Kidney Failure In Cats

Jamie Case, DVM
By Jamie Case, DVM on Dec. 6, 2022

In This Article


What is Kidney Failure in Cats?

Kidneys serve many vital roles in the body, include filtering and removing waste in the form of urine. They maintain proper hydration by balancing water and electrolytes, create the hormones responsible for red blood cell production, and help regulate blood pressure. In addition, the kidneys help modify vitamin D so it can be used by the body.

As in people, cats have two kidneys, one on each side of the abdomen. Unfortunately, as in people, kidney failure can occur when these organs become too damaged to work properly. Kidney failure usually develops because of chronic kidney disease.

Kidney failure is a life-threatening situation, and there are few treatment options when a cat reaches this stage. Pet parents are advised to discuss their cat’s prognosis with their veterinarian, monitor their cat’s quality of life, and discuss euthanasia.

Types of Kidney Failure in Cats

Kidney failure can be described as acute or chronic:

Acute Kidney Failure: (also called acute renal failure) occurs when the kidneys are suddenly damaged, usually within hours or days. This may be due to poison or from a fast-acting infection. Cats with ARF may regain some kidney function with treatment, supportive care, and time, depending on the cause.

Even with treatment, ARF is terminal in about 50% of cases. However, cats that do survive the initial cause usually have a better outcome compared to cats with chronic kidney disease (CKD).

Chronic Kidney Disease: CKD eventually leads to end-stage renal failure, or ESRF, which is considered stage 4 of kidney disease.

In CKD, a gradual loss of kidney tissue occurs over a period of months or years due to underlying genetic factors, chronic infections, age, cancer, or other underlying medical conditions. Clinical signs of chronic kidney disease show up when about two-thirds of normal kidney tissue has been lost. As it worsens, medical management becomes ineffective in helping the kidneys perform their crucial roles. 

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Symptoms of Kidney Failure in Cats

Clinical signs of kidney failure differ slightly, depending on if the condition is acute or final stages of CKD.

In cats with acute renal failure, clinical signs include:

  • Sudden onset of decreased appetite

  • Lethargy or listlessness 

  • Vomit, sometimes tinged with blood

  • Diarrhea or bloody diarrhea

  • Ammonia-like odor to the breath (due to uremic toxins building up in the blood)

  • Changes in urination (large amounts or cessation)

  • Abdominal pain due to swollen kidneys (seen in cases of acute renal failure)

  • Seizures

In cats with end stage renal failure associated with chronic kidney disease, clinical signs include:

  • Anorexia/refusal to eat 

  • Vomiting

  • Lethargy/excessive sleepiness 

  • Dehydration

  • Confusion (possibly pacing and restlessness)

  • Changes in behavior (withdrawn, irritability)

  • Uncontrolled urination or defecation

  • Ammonia-like odor to the breath

  • Seizures

  • Decreasing body temperature

  • Greasy, unkempt, thin hair coat

Causes of Kidney Failure in Cats

Acute kidney failure has numerous causes, but it can be categorized as due to toxins or from an underlying medical issue.

Toxin exposure may be caused by ingesting:

  • Ethylene Glycol (antifreeze)

  • Lilies 

  • NSAIDs for people, such as acetaminophen or ibuprofen

  • Heavy metals  like arsenic, lead, or mercury

  • Rat poisons

Underlying medical issues

  • Urethral obstructions (inability to urinate)

  • Low blood pressure

  • Clotting disorders

  • Heart disease

  • Pyelonephritis (infection in the kidneys)

  • Parasitic infections (toxoplasmosis or kidney worms)

  • Tick-borne diseases

  • Feline Infectious Peritonitis (FIP)

  • Trauma or severe allergic reactions that result in shock

Chronic kidney disease eventually progresses to end-stage kidney disease and kidney failure. How quickly this happens is hard to predict. It is very common in geriatric cats, and some breeds have a higher incidence, such as Abyssinians, Burmese, Maine Coons, Persians, Ragdolls, Russian Blues, and Siamese.

Other risk factors include:

  • Tumors and cancer (such as lymphoma)

  • Viruses specific to cats, such as feline leukemia virus or feline immunodeficiency virus

  • Chronic pyelonephritis (a slow-developing infection in the kidneys)

  • Underlying genetic disorders like polycystic kidney disease or amyloidosis

  • Immune-mediated disorders

  • Previous acute renal failure/acute kidney injuries that did not fully respond to treatment

  • Underlying medical conditions, like hyperthyroidism

How Veterinarians Diagnose Kidney Failure in Cats

In cases of acute renal failure, bloodwork, urine samples, and imaging (x-rays and ultrasound) will likely be performed to diagnose the condition and help determine the best course of treatment. Your veterinarian will look for signs of:

  • Anemia

  • Elevated blood urea nitrogen and creatinine

  • Abnormal hydration levels, by measuring electrolyte concentration (sodium, potassium, calcium, and phosphorus)

In cases of end-stage renal failure, many of the same signs listed above will be monitored to help determine the stage of renal failure.

What are the final stages of kidney failure in cats?

When a cat’s kidneys cannot perform their job, anemia, dehydration, and the build-up of uremic toxins will occur. Ulcers can develop on the tongue, gums, and along the digestive tract. The cat may act dull and “out of it,” with possible seizures. They may go into respiratory distress. Medical management may not be able to stop the downward spiral.

Treatment of Kidney Failure in Cats

Options for treating end-stage kidney failure in cats are limited. They include strategies to manage kidney disease such as special diet, supplements, and anti-nausea medication. In many cases, hospitalization with IV fluids and the placement of a feeding tube can stabilize the cat. Some respond well and may be able to return home for continued management of their underlying kidney disease.

For more intensive treatment, hemodialysis to filter the blood of cats is available. This will not cure kidney failure but may improve quality of life.  However, few veterinary clinics possess the necessary equipment and the cost is very high. This treatment requires working with a board-certified veterinary internal medicine specialist and consultation with a member of the American Society of Veterinary Nephrology and Urology.

Kidney transplant is another experimental route, but this has not widely been used and would require working with specialists to determine if your cat is a good candidate.

When a cat has kidney failure, it is important to work closely with your veterinarian to discuss prognosis, strategies to monitor quality of life, and when euthanasia should be considered.

Recovery and Management of Kidney Failure in Cats

The prognosis for cats with renal failure is grave.  At some point, medical management will not keep a cat comfortable and end-of-life planning will need to be discussed. This is one of the hardest (if not the hardest) decision a pet parent will make. Your veterinarian can help you understand questions about your cat’s quality of life and develop a plan should euthanasia need to be considered outside of normal business hours.

Kidney Failure in Cats FAQs

How long can a cat live with kidney failure?

In about half of the cases of acute renal failure, cats may have a few days to live. If their lab work and clinical signs are not showing signs of improvement, their veterinarian will likely recommend euthanasia. In cats with chronic kidney disease that has progressed to end-stage renal failure, the median survival time for cats in stage 4 is 35 days. 

Are cats in pain when they have kidney failure?

In ARF, the kidneys may be swollen and painful (sort of like a lower backache).  In cases of end-stage renal failure, there is typically no pain associated with the kidneys. The big concern in cats with kidney failure is quality of life, because rather than feeling pain, they may feel sick and have nausea and weakness due to the buildup of uremic toxins.

Featured Image:

Jamie Case, DVM


Jamie Case, DVM


Dr. Jamie Case graduated from the University of Missouri College of Veterinary Medicine in 2017, after receiving a Bachelor of Science...

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