Chronic kidney disease (CKD) is a common condition in middle-aged and older cats, where the kidneys gradually lose their ability to function properly over time.

Cats have two kidneys, which play a vital role in filtering waste products from the blood, regulating blood pressure, and controlling urine output. As CKD progresses, waste begins to build up in the body, leading to serious health issues if not managed early. While CKD can't be cured, it can often be managed with the right care.

Read on to learn about the signs of CKD in cats, how it's diagnosed, treatment options, and what to expect in terms of long-term care.

What Causes Kidney Disease in Cats?

Chronic kidney disease (CKD) in cats can develop for many reasons, and in some cases, the exact cause remains unknown (idiopathic). While CKD often progresses slowly over time, it can be triggered or worsened by a range of underlying conditions.

Common causes of chronic kidney disease in cats include:

• Acute kidney injury: Exposure to toxins (like lilies or antifreeze), certain medications, or severe dehydration can cause sudden damage that leads to chronic disease.
• Genetics: Some breeds, including Siamese, Persian, Maine Coon, and Russian Blue cats, are more prone to kidney issues.
• Inherited diseases: Conditions like polycystic kidney disease in cats can lead to CKD.
• Infections or inflammation: Bacterial infections, such as pyelonephritis, or other chronic inflammatory processes can damage kidney tissue.
• Other diseases: Viruses like feline infectious peritonitis (FIP) or immune-mediated conditions may also play a role.

Despite all we know, many cases of CKD in cats have no clear cause, highlighting the importance of regular health checks to catch the disease early.

​Signs and Symptoms of Kidney Disease in Cats

The early signs of kidney disease in cats are often subtle and easy to miss, especially in the beginning. That's why many vets recommend annual blood tests for older cats to help catch CKD early, before noticeable symptoms appear.

Common signs of kidney disease in cats include:

• Drinking more and seeking out fresh water more often.
• Increased urination or, in some cases, very little dark-coloured urine (difficult to spot in outdoor cats).
• Reduced appetite or becoming fussier with food.
• Weight loss and a thinner, less muscular body condition.
• Lethargy or appearing older and more frail.
• Vomiting or nausea.
• Bad breath.
• Ulcers on the gums, tongue, or roof of the mouth.

You may also notice changes in your cat's coat or grooming habits. Because cats are good at hiding illness, even small changes in behaviour, appetite, or weight should be taken seriously. If you're concerned, a vet check-up is the best next step.

Diagnosing Chronic Kidney Disease in Cats

Your vet may also test your cat's urine to assess its concentration and check for protein in their urine. If your vet feels the above tests show signs of kidney disease, your cat may need their blood pressure measured and an ultrasound to measure the size of their kidneys and check if there is an underlying cause of the disease or any other abnormalities.

If your vet suspects chronic kidney disease, they'll likely recommend diagnostic tests to confirm the condition and assess how advanced it is. The first step usually involves blood tests to measure levels of waste products like creatinine and blood urea nitrogen (BUN), which build up in the body when there's damage to the kidneys.

Blood work may also include checking your cat's red blood cell count. The reduced production of erythropoietin by the struggling kidneys means the bone marrow produces fewer red blood cells, and high urea levels can reduce the lifespan of red blood cells. These factors lead to anaemia - a common complication in cats with CKD.

Urine testing is another important part of diagnosis. It helps your vet check how well the kidneys are concentrating urine and whether there's protein present, which can be a sign of further kidney damage.
If your vet believes the above tests indicate signs of kidney disease, additional tests such as blood pressure monitoring and a kidney ultrasound may be recommended to identify an underlying cause of the disease or any other abnormalities.

Kidney Disease Stages

Your vet may talk to you about the stage of chronic kidney disease in your cat. Staging helps track how advanced the disease is and guides the most appropriate treatment plan. There are four stages of CKD, with stage 1 being the mildest and stage 4 indicating severe kidney function impairment.

Cats in earlier stages may show few or no symptoms, while those in later stages often need more intensive support and monitoring. Regular blood and urine tests help determine your cat's stage and monitor any changes over time, ensuring their treatment stays appropriate for their condition.

Treating Chronic Kidney Disease

While chronic kidney disease in cats can't be cured, there are many ways to manage the condition and help your cat maintain a good quality of life. The treatment plan will depend on your cat's symptoms, test results, and overall condition. 

Cats with chronic kidney disease often benefit from being placed on a specially formulated diet for their kidneys. These diets are designed to reduce the workload on the kidneys and help preserve remaining kidney function. They typically contain lower levels of phosphorus, sodium, and protein.

Because cats can be sensitive to diet changes, it's important to introduce the food gradually to avoid food aversion. Once your cat is eating the diet, it's best not to offer other foods or treats that may interfere with its benefits.

If your cat refuses a kidney-friendly diet, your vet may recommend adding a phosphorus binder to their regular food instead. Your vet will advise you if and when this step is necessary.

Specific Symptoms of Kidney Disease in Cats and Treatments

• High blood pressure: managed with anti-hypertensive medication.
• Protein in the urine: treated with medications that reduce protein loss.
• Anaemia: managed with medication and/or supplements.
• Electrolyte imbalances: corrected through diet or fluid therapy.

Some cats with CKD may need regular subcutaneous fluids administered at home to keep them well-hydrated and support kidney health. Many cats tolerate this treatment well, and your veterinary team can show you how to do it safely and comfortably.

If your cat's clinical signs worsen, or if their quality of life is significantly affected (especially in advanced stage), it's important to have an honest conversation with your vet.

In some cases, putting your cat to sleep may be the kindest option, particularly for older cats that have had CKD for a long time or are living with other health conditions.

Home Care for Cats With CKD

Home care plays an important role in maintaining your cat's comfort, happiness, and overall quality of life when living with chronic kidney disease. One of the most important things you can do is ensure your cat always has access to fresh, clean water, as hydration supports kidney function and helps flush out waste products.

Because cats with CKD often urinate more frequently, adding multiple litter trays around the home can help avoid accidents. Clean trays are essential, as cats are very particular about hygiene and may choose other locations if their tray is soiled.

Providing soft, padded bedding is also helpful, especially for cats with muscle loss or lethargy, as they may be prone to pressure sores from lying on hard surfaces.

Monitor your cat's appetite, weight, drinking, urination, and energy levels regularly. Noticing subtle changes early allows for quicker veterinary intervention and better long-term outcomes.

The progression of chronic kidney disease varies significantly between cats. With early diagnosis, regular monitoring and proper management, many cats can enjoy a good quality of life for months or even years. How your cat responds depends on several factors, including how advanced the disease is at diagnosis, how quickly it progresses, and how well both you and your cat adapt to the new routine. Some cats tolerate treatment well, while others may struggle. This should always be taken into account when evaluating their comfort and welfare.

As kidney disease is progressive, there may come a time when discussing euthanasia with your vet is the kindest option. Regular veterinary check-ups are essential to monitor your cat's condition and adjust treatment as needed. Remember, your veterinary team is there to support both you and your cat throughout every stage of this journey.

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Content provided from Vetstream's Vetlexicon Felis - www.vetlexicon.com/treat/felis

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