The kidneys are part of the urinary system, they filter blood to remove waste products. This forms urine, which is transported to the bladder. The kidneys have a huge number of roles within the body; alongside getting rid of waste products via urine, they also help to maintain blood pressure and the fluid balance within the body, make hormones, control salt levels and stimulate the production of red blood cells. If a cat’s kidneys are diseased, all these functions are affected and this causes them to become unwell.

What is kidney disease and what is the cause? 

There are two types of kidney disease: chronic and acute disease. 

Acute kidney disease occurs when the kidneys suddenly stop working. Which may be caused by the cat having eaten a toxic substance (e.g.  lilies or antifreeze), due to a drug that is damaging to the kidneys, or because of a serious infection. 

Chronic kidney disease occurs when kidney function slowly declines over time. Most often this is associated with older cats in which no underlying cause can be found,=. Although inherited diseases, kidney tumours, infections or inflammation can also cause chronic kidney disease. 

What are the symptoms of chronic kidney disease in cats?

As you may know from human kidney donation, it is entirely possible to function with only one kidney. In fact, around two thirds of functioning kidney tissue (one and a third kidneys, as it were) needs to be lost before signs of kidney disease will develop! This means that in the early stages of disease, symptoms may be very mild, but will gradually worsen over time.

As kidney disease progresses, the following symptoms may appear. Drinking more than usual, urinating more than usual, low energy levels, weight loss, a poor appetite, bad breath, an unkempt coat and vomiting. As the disease advances, these symptoms become more pronounced. In end stage kidney disease, cats will often be collapsed, vomiting, dehydrated and not eating, drinking or urinating.

At what age do most cats develop kidney disease?

Middle aged cats (over 7 years old) and older cats are most likely to develop kidney disease. In cats over 15 years of age it has been estimated that 20-50% of them have chronic kidney disease!

How is kidney disease in cats diagnosed?

Following a physical examination, your vet will usually collect a blood and urine sample from your cat.

The blood sample not only checks the kidneys, but also salt levels and the number of red and white blood cells. In particular, your vet will assess two parameters known as urea and creatinine. Healthy kidneys will usually get rid of these waste products into the urine. However as kidney function declines with disease, these two parameters will increase in the bloodstream. 

Your vet will also analyse a urine sample. They assess how well the kidneys are concentrating urine. Check for urinary infections (which are a common complication in kidney disease). Assess whether proteins are being lost into the urine through defective kidneys. 

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A relatively new blood test, known as SDMA, is used alongside urea and creatinine measurements. In some cats can detect kidney disease in the very early stages.

To check for underlying causes of kidney disease, ultrasound or X-rays may be necessary if your vet suspects cancer or kidney stones are present. 

Is kidney disease painful?

Most cases of kidney disease are not painful, however, it does depend on the cause. If you notice your cat in a hunched-up position, shying away from attention, struggling to urinate, or not eating, take them to your vet for a check-up.

Can chronic kidney disease be cured?

Unfortunately, chronic kidney disease cannot be cured and it is not a reversible disease. However, if your cat receives the appropriate veterinary care and supportive treatment, the progression of the disease can be slowed down. Increasing your cat’s lifespan and improving their quality of life.

As part of your cat’s annual veterinary examination as they get older, urine samples can be taken and their weight monitored. A decreasing body weight and declining concentration of urine will alert your vet that something may be wrong. They will recommend further investigations to check for kidney disease. 

How is chronic kidney disease managed?

Treatment for chronic kidney disease is supportive and not curative. In order to manage the condition effectively, repeat assessments of blood pressure and blood and urine tests are required. To not only monitor the progression of the kidney disease, but to identify any medical complications and treat them appropriately. 

Medications

Depending on the stage of kidney disease, your vet may recommend medications to decrease blood pressure and reduce the pressure on the kidneys. To control symptoms, anti-nausea medications and appetite stimulants are often used. 

Water intake

Dehydration is a common complication of kidney disease. As the kidneys lose their ability to conserve water and it all passes out into the urine. Cats with chronic kidney disease should be fed “wet” food in cans or sachets to increase their water intake. They should also be provided with water fountains to encourage them to drink. 

Diet

We recommend feeding cats that have been diagnosed with kidney disease a special prescription diet. These special kidney diets contain high quality protein, controlled levels of phosphorus, (which can build up to high levels in the body when the kidneys aren’t working properly), low sodium (to help to reduce blood pressure) and omega 3 oils (fish oils). 

What is the prognosis for cats with kidney disease?

Unfortunately, kidney disease is progressive and life expectancy varies greatly as the progression of the disease is different for each cat. With appropriate treatment and supportive care, the quality of a cat’s life can be greatly increased and the progression of the disease can be slowed down.

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If you think your cat has any of the symptoms of kidney disease listed above, or if you have an older cat, talk to your vet about checking the kidneys so you can catch a problem early.