By Brenda Brown, DVM, CVA

Role of Kidneys:

The kidneys act to filter waste products from the blood and to retain nutrients, hormones, and other proteins for use in the body. The waste products are then excreted into urine. When more than 70% of the kidneys (specifically the nephrons) have been damaged the kidneys cannot do their job properly.

Common Signs of CRF:

• The number one sign is drinking and/or urinating excessively
• Vomiting
• Diarrhea
• Inappetance (anorexia)/ weight loss
• Lethargy
• Poor coat quality, failure to groom

Common Causes of CRF:

• Congenital malformations - genetically passed on
• Bacterial infections, viral infections
• Cancer
• Glomerulonephritis from a number of kidney–toxic things (ie antifreeze or Tylenol or amyloid)
• Non-specific – can be seen in older cats, or cats with other diseases that cause damage to the kidneys

How is CRF diagnosed:
Renal failure is usually diagnosed with a thorough exam including proper history, blood pressure, retinal exam and physical. Most cases require lab work including bloodwork and urinalysis to confirm the diagnosis. In some cases an x-ray and/or ultrasound may be required to get a definitive diagnosis.

Typically BUN (blood urea nitrogen) and creatinine, in conjunction with a dilute urine specific gravity indicate renal failure. Other electrolytes and proteins help diagnosis severity and give direction toward treatment.

CRF in cats is one reason to have annual testing done on your cat, especially if your cat is over the age of 7. Though it may or may not be preventable in your cat, early diagnosis can lead to possibly prolonging your cats life by years. Giving your cat WET FOOD as part of its daily food rations is also thought to help stave off the disease. FRESH WATER daily and/or FOUNTAINS are also aimed at attracting a cat towards frequent drinking and easing the burden on the kidneys.

What treatments are available?
Once the severity of the disease is ascertained some or all of the following may be employed to help your cat:

• Special diets (ie K/D or Renal LP): diets that are lower in protein and lower in phosphorous can reduce the level of waste products in the cat’s bloodstream.
• Phosphate binders (ie aluminum hydroxide): can be given to help prevent further damage to kidneys (must be given with a meal)
• Potassium supplementation: potassium (K) is often lost by the kidney when there is damage, this can lead to heart problems, and weakness, poor hair quality and lethargy. Supplementing may improve the overall quality of life as well as prevent other complications.
• Vitamins B and C supplementation: these are also lost by damaged kidneys and supplementing them can lead to improved health.
• Fatty acid supplements (ie Fish Oil and Vitamin E): these are powerful antioxidants and help the body defend against free radicals – help in healing and prevent further kidney damage.
• Anti-emetics (anti–vomit medicine – ie metoclopromide) and antacids (ie famotidine): the kidneys also alter the pH of stomach acid and giving antacids or other drugs aimed at nausea can improve the cat’s appetite and keep them strong.
• Blood Pressure Medicine (ie benazepril): another protein lost by damaged kidneys can affect blood pressure, it is also thought that by regulating the blood flow to the kidneys with these drugs we can improve the functioning of the undamaged kidney.
• Erythropoeitin (EPO) for anemia: EPO is lost by damaged kidneys. Without it the body does not know it needs to replenish its red blood cells. As a result many CRF patients have anemia (low red blood cell count) and benefit from the administration of exogenous EPO.
• Subcutaneous Fluid Administration: Many CRF patients benefit from the added fluids we can give them under their skin. It may seem uncomfortable, but it rarely hurts and most cats learn to accept the treatment because they feel so good after having had the treatment.
• IV Fluid Diuresis and Hospitalization: In severe cases, CRF patients benefit from a hospital stay of 1-5 nights wherein they are given IV Fluids to flush their system of toxins.
• Acupuncture: Acupuncture has been shown to lower blood pressure, increase appetite, decrease nausea, and improve renal function in CRF patients.

What is the cost/prognosis?
Costs vary depending on severity, but in general it is not overly expensive to treat, although frequent blood tests may add to the cost.

In general, once a diagnosis of CRF has been made, there is no going back. With appropriate treatment in the appropriate patient, your cat may have years of good, quality life ahead. In some, treatment is not well tolerated or the disease is too far progressed and weeks to months may be all your cat has. It is highly variable, and most always worth treating to see how well your cat can do.

If you have any questions, please contact your veterinarian.