Kidney Disease

What are the kidneys?

Your cat or dog has 2 kidneys and their job is to filter the blood to excrete waste products, maintain fluid balance, electrolyte (salt) levels and the acid balance of the body maintain normal blood pressure and produce hormones to control calcium levels.

The kidney is a complex organ that has hundreds of thousands of microfilters called glomeruli that filter the blood and the filtered fluid is then processed in a dynamic way reabsorbing water and salts that the body needs to stop dehydration and produce urine which is excreted into the bladder.

What is Chronic Kidney Disease?

This is a progressive disease of the kidneys seen mainly in older cats where the number of glomeruli functioning gets less and less leading to loss of weight reduced appetite and lethargy increase thirst and urination. Other signs are lank coat. high blood pressure,bad breath,weakness anaemia and vomiting.

What causes Chronic Kidney Disease?

The actual reason is uncertain in most cases, though we know toxins and infections can damage kidney functioning. The kidney has to be severely affected (losing 75% of functioning capacity) before disease is seen as the body has a huge reserve capacity.

How common is Chronic Kidney Disease?

It can be seen in cats of any age but typically is seen in older cats (over 7 years old) and the percentage of cats affected increases with age.


This is done by analysing urine and blood. The urine can be analysed to compare levels of protein and creatinine. In a healthy kidney protein levels are very small while in diseased kidney protein levels are high so the protein/creatinine ratio will increase with disease.

Blood samples will show raised urea and creatinine levels as disease progresses as the kidneys are not clearing these molecules from the blood. Also blood counts can be done to see if there is any anaemia. Blood pressure is also measured to assess whether the disease is affecting it.

Managing Chronic Kidney Disease

This is done in several ways.

Diet – Feeding a kidney friendly diet that has a higher quality protein which is more easily digested by the body at a lower level reduces the pressure on the kidneys by producing less toxins.

Blood pressure – Reducing the blood pressure in the kidneys so that the filtering mechanism of the glomeruli is put under less strain.

Thirdly by reducing the level of phosphates in the blood through adding phosphate binders to the diet.