Overview

This page is a summary page. The goal is to explain:

• what is CKD

• what the main test results mean;

• what are commonly seen symptoms of CKD; and

• what treatments are commonly used.

This page has links to more detailed information about each issue that is mentioned. However, I recommend that the first time you visit this page, you read it in its entirety without following any of the links, so as to obtain a general overview of what lies ahead.

Getting Started

You've just been told your cat has CKD and you are scared and frightened. So you found this site, and now, to add to your woes, you feel overwhelmed by all the information here. Clearly this is a complicated disease and you are not sure you can deal with it!

Well, take a deep breath because, honestly, it is not that bad. I had no scientific training at all when I first began dealing with CKD, in fact I was a linguist who was intimidated by scientific subjects, which I absolutely hated at school. But I did manage to learn about CKD, because it was essential if I was going to save Thomas's life; and you can do the same. Remember, knowledge is power! You need to be able to understand what is going on with your cat so you can obtain the most suitable treatments for him/her.

The good news is, you won't need to learn everything at once; and you certainly won't need to learn as much as I have. This site aims to cover every eventuality regarding CKD, but most people find they only have a few issues to tackle, needing maybe 10-20 minutes a day (including time needed to give fluids if necessary). You are highly unlikely, for example, to be faced with all the symptoms or to need to use all the treatments mentioned below. Yes, CKD is scary at first, but given time you should find that it becomes a manageable and routine part of your lives.

If even this page looks too overwhelming, try the Key Issues page instead. This page talks about what the tests mean, what symptoms you might be seeing and which treatments help. The Key Issues page simply gives a short overview of the most important things to focus on to help your cat feel better and increase his/her chances of survival. After you've read it, you can always come back here for more detailed information or dip into the other pages of the site.

What is CKD?

CKD is a progressive disease of the

I Don't Know What the Test Results Mean or Which Are Important

The tests which your vet runs will confirm the existence of CKD, and give some idea of how bad your cat's case is. Most people don't have the faintest idea what most of the test results mean, so to get you started, here is a summary which tells you what the main test results mean and what sort of symptoms they may cause. 

You should ask your vet for a copy of all the tests that are run, because these are helpful if you join Tanya's CRF Support Group. However, you can still join even if you do not yet have a copy of your cat's test results.

• Bloodtests

• Other types of test

Tests: Bloodwork

Your vet will probably run :

1. a blood chemistry panel, which checks kidney function and looks for any other abnormalities caused by poorly functioning kidneys; and

2. a complete blood count (CBC), which looks at the cat’s blood cells. This enables the vet to check for anaemia, a common problem in CKD cats.

You will probably have 1-2 pages of results, but the six items discussed below are the most important for you to understand at the beginning. If your cat's results show other items that are out of range, such as calcium, you should be able to find more information about these in the Diagnosis section.

If your vet has not addressed any results which are out of range, be sure to ask them why. Not everything needs treating (high cholesterol, for example, is not a worry in cats as it is in humans) but the items mentioned below do need treating.

The USA uses a different measuring system to the rest of the world. Tanya's CRF Support Group tends to use the US measurement system, so if you join, you will get more responses if you convert your international values to American ones. The Veterinary Information Network converter will do this for you. Scroll down the list to find what you want to convert (e.g. creatinine) and enter your cat's value in the "Enter SI Units to Convert to US Units" box. There is no need to convert potassium or PCV/HCT, which are the same in both systems.

• BUN
• Creatinine
• Phosphorus
• Potassium
• TCO2
• PCV or HCT

 BUN (blood urea nitrogen) or Urea

If you are in the USA, you should see blood urea nitrogen (BUN) on your cat's bloodwork. In Europe, you will probably see urea listed instead, which is not exactly the same thing but very close. 

BUN is one of the two main measures of kidney function (the other one is creatinine). In a cat with CKD, BUN will normally be elevated. BUN is a by-product of the breakdown of dietary protein during the digestive process. The kidneys filter it out of the blood and excrete it via urination. BUN rises in CKD because the damaged kidneys are no longer able to excrete it efficiently, so it builds up and makes the cat feel poorly. BUN is not a toxin in itself, but if it is elevated, then the chances are high that actual toxins (which are difficult to measure, but which make the cat feel poorly) will also be elevated. BUN can also rise for other reasons though, such as dehydration, stress or a high protein diet, so it is not an entirely accurate measure of kidney function by itself.

It is important to try to control high levels of BUN because they can cause lack of appetite, excess stomach acid, nausea and vomiting. 

BUN can be controlled via fluid therapy and dietary management. Treatments for vomiting and excess stomach acid are also very useful and can make a CKD cat feel much better.

You can read about BUN in more detail in the Diagnosis section. 

Creatinine (Crea)

Creatinine is another waste product excreted through the kidneys. It is generally considered to be a more accurate measurement of underlying kidney function than BUN or urea because it is less affected by diet, stress and dehydration.

Because creatinine is the basic measure of kidney function, you will probably not be able to reduce it to within normal range in a CKD cat, but that does not mean that it cannot reduce from the level you see at initial diagnosis. If you treat CKD effectively, it may well lead to improvements in creatinine levels, so try not to panic if your cat has high levels to start with.

You can read about creatinine in more detail in the Diagnosis section.. 

Phosphorus (Phos, P or Pi)

Phosphorus and calcium are minerals which are important for nerve function, muscle contraction and bone formation. A healthy body has a natural balance between levels of phosphorus and calcium. CKD kidneys can no longer excrete phosphorus properly so levels of phosphorus rise (hyperphosphataemia), which can then adversely affect the cat's calcium levels, with potentially serious consequences (see secondary hyperparathyroidism). Not only that, but high phosphorus levels may make the CKD progress faster and can make a cat feel lousy. So controlling phosphorus levels is one of the most important steps in managing CKD and helping your cat feel better.

Symptoms of high phosphorus levels may include weakness, an unsteady walk, itching and scratching, loss of appetite, twitching and weight loss.

Your vet may say that your cat's phosphorus levels are within normal limits, but the high end of the normal range actually applies to kittens rather than to adult cats, particularly those with CKD. You should aim to actively controlling phosphorus levels once they are above 1.9 mmol/L/l (US: 6 mg/dl). This can be done by feeding a low phosphorus food (usually a prescription diet) or by adding odourless, tasteless phosphorus binders to your cat's food, see below.

You can read about phosphorus in more detail on the All About Phosphorus page. 

Potassium (K+)

Potassium is an electrolyte (a type of salt), which the body needs in order to function properly at the cellular level. If potassium is out of balance, it can affect the muscles, including the heart.

Cats with CKD usually urinate a lot, and may also vomit, and this can cause loss of potassium, leaving levels low in the cat's body. However, a few CKD cats have the opposite problem of too high levels of potassium, particularly if they have high creatinine levels.

Low potassium levels (hypokalaemia) can have various effects, such as weakness (especially in the back legs), twitching, hoarseness or constipation. Severe cases may be unable to lift their heads because of a weak or stiff neck.

Although the range for potassium often starts at around 3.5, for CKD cats it is often recommended to treat low potassium levels when they fall below 4.0 mmol/L/l (US: 4.0 mg/dl). The goal is to have a level of around 4.4 mmol/L/l (US: 4.4 mg/dl) or a little higher. The usual treatment method is a supplement in the form of a pill, though it does come in other forms too if your cat is difficult to pill.

Not all CKD cats have low potassium levels. Cats with a level of 4.4 or higher do not usually need supplementation of potassium. Cats with high levels of potassium (over 6.0) may experience twitching, seizures, and in the worst case scenario, even a heart attack.

There is information below about treating high or low potassium levels.

You can read about potassium in more detail on the All About Potassium page. 

TCO2

Acidity levels in the body tend to rise in CKD cats i.e. the body’s pH becomes too low – this is known as metabolic acidosis. It is not the same thing as stomach acid, which is excess production of acid in the stomach only.

Unfortunately many vets do not watch for metabolic acidosis routinely, which is partly because it can be hard to measure. TCO2 or total carbon dioxide in the blood is the most accurate way to diagnose metabolic acidosis but TCO2 has to be measured on a special blood gas machine, which not many vets and not all laboratories have. If your vet or his/her laboratory cannot measure TCO2 at all, your vet may be able to test for carbon dioxide (CO2) levels instead - if they are low, they may also indicate metabolic acidosis. 

Metabolic acidosis can have a variety of effects, including muscle wasting, a bony spine, back leg weakness, vomiting, mouth ulcers, twitching and seizures, so it is very important to diagnose and treat it if it is present.

Treatments may include fluid therapy, potassium citrate or bicarbonate of soda.

You can read about metabolic acidosis in more detail on the Metabolic Acidosis page. 

PCV or HCT

The kidneys produce a hormone called erythropoietin, which stimulates the bone marrow to make red blood cells. Damaged CKD kidneys may no longer perform this task properly, and if red blood cells are not made, anaemia is the result.

PCV and HCT are both used to measure anaemia. Your vet will run one test or the other. PCV is not quite the same thing as HCT; but the difference between the two is too small to be concerned about. 

Technically, a cat is anaemic if his/her PCV level is below 30% (or with some laboratories, 25%), but you may not start to see any differences in your cat's behaviour until the level is in the low 20%s. Dehydration will make PCV look higher than it really is, so once a cat is rehydrated, PCV will often have fallen.

Symptoms of anaemia include weakness, loss of appetite, heavy breathing, feeling cold, eating litter or licking cement.

It is essential to treat anaemia. Cats with a PCV or HCT below 20% have severe anaemia, and you have to treat it quickly, because untreated severe anaemia can be life threatening. Cats who are severely anaemic may appear very ill (though some of them adapt to the anaemia if it happens gradually, and cope quite well), but you should see a dramatic difference once the anaemia is under control. Treatments include iron or vitamin B supplements for milder cases, or the use of a synthetic hormone replacement known as ESAs (trade names are Epogen, Procrit or Eprex) for more serious cases.

You can read about anaemia in more detail on the Anaemia page. 

Other Tests

Blood Pressure

Hypertension (high blood pressure) is very common in CKD cats, because the kidneys produce renin, which controls blood pressure, but damaged kidneys may not do this effectively.

High blood pressure is very dangerous - it can cause strokes, seizures and blindness, and may even kill; but since it has few visible symptoms until a crisis occurs, it really needs to be measured with a blood pressure monitor.

Unfortunately, many vets do not have the equipment to measure blood pressure (even though it only costs about US$1000). Do ask your vet if s/he has this equipment, and if so, make sure s/he uses it to check your cat's blood pressure. If they do not have it, politely ask them to consider investing in it, and then call around other vets in your area (or ask your vet to do so) to see if you can find somebody who can measure your cat's blood pressure. If you cannot find anybody to measure it, check the All About Hypertension page for alternative checks, though they are far from ideal.

If blood pressure is consistently over 160, it should be treated. This is easily managed through the use of a medication called amlodipine (known as Norvasc in the USA and Istin in many parts of Europe).

Urinalysis

This is a test of your cat's urine. It may include a check of urine specific gravity (USG), which tells your vet how dilute your cat's urine is (CKD cats usually have very dilute urine). It often will also give the vet some information on whether your cat has a urinary tract infection (UTI). Urinalysis also can show if a cat has proteinuria (protein leaking into the urine).

You can read about urinalysis in more detail in the Diagnosis section. 

Ultrasound

Sometimes vets want to run an ultrasound of a cat's kidneys. This can be helpful if a cat has larger than expected kidneys (which may indicate cancer, a blockage of some kind or a genetic disease known as PKD), or if you suspect a kidney infection. However, in many if not most cases of CKD, an ultrasound merely confirms that a cat has CKD and adds nothing to the overall treatment plan. If this is the case for your cat, it is probably worth passing on an ultrasound and saving your money.

You can read about ultrasound in more detail in the Diagnosis section. 

There are a number of other tests which are occasionally offered, and you can find more information about them in the Diagnosis section. 

So Just How Sick is My Cat?

People are often scared stiff when their vet says things like "your cat only has 25% kidney function remaining" but actually, it is normal not to be able to diagnose CKD until 66-75% of kidney function is gone. The  What Happens in CKD page explains why this is the case.

If the vet uses the old style terminology, chronic renal failure, the word "failure" also terrifies most people when they first hear it, but in fact the word "chronic" is what matters. This means that in most cases, CKD is a progressive disease, and therefore death is not necessarily imminent.

The How Bad is It? page gives you some idea of how serious your cat's bloodwork results are but remember, these are not the be-all and end-all. How sick your cat is depends upon whether s/he is in crisis or not at diagnosis, and also on how well your cat copes with CKD - some cats can cope astonishingly well with horrible bloodwork.

Below I talk a bit more about some common scenarios when you first get the diagnosis:

• The crashing cat

• The stable cat

• If your vet has recommended euthanasia

Cat in Crisis: Crashing

Many cats who are diagnosed with CKD are in crisis (known as "crashing"), often because of severe dehydration. CKD cats tend to urinate more as their kidneys deteriorate. They then drink more to compensate for the increased urination, but eventually they can no longer drink enough to keep up with the fluid lost from dehydration, and they crash.

Before you go to the vet (which you should do as soon as possible if you think your cat is crashing), here are some of the signs you may see:

• the cat will often be unable to get comfortable and may lie in the meatloaf position (a bit like a Sphinx but not exactly the same: click on the link for a photo which gives a rough idea);

• you may notice a bad breath smell, and your cat may also have a generally strong body odour;

• he/she will have dull, perhaps sunken eyes and not make eye contact;

• your cat will probably refuse to eat and may also refuse to drink.

When you reach the vet, and bloodwork and other tests are run, you will usually be told that your cat's bloodwork values are very high. This occurs because severe dehydration artificially inflates most of the values.

I cannot emphasise this enough: it does not matter how bad your cat's values are at initial diagnosis, particularly if s/he is severely dehydrated. You have to wait and see what they look like when the cat has been stabilised. My Thomas's BUN was 241 at initial diagnosis (the top of the range was 36) yet he pulled through.

If your cat is in crisis, the first thing to deal with is the dehydration. This will usually be treated via intravenous (IV) fluids (a drip), which requires hospitalisation for a few days. Personally, I would want to put any cat of mine with creatinine of over 6 on IV for 3-4 days (one day is not enough).  As the cat becomes rehydrated, s/he should gradually start feeling and acting a little better, though some cats do not do well as in-patients and will only turn the corner once they return home.

The cat may continue to exhibit a loss of appetite, so it is essential that sh/e eats, via assist feeding if necessary. Since cats with high BUN tend to have problems with excess stomach acid, ask the vet to treat this (the excess stomach acid) too.

A cat with high bloodwork will almost certainly have high phosphorus levels, and may also have anaemia, though anaemia may not be apparent in blood tests until the dehydration has been corrected. Hypertension (high blood pressure) may also be present. Treatment needs to be started for all of these as appropriate. I do not advise starting benazepril (Fortekor) treatments for cats with high creatinine levels.

Your cat may still have high numbers when you bring him/her home, but don't panic, they may continue to fall with a home treatment programme, as happened to our Thomas. Once your cat is home, you can follow the advice for the stable cat below.

The Stable Cat

If your cat is not in crisis, then creatinine levels will usually be 300-350 or below (USA: 3-3.5 or below). Yes, those numbers are still a lot higher than they should be but really, they are considered medium level numbers. They may even be higher - some cats cope better with high numbers than others.

Whatever the level, if your cat is not in crisis and dehydrated, then it is highly unlikely that your cat needs IV fluids. I have heard recently of some vets putting non-crashing cats with creatinine of 300 (USA: 3) or lower on IV fluids, which seems like overkill to me - chances are these cats do not even need regular subcutaneous fluids, let alone IV fluids; plus it is much cheaper for you and less stressful for your cat if you can avoid IV fluids.

However, you will probably need to begin a home treatment programme. This need not be particularly complicated if your cat has been diagnosed early enough. In that case, you will probably merely need to focus on the things that will keep your cat stable (e.g. controlling phosphorus levels, and, for cats with creatinine over 300 (USA: 3.5), perhaps giving sub-Q fluids regularly to prevent dehydration), and comfortable (e.g. controlling constipation or excess stomach acid). Basically, you need to check the bloodwork and symptoms, see what issues may be a problem, and take the appropriate action.

Most people find they only need to spend 10-20 minutes a day dealing with their cat's additional CKD needs, and that includes time spent giving fluids (which not all cats need immediately). If you focus on any problems that are present and have a bit of luck on your side as well, you should soon see a big improvement in your cat's wellbeing. For more detailed information on the symptoms which you might be seeing, see the Index of Symptoms and Treatments page.

Even when a CKD cat is stable, it is normal for him/her to have the occasional bad day, particularly when first diagnosed. Try not to panic if this happens, just try to treat anything that may be contributing to the problem (e.g. if your cat is constipated, s/he won't feel great) and with luck you will find that once any problems are under control your cat will have a reasonable quality of life overall.

However severe your cat's case may be, if I were to give you only one piece of advice, it would be to make sure your cat eats. Cats who go just a short time (a day or two) without eating are at risk of a condition called hepatic lipidosis, a potentially life threatening liver problem. Not eating can also worsen dehydration and make the cat very weak; whereas food in the stomach can often make a cat feel better and stronger. See below and the Persuading Your Cat To Eat page for information on getting food into your cat.

If Your Vet Has Recommended Euthanasia

Recently I have been hearing from more and more people whose cats have only just been diagnosed, yet the vet is already recommending euthanasia. I hear things like "the vet said my cat has anaemia and it's untreatable, so I should put him to sleep", or "the vet says his bloodwork is so high that it can never reduce to a reasonable level" (this even for cats with creatinine of around 300, or 3.5 in US terms), and of course the classic "he's very sick, and it would be the kindest thing to do".

Often these vets do not even offer any IV (intravenous fluids) treatment for high number cats, or if they do, they only offer one day, tell the person their cat's numbers have not improved after that short stint, and recommend euthanasia. In some cases people are told even before their cat is placed on IV that if s/he does not respond within 24 hours, they have to put their cat to sleep.

I'm not in the business of vet-bashing, but this trend does give me pause for thought. No vet has a crystal ball. And CKD cats can look horribly ill when they are first diagnosed, particularly if they are dehydrated. I was dehydrated myself last year following surgery, and I definitely looked as bad as I felt. Note I say that I felt bad; but I was not in actual pain. CKD is not generally considered to be a painful disease (although end stage PKD, a genetic kidney disease, may be painful if some of the cysts rupture, but this is rare). Dehydration basically feels like a bad hangover, with a bad headache and a queasy stomach. CKD cats often have excess stomach acid, so that feels like stomach ache. They may be constipated, and may have anaemia which makes them feel weak. But none of these things is outright painful. And all of these things are treatable, in fact often relatively simple treatments can soon make a CKD cat feel and act much better. 

So I would say that in most cases, you should definitely try treatments, for a period of two weeks if not longer, before opting for euthanasia. And if your cat has high bloodwork levels, then one day on IV fluids is simply not long enough to decide whether a cat is going to turn the corner or not! Read the rest of this page, particularly the Cat in Crisis section, see what problems your cat is experiencing, and do your best to treat them. I cannot promise that treating your cat is going to work. But there is a pretty good chance that it will. And even if it doesn't, at least you would have the peace of mind of knowing that you tried your best. And remember: it is not the vet's decision to put your cat to sleep, it is yours.

Commonly Seen Symptoms

This is a short list of symptoms which may be seen in CKD. Some of these problems, such as constipation, are not life threatening, but they can make a big difference to how well a cat feels. Others, such as not eating, can cause severe problems if left untreated.

• Vomiting
• Excess stomach acid
• Mouth ulcers
• Weakness
• Constipation
• Howling
• Refusal to eat
• Eating litter
• Twitching
• Blindness
• My cat has symptoms not listed here

Vomiting

Mouth Ulcers

Weakness, Especially in the Back Legs

Many CKD cats are weak at initial diagnosis. This may be because they are dehydrated, or anaemic. Other possible causes include high phosphorus levels, low potassium levels, metabolic acidosis, constipation and calcium imbalances. If you and your vet can work out what the cause is and treat it appropriately, you should find that this symptom improves greatly.

Constipation

The dehydration that accompanies CKD may cause constipation. Symptoms - apart from the obvious one of no poop in the litter tray - may include an ungainly walk, vomiting after using the litter tray, loss of appetite, pooping outside the litter tray, and, surprisingly, diarrhoea. Constipation can usually be treated easily and quickly.

Howling

CKD cats often howl, especially at night. Howling is commonly caused by high blood pressure. It may also have other causes such as toxins, deafness, hyperthyroidism, or occasionally just old age and possibly cognitive dysfunction (senility). Certain medications such as periactin (Cyproheptadine), an appetite stimulant, or anabolic steroids, such as stanazole (Winstrol), can make a cat become vocal. 

Refusal to Eat

This is really common in CKD cats. Common causes include excess stomach acid, high phosphorus levels, dehydration, constipation, fluid retention and loss of sense of smell. Many cats refuse to eat the CKD prescription diets in particular. Treating the cause will usually help, though some CKD cats will always need encouragement to eat.

Twitching

Commonly Used Treatments

The following is a list of some of the treatments which you may be offered. If you are in the UK, I can virtually guarantee that you will only be offered a prescription diet, Fortekor, and occasionally Renalzin or Ipakitine; but many of the other treatments are equally, if not more important, depending upon your cat's condition. 

• Diet and vitamins

• Vomiting, nausea and excess stomach acid

• Phosphorus binders

• Amlodipine (Norvasc or Istin) for High Blood Pressure

• ACE inhibitors (e.g. Fortekor)

• Steroids

• Fluid therapy

• Mouth ulcers

• Potassium supplements

• Constipation

• Phosphorus binders

• Metabolic acidosis

• Cyproheptadine

• Epogen, Procrit or Eprex

• Azodyl

• Antibiotics

• If you have recently used meloxicam(Metacam)

Vitamin B is a water-soluble vitamin, and is often lacking in CKD cats, who lose much of their Vitamin B through urination. A lack of vitamin B may be related to a lack of appetite, or occasionally may cause twitching or itching. Vitamin B deficiencies are also known to cause non-regenerative anaemia. Your vet may therefore suggest a supplement in order to avoid these problems. British vets often give Vitamin B injections, but you can also give Vitamin B orally.

Vomiting, Nausea and Excess Stomach Acid

The most effective treatments for excess stomach acid are slippery elm bark, from health food stores (see Holistic Treatments) and/or a drug called famotidine, trade name Pepcid AC (not Pepcid Complete).

With Pepcid AC, you usually start with a quarter of a 10mg tablet once every other day, but if necessary you can go up to a quarter of a 10mg tablet twice a day (all with your vet's approval, of course).

In some cases, you will also need anti-nausea medications.

The All About Stomach Acid page has more information about excess stomach acid, nausea and vomiting

High Phosphorus Levels

If your cat's phosphorus level is above 6 mg/dl US or 1.9 mmol/L/ international, and you are not feeding a prescription diet, you should ask your vet about using a phosphorus binder. Phosphorus binders bind with the excess phosphorus in cat food and therefore reduce the load on the kidneys. They must be given with food in order to bind properly, and ideally an hour or so apart from other medications.

The phosphorus binder which binds best is aluminium hydroxide. Many vets are not aware that this can be obtained in odourless and flavourless formulations and simply added to the cat's food without the cat knowing.

In the UK, you may also be offered a binder called Renalzin, which is relatively new but it seems to be effective.

You may be offered a binder called Epakitin or Ipakitine but this is not always the best choice. Another common choice by vets is Alternagel, but this is peppermint-flavoured, which most cats hate.

In some cases, you will also need a phosphorus binder even if you are feeding a prescription diet if the levels do not reduce far enough, but I would try the diet two weeks on its own first to see if it is sufficient.

The All About Phosphorus page explains more about phosphorus control.

Hypertension (High Blood Pressure)

This is present in up to two thirds of CKD cats, so do ask your vet to monitor your cat's blood pressure; many do not do so routinely. If your cat has suddenly gone blind, the most common cause is hypertension; and if you act quickly enough, your cat may be able to regain some or all of his/her sight.

Even if your cat has not gone blind, if hypertension is present, it must be treated. The treatment of choice for CKD cats with hypertension is a drug called amlodipine (trade names are Norvasc or Istin) This is very well tolerated by the majority of cats, is less likely than some other treatments to cause the opposite problem of low blood pressure, and is the only treatment which gives your cat a chance of regaining his/her sight if it has been lost.

There are two commonly used appetite stimulants in cats, cyproheptadine (Periactin) and mirtazapine (Remeron). They are usually very effective, but may have side effects, such as making the cat agitated, causing howling etc.

Please see the Anaemia page and Erythropoiesis Stimulating Agents page for more information.