Kidney (renal) disease in cats happens when their kidneys stop working properly. Kidney disease may be chronic (comes on gradually) or acute (sudden).

Chronic kidney disease (CKD) is one of the most common illnesses affecting cats. Cats of any age, sex or breed may develop chronic kidney disease, but it’s most common in older cats. Around 30% of all cats over 10 years old (of any breed) have chronic kidney disease, rising to 50% of cats over 15 years old. Younger cats who get chronic kidney disease are more likely to belong to certain breeds, including Maine Coon, Ragdoll and Siamese.

Kidneys carry out essential functions in the body. As cats get older, their kidneys become less efficient. The reason why this happens isn’t known. There are triggers which can make it happen earlier or progress quicker. These include toxins, infections and other illnesses. There’s no cure for Chronic Kidney Disease. Eventually, the kidneys will fail completely. But the rate of deterioration varies between cats. Symptoms of CKD can often be stabilised for prolonged periods. Early diagnosis and treatment help achieve the best outcome for the longest time.

What is chronic kidney disease in cats?

Chronic kidney disease means your cat’s kidneys have suffered damage over a long time. The damage can’t be reversed or cured.

We often don’t know how the kidneys get damaged. Ageing change is part of the cause, but other factors can include:

• Exposure to toxins; anti-freeze, grapes, raisins, some antibiotics

• Severe or recurrent kidney infections (pyelonephritis)

• Certain immune-mediated illnesses

• Inherited kidney defects in some breeds

Why the kidneys matter

The kidneys are two small organs in your cat’s tummy.

They carry out a number of essential functions, including:

• Controlling fluid and salt levels in the body

• Removing toxins and waste from the blood

• Producing some hormones.

When the kidneys stop working properly, the body can’t control fluid and salt levels. All the organs and tissues which depend on this control also start to struggle. This includes the heart, muscles and brain. The damage gets worse as harmful waste products continue to accumulate.

Symptoms of chronic kidney disease in cats

The symptoms of kidney disease result from losing control of fluid balance in the body and from build-up of waste products. Common symptoms include:

• Drinking and peeing (urinating) more

• Losing weight and eating less

• Sleeping more

• Vomiting from time to time

• Developing a dull staring coat

• Developing bad breath and pale gums (anaemia)

Chronic kidney disease isn’t painful in the early stages or when controlled

In the later stages of chronic kidney disease, your cat may develop high blood pressure (hypertension), This is a dangerous complication of chronic kidney disease.

Symptoms include:

• Head-pressing and staring into space

• Sudden blindness

• Seizures

Call your nearest vet if you think your cat has developed symptoms of high blood pressure.

Cats at higher risk of chronic kidney disease

Although we don’t usually know why chronic kidney disease happens, some factors increase your cat’s risk of developing the condition. For example:

Recurrent kidney infections (pyelonephritis)

Inherited abnormalities:

• Amyloidosis – abnormal proteins build up in the kidneys and stop them working properly. Amyloidosis happens in Siamese and Abyssinian cats but is rare in other breeds.

• Polycystic kidney disease (PKD)- fluid-filled cysts may develop in the kidneys. Persian cats (and their related breeds) are susceptible.

Illness elsewhere in the body, such as sugar diabetes (diabetes mellitus) and overactive thyroid (hyperthyroidism)

Are humans or other pets at risk?

Chronic kidney disease does not spread between cats or from cats to humans.

Diagnosis of chronic kidney disease in cats

Cats only develop symptoms of CKD when they’ve lost about 70% of their kidney function. Another way of looking at this is that your cat only needs about half of one kidney to look normal. This means we usually only identify chronic kidney disease in advanced stages

Vets diagnose chronic kidney disease based on:

Symptoms

Urine tests:

• Urine specific gravity (USG) – cats with chronic kidney disease have very dilute (weak) urine

• Protein levels – Diseased kidneys leak increasing amounts of protein into the urine

• Bacterial Culture – Bacterial infection can cause kidney disease or make it worse

Blood tests:

• Urea (blood urea nitrogen, BUN) and Creatinine Levels. These raise when kidney function falls by around 60-70%. Both are very useful tests. But things like diet, dehydration and exercise can also influence them.

• SDMA (symmetric dimethylarginine) is a new test. It detects kidney disease early when around 25% of kidney function is lost (rather than 60-70%). This means diagnosing chronic kidney disease one to three years earlier than with BUN and creatinine alone.

• Phosphorus Levels. These increase because diseased kidneys can’t get rid of excess phosphorus from the body.

X-ray or Ultrasound scan to check the shape, size and structure of the kidneys. These tests can detect kidney stones (uroliths, calculi), which can cause chronic kidney disease or make it worse.

Vet treatment for chronic kidney disease

Treatment for severe or advanced chronic kidney disease

• Giving fluids to treat dehydration caused by losing of too much fluid from the body as weak urine. If your cat is very dehydrated, they may need to have fluids and medicine through a drip into their leg

• Stabilising electrolyte (salt) levels in the blood to help nerves and muscles continue to work properly

• Controlling of high blood pressure

Ongoing treatment

Special diets: prescription diets for kidney disease contain the correct balance of high-quality protein, salt levels, essential fatty acids and appetite stimulants for cats with chronic kidney disease.

Medication: prescription tablets and liquid medicine

• Anti-sickness medication to reduce nausea and vomiting

• Appetite stimulants to encourage eating

• Medicine to reduce protein loss in urine and minimise weight loss

• Potassium supplements – Essential support for heart and muscle function

• Gastric (stomach) protectants – To protect the stomach lining

Kidney transplants? Although these are carried out in some other countries, kidney transplants in cats are banned in the UK

The goal of treatment is to stabilise symptoms and quality of life for as long as possible. Chronic kidney disease is harder to control in advanced stages, especially with raised phosphorus levels and high blood pressure. Successful control is also harder in cats with other illnesses.

Home care for your cat with kidney disease

Most cats with chronic kidney disease do very well on home treatment. The following tips will help to keep your cat well for longer and minimise extra trips to the vet.

• Ensure your cat has free access to water at all times

• Feed a special prescription diet for kidney disease

• Always give prescribed medicine and supplements as directed

Living with a cat with chronic kidney disease

When the symptoms are under control, your cat can enjoy a full and happy life.

• Encourage your cat to drink as much as possible. Use water fountains and add water to food

• Find a prescription kidney diet your cat likes and keep to it

• Warm food up and add low-salt chicken stock or fish broth to encourage your cat to eat if their appetite is poor

• Give prescription medicines as directed and in a way that doesn’t stress your cat or you

Getting your cat to eat is more important than persisting with things which won’t work.

Helping your cat to enjoy good quality of life is the most important goal.

Chronic kidney disease gets progressively worse. Eventually, the symptoms can no longer be controlled. When this happens, it may be kindest to end your cat’s life peacefully through euthanasia.

You may be anxious about how you’ll know if it’s time to say goodbye. It’s a decision that’s very hard to make and distressing for everyone involved. The best any of us can do is focus on what’s best for our beloved companion. We can start by thinking about their quality of life.

• Do good things outweigh the bad?

• Is your cat still interested and responsive?

• Is pain or distress controlled?

• Are they exhausted?

• Is giving medication straightforward or is it a fight that’s worsening quality of life for both you and your cat?

There are guides available online to help you assess your cat’s quality of life. Talk things through with a vet if you are concerned about your cat’s quality of life.

Assess quality of life

Can chronic kidney disease be prevented?

We can’t prevent chronic kidney disease because the cause is usually unknown. However, we can reduce additional risk factors.

• Feed your cat a high-quality diet that’s appropriate for their age and lifestyle

• Ensure your cat gets regular health checks with a vet

• Check your cat’s weight regularly for any unexpected weight loss

• Treat any other illnesses promptly

When to worry about your cat with chronic kidney disease

Call your nearest Vet Practice if your cat :

• Goes suddenly blind

• Collapses

• Develops severe vomiting or diarrhoea with blood

• Is having a fit or seizure

• Stops drinking altogether

Joii can help with

• Recognising the signs of chronic kidney disease

• Caring for a cat with chronic kidney disease

• Finding the best diets for your cat with kidney disease

• Giving medicine to cats who are unwell

• Tempting your poorly cat to eat