Kidney Failure in Cats

Medically Reviewed by Amy Flowers, DVM on November 09, 2022
3 min read

Your cat’s kidneys do many important things. They help manage blood pressure, make hormones, stimulate the bone marrow to make more red blood cells, and remove waste from the blood.

Cats’ kidneys can begin to fail with age. Untreated, kidney disease can lead to a series of health problems. When it’s chronic, there’s no cure. But with early diagnosis and good care, you can help boost both the quality and length of your pet’s life.

Older cats aren’t the only ones at risk. Kittens can be born with kidney diseases. Trauma, toxins, and infection are also causes.

There are two types of kidney failure in cats. Each has different causes, treatments, and outlooks.

Acute renal failure develops suddenly, over a matter of days or weeks. It happens in cats of all ages and is usually the result of:

  • Poisons, which are the most common cause of acute renal failure. Antifreeze, toxic plants like lilies, pesticides, cleaning fluids, and certain human medications are highly poisonous to your cat’s kidneys. Even a single tablet of ibuprofen can lead to their kidneys shutting down. Check around your house and garage for these substances and make sure your cat can’t get into them.
  • Trauma, especially involving a broken pelvis or burst bladder
  • Shock from losing a lot of blood quickly or rapid dehydration; overheating in hot weather, a significant rise in activity, vomiting, and diarrhea can all cause a big dip in fluids.
  • Infection in the kidneys
  • Blockages that change the flow of blood into the kidney and the flow of urine out of it (such as in a male cat that can't pee because of a urethral blockage)
  • Heart failure with low blood pressure, which reduces blood flow to the kidneys

If diagnosed in time, acute renal failure can often be reversed. But chronickidney problems can be harder to treat. Found mostly in middle-aged and older cats, they develop over months and even years. If your cat is 7 years or older, pay special attention to their health.

While the exact causes of chronic kidney disease aren’t always clear, even to vets, they include:

  • Kidney infections and blockages, which may not result in acute renal failure, but wear down kidney function at a low level for months or years
  • Other conditions, from advanced dental disease and high blood pressure to thyroid problems and cancer


  • Frequent urinating. While you might think this is a sign your cat’s kidneys are working well, it actually means they are no longer able to hold water. Urinating outside their litter box is another signal.
  • Drinking a lot of water; this means your cat is trying to replace the fluid they have lost through urinating.
  • Bacterial infections of the bladder and kidney; these develop more easily in the dilute urine produced by failing kidneys.
  • Weight loss and decreased appetite
  • Vomiting, diarrhea, and bloody or cloudy urine
  • Mouth ulcers, especially on the gums and tongue
  • Bad breath with an ammonia-like odor
  • A brownish-colored tongue
  • A dry coat
  • Constipation
  • Weakness and indifference

Your vet will do blood and urine tests. X-rays, an ultrasound (an image of your cat’s insides), or biopsy (tissue sample) might also be needed to make a diagnosis. If kidney disease is found, treatments can range from surgery to remove blockages to IV fluids to a special diet and medications. You may also be able to inject fluids under your cat’s skin at home. Talk to your vet about the best options.

A kidney diet is low in both phosphorus and protein, and is enriched with vitamin D and omega-3 fatty acids. Remember that it’s important to introduce your cat to new foods gradually. Your vet can advise you how to make this transition an easy one.

With a carefully managed diet. plenty of clean fresh water, a serene environment, and regular check-ups, you can help your cat live their best life possible.