Kidney Disease in Cats: Your Complete Guide to This Common Feline Condition

Like all mammals, cats have two kidneys located in their abdomen. Healthy kidneys are hard-working organs that perform many vital functions necessary for life. 

As a cat’s kidneys age, or if something damages their kidneys, the cat can develop kidney disease. Read on to learn what causes kidney disease in cats, the symptoms and what to expect if your cat is diagnosed with kidney disease.

What causes kidney disease in cats?

Anything that damages the kidneys can cause kidney disease. As the kidneys filter the blood, they are exposed to toxins and pathogens that can damage the sensitive structures of the kidney. 

The following are some causes of kidney disease in cats:

• Exposure to toxins, such as antifreeze

• Exposure to certain medications, such as aminoglycoside antibiotics or non-steroidal anti-inflammatory drugs (NSAIDs)

• Hypercalcemia (unusually high levels of calcium in the blood)

• Bacterial infections

• Kidney stones

• Cancer (lymphoma)

• Urinary blockage

• Viral infections, including feline infectious peritonitis (FIP)

• Chronically elevated blood pressure (often caused by concurrent hyperthyroidism)

• Abdominal trauma

• Shock (acute low blood pressure)

Sadly, the cause of kidney disease in most cats is unknown. Early kidney disease typically doesn’t cause symptoms. Most cats aren’t diagnosed until their kidney disease is far advanced. By then, it is much more difficult to determine the cause of chronic kidney disease in most cases. 

Which cats are most likely to develop kidney disease?

In general, older cats are at higher risk for developing chronic kidney disease. Kidney disease falls into two broad categories: acute (occurs all of a sudden) and chronic (occurs slowly over time and lasts longer than 3 weeks). 

Genetics may play a role in some cat breeds, including Abyssinian and Persian cats. Brachycephalic cats — breeds with flat faces — are also at higher risk for polycystic kidney disease, which can cause the symptoms of kidney disease. 

Symptoms of kidney disease in cats

Symptoms of kidney disease in cats occur when the kidneys become too damaged to do their jobs normally. Common symptoms include:

• Excessive thirst and urination

• Weight loss

• Decreased appetite

• Hiding

• Low energy

• Changes in stool patterns — either constipation or diarrhea

• Vomiting

• Pale gums

• Drooling

• Bad breath

• Ulcers in the mouth

• Sudden blindness (due to retinal detachment caused by high blood pressure)

• Seizures 

• Coma

• Signs of dehydration, such as decreased skin elasticity and dry gums

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If you notice any of the above symptoms, get your cat checked right away by a veterinarian.

Unfortunately, kidneys are so good at their jobs, most cats do not show symptoms of kidney disease until they have lost more than two-thirds of their normal kidney function. This means cats could have early kidney disease and not show any signs at all. This is why it is critical for your cat to be checked yearly by a veterinarian, as they can detect problems before symptoms start showing. 

How is kidney disease diagnosed in cats?

Kidney disease in cats is diagnosed by veterinarians using a combination of: 

• History from the owner

• Physical examination

• Laboratory tests

• Imaging studies, such as X-rays and abdominal ultrasounds, in some cases

The most common laboratory tests used to diagnose feline kidney disease include the following:

• Bloodwork: This is used to check internal organ function, including kidney function.

• Complete blood count: This is used to check the health and numbers of red and white blood cells in your cat’s system.

• Urinalysis: This test checks urine to ensure that the kidneys are filtering the blood and conserving body water appropriately.

• SDMA: SDMA is a newer blood test that can detect abnormal kidney function earlier than most standard laboratory tests.

Stages of kidney disease in cats

Once a cat has been diagnosed with chronic kidney disease, a veterinarian will further categorize the disease by stages, based on their lab work and blood pressure. Then, treatment is based upon the stage of kidney disease diagnosed. 

There are 4 stages of kidney disease based on the International Renal Interest Society (IRIS) system. Veterinarians use this to track the progression of the disease and your cat’s response to treatment. Staging is complex, but in general, here’s what each stage means for your cat.

Stage 1: Early kidney disease 

Cats don’t usually have symptoms at this stage, but a veterinarian will notice mild kidney abnormalities on their blood-work results. Treatment isn’t typically required at this point, but you’ll want to have your cat checked by a veterinarian every 6 months. 

Stage 2: Moderate kidney disease

Cats at Stage 2 kidney disease may show symptoms such as: 

• Weight loss

• Dehydration

• Decreased appetite

• Increased thirst and urination

At Stage 2, your veterinarian will likely recommend transitioning your cat to a therapeutic kidney diet.

Stage 3: Moderate-severe kidney disease

Symptoms at this stage include all of the above. Treatment is the same as at other stages and also includes giving the cat fluids under their skin to maintain hydration.

Stage 4: End-stage kidney disease

Cats at Stage 4 are approaching kidney failure. Additional symptoms at this stage include pale gums, oral ulcers, and possible blindness due to retinal detachment caused by high blood pressure. 

Your veterinarian will treat your cat’s symptoms and other complications, such as high blood pressure. Your cat may also be prescribed medications for nausea and may need a feeding tube.

Treatment for kidney disease in cats

Treatment for kidney disease in cats is based upon several factors:

• Type of kidney disease (acute or chronic)

• Cause (if determined)

• Stage 

• Co-occurring illnesses

• Overall health 

Treating early kidney disease in cats

If your cat doesn’t have symptoms and has only minimal changes on their lab work, your veterinarian may not recommend any treatment. They will likely recommend getting your cat checked every 6 months. 

Treating chronic kidney disease in cats

If your cat has chronic kidney disease, treatment is aimed at slowing the progression of disease and managing your cat’s symptoms. 

Treatments for chronic kidney disease can include:

Renal diet

Cats with chronic kidney disease are not able to process protein or phosphorus normally. So a veterinarian will prescribe a therapeutic diet that is lower in protein and phosphorus to ease the burden on their kidneys. 

Cats do not need to be switched to a kidney diet until their kidneys cannot process normal levels of dietary protein or phosphorus. Until then, feed them a high-quality maintenance diet. Your veterinarian will advise you on when or if your cat needs to be switched to a therapeutic kidney diet. 

Hydration

Because their kidneys cannot conserve water, most cats with chronic kidney disease are dehydrated to some degree. Provide fresh water at all times. In later-stage kidney disease, cats need to receive regular subcutaneous fluids that are delivered under the skin with a needle.

Medications

Cats with chronic kidney disease experience other complications related to the disease. These include high blood pressure, anemia, and nausea. Medications are used to manage these issues. 

Some examples include:

• Amlodipine to manage high blood pressure

• Cerenia (maropitant citrate) for nausea

• Potassium supplements, if your cat’s levels are low

Advanced treatments

Cats with more advanced disease will require more extensive treatment, which can include:

• Dialysis

• Intravenous fluid therapy and IV medication

• Feeding tube

Treating acute kidney disease in cats

In general, sudden kidney failure in cats due to any cause is considered an emergency. It typically requires extensive hospitalization and treatment. If the cause is determined, it is treated — if possible. The goal of acute kidney failure treatment is to:

• Resolve what caused it

• Minimize symptoms

• Preserve and heal as much of a cat’s kidneys as possible

What to expect if your cat has kidney disease

What to expect if your cat has kidney disease varies based on several factors, including: 

• Type of kidney disease (acute or chronic)

• Response to treatment

• Stage 

• Overall health 

Prognosis and life expectancy typically improve the earlier a cat is diagnosed. A cat in early stages of kidney disease can live for years with the right care. But if they’re not diagnosed until they have late- or end-stage chronic kidney disease (kidney failure), most cats may only live a couple of months after receiving their diagnosis. 

If your cat is diagnosed with chronic kidney disease, your veterinarian will likely recommend scheduling an appointment for them every 6 months. They’ll check your cat’s vital signs, weight, and lab work to determine if the disease is progressing. 

Chronic kidney disease is not curable, but it can be managed at home successfully for many cats. Typically, chronic kidney disease progresses slowly over time. Many cats can enjoy a good quality of life for quite some time even after they are diagnosed. 

How quickly can kidney failure occur?

Depending on the cause of kidney failure, cats can slowly develop symptoms over months to years, or they can develop them overnight. 

Acute kidney failure can often be reversed if caught and treated in time. However, the most common type of kidney disease in cats is chronic, which is incurable and slowly progressive over time. How fast it advances varies from cat to cat, and it is dependent on how early the disease is caught and treated, as well as the type of kidney disease the cat has. 

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Written by:

Sarah J. Wooten, DVM, CVJ

Dr. Sarah Wooten, DVM, CVJ, is a well-known international influencer in the veterinary and animal healthcare spaces. She has 16 years of experience in private practice and more than 15 years experience in veterinary media work.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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