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 excrete waste products, produce hormones and regulate the chemical composition of body fluids, all of which are crucial functions for your pet’s health. Chronic kidney failure will cause kidney function to decrease slowly over a long period of time so physical symptoms will appear gradually.

Acute kidney failure is characterized by a sudden decline in kidney function that causes changes in body chemistry such as alterations in fluid and mineral balances. These abrupt changes will negatively affect almost every body system. Because kidney function declines so quickly, the physical symptoms are more dramatic with acute kidney failure.

Causes of kidney failure

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

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 kidney failure — kidneys “wearing out” due to old age — it is possible to treat it. Outdoor dogs and cats are at greater risk of kidney failure because they are more likely to be exposed to antifreeze, which is fatal when ingested (even in small amounts).

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

What types of pets may experience kidney failure?

The prevalence of kidney failure increases as pets age. Cats and small dogs may show early signs of kidney failure at 10 to 14 years of age and large dogs can experience kidney failure much earlier. Cats are more likely than dogs to experience kidney failure and certain breeds of 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 order to establish baseline values. These baseline values can be used for comparison later in your pet’s life to determine if your pet is experiencing kidney problems or other disease.

Treating kidney failure

Laboratory tests are crucial to diagnose both chronic and acute kidney failure and to rule out other diseases. Your veterinarian will take blood and urine samples from your pet to test for values related to different kidney functions and ensure that an infection is not causing the physical signs of kidney disease.

While acute kidney failure is potentially reversible, chronic kidney failure is not and an acute kidney problem may develop into a chronic problem. Pets experiencing chronic kidney failure may not respond to treatment at all or they may live for another few months or years. Your veterinarian will take into account your pet’s history, physical examination and laboratory test results to determine if your pet is suffering from acute or chronic failure. Your veterinarian may also wish to conduct a kidney biopsy to give you an accurate prognosis of your pet’s condition and life expectancy.

Chronic and acute kidney failure can be very serious, even life-threatening conditions that require hospitalization. Treatment options 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 veterinarian will want to keep a close eye on his condition with frequent blood and urine tests. Make sure to give your pet any and all prescribed medications and diets according to your veterinarian’s instructions. If necessary, some pet owners can administer subcutaneous (under the skin) fluids at home and your veterinarian will instruct you on how to do this.

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