Tuesday, February 17, 2009

Kidney Disease in Cats and Dogs Part I

Many cats and some dogs will develop renal (kidney) insufficiency as they age. Some cats and dogs may be born with malformed or dysfunctional kidneys or a congenital kidney disease which will result in renal insufficiency early on as well. What are the signs to look for? What can you do if your pet has been diagnosed? Listed below is a discussion of your options from both a conventional (Part I) and holistic veterinary perspective (Part II). Click here to view our Kidney Disease Support Program

Conventional Veterinary Perspective on Kidney Disease in Cats and Dogs

By Dr. David Gordon, Holistic Veterinarian

The kidneys are bean-shaped organs that operate as filtering mechanisms in the body. The kidneys filter out toxins in the blood such as metabolic wastes, drugs and excess mineral salts as well as regulate the acidity of the blood. The kidneys also help regulate blood pressure, the production of calcium and phosphorus metabolism, and produce a hormone that stimulates red-blood-cell production called erythropoietin.Since the kidneys perform so many important functions, it is easy to see why kidney malfunction would greatly impact the way your pet feels and behaves. Unfortunately, laboratory tests don’t typically show kidney insufficiency until your pet’s kidney function is about 65-70% deteriorated. Thus, it is extremely important to watch these signs in your pet and get regular laboratory tests to closely monitor their health.

Signs of Kidney Disease in Cats and Dogs

• Increased urination

• Increased thirst

• Weight loss

• Loss of appetite

• Vomiting

• Strong (ammonia-like) breath odor

• Pain,discomfort in the back

Please note that many of the above signs are also seen in pets that do not have renal insufficiency. Regardless, these are signs your pet has some type of health condition and a visit to your veterinarian is warranted.

Many times pet owners will notice some of the above signs and bring their pet in for a check-up. Depending upon the timing of bringing their pet in, more or less will be able to be done to help the pet. Initially the veterinarian will recommend some initial laboratory tests such as bloodwork, urine analysis and XRAYS (As a general rule, it is recommended that bloodwork and urine analysis be performed on pets over 6 years annually).
In the blood, three levels are especially important to test for kidney disease. These are creatinine, BUN (blood urea nitrogen) and phosphorous. BUN measures the amount of urea nitrogen, a waste product of protein metabolism in the blood. Urea is formed by the liver and then taken by the blood to the kidneys for excretion. Because urea is cleared from the bloodstream by the kidneys, a buildup in the blood is an indicator that the kidneys are not functioning properly. Creatinine and phosphorous are also important markers for kidney disease, as they are also products excreted by the kidneys.A urine analysis also provides important information regarding your pet’s kidney health. Specific gravity of the urine measures the degree to which your pet is properly concentrating urine. In addition, your veterinarian will look to see if there is protein in the urine. Healthy kidneys will remove the waste from the blood but retain the protein. Impaired kidneys may fail to separate blood protein from the wastes. At first, only small amounts of protein may leak into the urine but as time and the disease progresses, the amount of protein in the urine increases.

Once diagnosed, there are several avenues a pet owner can explore. In human medicine, dialysis and kidney transplantation are the main methods of treating people with advanced kidney disease. These options are extremely costly, time consuming and only available to a limited degree for pets. Treating kidney disease can be especially challenging particularly if the disease is only detected once the pet is in an advanced state. (Again, we cannot emphasize the importance of routine laboratory testing so that if your pet is diagnosed with kidney disease, you will have a greater opportunity to help your pet.)

The difficulty in treating pets with kidney disease is that the ability to remove metabolic waste products is often outweighed by the buildup of those toxins. The pet is not able to keep up with the regular detoxification required because the kidneys are impaired. Thus, the pet gradually becomes more toxic and the body chemistry becomes more acidic. Unlike liver disease where the body can build and repair new liver tissue, the nephrons (functional units of the kidney) are damaged forever and cannot be replaced. What is important is to help the functioning nephrons perform at an optimal level. Many times, pet owners are hoping unrealistically that their pet’s kidney function will miraculously improve—while it is possible to see improvement in kidney values—what is most likely to occur with conventional and holistic treatment is a decline in the rate of kidney deterioriation. In other words, if your pet’s creatinine level has jumped from 2.4 to 3.4 in a few weeks, treatments may help to keep the value from rapidly rising to 4.4 in the following week but most likely won’t ever return the values to normal (except in rare cases).
The goal of treatment is to help the pet to live as close to a normal life as possible, given the kidney disease diagnoses. Since the kidneys do not heal or regenerate new and functioning tissue, supplements and vitamins can help the healthy nephrons handle the additional burden. Intravenous and subcutaneous fluids can provide much needed relief for pets. Intravenous fluids are administered by your veterinarian at the veterinary hospital while subcutaneous fluids can be administered by you at home under the direction of your veterinarian. Fluids help to flush out the toxins and control acid-base imbalances. Pets can be given medication for nausea and vomiting. Many pets with kidney disease develop high blood pressure, anemia and ulcers as the disease progresses. These can be helped with medication and supplements as well. Phosphorous binders and Omega 3 fish oils (e.g. Amazing Omegas) are also helpful. High quality, low protein phosphorous diets have been proven to be helpful in lessening the metabolic tasks that must be performed by the kidneys and this is a very critical component in managing the disease. Finally, acupuncture can also be helpful because it increases blood flow to the kidneys.
  1. Thank you for the very informative article. You mentioned that the pet should have a high quality, low protein phosphorous diet, do you suggest any particular dog food? My current vet has her on Hill's k/d diet which I have heard some negative things about. Thank you again.

    ~One nervous pet owner

  2. In 2006 I noticed that my 14 year old cat was drinking more than usual. She was 'diagnosed' with early crf on the basis of blood tests which showed moderately raised levels of Creatinine and Urea (BUN).

    I switched her to a low phosphorus diet and her Creatinine levels are now only slightly raised, though her Urea is unchanged.

    Although she drinks more than she did in her youth, my cat is still concentrating her urine - her gravitation index is normal. She is in great shape for a 17 year old cat - she eats well, has a glossy coat and still jumps up on our beds.

    So was the diagnosis of early crf incorrect? If the gravitation index is still normal, maybe the term pre-crf would be more accurate. What do you think?