Living with feline kidney disease

If your cat has kidney disease, you will need sufficient information to understand the disease and sufficient time and support to help you make the right decisions for your cat - and we can help. So can you spots the signs?

How do you know if a cat has kidney disease?

Does kidney disease make a cat drink a lot?

While several things can cause increased drinking and urination (including diabetes and an overactive thyroid gland), kidney disease is high up the list of possible causes.

Kidney disease can be classed as acute (sudden onset) or chronic (longer-term onset). Acute kidney disease tends to result in sudden and dramatic illness and deterioration, whereas chronic kidney disease (CKD) can be more subtle and can often go unnoticed until the later stages of the disease.

To understand the disease better, let’s look at what kidneys do:

What do the kidneys do?

A little science for starters, then: in cats, the kidneys are a pair of small, plum-sized organs tucked up in the abdomen under the back muscles. Essentially a sophisticated detox system, they filter waste products and toxins from the bloodstream into the urine and regulate the body’s electrolytes (salts).

Vitally, they keep the body hydrated by altering the concentration of the urine, either to keep water within the body or to expel it in the urine. They also have roles in maintaining blood pressure, producing red blood cells, and making hormones.

What are the signs of kidney disease in cats?

The main signs of kidney disease are:

  • lethargy
  • increased thirst (polydipsia) and increased urination (polyuria)
  • weight loss and poor appetite

What happens when the kidneys start to fail?

An increase in urination occurs because the kidneys lose the ability to concentrate urine. Because too much water is now lost from the body, a resultant thirst drives an increase in drinking to try and compensate.

Note that signs can be subtle in the early stages and may initially be missed. Sometimes a cat with mild and undetected CKD may deteriorate suddenly, if vomiting or diarrhoea from such as a gut upset causes dehydration.

As the detox systems start to fail, by-products from the diet and normal bodily functions increase in the bloodstream, making the cat feel off-colour and off food. Loss of protein through “leaky” kidneys may worsen weight loss; vitamin losses and anaemia can occur, and rising blood pressure may complicate the picture.

As the disease progresses to a more advanced stage, signs can include:

  • mouth ulcers and bad breath
  • increased blood pressure, which may lead to haemorrhages in the eyes and blindness
  • pallor, weakness and depression

What causes kidney disease in cats?

In many cases, the precise cause is never found, but causes of kidney damage include:

  • toxins (such as anti-freeze and lilies)
  • kidney stones
  • drugs (including some human drugs such as paracetamol)
  • polycystic kidney disease (an inherited disease of pedigree cats)
  • cancers such as lymphoma
  • bacterial infection

How is kidney disease diagnosed in cats?

There is no one specific test for CKD but diagnosis is based on interpreting changes in blood and urine.

Traditional blood testing looks at the levels of urea and creatinine in the blood. These two chemicals are products of metabolism and their levels in the bloodstream start to rise as the kidneys lose their capacity to filter out waste material.

Because other things such as dehydration can also cause these increases, they need to be present with a low urine concentration (that is, abnormally dilute urine) identified as well, to reach a diagnosis of kidney disease.

A more recent test called SDMA may allow the earlier detection of CKD in the future. Other blood tests can identify complicating factors such as anaemia or electrolytes imbalances.

Functionally, the kidneys have a great reserve. This is to the good as it protects the body, but it also means that, sadly, by the time we see signs of CKD, at least two-thirds of the functioning kidney tissue has already been lost and lost for good.

What treatments are there for kidney disease in cats?

In most cases of CKD, there is no specific treatment that can target the cause. This means that most treatments are aimed at managing the effects and slowing the progression of the disease. There are several areas to address, which include:

Water intake and hydration:

If a cat presents suddenly with kidney disease, an initial period of hospitalisation is often needed for intravenous fluid therapy to rehydrate them. Cats with CKD lose more water in urine than healthy cats.

Feeding a wet food will help to manage this, as will making sure fresh water is always available from a variety of sources. You may need to be creative; for example, some cats will prefer a water fountain or a slow-running tap, while others drink from their owner’s unattended glass!

And cats with kidney disease must always have access to water. Unlike their healthy companions, they have lost the ability to cope without water for any length of time.

Special diets:

Dietary management is the cornerstone of kidney disease treatment and there are many diets on the market specially formulated for this, such as the Royal Canin Feline Renal range, Hill’s Feline KD diets and Specific FKW feline diets. These diets contain calorie-dense recipes with antioxidants, additional vitamins, reduced phosphorus and sodium levels, and a controlled amount of high-quality protein, helping to reduce the build-up of phosphate and the toxic products of protein breakdown.

Remember to introduce new foods gradually to reduce the chances of your cat rejecting the new food. Work with your vet to control nausea medically before offering a new diet and be prepared both to try a number of these foods and to vary them according to your cat’s preferences.

Phosphate binders:

These compounds, such as Ipakitine powder, may be needed if blood phosphate levels remain too high even when feeding a special diet, or if such diets are refused.


Medicines may be used to lower blood pressure, reduce gastric irritation, treat nausea, or to increase the blood flow through the kidneys.

Regular health checks, perhaps every 2-3 months, with repeated blood and urine samples, help to monitor the disease and adjust treatments as required.  Urine sampling may be recommended to check for urinary tract infection, which is more likely to occur in cats with CKD and may warrant antibiotics.

What is the outlook for cats with CKD?

If detected early and treated quickly, cats with chronic kidney disease may live happy and active lives for several years. Although the damage cannot be reversed, treatment can help to slow its progression and, importantly, to enhance your cat’s quality of life.

Find more information on introducing new foods, combating dehydration and managing all aspects of CKD at the wonderful icatcare site, a resource created by feline specialists for all things cat, in sickness and in health.

How can we help you?

There is no “one-size-fits-all” protocol for managing CKD and at Vet on the Net, we are here for consultation. Remember, nobody knows your cat as you do. While your face-to-face vet can give you insights into the stage of disease and how it is progressing – numbers, trends, medication – you will bring experiences of life at home with the furry feline to bear on the decisions.

It’s vital that we work out which interventions are supportive and doable and which cause more stress – and thus harm – than good. So, what you should do is a thoughtful balance of what you could do and what it is right for you and your cat.

If you’d like more time to explore all your options without the stress of a visit, we can help. Whether it’s the best resources for information, dietary choices, medical options or, most importantly, quality of life – how to judge it and how to help it – we are here for you.