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Home > Symptoms > Miscellaneous Symptoms



  • This page covers miscellaneous symptoms which you may see in a CKD cat.

  • For a complete list of CKD symptoms, or to look up a symptom which is bothering you, please see the Index of Symptoms and Treatments, where all the symptom are listed alphabetically, with quick links to each individual symptom and appropriate treatment options.



I am often asked if CKD cats are in pain. No, it is thought that the typical CKD cat is not in pain. Some of the symptoms of CKD can be uncomfortable (e.g. dehydration is often described as feeling like a hangover), and pain may arise if your cat experiences certain complications, such as calcification, but CKD generally is not painful.


However, most CKD cats are older, so they may be experiencing pain for other reasons, e.g. from arthritis or dental problems. Other possible causes of pain include kidney infections or kidney stones, or if the cat is having trouble breathing. Again, most painful conditions can be managed.


Unfortunately cats who are in pain or discomfort are often very good at hiding it (this is instinct, in order to protect them from predators). Evaluation of facial expression in acute pain in cats (2014) Holden E, Calvo G, Collins M, Bell A, Reid J, Scott EM & Nolan AM Journal of Small Animal Practice  55(12) pp615-621 looked at whether it is possible to tell if a cat is in pain from his/her facial expressions. The study found there were differences between pain-free and painful faces, such as the position of the ears, but also found that "Observers had difficulty in identifying pain-free from painful cats, with only 13% of observers being able to discriminate more than 80% of painful cats." A more recent study, Facial expressions of pain in cats: the development and validation of a Feline Grimace Scale, (2019) Evangelista MC, Watanabe R, Leung VSY, Monteiro BP, O’Toole E, Pang DSJ & Steagall PV Scientific Reports 9(1) 19128, found trained observers were often able to detect pain, but most of us are not trained observers. Feline grimace scale training manual Evangelista MC, Watanabe R, Leung VSY, Monteiro BP, O’Toole E, Pang DSJ & Steagall PV Scientific Reports 9(1) 19128 may help with this.


Immediately below I discuss some possible symptoms of pain in more detail, but these are not the only ones. WSAVA guidelines for recognition, assessment and treatment of pain (2014) Mathews K, Kronen PW, Lascelles D, Nolan A, Robertson S, Steagall PVM, Wright B & Yamashita K Journal of Small Animal Practice 55(6) ppE10–E68 discusses how to recognise pain, whether acute and chronic. It states that changes in any of the following categories should be considered:

  • General mobility, e.g. reluctance to move, jumping less

  • Problems with the litter tray, e.g. finding it harder to climb into the tray

  • Reduced appetite

  • Reduced grooming, e.g. can the cat reach and scratch easily

  • Relaxing, e.g. does the cat seem able to lie comfortably, or is s/he sitting hunched up (which sometimes is a symptom of a crash)

  • Less sociable, both with humans and other feline family members, maybe even hiding

  • Temperament, e.g. is the cat unhappy or even aggressive when picked up, which was never previously the case

Pet Place has an overview of pain in cats.


Behavioural signs of pain in cats: an expert consensus (2016) Merola I & Mills DS PLOS One pp1-15 reports on possible signs of pain in cats.


Cat Behavior Associates lists ten signs that a cat might be in pain.



Because it can be so difficult to detect pain in cats, a number of pain scoring tools have been developed, including:


2015 AAHA/AAFP pain management guidelines for dogs and cats (2015) Epstein ME, Rodan I, Griffenhagen G, Kadrlik J, Petty MC, Robertson SA & Simpson W Journal of Feline Medicine and Surgery 17 pp251–272 discuss the importance of recognising pain in cats and the various pain scoring systems that are available.


Glasgow composite measure pain scale is an assessment tool for acute pain in cats, with helpful drawings of feline facial expressions to help determine if pain is present.


UNESP-Botucatu multidimensional composite pain scale is a painscoring tool for use post-surgery which is available in several languages.


Assessment of acute pain in cats (2014) Robertson S Today's Veterinary Practice Jan/Feb 2014 pp33-36, 83 discusses pain scoring systems and gives a short list of possible signs of acute pain in cats.


Feline pain assessment and scoring systems (2013) Barratt L The Veterinary Nurse 4(8) pp470-477 also discusses pain scoring systems.


Pacing or Restlessness

Cats who are in pain may pace up and down or just act restless generally.


Other causes of restlessness include:


It is relatively common for CKD 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 or stressed so as to minimise the risk of attacks by predators. Will a hiding box provide stress reduction for shelter cats? (2014) Vinke CM, Godijn LM & van der Leij WJR Applied Animal Behaviour Science 160 pp86-93 found that cats in a shelter who were given a hiding box appeared to cope more effectively with the stressors of that environment than cats who had nowhere to hide.


Hiding may also be a sign that a cat is in pain. Behavioural signs of pain in cats: an expert consensus (2016) Merola I & Mills DS PLOS One pp1-15 reports that hiding may be frequently seen in cats who are in pain.


As your cat improves with treatment, you should find s/he will hide less, though a CKD cat may always require more rest and peace than a healthy cat, and may well choose a place that is less public than was previously the case.


One thing to be aware of is that some cats may take this a step further and go away from home to hide. Therefore if you usually let your cat go outdoors, I would be careful or perhaps restrict access until you know your cat is stable once again, because there is nothing worse than not knowing where your cat is and being unable to give the medications that are necessary to keep the cat happy and comfortable.


Seeking You Out

Conversely, some cats will seek you out, and want to snuggle more. This may even happen with cats who previously were somewhat stand-offish. This may simply be because the cat does not feel well and wants you close for comfort and reassurance. However, Behavioural signs of pain in cats: an expert consensus (2016) Merola I & Mills DS PLOS One pp1-15 reports that seeking contact with a person may be seen in cats with high or low level pain.



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 it is also possible that 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. Behavioural signs of pain in cats: an expert consensus (2016) Merola I & Mills DS PLOS One pp1-15 reports that purring may be seen in some cats with high or low level pain, though this is rare.


The precise mechanism of purring is not known, but it is thought it may produce endorphins or "feel good" hormones in a cat. Why do cats purr (2003) Lyons L Scientific American explains more about this. In the case of a cat in pain, this may help the cat cope with the pain, or comfort the cat in some way. Dr Lyons also mentions that the sound frequencies used in purring may actually promote healing.


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.


Cognitive Dysfunction


Some older cats develop cognitive dysfunction, which is sometimes referred to as senility or feline Alzheimer's). Humans with cognitive dysfunction are often confused, though this may also be a sign of a urinary tract infection in humans, and possibly in cats.


Geriatric cats and cognitive dysfunction syndrome (2008) Gunn-Moore DA Presentation to the 33rd World Small Animal Veterinary Association Congress provides a detailed list of possible signs, including inappropriate elimination or seeking you out.


Pacing or Restlessness

Cats with cognitive dysfunction often pace up and down or just act restless generally. This may be combined with howling, especially at night.


Other causes of restlessness include:

Howling (Particularly at Night)

This is sometimes caused by cognitive dysfunction. One of my older cats liked to wander around the house at night letting out a mournful howl (and peeing on the front door mat).


Howling may have other causes such as:

I would recommend always having blood pressure checked in a howling cat.


Increased vocalisation in elderly cats (2015) Gunn-Moore DA European Journal of Companion Animal Practice 25(3) pp20-29 states "The most common causes of increased vocalisation are cognitive dysfunction syndrome, hyperthyroidism (with or without systemic hypertension), systemic hypertension (most commonly associated with chronic kidney disease, hyperthyroidism or hyperaldosteronism), deafness, osteoarthritis (or other causes of chronic pain) and brain tumours."


See Treatments for treatment options for cognitive dysfunction.


Hair and Coat-Related Symptoms


Hair or Fur Loss

Anagem effluvium in chronic renal failure (2001) Suwanwalaikorn S, Sivayathorn A, Chiba M, Vareesangthip K, Manonukul J, Tsuboi R & Ogawa H Presentation to the European Hair Research Society Conference found that the sudden loss of hair is not unknown in human CKD 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 subcutaneous 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. Once his allergies were under control, the fur grew back.


Cats with flea allergies may also lose hair (flea allergy dermatitis). University of California at Davis discusses this. There is information on flea treatments here.


PetCoach has some information on causes of hair loss in cats.


Feline alopecia: a problem-oriented approach to diagnosis (1998) Harvey RG Presentation to the Waltham Feline Medicine Symposium explains more about how to narrow down possible causes.


Alopecia (pulling out hair)

Possible causes include food allergies or other types of allergy. If allergies are ruled out, this may be a symptom of hyperthyroidism. Cats in pain may pull out their hair.


Cats who overgroom so that they suffer fur loss on the rear end and abdomen may have urinary or anal gland problems.


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 a medication called methimazole, which is used to treat hyperthyroidism.


Occasionally itching can be a sign of liver problems; if this is the case, your cat's bloodwork should show elevated liver values.


Pet Place has some information about hair loss in cats.


Feline alopecia: a problem-oriented approach to diagnosis (1998) Harvey RG Presentation to the Waltham Feline Medicine Symposium explains more about how to narrow down possible causes.


Dull Coat/Dandruff/Spiky Fur

This reflects the general loss of condition of a CKD cat, and is also influenced by dehydration. The body is fighting a tough battle with CKD and concentrates its efforts on its more critical functions; a glossy coat is not one of them.


Occasionally spiky fur may indicate a lack of essential fatty acids, or may be a symptom of hyperthyroidism. Cats eating a reduced protein diet may sometimes have this problem.


Coat Colour Change

If you look at the photograph of Thomas on the homepage, you will 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 CKD under control should help with this problem — it did help with Thomas.


Reduced protein diets may also be a factor in coat colour change, because tyrosine, an amino acid, is important for the production of coat colour, but reduced protein diets contain less tyrosine than normal diets. The carnivore connection to nutrition in cats (2002) Zoran D Journal of the American Veterinary Medical Association 221 pp1559-67 explains more about this (see page 3). The addition of tyrosine 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.


Coat colour change in a cat with diabetes mellitus and adrenocortical carcinoma (2017) Mui ML, Mahony O & Ferrer L Clinician's Brief Nov/Dec 2017 reports on the case of a cat with coat colour change caused by an adrenal tumour, but this is very rare.


Red hair in black cats is reversed by addition of tyrosine to the diet (2002) Morris JG, Yu S & Rogers QR The American Society for Nutritional Sciences Journal of Nutrition 132 pp1646S-1648S discusses how the absence or presence of tyrosine in the diet affected the coat colour of healthy kittens.


Why do some black cats' coats turn that reddish brown colour? is an article from Cat World.


We are Siamese if you please (1987) Bowling SA is an article about Siamese coat colour changes from the University of Alaska Fairbanks.


Increase in Appetite (Polyphagia)

Believe me, this is incredibly rare in a CKD cat! If you see it, it most likely is caused by hyperthyroidism. Some cats with diabetes may also have an increased appetite. Alternatively, a cat who has had a seizure will often feel suddenly very hungry afterwards.


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.



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This page last updated: 21 June 2020

Links on this page last checked: 21 May 2020






I have tried very hard to ensure that the information provided in this website is accurate, but I am NOT a vet, just an ordinary person who has lived through CKD with three cats. This website is for educational purposes only, and is not intended to be used to diagnose or treat any cat. Before trying any of the treatments described herein, you MUST consult a qualified veterinarian and obtain professional advice on the correct regimen for your cat and his or her particular requirements; and you should only use any treatments described here with the full knowledge and approval of your vet. No responsibility can be accepted.


If your cat appears to be in pain or distress, do not waste time on the internet, contact your vet immediately.



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