Chronic Kidney Disease

What is chronic kidney disease?

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Chronic kidney disease is a common health condition in cats and dogs, especially those who are in their senior and geriatric years. The onset of chronic kidney disease is usually slow and the signs are usually generalized and non-specific, usually your pet is “just not doing well”. Some symptoms may also not be noticed until your pet has progressed to a later stage of kidney disease. These symptoms can include, but are not limited to:

  • increased water consumption
  • changes in urination habits (increased, decreased, blood in the urine)
  • weight loss
  • not eating
  • poor hair coat
  • vomiting

If your older pet is showing these symptoms, kidney disease may be the problem. A proper work up is needed so that the veterinarian confidently diagnose kidney disease and decide on the best treatment for the current stage of kidney disease your pet is dealing with. Unfortunately, kidney disease is progressive, ultimately resulting in kidney failure. Once diagnosed, focus turns to monitoring, slowing the progression and maintaining quality of life.

Stages of chronic kidney disease

The stages of kidney disease are numbered 1 through 4. Stage one is the least severe, progressing to stage 4, which is the most severe. Initial testing to identify what stage of kidney disease your pet is in requires blood and urine testing. Learn more about kidney disease staging here.

Stage One

Blood work shows the parameters associated with kidney function are normal. Urine testing may show slight abnormalities, such as mildly elevated protein levels or decreased urine concentrating ability. On a physical exam the veterinarian may notice abnormal kidney size or shape (noticed by palpating on exam, or imaging such as X-rays or ultrasound). Most pets in stage one kidney disease will not be showing any major outward symptoms.

Stage Two

Your pet may still not be showing any outward symptoms of kidney disease. Pets in stage two will have all the concerns as a pet in stage one, however stage two is where we will see mild elevations in kidney parameters on the blood work.

Stage Three

Pets with stage three kidney disease are now showing visible symptoms of kidney disease. Blood work shows definite elevations in the kidney parameters. Urinalysis will show low specific gravity, indicating a worsening ability to concentrate urine. Protein levels in the urine may actually decline as kidney function worsens into stage three.

Stage Four

Stage four kidney disease pets are sick and going into kidney failure. They will be showing many of the symptoms associated with kidney disease. Blood work will show major elevations in the kidney parameters, urine specific gravity will be very low indicating the kidneys have low to no ability to concentrate urine. At this stage your pet is in kidney failure, and quality of life needs to be monitored.

Diagnostics and Monitoring

Diagnosing and monitoring your pet’s kidney disease will require ongoing follow up appointments with your veterinarian frequent blood work and urine testing.

Blood work

Slide and PCV tube preparation for a CBC

Slide and PCV tube preparation for a CBC

Complete Blood Count (CBC): this test is done on whole blood. It checks the white and red blood cells for signs of anemia and of infection.

Blood Urea Nitrogen (BUN): is a waste product of metabolism, it is extracted by the kidneys. In the case of kidney disease, it is not properly removed by the kidneys into the urine, leading to build up of it in the bloodstream.  Blood work can check for levels of BUN building up in the bloodstream, the higher the level of BUN, the more severe kidney disease.

Creatinine: is another waste product of metabolism, and builds up in the bloodstream just as BUN does if the kidneys can’t remove it properly. It is a more sensitive test when it come to motoring kidney function and is usually always tested alongside BUN.


Electrolytes: include blood sodium, potassium and chloride levels. In kidney disease we are mostly concerned with the potassium and sodium levels. If your pet has increased urination as part of their kidney disease symptoms, they may also have an electrolyte imbalance. Low potassium levels are usually the result of kidney disease and may lead to seizure activity.

SDMA (symmetric dimethylarginine): is a fairly new blood test for kidney function. SDMA is a renal biomarker specific to kidney function. It is a more reliable indicator of kidney function than creatinine and BUN allwoing veterinarians to detect chronic kidney disease in it’s very early stages. If stage one or two kidney disease is suspected in your pet, this can be a very valuable test as it will show up as elevated before BUN and creatinine. This test is exclusive to Idexx Laboratories.

Phosphorus:  is mineral essential to your pets health.  However, excess phosphorus is eliminated through the kidneys. In pets with kidney disease too much phosphorus can be a problem.  Excess phosphorus in their diet can lead to buildup of phosphorus in their bloodstream. This can cause the kidney disease to progress faster and interferes with calcium function in the body.

Calcium: phosphorus levels in the bloodstream can have a direct influence on calcium levels in the bloodstream. Proper calcium levels are essential to proper body function. Therefore monitoring calcium levels alongside phosphorus levels is important when monitoring kidney disease.

Urine testing

Refractometer, urine sample, urine chemistry sticks, sediment slide

Refractometer, urine sample, urine chemistry sticks, sediment slide

Urine Specific Gravity (USG): this test is part of a complete urinalysis. It checks your pet’s ability to concentrate urine. Pets with kidney disease have an inadequate ability to concentrate their urine. The lower the USG, the more severe the kidney disease. USG is best tested on a first morning urine sample, before they have consumed any water.

Urine Stick: this is also a part of the complete urinalysis. The urine stick test tests many parameters in the urine. In the case of kidney disease, protein is what we are interested in. Elevated urine protein levels can indicate early kidney disease.

Sediment: The final part of the complete urinalysis  is the sediment evaluation.  This can check for signs of a urinary tract infection, as well as renal (kidney) cells in the urine. Renal cells seen in the urine is an indication of kidney disease.


Imaging: diagnostic imaging such as X-rays or ultrasound may be recommended to determine kidney size. Imaging will also help rule out cancer of the kidneys.

Blood Pressure: pets with kidney disease can also have elevated blood pressure. If your pet is has high blood pressure this will add another factor that needs to be considered when treating your pet’s kidney disease.


Treatment for chronic kidney disease will vary from pet to pet. Treatment will also need to be adjusted as the disease progresses. Remember there is no cure for kidney disease, the goal of treatment is to manage and monitor your pet to keep them comfortable as long as possible. Management of chronic kidney disease involves a proper diet, fluid therapy, medications and supplements.



If your pet has been diagnosed with kidney disease, it’s a good idea to change them over to a kidney diet. These diets are specially formulated to help support your pet’s kidneys. The are formulated with:

  • concentrated energy- so if your pet isn’t eating well or not wanting to eat a lot, they can still meet their calorie requirements, reducing the potential for weight loss.
  • restricted amounts of high quality proteins- the higher the quality of protein, the less waste created in the body. This lessens the workload for the kidneys, as they do not have to remove as much waste into the urine.
  • contain low phosphorus levels- as mentioned earlier, excess phosphorus in the body is eliminated through the kidneys. By lowering the phosphorus levels in the food, the kidneys will have less work to do to manage phosphorus levels in the body.
  • have reduced sodium levels- excess sodium is also eliminated by the kidneys. By lowering the sodium in the diet, the workload placed on the kidneys will be less. Sodium also can affect your pet’s blood pressure. Since pet’s with kidney disease can also have high blood pressure, a low sodium diet is beneficial for supporting both the kidneys and blood pressure.image

Kidney diets are available commercially at veterinary clinics as prescription diets. They come as both canned and kibble formulations. You may also choose to cook for your pet. If you go the home cooked route, please make sure your recipes are properly balanced for your pet and their kidney condition by consulting a pet nutritionist. Veterinary nutritionist Hillary Watson has an entire cookbook dedicated to kidney diets.

Fluid Therapy

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Maintaining your pet’s hydration is critical in the management of kidney disease. Make sure your pet always has access to fresh, clean drinking water. Feeding a canned or homemade kidney diet can also provide extra water to your pet. Eventually, supplemental fluid therapy will be recommended. This is usually done by giving your pet subcutaneous fluids (fluids under the skin). It can be done in-clinic or if your pet tolerates it well and you are not squeamish around needles we can teach you how to do this at home. The frequency and amount of fluid administrated will be determined by the veterinarian. If your pet is in a kidney disease crisis (weak, dehydrated, not eating or drinking, overall very sick and overall not doing well) IV fluid therapy and hospitalization for a few days will be recommended to attempt to correct the body’s fluid imbalances and stabilize your pet enough to continue with care back at home.


There are no medications to treat the kidney disease itself. Medications prescribed to you pet with kidney disease are usually to treat secondary issues. Antibiotics may be needed for urinary tract infections and blood pressure medications may also be indicated if your pet has concurrent high blood pressure. If your pet is on a any medications prior to the diagnosis of kidney disease, it’s a good idea to review all current medications with your veterinarian to ensure the medications are safe for the kidneys.


Supplements are where we go to manage kidney disease. There are various supplements available, each of them helping out the kidneys in a different way.


Phosphate binders can help block the absorption of phosphorus from your pet’s food into their system. As mentioned earlier, keeping phosphorus levels low for a kidney disease pet is beneficial.

Potassium supplements may be needed if your pet’s potassium level drop to low. These supplements can sometimes help with lethargy and weakness.

Specially formulated probitoic/prebiotic supplements can be beneficial for helping pets with kidney disease. These bacteria metabolize urea, uric acid and creatinine, all which are waste products of metabolism that the kidneys have to deal with. By “feeding” these waste products to the pro/prebiotics, the kidneys won’t have to deal with them.

Omega fatty acids have shown to reduce inflammation and reduce glomerular hypertension (the glomerulus is a part of the kidney), thus improving kidney function.

Chinese herbs are also available for helping kidney function. Animals are often highly responsive to appropriate herbal formulas. After an assessment with one of the veterinarians that practices Traditional Chinese Medicine, the appropriate herbal supplement can be prescribed. Herbal supplements are usually used long-term to support your pet with kidney disease.

Calcitriol is a form of active vitamin D and it increases calcium levels in the blood. This is generally recommended when your pet’s blood calcium and phosphorus levels and ratios become abnormal.


As you can see chronic kidney disease is a major health concern to manage. It takes a lot of time, care and effort on your part to help slow the progression and keep your pet comfortable and feeling good. If you have any questions about chronic kidney disease, please give us a call!