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An estimated 50% of cats will at some stage in their life suffer from kidney failure.

The number rises even higher to 68% if your cat is getting NSAIDs for the treatment of degenerative joint disease.

Those are scary numbers!

The reason being that your cat’s kidneys perform so many important functions in the body, they’re irreplaceable. And the saddening part is that kidney damage often goes unnoticed until it’s too late.

Is there anything you can do to prevent the disease? How is kidney disease detected in cats?

Are there useful tips your vet would have loved to share during your last visit but forgot to do so?

These are all questions we’re going to answer in this article. Let’s start by looking at what kidneys do.

What are the functions of the kidney?

The kidneys are directly involved in so many critical bodily functions. To understand the importance of the kidneys, we’ll go over some functions it performs.

  • The kidney is responsible for filtering toxins from the blood flowing through the body. It helps regulate acid-base balance, water and electrolyte balance, as well as the arterial pressure.
  • It also controls the production of the active form of vitamin D and regulates blood calcium content. The kidney plays a critical role in the production of erythropoietin, a special substance that stimulates the creation of red blood cells in the bone marrow.
  • The kidney is also responsible for getting rid of toxic and metabolic waste through excretion in the urine.

These are just a few of the functions performed by the kidney.

You can see that if this vital organ is not functioning properly, many systems depending on it fail too.

What is kidney disease?

Kidney disease simply means that the kidney is damaged and cannot perform its function properly – or do so at all.

There are two types of kidney failure, each with different causes, treatment, and recovery outlook.

Types of kidney disease.

Acute renal failure.

What’s acute renal failure?

It is kidney damage that comes on suddenly without warning, usually in a matter of days or weeks. Acute renal failure can affect all cats, irrespective of age, and is usually caused by:

  • Trauma could be from a burst bladder or an accident involving a broken pelvis.
  • Kidney infections.
  • A bad heart that cannot pump blood with pressure, which affects the flow of blood to the kidneys.
  • Shock from rapid dehydration or losing a lot of blood quickly. Vomiting, diarrhea, and overheating in the summer can cause a dip in fluid levels.
  • Blockages, such as urethral blockages in male cats, that change the normal flow of urine and blood through the kidneys.
  • Poisoning, from the ingestion of antifreeze, pesticides, human medications, and toxic plants like lilies can cause serious damage to your cat’s kidneys. Something like ibuprofen, which is relatively harmless to you can shut down your cat’s kidneys. Be sure to check and remove these harmful substances from the house and garage so your cat cannot get to them.

Chronic kidney disease (CKD).

Unlike the previous kidney disease that develops suddenly, Chronic kidney disease happens slowly over a long period. CKD often occurs as a result of normal wear and tear of the kidney and it mostly affects aging cats (7 years and above).

However, untreated kidney infections or other kidney problems can slowly wear the kidneys. While the exact causes aren’t always clear, vets think that these factors may contribute to the early onset of the problem:

  • Infections or partial blockage of the kidney that does not result in acute renal failure, but gradually wear the kidney down undetected for months or years.
  • High blood pressure, thyroid problems, cancer, and advanced dental disease which interfere with the working of the kidneys.

Acute renal failure can often be reversed if it is diagnosed early. However chronic renal failure is much more difficult and tricky to treat since the damage happens slowly. If you have a kitty that’s over 6 years, then you need to pay special attention to her health and diet.

Since healthy kidneys are so important to the overall wellbeing of your cat, what are the symptoms that could signal to you that something is wrong with your cat’s kidneys?

Signs of failing kidneys.

As the kidney disease progresses and it fails to remove waste from the body, your kitty will show many signs some of which are:

  • Very dilute urine.
  • Increases thirst.
  • Poor appetite, weight loss, and lethargy.
  • Nausea or vomiting (may contain blood).
  • Bad breath.
  • Depression.
  • Seizures.
  • Frequent or no urination.
  • Arched back (a sign of renal pain) and stiff-legged gait.
  • Bruising or bleeding easily.
  • Anemia
  • Mouth ulcers.

Do not try to self-diagnose kidney disease by reading the symptoms only. Dr. Google will lead you to think that your pet is dying whereas the problem is a minor medical issue.

The symptoms listed above could also be connected to other medical issues. So always take your pet to the vet for proper diagnosis and advice on treatment.

How do they know that your cat’s kidneys are failing?

How is kidney failure diagnosed?

Evaluating kidney function usually involves a blood test and urine analysis (urinalysis). The result will tell the veterinarian how many waste products and other components. This is then compared to the normal levels which a healthy kidney would have filtered or regulated.

What does the blood test reveal?

The blood test checks the concentration of two important waste products: creatinine and blood urea nitrogen (BUN). However, creatinine is a more specific indication of kidney health.

While a significant spike in the concentration of these substances in your kitty’s blood may suggest that her kidneys are failing, these values need to be weighed against other factors.

For instance, dehydration can mess with the concentration of creatinine and BUN in the blood even though the cat’s kidneys are still healthy. This is why it is necessary to perform at least two blood samples – usually 2 weeks apart.

There’s a new test method that checks the concentration of symmetric dimethylarginine (SDMA), a by-product of protein metabolism. The result can help detect and treat chronic kidney disease earlier than other available test methods. 

What does urinalysis reveal?

A urinalysis test result reveals the concentration of your cat’s urine, the pH, the presence of bacteria, blood cells, protein, and other cells that normally shouldn’t be present in a healthy cat’s urine. All of them offer vital information concerning the health of your cat’s kidneys.

Other studies can provide valuable information about the state of a cat’s kidneys. They include radiographs (x-rays), abdominal ultrasound, and microscopic evaluation of biopsy samples.

Since cats with bad kidneys are likely to suffer hypertension, checking the blood pressure can also help.

Every problem, at least, has a temporary solution, how is kidney failure treated?

Treatment of kidney failure.

While there is no definitive cure for chronic kidney damage, cats with the disease can still live longer and improved lives with the help of treatments.

The main purpose of treatment is to reduce the concentration of toxic waste products floating in the bloodstream, control blood pressure, address disturbances in electrolyte balance, slow the progression of the disease while maintaining adequate hydration and appropriate nutrition at all times. 

One important and proven aspect of chronic kidney disease treatment is dietary modification. Studies show that therapeutic diets that contain low protein, sodium, and phosphorus but high in antioxidants, fiber, and water-soluble vitamin concentration may improve and prolong the life of cats with the disease.

The problem, however, is that cats are creatures of habit and would actively refuse dietary changes if done too fast. It is very important to make the transition gradual and consider food texture, flavor, and temperature when making the switch.

Cats with chronic kidney disease may develop other health problems if they go without food for a short time. If your cat still won’t eat after switching her to a new diet, then you need to stimulate her appetite.

But, what if your cat shows improvements, does that mean she no longer needs treatment?


Your cat’s kidneys are still bad and, bar a miracle, will never work like normal kidneys again. If treatment is halted for whatever reasons, she’ll soon be back to showing the symptoms of kidney failure. 

Here are some of the therapies your cat might need:

Dietary modifications. 

The purpose of dietary modification is to control the concentration of toxic waste in the bloodstream. Most diets for cats with chronic kidney disease are low in protein, phosphorus, and are not acidified.

This helps keep waste products in the blood close to the normal levels of cats with healthy kidneys. This alone can make your cat feel better as the low protein diet reduces the workload on the kidneys.

A phosphate binder. 

The kidney is responsible for removing excess phosphorus from the body. However, when the filtration process is faulty, phosphorus begins to build up in the blood. This also contributes to poor appetite and lethargy in cats with failing kidneys.

Some drugs can prevent excess buildup of phosphorus by restricting the rate of absorption in the intestinal tract.

Potassium supplements. 

Potassium is lost when there’s excess production of urine. Low potassium level leads to muscle weakness, stiffness, poor hair quality, and further affects kidney function. A cat with kidney disease will need a potassium supplement to replace the ones lost and also help maintain what’s left of the kidney functions.

A drug for excess stomach acid. 

Excess stomach acid causes nausea and can affect your cat’s appetite. These drugs can help improve your cat’s appetite, however, they’ll usually be given if appetite improves while the cat is taking the drugs. 

Fluids administered at home.

Once your cat’s condition begins to stabilize, fluids can be administered under the skin. The purpose of the fluid is to ‘restart’ the kidneys to prevent their functions from failing completely.

This can be done on a daily or weekly basis, depending on how damaged the kidneys were. While this sounds like something that might be difficult to do, it will surprise you how easy it is to learn the technique and how most cats don’t mind going through it.

A drug to regulate calcium levels and the parathyroid gland.

It is very important that the calcium and phosphorus in your cat’s blood remain at a ratio of 2:1.

When the kidney is failing, the blood phosphorus level increases. This increase in phosphorus stimulates the parathyroid gland to increase the blood calcium level, and it does this by removing some from the bones.

This is helpful and normal for regulating the blood calcium-phosphorus levels. However, this makes the bones susceptible to fractures or breaking.

There are special drugs that can be given to the cat to reduce the function of the parathyroid gland and to stimulate the absorption of calcium from the intestinal tract. 

A drug to stimulate the production of new red blood cells in the bone marrow. 

The kidneys produce a hormone known as erythropoietin that stimulates the production of red blood cells in the bone marrow. Cats with failing kidneys lose this important function and become anemic.

To counter this problem, your cat can be given synthetic forms of erythropoietin, which helps correct anemia in most cats.

The only problem is that the drug cannot be used as a long term solution. That’s because the body’s immune system recognizes it as a foreign substance and makes antibodies for it.

Medications for high blood pressure (HBP). 

It’s normal for cats with kidney problems to have high blood pressure – remember the kidneys help regulate blood pressure.

After being treated at the vet, the blood pressure will likely drop. However, in some cats, the blood pressure remains elevated and these drugs help restore normalcy.  

Antibiotics and vitamin supplements.

Since the failing kidneys are unable to concentrate urine, cats with kidney problems often suffer bladder infection and lose a lot of water-soluble vitamins. Antibiotics are necessary to keep the bladder free of bacterial infection and daily vitamin boost to replace lost vitamins.

What can you expect from the treatment?

Only 3 outcomes are possible from the treatment of kidney disease and they are:

  • The kidneys resume functioning and continue to do so for a couple of weeks or years after treatment.
  • The kidneys resume functioning but fail soon after the treatment is completed.
  • Kidney functions never return.

There’s no way to tell the outcome of the treatment, just the ‘likelihood’ of the kidneys returning to normal, and even that isn’t set in stone.

Is there anything you can do to prevent kidney failure?

Monitor water intake.

Cats are not enthusiastic about drinking a lot of water, but they have to.

Without enough water in your cat’s system, the kidneys are running on low fluid levels. This means there are more toxins to filter out in the little water that’s in the body.

How do you pass out waste with water when you don’t have enough water in the system?

You need to find a way to get your cat to drink. Whether you choose to place multiple stainless steel bowls around the house or getting her an easy-to-clean, quiet cat water fountain, you have to get her to drink.

Healthy proteins only.

Some proteins are difficult to break down and might end up clogging the kidneys. Make sure you’re feeding your cat only healthy protein. There’s no need to go cheap with cat food.

If you need help choosing, talk to your vet.

Check if your cat food has been recalled.

Lots of cat food get recalled due to an error while manufacturing the batch, or a lab test result. Always keep tabs on your cat food of choice so you know when it has been continued or recalled. This way you can either throw them out or gradually introduce your cat to a new brand. Failure to do so and you might struggle with raising your cat’s appetite.

Get rid of toxins.

Get rid of toxic plants and chemicals around the house.

Keep drugs out of reach of cats. Even a single dose of most human drugs can cause serious damage to a cat’s kidneys, liver, and other vital organs.

Tuck them away in a locked cupboard.

Careful about giving them leftovers.

Not all human foods are ‘okay’ for a cat to consume – especially recipes that contain onion and garlic.

In the article on how to help stray and feral cats, there’s a section dedicated to the leftovers that you should/ shouldn’t offer cats. Check it out.

Treat UTIs immediately.

When you notice symptoms of UTIs in your cat, the best thing you can do is visit the vet ASAP. Some UTIs can affect the kidney if left untreated.

Monitor urine frequency.

Same as the first point about monitoring water intake, you also have to monitor how much fluid comes out of your cat.

This can help you tell if your cat is getting enough water or has a blockage in her urethra. Blockages are very painful, they stress the bladder and kidney, and they need to be treated ASAP. 

How long does the average cat with kidney problems live?

Can’t say, it depends on the cause of the damage and how early the damage is detected and treated.

Acute renal failure is life-threatening, even in very young cats. If the cause of the kidney issue is bacterial then recovery is almost certain once the bacteria is treated. However, with toxic substances, one can’t tell what to expect after treatment.

In chronic renal failure, there’s nothing you can do other than managing the condition and making changes that will help slow down the disease.  

Your vet will provide you with a more accurate prognosis after considering your kitty’s clinical signs, individual condition, lab test result(s), and other determining factors.

If you have any questions – which you probably will – write them down and ask you vet on your next visit.

The truth is, your vet would love to tell you about these things, but mst owners never as until it’s too late!

Assume every symptom in your cat is something serious.

Start asking the vet questions today!