What to do when your cat has a kidney disease

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What to do when your cat has a kidney disease

Cats with kidney problems. Unfortunately, it is one of the most common diseases among cats. Especially older cats suffer often from kidney issues. Why does this happen? What can you do to prevent your cat from getting kidney problems? And what to do when you think your cat has kidney failure? In this post, we will answer all your questions.

The role of the kidney

The kidney plays a vital role in regulating the amount of liquid in the body of the cat. This organ basically determines how much a cat should drink and how often it needs to pee. If you notice that your cat is drinking more than normal and visits the litter box more frequently, then this could be an indication that there is something wrong with your cats’ kidney.

Another important function of the kidney is filtering the blood. It keeps the blood clean and removes all the bad stuff that should not be in the bloodstream. The kidney makes sure that all the waste leaves the body by ways of urinating. 

A cat with a slightly damaged kidney won’t show any symptoms, only when the kidney is severely deteriorated you will notice symptoms of kidney failure.

Cats can have two variations of kidney failures or renal disease.

1.Chronic kidney failure

This occurs because a part of the kidney has been permanently damaged. Just like humans, cats also have two kidneys and we can live just fine with only one kidney. You will start to notice trouble when a kidney only functions at 30% (or less) of its capacity.

2.Acute kidney failure 

This type happens suddenly. Common reasons are lack of oxygen being transported by the blood to the kidneys. This type of failure is also known as prerenal kidney failure.
Acute kidney failure occurs often when a cat suffers from heart failure or dehydration.

Renal kidney failure is caused when a cat eats or drinks something poisonous (e.g. lilies). Or when infections damage the nephron of the kidney. This is the part of a kidney which does all the filtering of the blood and creates the urine.

The third and final cause of acute kidney failure is post renal kidney failure. This is caused by obstruction of the urinary tract and results in your cat having bladder stones.

This all paints a pretty grim picture. However, a good and healthy diet and certain supplements can help your cat from getting kidney problems and help those who suffer from the disease in order to lead a normal and painless life.

Signs of cats with chronic kidney problems 

In order to spot chronic kidney problems of your cat, keep an eye out for the following symptoms.

Lots of drinking and peeing

If the kidney won’t be able to filter the blood properly your cat will drink more then usual and he will need more trips to the toilet. You will notice that the urine is more transparent as in it will be less yellow. Your vet will be able to tell from a urine analysis that the specific gravity of the urine will be lower.

Cat drinking water

Nausea, throwing up and less appetite

Because the blood is not properly filtered, certain waste products remain in the cats’ bloodstream. Two of these toxic products which should not be in the blood are creatinine and urea, also known as carbamide. If high values of these elements are found in the blood, it is an indication there is something wrong with the kidney.

What happens is that little sores or ulcers will appear within the alimentary canal, the stomach, bowels, mouth or on the tongue. You should be able to spot the little wounds on the cat’s tongue and in its mouth yourself. These ulcers cause the vomiting, the lack of appetite (it hurts to eat) and diarrhea.  

Bad breath

Obviously, the breath of a cat will not smell as if it has just brushed its teeth. A cats’ breath will always have a smell, however, when its breath has a strong ammonia/urine smell, this could be a sign your cat has some kidney issues.

Anaemia – Lack of red blood cells

The kidney normally produces erythropoietin, or EPO, which is a hormone which stimulates the production of red blood cells. If there is a shortage of red blood cells, it affects the transportation of oxygen.

A dull coat and an overall bad condition

A cat with kidney failure will struggle to maintain its fluid levels. The fur will also lose water and instead of a shiny healthy fur coat, the cats’ fur will appear dull. Cats with kidney problems also tend to wash less regularly. They lose interest in keeping their fur coat in a good condition. So if your cat doesn’t wash itself as often as it used to, it could be a potential signal something is wrong.

What will a vet do to determine chronic kidney disease?

For a vet to determine whether a cat has chronic kidney disease he or she will do 3 things.

The veterinarian will ask if you have noticed any of the above symptoms and inspect the cat’s mouth and it’s posture. Furthermore, he will take blood and urine samples. Establishing a chronic kidney disease is pretty straightforward.

When the values of creatinine is over 140 micromol per liter combined with a specific gravity of the cats urine  <1035 the veterinarian will conclude the cat has a chronic kidney disease.

When they test the blood they will measure the hematocrit, which is the total percentage of red blood cells in the blood and the levels of phosphate. Phosphate is something which the kidney is supposed to filter, so if this turns out to be high it’s considered another indicator of kidney disease.

The posture of a cat changes due to a low level of potassium in the cats’ blood which has an effect on the muscle strength of the animal. The cat becomes weaker and typical for cats, they express this by letting their head hang and bend through their back legs, they don’t stand up straight.

When the vet examines the cats’ urine, he looks at the concentration of the urine. If there is a problem with the kidney, the concentration will be low. Another thing the vet will be alert to is the number of proteins in the urine. This gives a good indication of the current filtration abilities of the kidney.

With these blood and urine test done, the vet can determine whether the cat actually suffers from a chronic kidney disease, but it doesn’t tell him anything on why this has happened.

In order to find out what has caused the kidney failure, the vet will need to do some more tests. He will do a needle aspiration and send the sample to a lab for analysis. He will measure the blood pressure of the cat and will take an x-ray to see the actual state of the kidney. This is often a standard procedure and helps the vet to recommend further medical treatment.

How will the vet cure the cat’s chronic kidney disease?

Perhaps not what you would like to hear, but unfortunately they can’t. Once a kidney failure has been diagnosed it usually means that the cat already has lost 70% of its kidney. This is an irreversible process.

What happens is that remaining healthy cells of the kidney are working overtime to keep up with the demands of the body. But eventually, these cells will give in as they can’t cope with the pressure. This is called a progressive development disease which means it gets worse over time.

So even though doctors can’t cure a cat with a chronic kidney disease, they will start a treatment which improves the quality of the cats’ life and will do anything possible to prolong its life.

What will the vet do?

Depending on the diagnosis the vet can decide to give the cat an intravenous infusion. This procedure requires your cat to be hospitalized. With this procedure, the vet will inject fluids directly into the veins of the cat and it will help the cat to get rid of all the excessive wastage and toxins which are present in its blood. This same method is also used to flush the kidneys, whereby fluids are injected under the cats’ skin.

What you as an owner can do is to make sure the cats drink a lot!
Directly from the tap or perhaps more convenient (and economical) from a cat water fountain.
Also feeding the cat wet canned food is better than dry food.

Cat water fountain

Special cat kidney diet

This is a very important part of the process of treating cats with kidney failure.

This diet basically asks you to feed your cat meals with a reduced intake of protein and phosphate. This will result in a lower production of harmful elements like creatinine, urea, and phosphate. Some good cat foods which are low in protein and phosphate are the special products for cats with renal disease from manufacturers like Hill’s or Blue Natural.

What’s in this cat kidney diet?

Reducing the intake of proteins is the key element of this diet. Proteins lead to higher values of urea. Since the kidney can’t get rid of the excessive amounts of urea, this will end up in the stomach where it turns into ammonia. This will make your cat feel nausea and will probably cause your cat to vomit.

Please don’t make the mistake of excluding all proteins. Proteins are an important part of any diet. The main difference is the type of proteins you feed your cat. Get rid of low-quality proteins and replace them with easily digestible proteins and proteins of high quality.

What you also need to avoid is the intake of phosphate and salt. Too much salt could lead to high blood pressure which could damage the kidneys and other organs.

The kidney diet also requires the use of water-based vitamin D and B and potassium supplements.

Cats lose both potassium and these vitamins when they urinate, but since the cat can produce it no longer by itself, they really need these supplements. Check out this post on vitamin supplements for cats.

And finally, in order to reduce inflammations, you will need to add Omega 3 fatty acids to the cats’ diet. Omega 3 fats which can be found in fatty fish like for example Salmon, are good for both humans and animals and it has also proven to be good for kidneys.

Salmon - source of Omega 3 acids

Hypertension – Control the high blood pressure

Cats with kidney problems often suffer from high blood pressure (Hypertension). Hypertension is known to speed up the deterioration process of the kidneys and it has an impact on the brains and eyes of the cat. It is therefore essential that you keep a very close eye on the blood pressure of the cat and if necessary use medicines to lower the pressure.

WARNING:  Please consult with a veterinarian before giving your cat any ACE inhibitors, some actually can cause kidney failure!!

Fight Anaemia

In order to help your cat produce more red blood cells, the veterinarian could suggest a treatment where they inject the cat with the hormone EPO. Perhaps you have heard of this hormone before. It has helped the famous cyclist Lance Armstrong to win the Tour de France several times by taking this (illegal) performance-enhancing drug.

When a vet considers a treatment with EPO injections they will always consult with the owner as this treatment is quite expensive. Most pet insurance companies will cover the costs, but do check your policy or contact your insurance company to make sure.

Reduce vomiting and nausea

In order to fight the symptoms such as vomiting and nausea, the vet can prescribe antacids or acid inhibitors. Sometimes they will give the cat tablets which stimulates the appetite and when the level of potassium in the blood is low, a vet might want to increase the intake as it can have a positive effect on the cats’ overall wellbeing.

What causes kidney disease with cats? 

Apart from those cats who were born with a kidney issue, there are several causes that lead to kidney failure in older cats.


This happens when a protein substance called amyloid, which is built in the cats bone marrow ends up in the kidney which causes kidney failure.

Cat breeds like the Persian cat, Abyssinian cat, and the oriental shorthair cat have a higher probability to be affected by Amyloidosis.


Cute Persian cat


Kidney stones

Kidney stones can be harmless. They do become a problem when they end up in the ureter and obstruct the flow of urine to the blatter. Because the urine can’t flow freely it will be stowed within the kidney, which causes serious damage.

Ethylene Glycol and Lily poisoning

Ethylene glycol is better known as antifreeze. The substance which is used in your refrigerator. Apparently, this stuff has a sweet taste and therefore attractive to cats.

Lilies are beautiful flowers, but they can be lethal to cats. Chewing on the leaves of the lily flower or drinking water from a vase which held lilies will cause kidney failure with cats. So please leave those lillies at the florist for a non cat owner to buy.

Polycystic kidney disease (PKD)

PKD is a genetic disorder which causes the growth of multiple cysts within the kidney. Cat breeds like the British Shorthair and Persian cats are more often diagnosed with PKD.

Urinary tract infections

Infections of any part of the urinary tract (ureter, bladder, urethra, and kidneys) can lead to kidney failure. A vet will always want to analyze the urine to establish if there is any infection. This especially applies when it’s a female cat. Females have a wider and shorter urethra, the part that helps to transports the urine from the bladder to the exit.

Other causes

The causes mentioned above are directly linked to kidney failure, however, there are other illnesses and diseases which can cause kidney problems. Some common ones are dehydration, heart failure or diabetes.

I hope this information has given you a good idea of how to spot kidney failure with your cat, what to expect when you bring it to the vet and what you can do to prevent kidney failure (good food is essential) and how you can support a cat who suffers from a kidney disease.

If you have read this article and your cat does not suffer from any kidney issues. Perhaps you might want to consider pet insurance. Medication to treat a kidney disease, the analysis, x-rays and an overnight stay in a pet hospital can be pretty expensive and the bills add up quickly.

Last but not least, please do not take this information as medical advice. Only a qualified veterinarian can analyze your cat and give medical advice. So if you think there is something wrong with your cat, please go and seek professional help.

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