Chronic kidney disease

Cross-section of a kidneyKidney disease is unfortunately very common in older cats. It is caused by long-term damage to the kidneys which is usually progressive (i.e. gets worse over time). There are some underlying conditions which may be able to be treated (e.g. lymphoma, a type of cancer, or pyelonephritis, a kidney infection) but in the majority of cases treatment is aimed at managing the problem and reducing the speed of decline, rather than being able to cure the condition altogether.  The earlier this treatment starts, the better the long-term outlook.

What do kidneys do?

The kidneys have a number of different roles:

  • removing toxic waste products from the body
  • maintaining fluid and electrolyte balance
  • regulating blood pressure
  • stimulating red blood cell production

The kidneys can cope with a significant amount of disease before showing signs of problems.  By the time a condition becomes apparent, usually around 75% of total kidney function will already have been lost.

What are the signs of kidney disease?

Black and white cat drinking from tapEarly signs of kidney disease include:

  • increased thirst and increased urination (PUPD)
  • weight loss
  • reduced appetite

Later stages of kidney disease will lead to:

  • very poor appetite
  • vomiting
  • smelly breath
  • weakness and lethargy
  • dramatic weight loss
  • sunken eyes
  • poor coat
  • anaemia (pale gums)
  • blindness (due to high blood pressure)

How is kidney disease diagnosed?

Blood samplesYour vet will need to do a blood test and collect a urine sample to diagnose kidney disease.  Two waste products will be raised (urea and creatinine), and the urine will be more dilute than normal.  The blood test will also indicate the stage of kidney disease (the higher the creatinine, the later the stage) and check for other problems such as high phosphate, low potassium, anaemia.

Blood pressure machine on toy catHigh blood pressure and urinary tract infections are common secondary to kidney disease so further tests will be needed to determine whether these are present and if so, treatment will be required.  Protein loss in the urine is another potential problem which should be checked.  If this is present, the long-term prognosis is poorer but there is medication to reduce the severity of this protein loss.  It is not known for certain whether this improves length of life but it seems to in humans.

For further information, visit Tests for cats with kidney disease.

The earlier kidney disease is detected and treatment started, the better so regular check ups with your vet are very important as your cat gets older as many early signs may not be noticed at home.

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