When talking about renal dysfunction or kidney disease it is very important to first understand exactly how the kidneys function. Their main functions are to: filter blood, process and eliminate excess protein waste into the urine, maintain red blood cells and balance the body’s electrolytes, water, and acids. That’s a heck of a lot to do!

Kidney dysfunction occurs when one or more of these functions are impaired. Unfortunately, our pets’ bodies are great at compensating for the loss of function and we often don’t become aware of a problem until there is already a significant percentage of function lost (approximately 66-75% loss). Once the kidneys are functioning at about 25-33% of their normal capacity there will be abnormalities that we can see on bloodwork. The earliest kidney enzyme to show elevations in the presence of kidney dysfunction is SDMA. It is also important to note that some diseases can occur simultaneously with kidney disease including metabolic disorders such as Cushing’s or Diabetes.

Some causes of kidney dysfunction include:  

  • Toxin ingestion (ex: grapes, antifreeze, lilies)
  • Kidney or urinary bladder stones
  • Autoimmune diseases and some viruses
  • Parasites or bacterial infections such as Leptospirosis
  • Cancer
  • Normal aging change



You may be wondering; how will I know if my pet has renal dysfunction? The answer is: sometimes you can’t! As a general rule, it is good to have an annual (once yearly) senior panel done on your pet once they are 6-7 years old. By screening patients around this time, we are often able to pickup on slight elevations in kidney enzymes (such as SDMA) and begin preventative measures or treatments to help keep your loved ones healthier longer.

As renal dysfunction (or kidney disease) worsens, you may notice some of the following general signs. Please keep in mind that these signs can also occur with a variety of other diseases, so it is very important to talk to your veterinarian as soon as you notice them.

  • Drinking and/or urinating more than usual
  • Lethargy (decreased energy or activity level)
  • Reduced appetite
  • Weight loss (or generalized loss of muscle/conditioning)
  • Vomiting
  • Oral ulcers and bad breath


There are many nutritional changes that need to be made to your pet’s diet once they have been diagnosed with kidney disease. The initial goal of treating kidney disease is first and foremost to eliminate and treat the underlying cause (whenever possible). Some of the secondary goals are to decrease protein in the diet, bind excess phosphorous, maintain good hydration and lower blood pressure. Some examples of available diets are: Hill’s Prescription k/d Kidney Care Diet, Royal Canin Renal Support Veterinary Diet, and Purina Veterinary Diet NF Kidney Function. There are also other diets available without a prescription that may be more appropriate for initial management of kidney disease (depending on other factors such as simultaneous Diabetes, etc). If you have any questions regarding your pet’s diet, we are ALWAYS happy to discuss nutrition!