Chronic Renal Failure (CRF) – Kidney Disease in Cats

Kidneys regulate electrolytes and eliminate waste products. With CRF, kidney function is diminished, so waste accumulates in the body, poisoning the cat. If the condition is detected early and treated, cats may have many happy, active years before they succumb to the condition.

Cats can get CRF at any age, but it’s most common in older cats. Abyssinian, Balinese, Burmese, Maine Coon, and Russian Blue cats have a slightly greater risk of developing CRF than other breeds.

Causes of Chronic Renal Failure in Cats

In addition to environment, age and genetics likely play a role in the development of CRF. Other possible contributing factors include high blood pressure, acidified diets that are low in potassium, and dental disease. Regular dental care can help prevent the development of bacteria in the mouth that contributes to CRF.

Symptoms of CRF in Cats

The earliest symptoms of CRF are increases in both thirst and urination. Cats with more advanced CRF will have some of the following symptoms:

• Nausea/gagging/vomiting/gastritis
• Drooling
• Licking lips
• Dehydration
• Decreased appetite
• Weight loss
• Muscle loss
• Lethargy/depression
• Weakness
• Oral ulcers
• Noise sensitivity
• Ammonia smell
• Dull coat
• Constipation

At the later stages, cats may experience detached retina, very low body temperature, coma, or convulsions. Many older cats develop hyperthyroidism, which can make CRF symptoms less noticeable initially.

Other Conditions That May Occur with CRF

There are a number of conditions that often occur in conjunction with CRF, including:

• Anemia – Causes weakness and loss of appetite; symptoms include pale or bluish nose, gums, or tongue. Treatment options include medication and transfusion.
• Constipation– Caused by inadequate water consumption. Treatment includes adding more fiber to the cat’s diet, adding water to the cat’s food, and/or administering subcutaneous (Sub-Q) fluids (which are injected into the scruff of the neck).
• Dehydration – You can check for this by pinching a bit of skin on the cat’s neck – if it doesn’t immediately fall back, the cat is dehydrated. Dehydration can be treated by encouraging the cat to drink more or administering Sub-Q fluids.
• Hypertension – This serious condition can cause more kidney damage, cardiovascular problems, blindness, and seizures. Diagnosis can be made by a veterinarian, and the condition is treatable with medication if discovered early on. In some cases, blindness can be reversed if the cat receives medication within approximately 24 hours of onset.
• Hypokalemia – Caused by potassium depletion, symptoms include muscle weakness, difficulty in holding the head up, stiffness, tiring easily, and difficulty moving. Veterinarian-prescribed potassium supplements can be used to treat the condition.
• Hyperkalemia – With this condition, excess potassium can lead to heart failure and other problems. Owners may accidentally cause this by overdosing their cats on potassium if they attempt to supplement without guidance from a veterinarian.
• Mouth and Tongue Ulcers – These contribute to weight loss and speed a cat’s decline. Bad breath may be a symptom. Ulcers can be treated with antibiotics and other medications.
• Stomach problems – Nausea, vomiting, and stomach irritation are common in CRF cats, and can contribute to anorexia and weight loss. A veterinarian can prescribe medications that will alleviate nausea and other stomach problems.

Older cats should be tested regularly for CRF during veterinary check-ups. Common at-home CRF treatments include dietary changes and Sub-Q fluid therapy. In the case of life-threatening dehydration, cats may require intravenous (IV) fluids. These are administered by a veterinarian, and most cats receiving them must stay in the hospital for 1-5 nights. Once the cat is rehydrated, she can usually come home, but her owner may need to administer subcutaneous (Sub-Q) fluids at home.

Many cats with CRF suffer a crisis in which they become very ill, appear to be at death’s door, and then bounce back completely for quite some time. Eventually these crises get closer and closer together, and the owner must decide when it is time to say goodbye. In the interim, with proper treatment, a CRF cat can enjoy a high quality of life.

How to Administer Sub-Q Fluids to Cats with CRF

Owners inject fluids into the scruff of the cat’s neck using a home injection kit comprising an IV fluid bag, tube, and needle. While Sub-Q does not repair kidney tissue, CRF cats receiving fluids live longer and feel better.

Ideally, you’ll have a two-person team so that one person can distract the cat with toys, food, or petting while the other does the injection, but the procedure is manageable with one person. When administering Sub-Q fluids at home, first check for holes in the IV bag by gently squeezing it—a hole means that the fluid is contaminated.

Fluids can be heated slightly by running warm water (body temperature) over the bag to make the injection more comfortable for the cat. Fluid should not be warmer than tepid as this could be dangerous, so owners who choose to warm fluids should be very careful not to warm them too much. A microwave should not be used because it heats unevenly.

Hanging the bag high above the cat helps the fluid flow more quickly. Very squirmy cats can be wrapped in a towel to prevent them from accidently dislodging the needle. Staying calm during the procedure will help your cat to stay calm as well.

Have a favourite treat or food on hand to give to the cat during or immediately after the injection to create a positive association with the procedure. Cats that know they will soon receive a reward tend to be better behaved.

Although it sounds intimidating, as these pictures indicate, it’s actually quite a simple procedure and a veterinarian can provide guidance and training, working with you for the first few injections until you’re comfortable doing it alone. You can view a video of Sub-Q fluid administration here.

Sub-Q fluids may be given once a week, every other day, or daily, depending on the severity of the CRF and the cat’s tolerance of fluids. Directly after injection, most cats have either a “camel hump” on their backs or a water pouch on their tummies or legs. This can last for up to 24 hours, but may recede more quickly.

Dispose of used needles in a sealed container that is labelled so that no one will accidentally open it up and stick themselves. Needles should never be used more than once, and if the needle becomes contaminated (you accidentally drop it on the floor or the cat squirms and it falls out), start fresh with a new needle.

Mistakes many people make when first administering Sub-Q fluids include accidentally pushing the needle right through the cat’s fold of neck skin and out the other side or jabbing themselves with the needle. Also, if the owner accidentally hits a muscle, the cat will react and the liquid flow will stop. With a bit of practice, the procedure gets much easier and mistakes are less likely.

Special Diets for Cats with CRF

While dietary changes cannot reverse kidney damage, they can slow the progress of the illness and improve your pet’s quality of life. In some cases a veterinarian may recommend a diet low in salt, protein, and/or phosphorus, though not all veterinarians agree that a low-protein diet is beneficial, and new research suggests that the risks of low-protein diets may outweigh any benefits they might provide (Hines, 2011).

Some cats with CRF refuse food, particularly if a new food is introduced. Switching a cat’s diet should be done a little at a time, mixing ever-increasing amounts of the new food in with the old food until the cat is eating the new diet. This may take up to a month if you have a very finicky cat. Cats with CRF should be weighed frequently to ensure that they are eating enough.

Adding a small amount of pumpkin to a CRF cat’s diet is a good idea, as it remedies the constipation that often accompanies kidney failure and may provide additional health benefits as well. Approximately one tablespoon per day is often sufficient, though some cats may need a little more. Use pure canned pumpkin, not pie filling.

Appetite Loss in Cats with CRF

Some cats lose their appetites completely with CRF and require appetite stimulants, or even syringe-feeding by hand or via a tube introduced into the stomach in extreme cases. However, many owners are able to coax their cats to eat with favourite foods and treats. CRF cats should be given healthy treats that are low in sodium. But in the case of a cat that isn’t eating at all, if “junk food” treats are the only thing she’ll consume, they’re better than nothing.

Heating food slightly and adding water, tuna juice, clam juice, beef broth, or chicken broth can encourage cats to eat. If using broth, make sure that it doesn’t contain onions, as they are toxic for cats. Broth should also should be salt-free (avoid bouillon, which is very salty).

Many cats love “people tuna.” Canned tuna designed for humans is not nutritionally complete for cats, but it’s okay to mix a little in with regular cat food to encourage a sick cat to eat, or give it as a treat from time to time. Some cats respond to a little catnip mixed into their food as well.

Other tricks that are particularly beneficial for older cats include cutting food into smaller pieces, putting it in a mound rather than flat in the dish, and putting the food dish on a stand so that it’s slightly higher. Hand feeding or placing food on the cat’s paws or mouth works with some cats.

Additional Hydration for Cats with CRF

It’s critical to ensure that cats with CRF take in plenty of water. Bowls of water should be provided at multiple locations around the house to encourage the cat to drink, and you can mix a little water in with the food as well. As most cats prefer free-flowing water, investing in a fountain-type cat water dish is a good idea.

Hemodialysis to Treat Kidney Disease in Cats

Cats that suffer renal failure may be treated with hemodialysis, which involves inserting a catheter into the cat’s jugular vein, extracting blood to pass it through an artificial kidney that filters waste products, and then returning the blood to the cat. This takes 3-5 hours, and approximately 3 sessions are required per week.

There are not many veterinary facilities equipped to offer hemodialysis for cats at this time. For more information on hemodialysis and a list of facilities that offer it for pets, see veterinarian Wendy Brooks’ Kidney Dialysis, Is It For Your Pet?

Kidney Transplants for Cats

A kidney transplant can add 2-6 years to a CRF cat’s life, though this will vary depending on the age of the cat at the time of the transplant. One cat has survived for 10 years after a transplant.

As with any surgery, there are a number of risks, both during the operation and afterward, but feline kidney transplants have advanced to the point where 80-90% are successful. However, at this time there are not many facilities that offer the procedure.

There are ethical issues surrounding feline kidney donation. Generally, donors are shelter cats, and the shelter will only allow the donation to proceed if owners of the recipient cat plan to adopt and care for the donor cat. Ideally, the sick cat gets a life-saving donation, while the shelter cat receives a loving home for life.

Cats undergoing kidney transplants require 1-3 weeks of intensive in-hospital care after surgery. When the cat is able to come home from the hospital, close monitoring, follow-up veterinary care, and medication are required. Cost ranges from $4,500-$8,000.

Other CRF Issues

Some CRF cats with low potassium levels experience muscle weakness that can make climbing and jumping difficult or painful. If your cat appears to be having trouble, adding ramps or stepping stools so that she can reach her favourite perches can be helpful.

Cats with CRF usually need to have their litter boxes changed more often as they urinate more frequently. If you have a CRF cat, you may find that you go through kitty litter more rapidly than in the past.

CRF cats should have up-to-date ID tags and a microchip implant if possible, as they need a higher level of care than healthy cats. If lost, a CRF cat could become very ill or even die quickly without proper nutrition and hydration support.

For more information on cat symptoms, medical conditions, and treatments, visit the Cat Health and Safety page. For a full list of cat articles, see the main Cats page.

This article is provided for informational purposes only and is not intended as a substitute for veterinary consultation and care.

Reference: FelineCRF.org: Comprehensive information on CRF causes, symptoms, treatments, and care, as well as information regarding kidney transplants