What Is Cat Kidney Failure?

What is Kidney Failure in Cats?

Kidney failure in cats refers to a condition in which the kidneys can no longer adequately filter waste products from the blood and regulate fluid balance in the body. It is one of the most common diseases affecting older cats. There are two main types of kidney failure:

Acute Kidney Failure – This happens suddenly, often caused by ingesting toxins, an infection or low blood pressure. It may be reversible if treated promptly. [1]

Chronic Kidney Failure – This is a gradual, irreversible decline in kidney function. The kidneys get damaged and progressively lose their ability to perform normal functions over time. It usually occurs in older cats, with a prevalence rate around 30-40% in cats over 15 years old. [2]

Causes and Risk Factors

Some common causes of kidney failure in cats include:

  • Kidney stones – Mineral deposits that form in the kidneys and block urine flow, causing damage and infection (Source 1).
  • Kidney infections – Bacterial infections often from an untreated urinary tract infection (Source 3).
  • Toxins – Ingestion of toxins like antifreeze, lilies, pesticides, household chemicals (Source 2).

Risk factors that can increase a cat’s chances of developing kidney failure include:

  • Older age – Kidney function declines naturally as cats age (Source 3).
  • Certain breeds – Persians, Siamese, and Abyssinians are more prone to genetic kidney issues (Source 1).
  • Existing conditions – Diabetes, high blood pressure, dental disease, etc. put extra strain on the kidneys (Source 2).


Some of the most common symptoms of kidney failure in cats include:

  • Increased thirst and urination – Cats will drink more water and urinate more frequently as their kidneys struggle to concentrate urine. This is often one of the first signs of kidney disease.
  • Loss of appetite – Kidney failure causes toxins to build up in a cat’s bloodstream, leaving them feeling nauseous, which leads to a decreased appetite.
  • Weight loss – Appetite loss coupled with the demands kidney failure places on the body often results in weight loss and muscle wasting.
  • Bad breath – The buildup of waste products in the blood creates a foul, ammonia-like odor in a cat’s mouth.
  • Lethargy – The loss of kidney function leaves cats feeling tired and weak.

Other symptoms may include vomiting, diarrhea, depression, pale gums, mouth ulcers, and unkempt coat. In advanced stages, seizures or coma may occur as toxins accumulate to dangerous levels. Symptoms tend to worsen gradually as kidney function declines over time. Early detection and treatment are key to slowing the progression of kidney failure.





A veterinarian will start the diagnosis process with a full physical exam of the cat, checking for signs like dehydration, feeling the abdomen, and listening to the heart and lungs. They will also take a full medical history of the cat, including any changes in water consumption, urination, or appetite.

The main diagnostic tests for kidney disease include:

  • Blood tests – To check levels of blood urea nitrogen (BUN) and creatinine, which are waste products that build up when the kidneys aren’t functioning properly. High levels indicate kidney dysfunction. A complete blood count may also be taken.

  • Urinalysis – Checking the urine sample for signs of dehydration, infection, protein loss, and abnormal kidney function. Concentrated urine can be a sign of kidney problems.

  • Imaging – X-rays or ultrasound may be used to get a visual of the kidneys and look for any anatomical abnormalities, stones, or masses.

Based on all these factors, the veterinarian will determine the stage and severity of the kidney disease.


Treatment for kidney failure in cats focuses on several main areas:

Fluid therapy – Giving subcutaneous, intravenous, or oral fluids helps flush toxins from the blood and rehydrate the cat. Fluids help improve kidney function and make the cat feel better. Vets often prescribe at-home subcutaneous fluids for owners to administer.

Medications – Drugs that help control vomiting, blood pressure, phosphorus and potassium levels, anemia, and acidity may be prescribed. Antibiotics treat infections. Blood pressure medication protects the kidneys. Phosphate binders prevent mineral buildup. Vitamin B and C supplements support kidney function.

Dietary changes – Feeding a kidney-friendly prescription diet low in phosphorus and protein but high in vitamins, omega-3s, and antioxidants helps manage kidney disease. Cats with kidney failure need more calories and fluids. Changing to wet food adds hydration.

Regular vet visits – Frequent checkups allow tracking of kidney values and making medication or diet adjustments as needed. Blood and urine tests help monitor organ function. Vets assess hydration, anemia, weight, blood pressure, and overall wellbeing.

Diet and Nutrition

Cats with kidney disease often require dietary changes to support their kidney health. The main modifications involve lowering phosphorus, protein, and sodium intake while increasing omega-3 fatty acids.

Phosphorus restriction is important because diseased kidneys cannot properly excrete excess phosphorus. This leads to a buildup of phosphorus in the blood, potentially causing joint problems and other issues. Prescription kidney support diets lower the phosphorus content and use high quality, digestible protein sources to reduce phosphorus absorption.1

Lowering dietary protein also helps reduce waste products the kidneys must filter out. However, cats still require adequate protein for muscle maintenance, so high quality, digestible protein sources are key. Increased omega-3 fatty acids from fish oil help reduce inflammation and may slow kidney disease progression.2

Phosphate binders, potassium supplements, anti-nausea medications, and appetite stimulants may also be recommended. Working closely with your veterinarian to find the right balance of nutrition and medication provides the best support for your cat’s individual needs.

At-Home Care

Caring for a cat with kidney disease at home can greatly improve their quality of life. Here are some important at-home care tips:

Give subcutaneous fluids – Giving subcutaneous fluids is an effective way to hydrate cats with kidney issues. Speak to your veterinarian about how much fluid to give and how often. They can show you the proper technique for administering fluids under the skin.

Monitor water intake – Keep track of how much water your cat is drinking each day. Increased thirst is a sign of kidney problems. Provide fresh water daily and consider getting a pet fountain to encourage drinking.

Provide easy litter box access – Make sure litter boxes are easy for your cat to access. Place boxes on every level of the home. Scoop waste daily and change litter regularly to promote usage. Boxes should be large with low sides for elderly or ill cats.

Other helpful at-home care tips include feeding wet food to increase hydration, keeping your cat warm, grooming matted fur, and spending quality time together with petting, play, and affection.


The prognosis for cats with kidney failure depends significantly on the severity and underlying cause of the condition. In cases of acute kidney failure, the prognosis can vary from good to grave depending on how quickly the condition is identified and treated.[1] With aggressive therapy, many cats with acute kidney failure can recover normal or nearly normal kidney function.

For chronic kidney disease, the prognosis is generally guarded to poor as the condition is not reversible and will progressively worsen over time.[2] However, the progression of the disease can often be slowed considerably with dietary changes, medications, intravenous fluids, and other treatments. While chronic kidney disease cannot be cured, cats can live comfortably for months to years with proper management of their condition.

In general, the earlier kidney disease is detected in cats, the better the prognosis. Severe or end-stage kidney failure usually has a grave prognosis, but cats can sometimes live for weeks to months with intensive hospitalization and treatment. Overall, the prognosis depends on the cat’s specific situation and response to treatment.

[1] https://vcahospitals.com/know-your-pet/kidney-failure-acute-in-cats

[2] https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-cats


There are several steps cat owners can take to help prevent kidney disease in their feline companions:

Get annual veterinary exams. Cats are very good at masking illness, so annual exams allow vets to check for early signs of kidney issues like elevated creatinine levels. Catching problems early greatly improves the chances of effective treatment.

Avoid toxins. Exposure to toxins like antifreeze, human medications, lilies, and xylitol can damage cats’ kidneys. Keeping cats away from toxins reduces their chances of kidney problems later in life.

Feed a high quality diet. Kidney issues are often linked to chronic dehydration. Feeding cats a high moisture, low carbohydrate cat food provides hydration and puts less strain on the kidneys. Consult a vet for diet recommendations.

Additional steps like providing abundant fresh water, avoiding obesity, and controlling hypertension can also help maintain good kidney health.

While kidney disease can’t always be prevented, an annual vet visit along with limiting toxins and feeding a kidney-friendly diet can dramatically reduce a cat’s chances of developing kidney failure.

When to See a Vet

It’s important to monitor your cat closely and contact your veterinarian if you notice any concerning signs of kidney disease progression. Some key signs that warrant an urgent vet visit include:

  • Signs of dehydration like dry gums, sunken eyes, weakness, or collapsed skin elasticity
  • Inappetence or not eating for more than 24 hours
  • Increased lethargy, dullness, or other personality changes
  • Persistent vomiting or diarrhea

As per VCA Animal Hospitals, acute kidney injury needs urgent veterinary assessment to halt further kidney damage through supportive IV fluid therapy for 24-96 hours[1]. For cats in end-stage kidney failure, you may need to discuss humane euthanasia options if their quality of life is poor.

Contact your vet promptly if you have any concerns about worsening kidney disease or deteriorating health. They can advise on the best course of treatment and supportive care options.

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