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Feline chronic kidney disease (CKD) is one of the most common conditions affecting older cats and results in a progressive decline of kidney function over time. It is estimated that up to one in three cats will develop chronic kidney disease at some point in their life with an increased incidence with age.

A cat’s urinary system consists of the two kidneys which connect to the bladder via two ureters, the urethra then empties the urine from the bladder. Kidneys have several vital functions, including removal of the waste products, maintaining the body’s water levels, producing certain hormones and regulating most electrolytes. 

There is no cure for CKD, however with an early diagnosis coupled with appropriate and careful management, many cats are able to live a quality life for extended periods, often years.

Causes of CKD

• Idiopathic chronic tubulointerstitial nephritis of unknown cause (majority of cats)
• Polycystic kidney disease (Persians, British Shorthair)
• Certain kidney tumours such as lymphoma
• Kidney infections (these carry the best prognosis if treated early)
• Toxins such as Vitamin D
• Ureteral obstructions (kidney stones)
• Glomerulonephritis

Common Symptoms of CKD

• Weight loss
• Increased drinking and increased urine production
• Pale gums/anaemia
• Reluctance to eat/poor appetite
• Depression/lethargy
• Gingivitis/oral ulcers
• Vomiting
• Bad breath
• Poor coat condition
• High blood pressure

Diagnosis

Kidney disease can be classified as either acute, meaning sudden in onset, or chronic, meaning slowly progressive. Acute renal disease is termed Acute Kidney Injury (AKI). The most common causes of AKI in cats include toxins such as lilies or certain medications, kidney infections or kidney stones.

Feline chronic kidney disease occurs much more gradually as it is a progressive disease. Up until late 2015, CKD was diagnosed in cats by detecting elevated blood creatinine paired with a poorly concentrated urine sample. Cats are able to live normally on as little as 30% of their kidney function meaning we were unable to diagnose CKD until about 75% of their kidney function was lost.

In December 2015, Idexx Laboratories released a new blood test to diagnose CKD called SDMA. SDMA is very specific to kidney function and picks up CKD when only 40% of the kidney function is lost. This means we are able to diagnose cats about 17 months earlier which will have a positive impact on their early treatment.

Many of our diagnosed cases of CKD are detected during senior wellness screens. This truly emphasises the value of performing regular routine wellness screening on all our patients.

Once CKD is diagnosed, it is important to proceed with staging in order to individualise treatment. Staging involves performing blood pressure measurements, thyroid testing and obtaining further urine tests to look for infection and protein loss. Some cases may also require imaging of the kidneys with x-rays and/or ultrasound. It is important to periodically repeat staging tests as the disease is often progressive. The IRIS staging will help guide what treatment recommendations are best for your cat. You can find more information on IRIS staging on their website: www.iris-kidney.com.

Treatment and Management of CKD

Dietary management

Dietary management is a crucial part of your cat’s treatment and includes two main aspects: preventing dehydration and feeding a specifically formulated renal diet.

Preventing dehydration

• Water is critical for CKD cats because their kidneys have lost the ability to concentrate urine.
• Ensure that your cat has permanent access to multiple sources of fresh water. Place water bowls at several extra places in areas where your cat has access e.g. upstairs, on the porch, downstairs, outside. Most cats prefer their water to be away from their eating areas.
• Offer more wet food or try adding water into the food. Start with small amount and gradually increase as your cat accepts it. Try to minimise dry food.
• Keep water bowls very fresh and change regularly.
• Work out what your cat’s specific drinking vessel preferences are; some like drinking from shallow water bowls, some prefer the bowl filled up to the brim, and some prefer to reach their heads down into a water container. Experiment to see which your cat likes best.
• Offer filtered, distilled or bottled water.
• Try a pet “fountain”. These are available from pet shops or online.
• Leave some water in the bottom of the sink, bath or shower.
• We can teach you how to administer subcutaneous fluids to your cat. This involves injecting fluids under the skin at home or alternatively as an outpatient at our hospital

Commercially available prescription renal diets

• Royal Canin and Hills Nutrition have both developed their own specially designed renal diets for cats available in both a wet and a dry formula. Of all the studies into treatments for CKD, dietary modification has been shown to have the most positive long term effect by increasing life expectancy in addition to reducing symptoms thus giving the cat a better quality of life.
• The prescription renal diets contain moderately restricted protein, phosphorus and sodium whilst supplementing B vitamins, potassium, omega-3 fatty acids and fat content.
• Dietary changes should never be made when your cat is unwell as this can cause them to develop food aversion.
• Renal diets must be introduce very gradually (over 1-3 weeks) to increase acceptance.

Home prepared renal diets

• Feeding a home prepared diet as the only source of food for a CKD cat makes it extremely difficult to ensure that it is nutritionally balanced. CKD cats are susceptible to developing a variety of different electrolyte and mineral imbalances. In a home environment, it is not realistic to expect to be able to analyse the nutritional content of each ingredient.
• Having said that, if your cat flatly refuses to eat renal prescription foods, a home cooked or raw meat based diet can be another option. Cats fed on a home prepared diet may need to be given phosphate binders to help reduce absorption of dietary phosphate. A local Perth company Raw Meow produces a balanced raw meat based diet with lowered phosphate content that may be suitable for your CKD cat.

Intensive care/hospitalisation

If your cat is very ill and dehydrated, we will suggest admission into our hospital to allow administration of intravenous fluids.  This is needed to correct their dehydration and helps flush toxins out of their bloodstream.

Specific medications

These are often prescribed for specific CKD associated illnesses. These may include antibiotics for urinary tract infections, ACE-inhibitors or AVE-blockers to reduce urine protein loss, or blood pressure medication to treat high blood pressure. Some cats develop electrolyte and mineral imbalances and may need supplements to address these issues.

Appetite stimulants and gastro-protectants

Some cats can benefit from intermittent or regular use of medication to help stimulate the appetite and treat nausea.

Ongoing monitoring

CKD is a progressive condition that needs to be monitored by your vet on a regular basis. The frequency of monitoring will depend on the severity of your cat’s illness and your vet will advise you of the best course of action. Following the initial diagnosis, we generally recommend a revisit every 2 to 4 weeks until the disease stability is established. After this period, we will generally recommend IRIS Stage 1 and 2 cats to return every six months and those in Stages 3 or 4 to return every one to three months depending on their progress.

At your cat’s revisit appointment we recommend the following:

• A thorough physical exam including checking your cat’s body weight and hydration status
• Repeat blood and urine testing to monitor for the development of electrolyte and mineral imbalances, anaemias and urinary tract infections. We  perform most pathology tests onsite in our own laboratory
• Blood pressure measurements may be indicated to screen or manage hypertension
• Some cats may also require repeat imaging such as ultrasound

Sadly there is currently no cure for CKD in cats but with an early diagnosis and regular monitoring we can commonly see our patients remain stable and happy for many years. With the correct individualised intervention, we can successfully make a huge impact on ensuring these kitties maintain an excellent quality of life well into their senior years.

Disclaimer: Please note that the information provided on this page does not replace the advice of your veterinarian. If you are concerned about your cat’s health in any way, we strongly recommend you seek veterinary advice.