Kidney disease is a common malady in cats, particularly in older cats. It is one of the most common causes of death in geriatric cats. Detecting kidney disease early in its course may allow you, as a cat owner, to take steps to slow the progression of the disease and prolong your cat’s life.

Let’s take a closer look at feline kidney disease, how it is diagnosed, and what can be done to help cats with kidney disease.

What Causes Kidney Disease?

In a normal healthy cat, one of the primary roles of the kidneys is to filter the waste products that are produced by the body. These waste products accumulate in the bloodstream and are filtered from your pet’s blood as the blood passes through the kidneys. The mechanisms for this filtration are complex but essentially the waste products end up being excreted by your cat in the urine.

There are many different causes of kidney disease in cats. Kidney disease may be chronic or acute. Often, chronic kidney disease is seen in older cats simply as a result of aging changes within the kidneys. However, cats of any age can develop kidney disease of either a chronic or an acute nature. Various viral and bacterial infections, toxins, and immune disorders can cause kidney disease as can trauma to the kidneys. Inherited diseases, such as polycystic kidney disease, can also be responsible for kidney disease. 

In cats suffering from kidney disease, this filtration process begins to work less efficiently, eventually causing kidney failure. This results in an increase in nitrogenous compounds (one of the primary waste products) in your cat's bloodstream. It also results in changes in the electrolyte levels in the bloodstream as well. Electrolytes in the blood, including potassium, calcium, phosphorus, and sodium are in large part regulated by the kidneys.

Other functions of the kidneys include the excretion of erythropoietin and renin. Erythropoietin controls the production of red blood cells. Renin is a hormone responsible for helping to maintain normal blood pressure. As a result, cats with kidney failure may also suffer from anemia (low red blood cell levels) and high blood pressure.

What Are the Signs of Kidney Disease in Cats?

One of the earliest and most common symptoms of kidney disease is increased thirst coupled with increased urine production. However, these symptoms may be difficult for all but the most observant cat owners to notice. Other symptoms include vomiting, nausea, diarrhea, lack of appetite, and weight loss. Reduced water consumption and reduced urine volume may be noted as the disease progresses. 

Cats that suffer from high blood pressure as a result of kidney disease may develop symptoms relative to the increase in blood pressure, including blindness and neurological symptoms. 

As the nitrogenous compounds continue to build up in your cat's bloodstream, you may be able to detect an abnormal odor in your cat's breath. You may also see ulcers (sores) on his tongue and gums. 

How Is Kidney Disease Diagnosed in Cats?

A visit to your veterinarian will be necessary to diagnose kidney disease. A thorough physical examination and history are essential. Blood and urine testing will be necessary as well and will help your veterinarian determine the stage of your cat's kidney failure. Blood pressure testing may also be recommended if your cat is diagnosed with kidney disease. 

How Is Kidney Disease Treated in Cats?

Your cat's treatment will depend, to a large extent, on his physical condition and the cause of the kidney disease. If there is an underlying cause that can be identified and treated, your veterinarian will likely do so. In many cases, this will not be possible though. 

Dehydration is a common finding in cats with kidney disease and fluid therapy will be necessary to correct the deficit and maintain your cat's hydration status. In some cases, depending on the severity of the disease, hospitalization and intravenous fluid therapy will be necessary. In other cases, you may be able to administer fluids under your cat's skin periodically at home. (This is a process called subcutaneous administration.)

Various medications may also be used to treat kidney disease. If your cat is nauseous and/or vomiting, drugs to calm and coat your cat's stomach may be recommended. Other medications to help regulate blood electrolyte levels and ACE-inhibitors such as benazepril may be indicated as well. Your veterinarian will help you decide what is necessary for your individual cat.

Your cat's diet may need to be changed as well. Canned diets may be recommended because of their increased moisture content but the individual nutritional requirements of your cat will vary depending on the stage of your cat's disease. Your veterinarian will help you find an appropriate diet. In some cases, simply keeping your cat eating and helping him to maintain his weight may be preferable to a change in diet, especially if your cat will not easily accept a new diet.

Water consumption is important for all cats but particularly so for those with kidney disease. This is the reason that canned diets are often recommended. Drinking fountains, dripping faucets, and water mixed with the food may be additional methods of increasing your cat's water consumption.

Regular checkups with your cat’s veterinarian are essential for your cat, even if your cat seems healthy. These checkups can help detect early changes in your cat’s physical condition, such as those associated with kidney disease. This can allow changes in your cat’s care that can significantly extend your cat’s life expectancy.