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How to spot Chronic Renal Failure in cats

Need to know

As a vet, it was always frustrating to see cat owners turning up fundamentally too late when their cat has chronic renal (kidney) failure, or CRF. In pretty much every case, it is not the owners fault as unfortunately one of the first clinical signs seen in CRF (excessive drinking and weight loss) occur only when two-thirds of the kidney’s function is disabled and non-reversible!
 It is only in cases where an owner has once to bi-yearly urine analysis checks (looking at specific gravity and levels of protein in the urine) with their veterinarian that kidney disease can be spotted earlier. Unfortunately, you will only see changes in the blood chemistry (notably urine and creatinine) when your cat is already in compensated CRF (ie: over two-thirds of the kidneys are already non-functioning).
Despite kidneys being relatively straightforward from a structure viewpoint, they have one major disadvantage when compared to other organs such as the liver, lungs, skin and bones which is that once a kidney filtering unit (called a nephron) has been destroyed, it cannot be re-generated.
Unfortunately for cats, it tends to be the organ that wears out first and first signs of ‘old age’ CRF can be seen as early as 7-8 years old. There are other causes of CRF including tumours, cysts, infections and kidney stones but these occur far less commonly.

Top kidney facts

-          Kidneys cleanse the blood daily with 95% of the fluid being filtered back in to the bloodstream
-          The remaining 5% is deposited into the urine and is composed of waste products that are created throughout the body. These products include urea, creatinine, mineral salts and other poisonous substances.
-          Produce EPO (erythropoietin) that increases the production of red blood cells
-          Release Renin which helps regulate blood pressure
-          Uses 25% of the bodies oxygen to maintain adequate function
-          Damage to the kidneys cannot be fixed, treatment is all about ensuring the remaining nephrons function normally for as long as possible
-          Treating your cat early can give it an extra  1-3 years’ worth of life from the time of diagnosis
-          Kidney disease can be spotted earlier than clinical signs or blood test with twice-yearly urine testing.
 
Eyes open

These are the most important common changes you will see in your cat with CRF:
-          Drinking more water than normal (visiting water bowl more often, drinking in more places)
-          Losing weight (you can start feeling ribs and top of spine easily)
-          Tacky skin indicating dehydration (lift skin at back of neck and release, it should spring back quickly if your cat is normally hydrated)
-          Loss of appetite or more picky with diet
-          Bad breath and painful eating (if mouth ulcers present)
-          Lethargy, depression in advanced cases
-          Vomiting and diarrhoea can also be present.
 
Helping your pet

Be aware of the common clinical signs described above and more importantly, carry out twice-yearly urine analysis for all cats over the age of 7! Absolutely nothing else will have a greater impact than this and it is very easy (and cheap) to do. Your vet will then do a quick in-house test to look at how well your cat is concentrating its urine (lack of concentration is the first thing noticed) and the level of protein in the urine (high levels indicating CRF).
Also always make sure there is plenty of fresh water in as many locations as possible. You can also use flavoured water (tuna or chicken for example) or water fountains to encourage them drinking.
 
Time to care

How to get a urine sample:
Well this may seem very hard to do but it really is quite straightforward. All you will need is an empty litter tray and some Katkor. Keep your cat inside for the day (I know they may not be happy about this but this is for their own good!) and put the whole bag of Katkor into the empty litter tray. Please do not add normal cat litter. You can add a few small strips of newspaper if it helps but not too much as we do not wish it to absorb the urine. The beads in Katkor are plastic and hence do not absorb (and can be re-used with a simple wash for the next time) the urine. After you cat has peed, you use the enclosed syringe to put the urine into the test tube. Ideally then give this to your vet as soon as possible and do not store it in the fridge.

There are many ways to manage kidney disease which your vet can talk to you about. The primary management is centred on their diet by having a reduced but high-value protein content, the use of blood pressure medications and phosphate binders. There are many other ways to treat CRF including kidney transplants but these are best discussed with your vet.

The key to this article is for you to ensure your cat is screened twice yearly for CRF from the age of 7 so that he or she can have the best possible quality of life when CRF does eventually occur.

EARLY DIAGNOSIS IS KEY!!