Chronic Kidney Disease (CKD) in cats

isolated cat


Kidneys filter toxic waste products from the blood into the urine so that your cat can pee them away. If the kidneys aren’t working properly, waste products build up and cause illness. There are two types of kidney disease, ‘acute’ and ‘chronic’. This article focuses on chronic kidney disease (CKD).

Symptoms of chronic kidney disease include: drinking and peeing more than usual, weight loss, vomiting and eating less. There is no cure for kidney disease but there are many things that can be done to help, especially if it’s caught early.

What is Chronic Kidney Disease (CKD)?

There are two types of kidney disease, ‘chronic’ and ‘acute’. This article focuses on chronic kidney disease.

Chronic kidney disease (CKD) is when the kidneys slowly stop working, often due to ageing but occasionally because something has harmed them in the past.

Acute kidney disease is when the kidneys stop working very suddenly, usually because they have been damaged by something such as a toxic substance (e.g. antifreeze), a drug or an infection.

Symptoms of CKD

Symptoms to look out for include:

Chronic kidney disease develops slowly until the body is unable to hide the symptoms anymore. Unfortunately, this means that when we see symptoms, the kidney disease is usually quite advanced.

Illustration showing a cat's urinary tract

The urinary tract in a cat.

When to contact your vet

If you notice any of the symptoms above, contact your vet. The earlier kidney disease is detected, the better the chance of slowing further damage and the longer your cat is likely to live.

Kidney disease is much more common in older cats. Have your cat checked by your vet regularly especially once they are in their senior years (8+).

You know your cat best. If they don’t have the symptoms listed above but you are still concerned it’s always best to contact your vet.

Causes of chronic kidney disease

Causes include:

Age (most common)

  • Many cats develop kidney disease when they reach their senior years (8+) due to wear and tear on the kidneys throughout life.

Polycystic kidneys

  • Polycystic kidneys causes cysts on the kidneys (fluid filled balloons) which stops them working properly. Cats with polycystic kidneys often develop kidney disease at a young age.
  • Polycystic kidneys is hereditary (passed down from a cat’s parents) and it’s much more common in certain breeds, for example Persians.

Very low blood pressure

  • Very low blood pressure (e.g. if a cat goes into shock) can cause kidney damage.

Substances poisonous to the kidneys

  • Some human medicines, foods and chemicals can cause kidney damage (for example antifreeze).

Bacterial infections

  • Kidney infections and bladder infections can cause kidney damage especially if they are very severe, happen repeatedly or are left untreated.

Viral infections

Stones forming in the urinary system

  • Stones (calculi) and sludge can form anywhere in the urinary system from minerals in the pee. These stones can cause blockages and kidney damage.


  • Kidney tumours are rare but can cause kidney disease.

How will kidney disease affect my cat?

Increased thirst

  • The kidneys make sure the right amount of water stays in your cat’s body. Diseased kidneys don’t retain water, so cats with CKD drink and pee much more than usual.

Sickness and reduced appetite

  • Toxic waste products that build up in the body cause nausea and a reduced appetite.

High blood pressure

  • Kidney disease causes high blood pressure. High blood pressure causes problems such as further kidney damage and even sudden blindness.


  • The kidneys help make red blood cells so cats with kidney disease often become anaemic.


Damage to the kidneys can’t be reversed but lots can be done to slow further damage and improve symptoms.

Your vet will use blood and urine test results to find out how badly your cat’s kidneys are affected and this will help to decide what treatment is best.

Change of food

  • Feeding your cat a special kidney diet is the most important change you can make. Of all the treatments available, it’s thought to make the biggest impact on how long your cat will live.
  • Special kidney diets are available with the right levels of protein, sodium and phosphorus. They support the kidneys and reduce toxin build up.
  • Your vet will advise which diet is best for your cat. You will need to change your cat over to the new food slowly - read our advice on how to successfully and safely change your cat’s food.
  • Feeding wet food instead of dry food helps the kidneys by increasing their water intake. Special kidney diets come in both wet and dry forms.


  • If your cat becomes dehydrated, your vet may give them fluids either through a drip or under their skin.

Phosphate Binders

  • Phosphorus can build up to dangerous levels in cats with kidney disease, especially if they won’t eat their kidney diet. Phosphorus binders can be put into food to keep levels stable.

Vitamins B and C

  • Your vet may prescribe vitamin supplements for your cat.

Appetite Stimulants, anti-sickness and anabolic steroid medications

  • Appetite stimulants, anti-sickness medication and anabolic steroids can help with vomiting, nausea and appetite.

Blood pressure medication

  • Your vet may prescribe medication to bring your cat’s blood pressure down. This helps stop further damage to the kidneys and other parts of the body.


  • Bladder infections are much more likely in cats with chronic kidney disease. Your vet may prescribe antibiotics if they detect an infection.

Regular Monitoring

  • Regular monitoring is an important part of treatment, it enables your vet to assess whether your cat’s kidneys are getting worse or still coping.

Not eating?

If a cat with kidney disease stops eating, they are at risk of becoming even more poorly. It’s better that they eat something rather than nothing.

If your cat won’t eat their special kidney food, you may have to tempt them with something else. Speak to you vet for further advice.


With a prompt diagnosis and the correct management, a cat with chronic kidney disease can live for many months or even several years. Damage to the kidneys can’t be reversed but lots can be done to slow further damage and improve symptoms. It’s impossible to predict how long each cat with kidney disease cat will live but the sooner treatment is started the better the outlook for your cat.

Cats suffering from chronic kidney disease will have good days and bad days. Sadly, over time, symptoms will gradually get worse. Once the CKD is very severe and treatment is no longer helping, you may need to have the difficult conversation about putting your cat to sleep.


Take the following measures to reduce your cat’s risk of developing kidney disease later in life:


Make sure your cat always has plenty of water on offer. Some cats prefer fresh water, some like it left down for a few days and others like it moving – i.e. a water fountain or a dripping tap. Offering wet food also helps to increase water intake.


Feed a good quality diet that’s suitable for your cat’s age. Most food for senior cats has the right ingredients to keep their kidneys as healthy as possible.

Regular checks

Regular vet checks throughout your cat’s life are important. Ask your vet how often your cat should be coming in for check-ups.

Consider insuring your cat as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them.


Which breeds are at risk of Chronic Kidney Disease

The following breeds may be more likely to develop kidney disease:

  • Persian
  • Abyssinian
  • Siamese
  • Ragdoll
  • Burmese
  • Russian Blue
  • Maine Coon.
Published: July 2018

Support PDSA

All of our work helping the UK's pets – including this article – is funded entirely by public support.

If you've found our information useful please donate today. This will ensure we can continue to help pet owners and their sick pets for many years to come.

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst