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TANYA'S
FELINE CHRONIC RENAL FAILURE INFORMATION CENTRE
SYMPTOMS
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The symptoms described on this page are not in alphabetical order. An alphabetical list of the many symptoms which may arise in CRF cats can be found at Index of Symptoms and Treatments
The symptoms of CRF are many and varied. If your cat suffers from one particular CRF-related problem, there may be several symptoms present, some of which you might not necessarily associate with each other. For example, you may know that weakness is a common symptom of anaemia, but not many people realise that eating litter is often a sign of anaemia.
Many of the symptoms discussed below can also be symptoms of other diseases. In addition, some symptoms (such as those of hypertension) may not be easily detected or immediately apparent to the layperson but it is very important that they be treated if they are present.
Therefore if your cat is showing any of the symptoms listed below, I strongly urge you to seek an early appointment with your vet, since no matter what might be causing the symptoms, the earlier you obtain a diagnosis (whether of CRF or some other condition), the more effectively you can start treating your cat.
Although the number of symptoms may appear overwhelming, you will not necessarily see all these symptoms, and which ones you see at any one time will depend upon the severity of your cat's CRF and his/her own particular weaknesses. Often you may only need to use one or two treatment methods in order to effect a real improvement in your cat's condition - simply controlling dehydration and stomach acid is all that many cats need.
Diagnosis and management of chronic renal failure in cats (c. 2000) Sparkes A, has a list on page 2 of the most commonly seen symptoms in CRF cats. Vet Help Direct allows you to select your cat's symptoms, answer a number of questions and be given advice on possible causes of the symptoms.
If you can, I recommend reading this entire section because it will give you a good overview of CRF. However, if you do not have time, then please visit the Index of Symptoms and Treatments, where all the symptom are listed alphabetically, with quick links to each individual symptom.
Some symptoms may also be caused by other conditions, such as hyperactive thyroid or heart disease. These are flagged both on this page and on the Index of Symptoms and Treatments page, while these diseases are discussed in detail on the Related Diseases page.
Crashing in a medical context means a sudden and severe downturn in the patient's condition. In a CRF cat it indicates a crisis usually associated with severe dehydration. Crashes are rarely treatable at home - in most cases the cat will require hospitalisation. If, after reading the information below, you think your cat may be crashing, please seek veterinary advice urgently.
I am often asked if CRF cats are in pain. No, the typical CRF cat is not in pain. Some of the symptoms of CRF can be uncomfortable, e.g. dehydration is often described as feeling like a hangover, but they are not painful, and in most cases are easily treatable.
In some situations a CRF cat may be experiencing pain e.g. from toothache or a kidney infection, or if s/he is having trouble breathing. Again, most painful conditions can be treated.
Cats who are in pain or discomfort are unfortunately very good at hiding it (this is instinct, in order to protect themselves from predators). One possible symptom is restlessness, moving around from one spot to the other. However, there are a number of other possible causes for restlessness, so don't panic if you see this symptom.
Treatment
Increased Urination (polyuria)
The ins and outs of polyuria and polydipsia is an article by Dr Carl Osbourne of the College of Veterinary Medicine at the University of Minnesota.
Healthy cats only have tiny amounts of protein in their urine because their kidneys do not allow the protein to leak through. In CRF cats, this mechanism can be faulty and excess levels of protein in the urine, known as proteinuria, may occur. The main proteins which leak through are albumin and globulin.
One commonly seen symptom of proteinuria is foamy urine. Proteinuria may also cause weight loss, and swelling in the legs, abdomen or face. Treatment
Other causes of proteinuria include hypertension and diabetes.
The National Kidney and Urologic Diseases Information Clearing House is a human site with information about the symptoms of proteinuria.
Increased Drinking (polydipsia) The increase in urination that occurs in CRF leads the cat to drink more and more in an attempt to avoid becoming dehydrated. Some cats, like Tanya, develop new behaviours, such as drinking from showers or gutters, or hanging around sinks and begging for fresh running water from the tap. Some cats like to play with their water bowls from an early age, but some CRF cats develop a bit of an obsession with water, and may play with their water bowl or paw at the water.
Increased drinking can also be a symptom of stomach acid or diabetes.
The ins and outs of polyuria and polydipsia is an article by Dr Carl Osbourne of the College of Veterinary Medicine at the University of Minnesota.
As mentioned above, the ability to produce concentrated urine gradually deteriorates in a CRF cat as the kidneys fail. Although the cat will drink more in an attempt to compensate for the increased urination, eventually it becomes impossible to maintain a balance, and dehydration occurs.
Many people believe that dehydration means the loss of water from the body. However, it actually means the loss of both fluids and electrolytes - salts which the body needs in order to function properly.
It is not possible to diagnose clinical dehydration until the cat is already at least 5% dehydrated, so by the time you see signs, you already have a definite problem. Colorado State University gives information on the likely degree of dehydration based on physical signs (scroll down to section 7).
Sunken eyes may indicate dehydration, as may vomiting. Cracked paw pads are also occasionally seen. Sometimes a cat with dehydration hangs his/her head over the waterbowl, though more commonly that is a sign of stomach acid. The cat may also grind his/her teeth, or lip his/her lips.
You should regularly check your cat's hydration levels: the most common method is to pinch the skin, usually at the scruff of the neck - the skin should fall back into place immediately. Most CRF cats experience some degree of dehydration so the skin may not fall back as quickly as in a healthy cat, but if it takes a few seconds you should look into improving your cat's hydration. Another way to check is to feel your cat's gums: they should feel slick. If they feel sticky, your cat is probably dehydrated. Pet Education has some information about how to use these two assessment methods. Some people weigh their cats daily, finding this a good guide to their cat's degree of hydration.
If you've ever been dehydrated, you know how awful it feels - like a bad hangover, with a dreadful headache and stomach ache. Dehydrated cats often stop eating, which then makes them even more dehydrated because they are not obtaining any fluid from their food. To make matters worse, cats who do not eat are at risk of developing a potentially life-threatening condition known as hepatic lipidosis. Therefore, it is important to detect and treat dehydration as quickly as possible. Treatment
This may be a sign of an upper respiratory tract infection (a cold or cat flu). CRF cats may be prone to these viral infections because they are immune-compromised; plus CRF cats are often visiting the vet more often and therefore being exposed to more viruses.
If your cat has no other signs of an upper respiratory tract infection, then the sneezing may be caused by dehydration - the nasal passages of a dehydrated cat will be drier and therefore more susceptible to irritation, such as dust.
Dental problems may sometimes cause sneezing.
Another possible cause is the long-term use of cyproheptadine, which may make the nasal tissues swell as the drug becomes less effective.
Sneezing and snorting - what should I do? (2001) is a presentation by Brendan McKiernan to the World Small Animal Veterinary Association World Congress 2001.
In addition to concentrating urine, a cat's body also tries to conserve water by reabsorbing it from the stool through the intestinal wall. This mechanism is very efficient, and remains so even in CRF cats, and since CRF cats are largely on the edge of dehydration most of the time, the intestine will wring every drop of water out of the stool that it can, leaving it quite dry. The lack of moisture as a lubricant makes it more difficult for the cat to have bowel movements and can lead to constipation. Low potassium levels may also cause constipation, as may high calcium levels.
Symptoms of constipation include loss of appetite, pooping next to the litter tray, vomiting before, during or immediately after using the tray, dry stools or an ungainly walk. Occasionally a cat may urinate outside the litter tray when s/he is constipated - our Karma peed on the sofa so we took her to the vet for a suspected urinary tract infection, but in fact she did not have one, her problem was constipation. Once the constipation was under control, her inappropriate elimination ceased.
The vet can usually feel the backed-up stool when s/he palpates the cat's abdomen, but sometimes an x-ray is necessary to confirm the problem.
Sometimes a cat will appear to have diarrhoea but in fact has constipation, and the runny stool is simply what can squeeze around the solid dry stool.
Harpsie once had an episode of fast breathing and fast heart rate. He had severe constipation, and his problems resolved once he had been given an enema. If a cat is very severely constipated, toxins can back up in the cat's system causing such problems. The opposite problem may also occur i.e. lethargy and fainting (vasovagal syncope - syncope means to faint). Medicine Net discusses this. Obviously you do not want your cat to have such severe constipation that these problems arise!
Meower Power has information on the different colours of cat poop. Columbia Animal Hospital has a diagram of a cat with an impacted colon. Newman Veterinary mentions that constipation may cause vomiting (scroll down a bit).
The concentrated urine of a healthy cat has the correct levels of acidity and good bacteria, which inhibit the development of bad bacteria which multiply and cause infections. The dilute urine of a CRF cat does not offer this protection, and so urinary tract infections (UTIs) are relatively common in CRF cats: Antech Diagnostics states that up to 30% of CRF cats have them.
Urinary tract infections may manifest themselves in your cat visiting the litter tray more frequently and producing little or no urine; or there may be slight traces of blood in the urine (see below for other causes of blood in urine); but often there can be no obvious signs, or less obvious signs such as urinating in inappropriate places such as on rugs or beds (see below).
UTIs can be very painful so keep a close eye on your cat and seek your vet's advice if you have any doubts; it may also be worth having regular urine cultures performed. Antibiotics can usually treat UTIs effectively, though some types of antibiotic may cause inappetance and vomiting in some cats. Treatment
KV Vet sells a product called Health Alert which can test for blood in the urine. The Pet Checkup is a similar test that checks for blood in urine, and which may also be used to check for other issues, such as diabetes. Health Meter Cat Litter can detect blood in urine, and also checks urine pH.
This may be a sign of a urinary tract infection, or bladder or kidney stones. It may also indicate high blood pressure. Sometimes this is caused by cancer. Occasionally it may not be possible to ascertain the cause. There is a condition called "benign renal haematuria" which means there is bleeding from the kidneys but the cause cannot be found. However, this is rare in cats.
Persistent haematuria and proteinuria due to glomerular disease in related Abyssinian cats (2008) White JD, Norris JM, Bosward KL, Fleay R, Lauer C & Malik R Journal of Feline Medicine & Surgery 10(3) pp219-29 discusses how in Abyssinian cats with haematuria, the cause may be glomerular disease.
Severe or ongoing haematuria may cause or worsen anaemia, so you should always take your cat to the vet if you see this symptom.
Pet Place has some information about haematuria in cats. KV Vet sells a product called Health Alert which can test for blood in the urine. The Pet Checkup is a similar test that checks for blood in urine, and which may also be used to check for other issues, such as diabetes.
Reduced Urination (Oliguria) or No Urination (Anuria) If your cat is struggling to urinate, i.e. visiting the litter tray more frequently but producing little or no urine, the most likely cause is a urinary tract infection.
Other possible causes of reduced or no urination include acute renal failure or kidney stones.
Certain antihistamines used as appetite stimulants such as periactin (Cyproheptadine) may cause reduced urination.
Alternatively, there is a very serious medical condition called a urinary tract blockage, which you can read about here. This is a medical emergency, but fortunately such blockages are relatively rare in CRF cats. Treatment
However, cats who are at the very end of their CRF journey may cease to be able to urinate because basically their kidneys have shut down. You can read more about this here, but be sure to rule out the causes outlines above before fearing the worst.
Incontinence means that your cat is unable to control when s/he urinates - s/he may urinate where s/he lies or walks, or perhaps urinate in his/her sleep. This may be caused by a urinary tract infection, or may be a symptom of uncontrolled diabetes. Occasionally, it may be your cat is simply getting "caught short", particularly if you are giving sub-cutaneous fluids, and the litter tray is a long way away. In some cases, it may indicate advanced renal damage.
Kidney Infections (Pyelonephritis) One of my cats gets regular kidney infections, and the main sign for him is that he becomes incontinent when the infection first appears. However, this is not inevitable with kidney infections - you may simply see more subtle signs, such as lethargy and inappetance. If you see these signs, particularly if your cat's bloodwork is worsening, ask the vet to consider that a kidney infection could be the cause.
This is a polite way of saying your cat urinates (and/or defecates) outside the litter tray. This can be a sign of a urinary tract infection or constipation, and it may also be a symptom of uncontrolled diabetes; but sometimes it is a behavioural problem. Treatment
Cats may lie in the litterbox if they have a urinary tract infection, or are constipated. This may also be a way to comfort themselves - many cats lie in their litter tray whilst hospitalised because it is the only thing that smells familiar to them.
In some cats, lying in the litter box is simply a sign of dominance - Harpsie loved lying in the litter tray, thus controlling the other cats' access to it.
This is a common symptom of CRF, and was the first sign with both Tanya and Thomas. Not only did they lose weight, but their spines became very bony (and their coats became dry with dandruff). This occurs because as the cat drinks and urinates more, s/he may lose protein and/or electrolytes. Weight-loss can also be associated with phosphorus imbalances or metabolic acidosis (particularly when accompanied by a bony spine), or may be a symptom of other diseases such as diabetes or hyperactive thyroid. Other possible causes include IBD (Inflammatory Bowel Disease) or cancer. Treatment
Swelling in the Legs (Oedema), Abdomen (Ascites) or Face This may be a sign of proteinuria. Alternatively it may be a sign of fluid retention/build-up and/or heart problems.
Occasionally (rarely in cats), such swelling may be a sign of nephrotic syndrome. Nephrotic syndrome is not a disease in itself, but rather a collection of symptoms that may be seen as a result of glomerular disease. The primary symptoms of nephrotic syndrome include proteinuria, oedema and/or ascites, low albumin levels and high cholesterol levels. You may also see diarrhoea, reduced urine output, anaemia and occasionally saddle thrombus (a blood clot in the leg).
Health A to Z explains more about ascites.
Sometimes a CRF cat may develop fluid retention or fluid build-up. This may be a sign of worsening kidney values or of heart problems, or a sign of over-hydration either via IV or sub-Qs. In the worst cases, fluid may collect in the lungs (pulmonary oedema), or around the lungs (pleural effusion) or in the abdomen (ascites).
Your cat may appear swollen in the legs, face or stomach. When Harpsie developed ascites, it felt like he had a hard little football in his stomach. However, it is normal for cats to have a soft, squishy "pouch" of fluid after sub-Qs, which may move down into the front legs; this should gradually disappear as the fluids are absorbed.
If your cat feels "squishy" when you stroke him or her, this may also indicate fluid retention caused by overhydration from excessive sub-Qs (although sometimes it merely means that air got into the line, in which case you need to work on your sub-Qs technique).
A cat with fluid retention may also show loss of appetite, because the
fluid may be pressing on the stomach causing a feeling of fullness. S/he
may also find it uncomfortable to lie down on his or her side, or may sit
up and refuse to lie down; this is because it is easier to breathe in this
position. Other
symptoms to watch for: if your cat appears to be gaining weight rapidly or
suddenly (within the space of a few days), particularly if he/she also starts
breathing from the flanks (as if pushing every breath out),
coughing, purring with a rattly noise and/or develops a nasal discharge, you need to see a vet.
Unfortunately, you may not always see symptoms until the problem is
severe.
If your cat starts breathing with the mouth open, or has a limp and
the limping leg is cold to the touch,
this is a medical emergency indicating
heart
problems
and you need to get to a vet as quickly as possible. Do not give any
sub-Q fluids if you see any of the symptoms above until you have had your cat checked
by a vet. You should also never give a cat sub-Qs until the fluids from
the previous session have been absorbed.
If you suspect your cat has fluid build-up, you and your vet do need to investigate this because your cat probably feels uncomfortable, and if the fluid is permitted to continue to build up, particularly in a cat with heart issues, your cat could develop congestive heart failure. However, in many cases, you may find that simply reducing the amount or frequency of sub-Qs solves the problem; so speak to your vet about this. The Intravenous Fluids and Sub-Cutaneous Fluids page has information on amount and frequency of fluids.
If your cat is prone to such problems, you may wish to monitor your cat's weight with baby scales.
Virginia-Maryland Regional College of Veterinary Medicine has examples of breath sounds, including the sound a cat with pulmonary oedema makes. Cancer Back Up explains more about pleural effusion. Health A to Z explains more about ascites.
Sometimes a CRF cat will suddenly gain a lot of weight in a short period of time, a matter of days or a week. This may indicate fluid retention, and needs to be investigated urgently, particularly if accompanied by coughing, loss of appetite, breathing from the flank (as if pushing every breath out), limping, and particularly open-mouth breathing. If you see the last three symptoms, your cat's heart or lungs may be affected and you need to go to the vet immediately. But do not give any sub-Q fluids if you see any of the above symptoms or if your cat has gained a lot of weight suddenly or quickly until you have had your cat checked by a vet.
Sometimes a weight gain may seem small but we have to allow for the relatively small starting weight of a cat. So if, for example, a cat who weighs 8 lbs gains 1lb in a week, that is a weight gain of 12%. The human equivalent would be a 140lb person gaining almost 17 lbs in a week, which clearly is not possible in terms of actual weight.
What is a reasonable weight gain? Be guided by your vet, but if your cat has just eaten or has been given fluids and has not yet urinated, then these will affect weight. 100ml of fluids weighs about 3.5 ounces (100g), for example, so if you weigh your cat immediately after giving fluids you might panic about a non-existent weight gain of 3.5 ounces. If you are trying to get weight onto your cat, a roughly acceptable rate of actual weight gain should be determined by your vet, based on your cat's current weight and goal weight, but roughly speaking an increase of 2-3 ounces (50-75g) a week should be acceptable.
But do not give any sub-Q fluids if you see any of the above symptoms or if your cat has gained a lot of weight suddenly or quickly until you have had your cat checked by a vet. Treatments
As with weight gain, coughing may be associated with fluid retention. Fluid retention may be a sign of worsening kidney values or of heart problems, although it may alternatively be a sign of over-hydration. Fluid retention is covered in Treatments and heart problems are covered in Related Diseases.
Nasal Discharge and/or Runny Eyes This may indicate fluid retention, particularly overhydration with Sub-Qs. See Treatments and Related Diseases. Other causes of runny eyes include an upper respiratory tract infection or dental problems.
This reflects the general loss of condition of a CRF cat. The body is fighting a tough battle with CRF and concentrates its efforts on its more critical functions; a glossy coat is not one of them. It is also influenced by dehydration. Occasionally spiky fur may indicate a lack of essential fatty acids, or may be a symptom of hyperactive thyroid. Treatment
Sometimes cats seem to seek out cool places in which to lie, such as on tiles or in draughty places. This may be caused by hyperactive thyroid rather than the CRF, so ask your vet about getting your cat's thyroid levels checked, particularly if you are seeing other symptoms such as weight loss, howling etc.
2. The Regulation of Waste Products in the Body
As the kidneys gradually lose their ability to regulate and remove waste products (toxins such as BUN) effectively, these waste products build up in the blood; this is called uraemia and can make a cat feel very unwell. In addition, CRF cats may have problems with stomach acid. Gastrin is a gastro-intestinal hormone which stimulates the secretion of gastric acid, which helps the stomach digest food. The kidneys are responsible for the excretion of gastrin, but in CRF this function may not work so well, resulting in the gastrin remaining in the stomach and stimulating the production of too much gastric acid. This excess stomach acid can make a cat feel very unwell. Generally speaking, cats with creatinine over 265 (US: 3) will need help controlling stomach acid. Pet Place has some information about gastric motility problems in cats (you don't need to register to read the article, just click on the Close This Window link at the bottom of the registration pop-up). Symptoms that may be seen as a result include: Loss of appetite is a very common symptom in CRF cats - because the cat feels ill, he/she feels disinterested in food. Stomach acid may also contribute to a lack of appetite. Human CRF patients have reported that their sense of smell and sometimes taste are impaired; this is thought to be caused by uraemic toxins, and probably occurs in cats too. Loss of appetite can naturally worsen weight-loss. There are several other possible causes of lack of appetite, including dehydration, high phosphorus levels, anaemia, fluid build-up, crashing, metabolic acidosis, mouth ulcers, the use of antibiotics, constipation or the use of medication for a hyperactive thyroid. Dental problems may also cause appetite loss.
Cats who do not eat are at risk of developing a potentially life-threatening condition known as hepatic lipidosis. Therefore, it is important to try to find the cause of the inappetance and treat it as quickly as possible. Treatment
Excess stomach acid is common in CRF cats, and in severe cases stomach ulcers may develop. Both of these are hard to detect but if your cat's stomach gurgles a lot, or if your cat has little appetite, then you should suspect that stomach acid is present, particularly in cats with creatinine levels over 265 (US:3). Sometimes the cat will appear to want to eat, but will sniff or lick the food, then walk away (this may also be a sign of mouth ulcers). Cats with stomach acid may also drink more, in some cases they may drink a lot in one go, then vomit afterwards. Treatment
Vomiting may be seen alone or in conjunction with the other symptoms in this section. Cats who vomit a lot are more likely to become dehydrated. Vomiting is self-evident, but it does not just include food - the classic symptom for a CRF cat is to vomit clear or white foam. Occasionally vomiting is caused by constipation, particularly if your cat vomits before, during or immediately after using the litter tray. If you are giving your cat sub-Q fluids and s/he regularly vomits after fluids, this may because of the type of fluids used.
Sometimes there may be blood in the vomit - bright red blood is fresh blood, whilst older blood looks like ground coffee grains. This may be a sign of mouth ulcers or of gastro-intestinal bleeding, but you should contact your vet immediately if you see this symptom - our George, a non-CRF cat, vomited old blood as the first symptom of severe liver disease.
Nausea is often manifested in a lack of appetite. High phosphorus levels, dehydration or anaemia may also cause nausea. Treatment
More information about vomiting can be found at these links: Washington State University has information on vomiting. Coco's page has practical advice from a CRF parent. Vet Info has information on vomiting. Pet Place discusses the possible causes of vomiting blood (you don't need to register to read the article, just click on the Close This Window link at the bottom of the registration pop-up). Diagnosis and management of acute and chronic vomiting in dogs and cats (2007) is a paper by Dr TR Tams. Newman Veterinary mentions that constipation may cause vomiting (scroll down a bit).
Sometimes CRF cats drink a lot on water in one go, them vomit all or most of it up shortly afterwards. This may be a sign of stomach acid. It is possible that the cat has an urge to drink before vomiting so as to dilute the stomach acid.
This can be a sign of nausea and stomach acid. Occasionally it is a sign of dehydration. Treatment
Some cats like to play with their water bowls from an early age, but some CRF cats develop a bit of an obsession with water, and may play with their water bowl or paw at the water. You may see other new behaviours, such as drinking from showers or gutters, or hanging around sinks and begging for fresh running water from the tap. All these types of behaviour may indicate stomach acid. Other possible causes include dehydration or diabetes.
This can be a sign of nausea and stomach acid. It may also be a sign of dehydration. Less commonly, it can be a sign of anaemia. In rare cases it may be caused by longer term (over three months) use of Reglan (metoclopramide. Treatment
These may sometimes be symptoms of nausea, which may be caused by stomach acid. Howling may have other causes (see howling below). Treatment
Cats who grind their teeth may have excess stomach acid. Dental problems are another possible cause. It may also be a sign of dehydration. Very occasionally, this might be a sign of "rubber jaw", caused by a condition related to the CRF called secondary hyperparathyroidism.
Animal Dental Center of Milwaukee and Oshkosh discusses the various courses of teeth grinding in cats.
Youtube has a video of a cat grinding his/her teeth (if you're
a member of youtube, which I am not, please post to point out that this is
no laughing matter but indicates a need for veterinary attention to find
out the cause in this poor cat's case). Drooling cats may have excess stomach acid. Dental problems or mouth ulcers may also cause drooling. Treatment
Cats commonly eat grass in order to help themselves vomit. They often do this if they want to bring up a hair ball, and this is sometimes also the reason why CRF cats eat grass. However, CRF cats do tend to feel nauseous generally, because of the disease rather than because of hair balls, and if you feel nauseous, you may feel a little better if you can actually vomit. Therefore CRF cats who feel nauseous may eat grass in order to make themselves vomit. It is normally fine to allow your CRF cat to eat grass, as long as it has not been treated with pesticides.
The toxins produced by the body have an effect on the bacteria in the mouth, which can cause a very strong and distinctive odour. It is hard to describe the aroma, though once smelled, never forgotten. It is sometimes described as being an ammonia smell (like bleach) but it may smell more like urine (ammonia is a constituent of urine), though neither description really captures the smell. This smell will be particularly noticeable if the cat crashes. If your cat's breath smells more like nail polish remover, this may indicate diabetes.
If the cat is very poorly or in a more advanced stage of renal failure, the toxins produced by the body can cause ulceration of the gums, which occurs when the uraemic waste is converted by the bacteria in the mouth into ammonia (hence the smell of the cat's breath being described as ammonia-like above). You may see ulcers in the cat's mouth if you look inside, or in severe cases your cat may vomit blood (which may also be a sign of bleeding from further down the gastro-intestinal tract). You may also see drooling.
Mouth ulcers are painful for the cat and often lead to a lack of appetite, or, even more distressingly, a desire to eat coupled with an inability to do so - the cat may approach the food bowl and sniff the food, then walk away. Mouth ulcers may also be a sign of metabolic acidosis.
Check inside your cat's mouth regularly for inflamed gums or ulceration or ask your vet to do so. I am sometimes asked what mouth ulcers look like. They are usually a small area of white or yellow, sore-looking skin with a thin red ring around it. Consequences of CRF has a photo of mouth ulcers in a CRF cat. Starbrite Dental has a couple of photos of human mouth ulcers.
Gastro-Intestinal Bleeding (Dark Stools) If the uraemia is particularly bad, the cat may develop gastro-intestinal bleeding. This is not easily detectable, but dark stools are one possible sign, as is vomiting blood. Occasionally, however, dark stools are caused by iron supplements.
If gastro-intestinal bleeding remains untreated, anaemia may result. If you suspect gastro-intestinal bleeding, you should take a stool sample to your vet for occult blood testing (when I did this for Ollie, I was the first client who had ever requested this test; but it was positive). You can also buy the EZ Detect test from pharmacies, which tests for blood in the stool or urine (this is a human test but can also be used for cats). CRF cats with this problem do not normally need to be treated in hospital. Treatment
Pet Place has some information about blood in stool (melena). You don't need to register to read the article, just click on the Close This Window link at the bottom of the registration pop-up.
Diarrhoea may sometimes be seen in CRF cats secondary to the CRF. However, there are a number of other different causes of diarrhoea, including hyperthyroidism, inflammatory bowel disease (IBD), malabsorption problems, and parasites, so if the diarrhoea lasts longer than a day or so, you must see your vet, both to ensure your cat is OK (diarrhoea may cause or worsen dehydration, including potassium loss) and for a proper diagnosis.
Possible causes of diarrhoea in a CRF cat include:
Diagnostic and therapeutic approach to cats with chronic diarrhoea (2001), Marks S is a paper presented to the World Small Animal Veterinary Association 2001 World Congress. Washington State University College of Veterinary Medicine discusses the causes of diarrhoea in dogs and cats. Vet Info discusses the problems of ascertaining the cause of chronic diarrhoea. Meower Power describes the various types of stool that may be seen when a cat has diarrhoea. Vet 4 Petz describes the different types of diarrhoea in cats. Newman Veterinary discusses causes of diarrhoea.
Some CRF cats have a distinctive aroma, which is caused by the levels of toxins in the body. It is similar to the bad breath aroma. You may notice an increase in this aroma or it may develop for the first time if your cat's bloodwork is worsening. In some cases, you may first notice this smell when your cat crashes: Thomas developed this smell seemingly overnight when he crashed, but after treatment it gradually disappeared. Treatment
If allergies are ruled out, this can be a uraemic itch, i.e. caused by the levels of toxins in the blood. If your cat is scratching a lot or grooming excessively, consider this possibility. Itching is fairly common in cats with high phosphorus levels, particularly if the high phosphorus levels go untreated, resulting in secondary hyperparathyroidism. Alternatively itching may indicate a Vitamin B deficiency or be a sign of an essential fatty acids deficiency. Occasionally itching can be a sign of liver problems; if this is the case, your cat's bloodwork should show elevated liver values.
If your cat actually pulls out fur rather than merely scratching, this may indicate hyperthyroidism. Itching, particularly on the face, may also be a side effect of the medication used to treat hyperactive thyroid. Treatment
Pruritus, an important symptom of internal diseases (2000) Peharda V, Gruber F, Kaštelan M, Brajac I & Čabrijan L Acta 9 (3). Scroll down to Uremic Pruritus.
Twitching, Trembling or Shaking This can be caused by the toxin levels, and if so, it should improve as toxins are controlled. It may also be related to potassium levels, or caused by high phosphorus levels, high blood pressure, calcium imbalances (especially head twitching), a hyperactive thyroid or Vitamin B deficiency. If your cat only twitches while you are giving fluids, it is probably caused by either the type of fluid used or by giving cold (room temperature) fluids. Treatment
Pharaoh's Shakes is a video showing a CRF cat twitching.
Occasionally, if toxin levels are really high (and particularly if a cat is in The Final Hours), a CRF cat may have seizures. In such cases, reducing toxin levels is essential in order to avoid permanent damage to the brain; but this may not be possible if the cat is in his/her final hours.
Seizures may take a number of different forms. There may be the classic jerking and loss of consciousness, but being "spaced out" or mentally absent or staring into space may also be a type of seizure. Harpsie's website has more information on what seizures may look like.
Seizures may also be caused by high potassium levels, calcium imbalances, metabolic acidosis or by high blood pressure. The use of Reglan (metoclopramide) for stomach problems or Advantage for fleas may lower the seizure threshold. Other possible causes of seizures include epilepsy or a brain tumour, but the causes mentioned above are far more likely in a CRF cat and should therefore be considered first. Treatment
Howling (Particularly at Night) This is sometimes the result of toxin levels in the blood. However, it may also have other causes such as deafness, hyperactive thyroid, high blood pressure 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. Metaclopramide (Reglan), used for stomach problems, may also have this effect.
I would recommend always having blood pressure checked in a howling cat.
CRF cats may occasionally become rather hoarse because of acid reflux caused by stomach acidity. In some cases, however, it may be a sign of low potassium levels. Hoarseness is also sometimes seen in cats with a hyperactive thyroid. If accompanied by coughing, consider the possibilities of fluid retention and/or heart problems. Treatment
3. The Regulation of Electrolytes in the Body
There is a complex balance of electrolytes (salts), including potassium and sodium, in the cat's body. Electrolytes are essential to the functioning of the body at cellular level, but with increased urination, imbalances may arise in these areas, and these may have various effects as follows:
This may be a sign of low potassium levels, anaemia or hypertension. Lethargy may sometimes be a sign of heart problems, especially if it appears after giving fluids.
Weakness and muscle wasting may be commonly seen in the back legs, or your cat may have a bony spine. There are a variety of causes, including low potassium levels or high phosphorus levels leading to secondary hyperparathyroidism. Muscle wasting may also be caused by metabolic acidosis, while weakness in the back legs is occasionally caused by low magnesium or low calcium levels.
General weakness may be caused by anaemia, or because the cat is simply not eating enough. It is essential that cats eat, because if they do not eat, they are at risk of developing a potentially life-threatening condition called hepatic lipidosis. The Persuading Your Cat to Eat page has tips on persuading your cat to eat.
If your cat is diabetic, the weakness may be caused by diabetic neuropathy. The Mayo Clinic has information about peripheral neuropathy, including that caused by diabetes.
If your cat no longer jumps, this may be thought to be weakness when in fact it is an unwillingness to jump because of blindness caused by hypertension. An inability to jump or climb may also be caused by arthritis. Treatment
Stilted Gait in the Front Legs This is usually a sign of low potassium levels. Treatment
Stiff Neck or Inability to Hold Up Head (Ventroflexion) The cat may be unable to raise his or her head properly - in most CRF cats, this is a symptom of potassium deficiency. Very occasionally, this may be a sign of thiamine (Vitamin B1) deficiency, which is sometimes seen in cats fed too much fish. Treatment
Diagnosis and management of chronic renal failure in cats (2000) Sparkes A, has a photo on page 4 of a cat with this condition. Long Beach Animal Hospital has a photograph of a cat with this problem - scroll down to find the photograph. Consequences of CRF has a photo of a cat with this condition at the end of the page. The feline patient: cervical ventroflexion (2007) Mitchell A Crystal discusses this problem and also has a photograph. If necessary, search for "ventroflexion cat" to find the relevant book and page - it should be the first one in the list.
A hoarse cat may have low potassium levels, which are adversely affecting the cat's vocal chords. Alternatively, this is sometimes a sign of stomach acid. If accompanied by coughing, consider the possibilities of fluid build-up and/or heart problems. Treatment
This can be a sign of low potassium levels. Other possible causes include fluid build-up, heart problems or anaemia.
Increased Night-time Urination One peculiarity which you may see is nocturia, or excessive urination during the night, which may be caused by low potassium levels. If you only give your cat sub-Qs late at night, this might also be the cause. Treatment
This may be a sign of low potassium levels. It may also be caused by dehydration or high calcium levels.
Potassium levels in CRF cats are often too low, but if they become elevated, which may happen as the CRF progresses, heart problems can arise, and short seizures may also occur, especially in end stage renal failure.
Seizures may take a number of different forms. There may be the classic jerking and loss of consciousness, but being "spaced out" or mentally absent or staring into space may also be a type of seizure. Harpsie' s website has more information on what seizures may look like.
Seizures can also be a sign of high blood pressure, high levels of toxins, metabolic acidosis or of calcium imbalances. The use of Reglan (metoclopramide) for stomach problems or Advantage for fleas may lower the seizure threshold. Other possible causes of seizures include epilepsy or a brain tumour, but the causes mentioned above are far more likely in a CRF cat and should therefore be considered first. Treatment
Twitching, Trembling or Shaking Twitching may be related to potassium levels in the body. In early CRF, it is likely to be due to potassium levels being too low, which can be treated with potassium supplements. However, in end stage CRF, potassium levels may rise and cause twitching as happened to Thomas on his last day.
Other causes of twitching include high phosphorus levels, a hyperactive thyroid, high blood pressure, calcium imbalances (especially head twitching) or Vitamin B deficiencies. Twitching may also be caused by toxin levels in the blood. If your cat only twitches while you are giving fluids, it is probably caused by either the type of fluid used or by giving cold (room temperature) fluids. Treatment
Pharaoh's Shakes is a video showing a CRF cat twitching.
Bicarbonate ions (which are alkaline) in the kidneys help protect against acid build-up in the body until the kidneys can get rid of it; but the excessive urine flow of CRF washes the usual bicarbonate ions out of the kidneys. Acid levels then rise in the blood, which promotes muscle breakdown, and weight loss - particularly lean muscle loss - results.
Acidosis occurs in 65-75% of cats with kidney failure, so it is important to check for this and treat it if necessary. Symptoms include weight loss, lean muscle loss, a bony spine, weakness, vomiting, twitching, and sometimes mouth ulcers or breathlessness. Breathlessness caused by metabolic acidosis is known as Kussmaul breathing.
In severe cases you may see seizures. Seizures can take a number of different forms. There may be the classic jerking and loss of consciousness, but being "spaced out" or mentally absent or staring into space may also be a type of seizure. Harpsie' s website has more information on what seizures may look like. Other causes of seizures in CRF cats include high potassium levels, high blood pressure, high levels of toxins, or calcium imbalances. The use of Reglan (metoclopramide) for stomach problems or Advantage for fleas may lower the seizure threshold. Other possible causes of seizures include epilepsy or a brain tumour, but the causes mentioned above are far more likely in a CRF cat and should therefore be considered first. Treatment 4. Regulation of Minerals in the Body
Phosphorus
and calcium are minerals used in the body, but imbalances may arise in CRF
cats and lead to a condition known as
secondary
hyperparathyroidism, which may make the CRF progress faster.
High phosphorus levels can make a cat feel bad and lead to a loss of appetite, particularly if secondary hyperparathyroidism develops. Other causes include levels of toxins in the blood which may cause stomach acid, anaemia, crashing, metabolic acidosis, mouth ulcers, fluid build-up, the use of antibiotics, constipation or the use of medication for a hyperactive thyroid. Dental problems may also cause loss of appetite.
Cats who do not eat are at risk of developing a potentially life-threatening condition known as hepatic lipidosis. Therefore, it is important to try to find the cause and treat it as quickly as possible. Treatment
Itching is fairly common in cats with high phosphorus levels, particularly if the high phosphorus levels go untreated, resulting in secondary hyperparathyroidism. It may also be caused by general levels of toxins in the blood. Alternatively itching may indicate a Vitamin B deficiency or be a sign of an essential fatty acids deficiency. Itching on the face in particular may be a side effect of the medications used to treat hyperactive thyroid. Occasionally itching can be a sign of liver problems; if this is the case, your cat's bloodwork should show elevated liver values. Treatment
Lack of Co-ordination in the Limbs/Back Leg Weakness This can be due to high phosphorus levels, which interfere with the nerve messages that control the limbs, a condition known as neuropathy. Some of the symptoms include "forgetting" where the hind legs are (getting up and leaving without them, for instance, or leaving them in the air even after licking them), or stumbling and feet crossing over when walking.
"Knuckling" may also be seen, where the cat walks on the top of the foot with the toes tucked underneath, appearing almost to be dragging the toes behind. I haven't been able to find a photo of a cat with high phosphorus levels doing this, but the University of Florida Veterinary Medical Teaching Hospital has a photo of a dog with a similar problem.
You may also see a plantigrade posture, where the cat walks on his/her hocks instead of his/her feet: this is most common in diabetic cats, but may sometimes be seen in cats with neurological problems from other causes. Long Beach Animal Hospital has a photograph of a cat with diabetic neuropathy doing this (click on Symptoms). Newman Veterinary has a good before and after photo of a diabetic cat with this problem, scroll down a little to Other Common Consequences, then click on Plantigrade Stance (in red font).
If your cat suddenly cannot walk properly on one leg, particularly a back leg, and the leg feels cold to the touch, this may indicate a heart-related problem known as a saddle thrombus. This is a medical emergency, and you need to contact your vet as soon as possible.
University of Chicago Jack Miller Center for Peripheral Neuropathy is a human site which discusses uraemic neuropathy (neuropathy caused by CRF).
This may be a sign of "rubber jaw", caused by a condition related to the CRF called secondary hyperparathyroidism. Clinician's Brief has photos of two dogs with an extreme form of rubber jaw; your cat's symptoms will probably be more subtle. Other more common causes of teeth grinding include excess stomach acid, dental problems and dehydration.
Animal Dental Center of Milwaukee and Oshkosh discusses the various courses of teeth grinding in cats.
Youtube has a video of a cat grinding his/her teeth (if you're
a member of youtube, which I am not, please post to point out that this is
no laughing matter but indicates a need for veterinary attention to find
out the cause in this poor cat's case). Seizures may be a sign of calcium imbalances. Seizures may take a number of different forms. There may be the classic jerking and loss of consciousness, but being "spaced out" or mentally absent or staring into space may also be a type of seizure. Harpsie' s website has more information on what seizures may look like.
Seizures in CRF cats may also be caused by high potassium levels, high blood pressure, high levels of toxins, or metabolic acidosis. The use of Reglan (metoclopramide) for stomach problems or Advantage for fleas may lower the seizure threshold. Other possible causes of seizures include epilepsy or a brain tumour, but the causes mentioned above are far more likely in a CRF cat and should therefore be considered first. Treatment
Weakness and muscle wasting may be commonly seen in the back legs, or your cat may have a bony spine. There are a variety of causes, including high phosphorus levels leading to secondary hyperparathyroidism. If your cat seems to be clumsy or stumbling, please also read this section.
Weakness in the back legs is often caused by low potassium levels or occasionally by low magnesium or low calcium levels; while muscle wasting may be caused by metabolic acidosis. General weakness may be caused by anaemia. If your cat no longer jumps, this may be thought to be weakness when in fact it is an unwillingness to jump because of blindness caused by hypertension. An inability to jump or climb may also be caused by arthritis. Treatment
This may be caused by high phosphorus levels. Other causes include proteinuria and electrolyte imbalances. Cats with metabolic acidosis often lose muscle tone as well as weight - in particular, they may have a bony spine. Weight-loss may also be a symptom of other diseases such as diabetes or hyperactive thyroid. Other possible causes include IBD (Inflammatory Bowel Disease) or cancer. Treatment
Purina has a Body Condition diagram showing how to gauge your cat's physical condition.
This may be caused by high calcium levels. It may also be caused by dehydration or low potassium levels. Treatment
High phosphorus levels and the resulting secondary hyperparathyroidism may cause nausea, which may be manifested as a lack of appetite. Alternatively, vomiting clear foam is a classic symptom for a CRF cat, and is often caused by toxin levels or stomach acid. Occasionally vomiting is caused by constipation, particularly if your cat vomits before, during or immediately after using the litter tray. Anaemia or metabolic acidosis may also cause nausea.
Twitching, Trembling or Shaking Twitching may be caused by high phosphorus levels. Other causes of twitching include high or low potassium levels, high blood pressure, calcium imbalances (especially head twitching), a hyperactive thyroid or Vitamin B deficiency. Twitching may also be caused by toxin levels. If your cat only twitches while you are giving fluids, it is probably caused by either the type of fluid used or by giving cold (room temperature) fluids.
Pharaoh's Shakes is a video showing a CRF cat twitching.
Eating Litter/Licking Concrete This is normally associated with anaemia, but is occasionally seen when there are calcium imbalances. Treatment
This may be seen when there are calcium imbalances. Other possible causes include anaemia and heart problems. A CRF cat's temperature may also fall during The Final Hours. 5. Stimulation of Red Blood Cell Production The kidneys produce a hormone called erythropoietin, which stimulates the bone marrow to make blood cells. As the kidneys fail, they cannot produce enough erythropoietin, and a particular type of anaemia called non-regenerative anaemia results (other types of anaemia must be excluded, of course). Anaemia may also be caused by infections or inflammation, or by gastro-intestinal bleeding. Signs of anaemia include:
This is quite common in anaemic cats; other causes include stomach acid, metabolic acidosis, dehydration and high phosphorus levels.
This is very common in anaemic cats; see stomach acid, high phosphorus levels and dehydration for other possible causes. Loss of appetite may also be caused by metabolic acidosis, mouth ulcers, fluid build-up, the use of antibiotics, constipation or the use of medication for a hyperactive thyroid. Dental problems may also cause loss of appetite.
Cats who do not eat are at risk of developing a potentially life-threatening condition known as hepatic lipidosis. Therefore, it is important to try to find the cause and treat it as quickly as possible.
Your cat may seek to lie in warm places, and/or may be hunched up in an attempt to keep warm: this is commonly a sign of anaemia.
This is more commonly associated with stomach acid, but in some cats it may be a symptom of anaemia.
These occur in anaemia because the blood flow to the skin is reduced.
This is caused by lower levels of oxygen in the blood which in turn is caused by anaemia. Lethargy may also be caused by low potassium levels or by high blood pressure. Lethargy may sometimes be a sign of heart problems, especially if it appears after giving fluids.
Weakness, especially in the back legs This is very common in anaemia; Thomas became unable to jump on the bed. See also low potassium, metabolic acidosis and high phosphorus. Cats with high blood pressure may also no longer jump.
Heavy breathing and Wheezing and Fast Heart Rate These may be related to a heart condition or to high blood pressure, but anaemia may in itself cause heart problems and high blood pressure: your vet can determine which came first.
Eating Litter/Licking Concrete This is known as pica. Many vets are not aware that this can be a symptom of anaemia, but it is surprisingly common, so if a CRF cat suddenly starts eating litter, PCV or HCT levels (anaemia measurement) should always be tested. Thomas was already being treated for anaemia when he began to eat his litter. Sure enough, when we tested him, his anaemia had worsened, so we increased his medication and as soon as his anaemia improved his litter eating stopped.
Very occasionally, licking concrete is a sign of a calcium deficiency.
In the winter a CRF cat might start licking ice or eating snow. Humans with iron deficiency anaemia sometimes crave ice, so this is probably the reason for such behaviour in cats.
This can be a sign of anaemia. Other possible causes include calcium imbalances and heart problems. A CRF cat's temperature may also fall during The Final Hours.
Since anaemia is a complex topic, there is an entire page devoted to the subject. Although one 2002 study (Prevalence of systolic hypertension in cats with chronic renal failure at initial evaluation, Syme HM, Barber PJ, Markwell PJ, Elliott J, Journal of the American Veterinary Medical Association 220 pp1799-804) indicated an incidence rate of high blood pressure of only 20%, it must be remembered that this only applies to cats at initial diagnosis. In practice, it appears that at least one third of CRF cats have high blood pressure, but, since the risk of high blood pressure developing increases as the CRF worsens, some estimates actually put the incidence of high blood pressure as high as two thirds. Cats with hyperactive thyroid are also prone to developing hypertension, so you need to be particularly careful if your cat has both a hyperactive thyroid and CRF.
Untreated hypertension can affect the brain, heart, kidneys or eyes. This means it may make the CRF worse, and may cause strokes or heart problems. One of the most common effects of untreated hypertension in cats is retinal detachment which means the cat goes blind (this is sometimes reversible if treated promptly). Yet for some reason many vets do not routinely check CRF cats for hypertension.
Cosequin, used to treat arthritis, may raise blood pressure, so speak to your vet about whether to continue using it if your cat has hypertension.
Humans with high blood pressure often report having a very bad headache. There is no way to know if our cats have a headache, but I have heard of a couple of cats pressing their heads against walls, which might be indicative of a headache. Such behaviour is sometimes also seen in cats with brain tumours.
Cats with hypertension may be lethargic. Anaemia or low potassium levels may also cause lethargy. Lethargy may sometimes be a sign of heart problems, especially if it appears after giving fluids.
These may be a sign of hypertension.
Petplace has some information about nosebleeds. Heart disease in the older cat (2006) Simpson K Presentation to the Feline Advisory Bureau Conference 2006 has a photo of a cat with a nosebleed caused by hypertension (page 4).
Bleeding Eyes (Retinal Haemorrhage) These may also be a sign of hypertension. The Feline Advisory Bureau has a photograph of a cat with this problem.
Blindness, particularly Sudden Blindness (Retinal Detachment) In a CRF cat, this is usually caused by high blood pressure. You may notice a change in your cat's eyes, such as dilated pupils or uneven pupils, or you can try moving your hand towards your cat's face and see if the cat reacts (a positive menace response) or not (a negative menace response). Another option is to get your cat's attention, then drop a cotton wool ball and see if the cat follows the ball with his/her eyes.
Blindness may also manifest itself in a less obvious manner. e.g. your cat may no longer jump and climb, which you might ascribe to weakness, when in fact it is caused by an inability to see where s/he is jumping. Your cat may also walk differently, perhaps keeping to the side of rooms, or walking through food (because s/he cannot see it).
Sometimes cats can appear blind after seizures and you will get a negative menace response, but this should not last for long, and in fact they are not normally blind - Harpsie had a negative menace response after his seizures and several vets were convinced he was blind, but he could still see and play with Cat Dancer.
Diagnosis and management of chronic renal failure in cats (c. 2000) Sparkes A, has a photo on page 2 of a cat with this problem. Pet Place has an article about detached retinas, including information on other possible causes. Feline hypertensive retinopathy (2007) is an article by Christi Benigni of Washington State University.
These may be a symptom of hypertension. Seizures may take a number of different forms. There may be the classic jerking and loss of consciousness, but being "spaced out" or mentally absent or staring into space, may also be a type of seizure. Harpsie' s website has more information on what seizures may look like.
Seizures in CRF cats may also be caused by high potassium levels, calcium imbalances, high levels of toxins, or metabolic acidosis. The use of Reglan (metoclopramide) for stomach problems or Advantage for fleas may lower the seizure threshold. Other possible causes of seizures include epilepsy or a brain tumour, but the causes mentioned above are far more likely in a CRF cat and should therefore be considered first.
A number of people have reported this symptom over the years. In all cases, the cat has turned out to have hypertension, often with a systolic reading over 200. Alternatively, red ears are sometimes seen in cats with food allergies.
In the worst case, a cat with untreated hypertension may have a stroke. A stroke means that the blood supply to part of the brain is cut off. Symptoms of stroke include an inability to walk properly (which may also be caused by low potassium levels, high phosphorus levels leading to secondary hyperparathyroidism or heart problems), weakness on one side of the body (which may include the head tilting to one side. This may also be caused by an ear infection but either way it is a medical emergency), circling and blindness. Staring into space may be a sign of a stroke or a seizure.
Davies Veterinary Specialists have some information on strokes in cats and dogs. Veterinary Partner has some information about strokes.
Twitching, Trembling or Shaking Twitching may be caused by high blood pressure. Other causes of twitching include high phosphorus levels, high or low potassium levels, calcium imbalances (especially head twitching), a hyperactive thyroid or Vitamin B deficiency. Twitching may also be caused by toxin levels. If your cat only twitches while you are giving fluids, it is probably caused by either the type of fluid used or by giving cold (room temperature) fluids.
Pharaoh's Shakes is a video which shows a CRF cat twitching.
This is sometimes seen when a cat is hypertensive. It may also indicate the presence of a urinary tract infection, or bladder or kidney stones. There is a condition called "benign renal haematuria" which means there is bleeding from the kidney but the cause is not known; however, this is rare in cats.
Persistent haematuria and proteinuria due to glomerular disease in related Abyssinian cats (2008) White JD, Norris JM, Bosward KL, Fleay R, Lauer C & Malik R Journal of Feline Medicine & Surgery 10(3) pp219-29 discusses how in Abyssinian cats with haematuria, the cause may be glomerular disease.
Severe or ongoing haematuria may cause or worsen anaemia, so you should always take your cat to the vet if you see this symptom.
Pet Place has some information about haematuria in cats. KV Vet sells a product called Health Alert which can test for blood in the urine. The Pet Checkup is a similar test that checks for blood in urine, and which may also be used to check for other issues, such as diabetes.
This may be a symptom of hypertension, or may be caused by toxin levels. However, it may also have other causes such as 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. Metaclopramide (Reglan), used for stomach problems, may also have this effect.
Inability or Reluctance to Walk If the hypertension causes a stroke, the cat may find it hard to walk, and may want to stay in one place, or may seem to have weakness in the legs. Other causes of weakness in the legs include low potassium levels or high phosphorus levels leading to secondary hyperparathyroidism. Muscle wasting may also be caused by metabolic acidosis, while weakness in the back legs is occasionally caused by low magnesium or low calcium levels.
General weakness may be caused by anaemia, or because the cat is simply not eating enough. It is essential that cats eat, because if they do not eat, they are at risk of developing a potentially life-threatening condition called hepatic lipidosis. The Persuading Your Cat to Eat page has tips on persuading your cat to eat.
If your cat is diabetic, back leg weakness may be caused by diabetic neuropathy.
Sometimes cats with hypertension will pace up and down or just act restless generally. This may also be a sign of hyperthyroidism or of pain. Cats on certain medications, such as metoclopramide (Reglan), cyproheptadine (Periactin) or mirtazapine (Remeron or Zistin) may also exhibit these symptoms, especially if they have been given a high dose.
Checking Blood Pressure Unfortunately high blood pressure can be hard to detect, and not many vets have the equipment with which to check blood pressure unless they work in a veterinary hospital. You could encourage your vet to buy the necessary equipment, which can be obtained relatively cheaply (US$600-700 in the USA, £400-500 in the UK). Some people with CRF cats have purchased blood pressure monitoring equipment for home use, and been trained in its use by their vet; this is not only more convenient, but it also avoids the problem of "white coat syndrome", where a cat's blood pressure appears to be higher than it is because of the stress of being at the vet's. Incidentally, with a Doppler, only the systolic pressure is measured.
Thames Medical (click on Doppler) shows a cat having blood pressure checked. Washington State University College of Veterinary Medicine has more information on hypertension, including pictures of blood pressure monitors. Scroll down to hypertension. Blood pressure measuring equipment which can be purchased for home use: Parks Medical (model no. 811) is a popular brand which has been used by a number people dealing with CRF over the years. You do need a vet's prescription to buy one. Vmed Vet Dop Doppler is another brand which several people with CRF cats have purchased recently. With all the extras, it costs about US$800-900.
In the meantime, or if you are unable to have your cat's blood pressure monitored properly for some reason, these are some things you and your vet should watch for:
Firstly, you and your vet should regularly examine the retina (a fundic exam) - often there are retinal changes due to the high blood pressure prior to detachment occurring. An older cat's pupils often do not dilate and contract the same as in a younger cat so you should try to ascertain how your cat's pupils respond to light i.e. what is normal for your cat. Permanently dilated or unevenly dilated eyes require urgent veterinary assistance, as do bleeding eyes.
Femoral Pulse You
can also try to become familiar with the way your cat's femoral pulse
feels (this is the pulse in the femur, the thigh bone). If your cat has high
blood pressure the pulse will usually feel stronger than the norm for
your cat. You can also watch for jugular pulsing: slightly elevate your
cat's chin and watch in the jugular area (in the neck) - you shouldn't see any pulsing.
Pet Health Care has instructions on how to take the
femoral pulse.
It is
relatively common for CRF cats to hide, perhaps in a cupboard or under a
bed, or somewhere up high. This is because the cat does not feel well - it
is instinctive for cats to hide when they feel ill so as to minimise the
risk of attacks by predators. As your cat improves with treatment, you
should find s/he will hide less, though a CRF cat may always require more
rest and peace than a healthy cat. Everybody
knows that cats purr when they are content or happy. However, fewer people
realise that a purr is not automatically a good sign, because cats may
also purr when they are in discomfort or pain. Some years ago, a cat was
run over by a car in front of my eyes. I ran to the cat and rescued it
from the road but s/he died in my arms within a minute or two - the cat
purred the entire time. The precise mechanism of purring is not known, but
it is thought to produce endorphins or "feel good" hormones in a cat, and,
in the case of a cat in pain, this may help the cat cope with the pain, or
comfort the cat in some way. Also, if
your cat's purr develops a rattle, this can sometimes indicate
fluid build-up.
So please do not assume that your cat must be well simply because s/he is
purring.
About has some information on why cats
purr.
Animal Voice discusses whether the purr helps in some way with
healing. One study from 2001,
Anagen effluvium in chronic renal failure,
Suwanwalaikorn S, Sivayathorn A, Chiba M, Vareesangthip K, Manonukul J,
Tsuboi R, and Ogawa H, found that the sudden loss
of hair is not unknown in human CRF patients. In all cases, no specific
reason was found but the hair grew back without treatment. The same may
apply to cats, but please also see alopecia below. Sometimes cats will
develop hair loss at the site of sub-cutaneous fluids; this is not
normally of concern. Cats with
food allergies may also lose their hair.
One of our cats, Harpsie, had food allergies, and lost the fur around his
neck in a ring, like a collar. He also lost fur in other areas. You can read more about
his experiences
here.
Pet Education has some information on
causes of hair loss in cats. Possible
causes include
food or other types of allergy.
If allergies are ruled out, this may
be a symptom of
hyperactive thyroid.
If your cat is scratching rather than pulling out hair, it might be
because of an uraemic itch, i.e. caused by the levels of toxins in
the blood. Itching is fairly common in cats with
high phosphorus levels, particularly if the high phosphorus levels go
untreated, resulting in
secondary hyperparathyroidism.
Alternatively itching may indicate a
Vitamin
B deficiency or be a sign of an
essential
fatty acids deficiency. Itching on the face in particular may be a
side effect of the
medications used to treat hyperactive thyroid.
Occasionally itching can be a sign of liver problems; if this is the case,
your cat's bloodwork should show elevated liver values.
Treatment
Pet Place has some information
about hair loss in cats.
If you look at the photograph of Thomas on the homepage, you'll notice his
back looks brown rather than black like his head and face. This is partly
because the photograph was taken in the summer, when Thomas loved
sunbathing, which seemed to turn his black coat brown. This is relatively
common in black cats, and is known as "rusting". However, his coat
also changed colour in winter when he was first diagnosed. My vet told me
this often happens to dark-haired cats when they are ill - the body has
more important things to focus on than the cat's coat.
Getting the CRF under control should help with this problem - it
did help with Thomas. The addition of tyrosine, an amino
acid, to the diet, may help, but this is not essential, and should not be
done without your vet's approval. See also
Dull Coat/Dandruff/Spiky Fur.
If your cat has any Siamese genes, the points may darken as a cat ages.
The coat colour of Siamese and Himalayans (colourpoint Persians) is
actually determined by temperature changes. As cats age, their circulation
often worsens, so their extremities become cooler and their points get
darker. However, sick cats with Siamese genes who have a raised
temperature (e.g. because of an infection) may actually develop lighter
colour fur. In either case, it is normally nothing to worry about.
Red hair in black cats is reversed by addition of
tyrosine to the diet (2002) Morris JG, Yu S & Rogers QR What makes a black cat's coat turn reddish brown is an article from Cat World.
The University of Alaska has some info on
Siamese coat colour changes. Treatment Options It is possible to treat all of the above symptoms, in many cases effectively, and details can be found in the Treatments section.
Crashing refers to a crisis situation for your cat. It may happen suddenly and be what finally alerts you to the existence of CRF in your cat; or it may happen after your cat has been suffering from CRF for some time.
If your cat exhibits some or all of the following symptoms: is severely dehydrated; has extremely strong bad breath; has a strong body odour; is lying in a "meatloaf" ("Sphynx") position ; eyes are dull; is refusing to eat and possibly also to drink; then s/he may be crashing.
Crashing usually occurs because your cat has reached a crisis point in terms of balancing his or her fluid intake and output. The cat has probably been drinking more to compensate for the increased urination, but can no longer drink enough. As a consequence most cats who crash are very dehydrated, and their bloodwork values when tested are very high. The bad breath smell will be particularly strong, perhaps with mouth ulcers present, and your cat may also have a generally strong body odour. The cat will often be unable to get comfortable because of all the toxins in the body - this may explain the meatloaf position. 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.
Crashing is a medical emergency. Your cat will usually need rehydration therapy at the vet's in an attempt to combat the dehydration and reduce the bloodwork values, and you should contact your vet WITHOUT DELAY. Delaying could be very serious for your cat, as the toxin levels in the body will continue to rise if left untreated. If caught early enough, your vet may be able to save your cat as our vet saved Thomas on two occasions.
During Thomas's first crash, his BUN was 86 (US: BUN 241), and this value did not change at all after four solid days and nights of IV. However, with home treatments, we did gradually reduce his numbers to urea 27 (BUN: 76) and creatinine 316 (US: 3.57), where they stabilised for some months. You can read Thomas's story in the Tanya and Thomas section.
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This page last updated: 28 May 2009 Links on this page last checked: 18 January 2008 Copyright Tanya's CRF Website 2000-2009. All rights reserved. You may print out one copy of each section of this site for your own information and/or one copy to give to your vet, but this site may not otherwise be reproduced or reprinted, on the internet or elsewhere, without the permission of the site owner, who can be contacted via the Contact Us page. If you wish to link to this site, please feel free to do so, and to use the banner ad on the Contact Us page if required. Please make it clear that this is a link and not your own work. I would appreciate being informed of your link. This site is best viewed using Internet Explorer. If you wish to print out the pages, I have found it works best if your margins are set to zero. |
The cat is an unusual animal in that it has the ability to concentrate
its urine, a little like a camel; this is believed to be a legacy of its
African heritage. However, in cats with CRF, this ability gradually
disappears, and cats then produce a very dilute urine: the urine looks
weaker in colour, has little odour, and the cat will often produce copious
amounts. Some cats also lose protein in their urine (
You may
also see a plantigrade posture, where the cat walks on his/her hocks
instead of his/her feet: this is most common in diabetic cats, but may
sometimes be seen in cats with neurological problems from other causes.
A
cat who has crashed will often be lying in a "meatloaf"
(Sphynx") position, but with the
head down and the front paws close to the body. I am often asked exactly
what the meatloaf position looks like. Indie to the left will give you
some idea. Many healthy cats such as Indie assume this pose too, so the
pose itself is not grounds for worry; you need to see the symptoms
described below in addition to the pose. Here Indie (non CRF) is in the
basic meatloaf position, but her head is not down, her eyes are not dull,
and she's making eye contact. The day Tanya died, she lay in this position
too but she refused to raise her head and her eyes were dull. She
also stayed in that position, seemingly unwilling to move. 