Also known as renal failure, kidney failure occurs when the kidneys are unable to function properly.

Healthy kidneys

Some functions that healthy kidneys perform include:

  • Remove metabolic waste products from your pet’s blood
  • Regulate the volume and chemical composition of body fluids
  • Produce hormones that stimulate the production of red blood cells
  • Control blood pressure

After the kidneys have done their job, the by-products produced by the metabolic process are excreted in your pet’s urine.

Two kinds of kidney failure

Chronic kidney failure occurs when the kidneys can no longer excretewaste products, produce hormones and regulate the chemical compositionof body fluids, all of which are crucial functions for your pet’shealth. Chronic kidney failure will cause kidney function to decreaseslowly over a long period of time so physical symptoms will appeargradually.

Acute kidney failure ischaracterized by a sudden decline in kidney function that causeschanges in body chemistry such as alterations in fluid and mineralbalances. These abrupt changes will negatively affect almost every bodysystem. Because kidney function declines so quickly, the physicalsymptoms are more dramatic with acute kidney failure.

Causes of kidney failure

The most common cause of kidney failure is kidneys “wearing out” withage. Kidney failure can also be caused by ingesting toxic substances,including antifreeze, some anti-inflammatory drugs and certain kinds ofantibiotics. Additionally, some infections may cause kidney function todecline.

Physical signs of kidney failure

The following signs may be indicative of kidney failure. Notify your veterinarian if you see any of these signs in your pet.

  • Excessive drinking
  • Increased urination
  • Lethargy
  • Vomiting
  • Bad breath
  • Not eating for more than one day
  • Weakness or lack of coordination when walking
  • Depression
  • Weight loss or wasting of muscle tissue

Preventing kidney failure

While it is not possible to prevent the most common cause of kidneyfailure — kidneys “wearing out” due to old age — it is possible totreat it. Outdoor dogs and cats are at greater risk of kidney failurebecause they are more likely to be exposed to antifreeze, which isfatal when ingested (even in small amounts).

There are no specific ways to prevent kidney failure, but generalrecommendations include allowing your pet frequent attempts to urinate;providing access to fresh, clean water at all times and avoidingexposure to antifreeze by minimizing the amount of unsupervised timeyour pet spends outdoors.

What types of pets may experience kidney failure?

The prevalence of kidney failure increases as pets age. Cats and smalldogs may show early signs of kidney failure at 10 to 14 years of ageand large dogs can experience kidney failure much earlier. Cats aremore likely than dogs to experience kidney failure and certain breedsof pets are more likely to develop kidney problems than others.

All breeds of dogs and cats can be affected by kidney problems though,so your veterinarian may recommend blood work at an early age in orderto establish baseline values. These baseline values can be used forcomparison later in your pet’s life to determine if your pet isexperiencing kidney problems or other disease.

Treating kidney failure

Laboratory tests are crucial to diagnose both chronic and acute kidneyfailure and to rule out other diseases. Your veterinarian will takeblood and urine samples from your pet to test for values related todifferent kidney functions and ensure that an infection is not causingthe physical signs of kidney disease.

Whileacute kidney failure is potentially reversible, chronic kidney failureis not and an acute kidney problem may develop into a chronic problem.Pets experiencing chronic kidney failure may not respond to treatmentat all or they may live for another few months or years. Yourveterinarian will take into account your pet’s history, physicalexamination and laboratory test results to determine if your pet issuffering from acute or chronic failure. Your veterinarian may alsowish to conduct a kidney biopsy to give you an accurate prognosis ofyour pet’s condition and life expectancy.

Chronic and acute kidney failure can be very serious, evenlife-threatening conditions that require hospitalization. Treatmentoptions include:

  • Intravenous fluids
  • Special diet to decrease protein and salt consumption
  • High blood pressure medication
  • Control of vomiting and gastrointestinal problems with diet and drug therapy
  • Anemia (decreased red-blood cell production) medication
  • Potassium supplements
  • Hospitalization and supportive care

When your pet is well enough to leave the hospital, your veterinarianwill want to keep a close eye on his condition with frequent blood andurine tests. Make sure to give your pet any and all prescribedmedications and diets according to your veterinarian’s instructions. Ifnecessary, some pet owners can administer subcutaneous (under the skin)fluids at home and your veterinarian will instruct you on how to dothis.

Following instructions and workingclosely with your veterinarian during your pet’s treatment will giveyour pet a better quality of life and possibly help prolong his life.

Copyright © 2009, American Animal Hospital Association

Reprinted with permission from the American Animal Hospital Association.