Acquired kidney diseases are the cause of most cases of kidney failure in cats, and tend to manifest in middle to old age. 
 

Some of the more common diseases are listed below.
 

Chronic tubulo-interstitial nephritis is the most commonly identified problem in cats suffering from CRF. It is often the end-stage of many causes of kidney disease, where damaged nephrons (the functional unit of kidney tissue) are replaced with fibrous tissue. Typically affected kidneys will be small and scarred.
 

Glomerulonephritis is a disease in which the glomeruli (which help filter urine from the blood), are damaged by inflammation.
 

Pyelonephritis is the name for a bacterial infection of the kidneys.
 

Amyloidosis is a disorder by which insoluble protein fibres are deposited in various organs of the body. When it occurs in the kidneys, their function is impaired and chronic renal failure can result. Amyloidosis can be seen as an inherited condition in Abyssinian cats.
 

Hydronephrosis is an excessive accumulation of urine in the kidney caused by an obstruction or blockage in the ureter - the tube linking the kidney to the bladder.
 

Renal lymphoma is a cancer of white blood cells affecting the kidney. Typically both kidneys will be very enlarged if this condition is present.