the patient must drink excessively to get enough water to excrete the day’s toxic load.  At certain times of the day our urine is more concentrated than others-our first morning urine tends to be our most concentrated of the day since we usually don’t drink much at night if we are in good shape, but if we just had a big drink, our next urine will be more dilute.

Blood Urea Nitrogen (BUN):  This is a protein metabolite excreted by the kidney (it is one of the toxins we are concerned about, though it may be more of a marker for other toxins that are less easily measured). In a normal animal, the BUN is around 25 mg/dl (milligram per deciliter). Often at the time of diagnosis, BUN is well over 150, 200, or even 300. We’d like to keep the BUN no more than 60 to 80 mg/dl. BUN is influenced by dietary protein (including the patient’s own blood that has bled into the intestine).

Creatinine:  This is another protein metabolite (though this one is less dependent on dietary protein intake than is BUN). A normal creatinine is less than 1.4 mg/dl, certainly less than 2.0. Patients begin to feel sick when values meet or exceed 5.0 so we try to keep the value at 4.5 or less. BUN and creatinine will be tracked (as will several other parameters) over time and in response to different treatments.

Therapy to address fluid loss and azotemia (elevated BUN and Creatinine): 

First, is giving fluids to help keep the pet hydrated, to optimize blood flow to the kidneys, and to help flush out toxins from the blood stream.  Also, we institute dietary management to give the body proteins that it can utilize best and to decrease excess protein metabolites.  Additionally, we use gastrointestinal medications such as stomach acid blockers of various kinds, appetite stimulants, and anti-nausea medications since kidney failure leads to excess stomach acid secretion, and nausea. 

Phosphorus:  The calcium/phosphorus balance becomes deranged in kidney failure due to hormone changes as well as the inability of the failing kidney to excrete phosphorus. If calcium and phosphorus levels become too high, the soft tissues of the animal's body will become more like bone with deposits of mineral in them that are inflammatory, uncomfortable, and often cause intestinal bleeding. The bones will weaken as well, in some cases actually becoming rubbery. Keeping phosphorus levels in the low normal range has been correlated with improved survival.

Therapy for excess phosphorous:  Phosphorous binders added to the diet, and if we can get the phosphorous and calcium down low enough (so that if you multiply the numbers you get for each mineral the answer should be less than 60), a medication called calcitriol may slow further kidney decline.

Potassium:  The failing kidney is unable to conserve potassium efficiently and supplementation may be needed. The sign of hypokalemia (the scientific name for low blood potassium) is weakness, especially drooping of the head and neck.

Therapy for low potassium is a potassium supplement.

Packed Cell Volume / Hematocrit:  This is a measure of red blood cell amount. More literally it represents the percentage of the blood made up by red blood cells. The hormone which stimulates the production of red blood cells is made by the kidney. The failing kidney does not make this hormone in normal amounts leading to a reduction in red blood cells (anemia), in turn leading to weakness, poor appetite, and overall poor life quality.

Therapy for anemia in kidney failure is using an injectable form of the hormone that stimulates bone marrow to make red blood cells. 

Blood Pressure:  Blood pressure is important to monitor in kidney patients as there is a tendency for hypertension (high blood pressure) to develop in kidney failure.

Therapy consists of medication to lower blood pressure and certain medications work better in certain species.

Thyroid Hormone:  In our cat patients, it is important to screen thyroid hormone level as hyperthyroidism can lead to high blood pressure and kidney damage.

Therapy involves stopping excess thyroid hormone production via one of several ways: a medication usually given orally, dietary management, surgery to remove the overactive tissue, or radioactive iodine treatment. 

Urinary Protein:  One of the functions of the kidney is to prevent loss of the body’s blood proteins. The kidney’s filtering mechanism that enables it to remove toxins is designed to leave larger molecules (such as proteins) inside the body where they belong. But if holes develop in the filter, protein can be lost. If this complication cannot be controlled, survival time is dramatically shortened.

Therapy consists of using a medication that is used in heart disease, called an ACE inhibitor.  These medications also reduce blood pressure somewhat and decrease protein excretion in some patients.

REMEMBER, While all of this information may seem overwhelming and insurmountable, remember that many cases of kidney failure can be treated successfully and patients can look forward to months or often years of quality life with management!

Blog by:
Dr. Dana Lewis
Dr. Dana assists families with Pet Hospice and In Home Euthanasia in the Raleigh North Carolina area (Raleigh, Durham, Chapel Hill and the greater Triangle, as well as Wake, Durham, Orange, and Chatham counties.)


  1. Awesome blog Dr. Dana! Thanks! Dr. Mary

  2. Very useful information. Thank you. jet.

  3. Tomorrow is the second anniversary of the day my dog went into kidney failure. I was told by the emergency vet to put her down. I'm not a fan of euthanasia and wanted her to die at home. I had an animal hospice tech come to my house to help me think things through. I put everything I had into getting her well and it worked. The past two years have been one of the greatest gifts I've ever been given. Thanks for the great information.

  4. WOW JA - that is great - two years - you have been doing a great job! With proper care - many pets in kidney failure live good lives. You are doing awesome - keep up the good work!!! And spread the word - more people need to know what you have done and to not be nervous about treating a pet long term. (especially sub-q fluids). Dr. Mary Gardner

  5. Wow, two years that's amazing....our beautiful boader collie has been given the diagnoses of renal failure two weeks ago....& it's been two weeks of hell our hearts have been breaking. Today & yesterday I tried to feed her some of her hills k/d nuts & she puked after 5 of them, we were told 80% function was gone at the very least.....they does not appear to be much support or advice here in Ireland or at least in Galway & there is nothing we would not do for her....but finding it hard to sift through information. I would give anything to anyone to tell me what is best to do to make the centre of our household even somewhat better, as she is still so interested in life & having fun....but food is an ordeal. She's been prescribed nothing from the vets bar the food & meta am for an old injury.

    1. Hi Danielle,

      I am so sorry to hear about your boarder collie. Here is an information sheet on kidney failure that may be helpful to you:

      In situations such as yours - we typically recommend fluid therapy, anti-nausea medication, antacids (as ulcers are common in kidney failure) and appetite stimulants.

      If you would like to email me privately - please feel free to do so:

  6. I appreciate this blog so much! I've been doing all I can to care for my GSD w/renal failure. The vet explained that his kidneys were not formed properly at birth so I've managed to keep him alive for 7 years as of this Friday Sept.13th! I'm grateful he's still alive but as of this past month I've noticed he's becoming more nauseous all the time & can't seem to hold down his Hills K/D kibble anymore so I've been alternating with the bland diet of rice w/low fat cottage cheese which he does well on. My question I guess is what can I give him for anti nausea? Thank you in advance for any help/advise on how to keep my baby more comfortable.

  7. Well, good for you with your GSD! I would strongly recommend you have bloodwork evaluated-perhaps you need to be doing SQ fluids (you didn't mention if you were) and maybe he needs a phosphorous binder. For nausea, getting the toxins down is very important. Medications for nausea are really short term fixes usually. He may benefit from antacid therapy. Specific antinausea meds: there is Cerenia, Ondansetron, and some others. And there are herbal antinausea remedies as well that your veterinarian may recommend. Dr. Dana

    1. Haven't started the SQ fluids yet but my vet did mention the phosphorus binders and I'll ask about the antacid therapy. Thank you Dr.Dana!! Superb blog!!!!

  8. hi there!
    I'm desperate to get info on home treatment for my 14 yr old terrier mix Louie.
    He's diabetic& has chronic pancreatitis, but we got news yesterday he's in acute renal failure.our vet said $1700 & they can give iv fluids and possibly turn this around. We don't have $1700 so now we have no other alternative but to try to treat this at home. we've given 600cc subcutaneous fluids, oral antacid,.and 1/2 a tramadol for pain. He refuses to eat,.but was taking by mouth water.he's urinated about 200cc .
    I don't want to give up,.but I don't want to prolong this if he's not gaining ground.
    How long would it be before we see improvement if this is working? any suggestions or advice on treatment is also appreciated.

    1. Hi Melvis,

      I am sorry to hear about your dog. The 'good' news is that if it is acute and he can recover from it, that is a positive. Chronic renal failure means that there is no recovery for the kidneys and long term management is necessary. So basically the kidney filter toxins and concentrate urine and when they are not doing that - toxins build up in the blood stream and we get dehydrated. This is why we HYDRATE - to flush out the toxins and help hydrate.

      I am also concerned about his diabetes - is this due to the pancreatitis? Is he on insulin - and are you NOT giving it if he is not eating.

      You have a triad of issues going on. :(

      The fluid therapy is EXTREMELY helpful so defenintely keep that going - along with the ant-acids. The toxins that build up can cause gastric ulcers.

      I cannot give you a time frame as every pet is different and we don't know how damaged the kidneys are. All I know is to not stop trying - if he has not eaten on his own in a week, I think it may be time to make end of life decisions. I wouldn't try to force feed him - just offer food and walk away. If he is nauseous - you don't want to exacerbate that.

      I am not sure this was helpful at all but don't give up hope. They have not dis-proven the power of positive thinking yet! :)

      Dr. Mary

  9. thanks so much Dr. Mary for your quick reply.
    I'll try to answer your questions best I can.
    Our vet said give him 1 unit nph regardless if he eats,.2 units to start since his blood sugar was over 600 last night. I had beem holding it up till then.
    not sure which came first, but he became ill shortly after we adopted him 5 yrs ago. He responded well to W//d dogfood, but being a street dog for so long, he would refuse dog food and only eat.hamburger or chicken. Now i find out he shouldn't of ate that, so I'm feeling guilty too. ugh....
    I just need some guidance on what to see if progress, even small amts are being made. right now he's just limp on my lap....:-(

  10. Don't take on any guilt with this - sometimes the pancreas just breaks down not matter how great we feed them.

    600 is REALLY high. I worry about Ketoacidosis at this level. The problem is - he is not getting any energy into his cells. The insulin is like a gatekeeper allowing glucose into the cells. Now all his glucose is in his bloodstream and not in the cells. That is one reason he is limp.

    To be honest, his best shot is monitored in the hospital. I know this is a lot of money but I must tell you that that is the best thing at this point. Care Credit is something to look into. 6 months no interest if your vet takes it.

    Otherwise this is very serious. Unmanaged diabetes, pancreatitis and kidney failure is a tough thing to manage at home. :(

    I would have a discussion with your vet (as I cannot give you advice personally) and letting him go may be what is best at this time. He found an angel in you 5 years ago and you may have to let him be an angle now as well. :(

  11. just to update, we hospitalized him late last night. the area around his neck became reddened and inflamed so I felt hospitalized was his best chance. Now fingers crossed, we can at least get him on the path to recovery before he comes home.
    Thanks so much for your help, bless you for all you do for gods little creatures. :-)

  12. hi Doc,
    Sorry its taken awhile to get back to you, the last few days have been a whirlwind, but big news!!
    After hospitalization for 24 hr, and not getting the questions answered I felt needed answering, we took him to a specialist about 50 miles away. Guess what? He was misdiagnosed, he wasn't in renal failure, it was his blood sugar, coupled with the nausea causing some dehydration. They admitted him to their ER, 24hrs in another facility with the proper treatment and strict glucose monitoring, he is STABLE!!!
    I'm so relieved, yet not very pleased with our regular vet for what appears to be a huge miss on their part.
    But, all in all, you had the correct concern, and I'm so grateful for your input!! It helped alot in my decision to pull him out of one hospital and put him in another. It helped save his life, and I am forever grateful!!
    God bless, and thank you thank you!!!!

    1. That is great news!! Fingers crossed for a speedy recovery! :)

  13. Hi Dr. Gardner,
    My 20 lb, 16 y old mixed breed is in kidney failure.
    After 36 hours of iv fluids at the vets, her creatinine had only dropped from 13.6 to 11.

    The vet said that due to her inability to halve that number after 36 hours of fluids, my baby does not have enough functioning nephrons to be able to be managed w sub-q fluids, and suggested I put her down.

    The problem is that she's still fairly vital. She'll happily walk multiple blocks with me twice a day, isn't incontinent, is weaker but will still climb a few stairs the few times that someone leaves the gate open, will eat (from 2x a day to 1x), gets excited sniffing her favorite "p-mail" spots, begs for cookies, etc.

    I've put two dogs to sleep before, but each time they were obviously already disconnecting from life (listless, dull eyed, not very mobile or responsive).

    The thought of putting my bright eyed, walking, tail wagging girl down now is killing me!

    I took her home last night for the weekend, because I didn't want her last memories to be two days in a cage. The vet sent me home with phosphorous binder, appetite stimulant, sub q, and had me pick up an antacid.

    I administered the antacid and aluminum hydroxide, and she hasn't even thrown up (which had become an every other day occurrence when her "sour" stomach kept her from eating).

    I know dogs hide pain well, and the last thing I want to do is to extend her suffering just because it will be so hard for me to let go.

    Yet, I do NOT want to put her down while she's still so engaged with the world.

    Is the fact that she only dropped to an 11 bun/creatinine (from a 13.6) after 36 hrs of iv fluids indicative that I shouldn't try home management?

    Will I be relegating her to a slow, painful degeneration, or do you think there's still a chance for her to have a good quality of life for some time yet to come based on her responsiveness and energy levels?

    Thank you so much for your blog as well as any advice, guidance, or perspective that you may have for us.

    1. Hi J,

      I am so sorry your girl is not well and in kidney failure. From what you told me, she is clearly in the hospice phase. Now it is up to you to determine what her quality of life and comfort is at home. I don't follow the numbers too much at this point - I follow the clinic signs. Is she eating, Is she still active, apart of the family life, grooming herself, affectionate, doing what she likes to do. OR is she not eating, laying around all day, has muscle wasted so much that she is just skeleton (or close to it), not wanting to be loved, not going to her favorite places, not jumping o the couch because she has no energy, etc.

      This is where you have to take a subjective look at her life and see if she is 'ok for now' or not well and your holding on. I encourage you to do the quality of life scale on our site. This is more intensive than regular quality of life scales but you may find it useful.

      If she is still having a quality of life - then I would do sub-Q fluids if she tolerates it. If she runs from you, hates it, etc. then it is not worth damaging your bond.

      I also would suggest you thinking about how you want her last days to be and how you will say goodbye. If you think about that for a moment you may realize that you do not want her to suffer or be in pain - and you want her last day to be a GOOD one. This may help you draw the line in the sand on when it is 'time'.

      Cats do not have the same emotional response to pain and discomfort as humans do. But they do FEEL pain and suffering. Kidney failure makes them feel very very sick - like us with the flu. That is why they don't eat, don't have every, don't want to be around the family, etc.

      While you are going through this - take lots of pictures and videos - they will be priceless when the time comes to give your angel back to heaven.

      Hope this help!

    2. Thank you for your compassion and timely response.

      Lol know it's hard to believe in 16.5 y old, but my baby is actually a dog (forgot to specify species).

      Funny, though, she actually jumped up on the bed today to sleep, and went up a flight of stairs while I was preparing her food.

      I'm going to monitor her weight, willingness and ability to walk, whether she still comes and presses against me for a cuddle/petting, and ability to hold down food.
      I know I have a hard road coming up soon, and will face it head on once she seems to be disengaging first herself.

      In the meanwhile she'll get plenty of attention, and I'll crush and dissolve her pills in a syringe so we don't have to have the "pill fight" we've always had since she was young.

      Thanks again for taking the time to reply to me.

    3. Oh my - that was my fault - you did say 'mixed breed' - which I guess could be a mixed kitty. :) I'm so sorry.

      16.5 is long - but never long enough is it?

      You are doing awesome. Monitoring every day is important. Take pictures too from a 'birdseye' view - that will help you see if she begins to muscle waste.

      This time is now about caring - not curing. And quality! Have you seen this... it is a tear jerker but amazing!


  14. Mary,

    Just wanted to thank you again for your advice. Gordita (my puppy) managed to have 10 good days with absolutely no incontinence or throwing up, and daily walks. Her 2nd to last day I took her to the park, which she thoroughly enjoyed (based on her sustained and intense sniffing of everything in sight), but could only walk in 20-30 ft increments. She spent the rest of the day sleeping, and didn't want to walk at all the next day. I knew it was time.

    Dr. Amanda came over that afternoon. She provided Gordita with a gentle and anxiety free passing, and me with compassion and understanding. I am so grateful for her, you, and Lap of Love.
    It's a wonderful service, and she made a trying and tragic time that much easier.

    Thank you so much.


    1. Oh Josh - I am so sorry - I didn't even know you lived in South Florida (that is where I am from originally). Dr. Amanda is an angel and I am so happy she was the one to help you say goodbye. How amazing that you got 10 more good days - they were blessed days and then 'knowing' you did the right thing at the perfect time. You will have no regrets.

      Please don't hesitate to let your regular veterinarian know about Lap of Love and Dr. Amanda so that they know Gordito was in good and gentle hands.

      May you have only smiles on your face when you think of your baby.

      Hugs from california!

  15. In our 6 month of sub q (3x/week) with our 14yr old border mix. Bad days starting to outweigh the good. Having a hard time getting him to eat.moving to chix and rice this week. Also starting antacid to see if that helps. Last bloodwork in oct was 36BUN and 2.6 Creatine before that...just really hard to monitor food intake.

  16. Oh Jajevi, I'm so sorry to hear that it's less good lately. In kidney failure, the eating is almost a tale tell sign because they internally feel so bad. Don't stop with the fluids as it does help. The antacids will also help as the BUN does form ulcers over time. My thoughts are with you!

  17. My twelve year old Papillion Yorkshire was began labored breathing while sleeping and was on Lasix injections and enalapril and vedmedin. Then his BUN went to 127 and the creatinine was no longer on the chart. He began black tar diarrhea and orange bile vomit so he was put to sleep. Did I make the right choice?

    1. Hi Mr. Keebler - YES - you made the right choice - besides his blood values being VERY high and not conducive to a quality of life, the labored breathing is even more of a concern. Difficulty breaking is the worst thing ever and I could not agree with your decision more.
      Dr. Mary


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