Chronic kidney disease (CKD) is the current term used to describe cats experiencing kidney failure, also known as chronic kidney failure.
Chronic kidney disease (CKD) is a progressive condition where the functioning of the kidneys gradually declines.
The kidney plays a crucial role in eliminating waste products from the blood and excreting them as urine. This process ensures that your cat's body remains healthy by removing toxins. However, if your cat's kidneys become dysfunctional, the accumulation of waste products can negatively impact their health.
When it comes to kidney function, the key word to remember is nephron. Nephrons are the ‘functional units’ of the kidney. Initially, we are born with more nephrons than required. However, aging and various diseases can gradually lead to the loss of nephrons due to natural deterioration or damage. If a significant number of nephrons are lost, it can result in renal failure.

CKD indicates that the kidney has been damaged by 70%.

The kidneys possess a significant reserve capacity to carry out their numerous functions. In fact, it is only when around two-thirds (67% to 70%) of the kidneys become dysfunctional that any noticeable clinical signs start appearing. In many cases, kidney damage has occurred over a period of several months or years (chronic) before the disease becomes evident.

CKD is very common in cats

Chronic kidney disease used to be called chronic kidney failure. It is mainly a problem in mature and senior cats (seven years and older),
affecting an estimated
30-40% of cats over 10 years
81% of cats over 15 years.
About 10% of the cases occur in cats less than three years old.

What is the role of the kidneys?

Cats have two kidneys situated in their abdomen. These kidneys play a crucial role in performing various important functions.

Removing waste products and toxins from the blood
Maintaining water balance
Maintaining electrolytes balance
Maintaining the acid balance of the body
Maintaining normal blood pressure

Conserve proteins in the blood
Producing hormones that stimulate red blood cell production
The kidneys play a vital role in our body by constantly filtering blood to eliminate harmful waste products. This process results in the production of urine. Additionally, the kidneys concentrate the urine by returning water to the body, preventing dehydration.

Some other specific problems can lead to CKD.

Polycystic kidneys — an inherited problem that causes cysts (fluid-filled sacs) to develop in the kidneys in certain breeds including Persians and British Shorthairs.

Poisons — there are lots of medicines, foods and chemicals that can damage the kidneys and later lead to CKD.

Bacterial or viral infections — urine infections can damage the kidneys, as can certain viruses such as Feline Immunodeficiency Virus (FIV).

Stones in the urinary system — stones and sludge caused by mineral build-ups in the bladder or urinary system can cause blockages and kidney damage.

Cancer — kidney tumours are rare but can lead to CKD.

Congenital disease amyloidosis —  (build up of protein in the kidneys)

Inflammatory disease — (glomerulonephritis)

High blood pressure

Sudden loss of blood flow to the kidneys, which can happen with rapid dehydration (eg heat stroke, severe vomiting/diarrhoea), shock (eg from blood loss, sepsis), low blood pressure (eg heart failure, anaesthetic agents) and blockages (eg blood clots)

Among the many different kidney diseases that may affect cats, CKD is the most common. It’s very common in older cats as they have more wear and tear on their kidneys.

Acute kidney disease

Develops if something suddenly causes a large amount of damage to the kidneys such as an infection or a poison such as antifreeze or lilies. Cats with acute kidney disease tend to develop serious symptoms very quickly. Neglecting proper care of acute kidney disease can result in the development of chronic kidney disease (CKD).