Comprehensive Guide to Cat Kidney Disease

Key Takeaways:

  • Early signs are often subtle and easily missed. Increased thirst and urination are the most common initial signs. As disease progresses, vomiting, bad breath, and lethargy can occur. Since cats are good at hiding illness, regular vet visits are crucial.
  • Chronic kidney disease is common, especially in older cats. Many cats develop kidney problems as they age. Early diagnosis through routine bloodwork and urine checks is vital for effective management and ensuring a better quality of life.
  • Treatment focuses on management, not a cure. Goals of treatment include: controlling waste product levels in the blood (often through fluid therapy), managing phosphorus levels, preventing stomach ulcers, and utilizing special prescription diets to support kidney function.


Cat kidney problems are difficult to catch early since the kidneys compensate for any loss of function. Early signs include more urination and drinking than normal. Occasional vomiting may occur due to toxins that are not being removed by the kidney.

The kidneys are responsible for filtering waste from your cat's blood and for the creation of hormones that stimulate the production of red blood cells. Chronic kidney disease is defined as kidney disease that has been present for months to years. Chronic renal disease (CRD), chronic renal failure (CRF), and chronic renal insufficiency refer to the same condition.

Many cats develop kidney problems as they age. The kidneys have a large reserve, meaning that they can function even if a large part of them is damaged. Therefore by the time we see signs of kidney problems, there is usually quite a bit of damage to the kidneys. More severe issues are called acute or chronic kidney failure. Acute kidney problems, or acute renal failure, suddenly appear and can often be reversed if diagnosed early, contrasting with chronic kidney disease in cats which means that the problem has existed for many months or years. There are three ways to refer to a chronic condition which all refer to the same problem including feline chronic renal insufficiency, chronic renal failure (CRF) and the general term chronic renal disease (CRD).

A condition that is primarily associated with Persians and Exotic Short hair cats is Feline polycystic kidney disease (PKD). In this condition cysts form in the kidney which keeps them from functioning.

Early Detection is Important

Early signs of cat kidney disease are often subtle and easily missed. Increased thirst and urination are the most common initial symptoms. 1 As the disease progresses, vomiting, bad breath, and lethargy can occur. Since cats are skilled at hiding illness, regular veterinary checkups are crucial for early detection through routine bloodwork and urine tests. 1Chronic kidney disease is common, especially in older cats, as many develop kidney problems with age. Early diagnosis through proactive screening is vital for effective management and ensuring a better quality of life.1

kidney anatomyThe pictures in this section are reprinted with permission by the copyright owner,  Hill's Pet Nutrition, from the Atlas of Veterinary Clinical Anatomy. These illustrations should not be downloaded, printed or copied except for personal, non-commercial use

Symptoms of Cat Kidney Problems

The clinical signs of chronic kidney disease in cats are often subtle at first and non-specific initially but become more apparent as the disease progresses. Early symptoms of cat kidney problems include drinking and urinating a lot more than usual (called polyuria and polydipsia). Your cat may begin urinating outside of the litter box. Other signs include depression, decreased appetite, foul smelling breath, and vomiting. At first vomiting may be occasional and then increase in frequency as the condition worsens over time.

If you notice that your cat is urinating drops of urine, then he or she could be suffering from feline kidney stones.  Symptoms of cat kidney stones also include blood in the urine, pain when urinating.  In severe cases a cat could suffer from abdominal pain and a secondary bacterial infection.

If the kidneys were damaged due to a poison such as licking antifreeze they could be damaged. Dehydration will also cause damage. Symptoms also begin due to the kidneys failure to remove waste from the bloodstream causing some of the symptoms such as vomiting.

You may see changes in your cat’s physical condition and changes in the color of the gums (pale color).

If your cat has signs of kidney problems, you should take her to the vet. Actually, you should take your cat to the vet anytime her litter box habits change, because that is often a sign of a medical problem, such as a kidney or bladder infection.

Early Diagnosis of Cat Kidney Problems

The most common sign of cat kidney problems is drinking more than usually. These are also symptoms of illnesses such as hyperthyroidism and diabetes. Your vet will do blood work to check for those conditions as well as checking for kidney problems. Early diagnosis through routine screening and monitoring changes in urine concentration and body weight, along with blood tests, is crucial in identifying and managing chronic kidney disease effectively, ensuring a better quality of life for cats.

One of the things your vet will look for in the blood tests is BUN (blood urea nitrogen). This is a chemical that the liver makes from ammonia. BUN is excreted by the kidneys and if they are not functioning properly, the BUN level in the blood will be high. Your vet will also look at the levels of creatinine and phosphorous in the blood. Additionally, measuring a cat's blood pressure is significant in the diagnostic process to assess the degree of kidney disease, as hypertension is a common complication of CKD.

In addition to doing blood work, the vet will examine your cat's urine. He or she will look for infection and loss of protein. Your vet may also take x-rays or do an ultrasound exam. In cats with chronic kidney problems, the kidneys often appear shrunken and irregular.

Treatment for Cat Kidney Problems:

Treatment of cat kidney disease has three main goals.

  1. BUN and other toxin levels must be kept low. This is primarily done with fluid therapy. Some cats require intravenous fluids, but most do well with subcutaneous (under the skin) fluids. Cat owners can be taught how to do this at home. Additionally, it's crucial to control blood pressure to prevent further kidney damage and complications such as blindness and worsening of the kidney disease.
  2. The phosphorus level must be kept low. A high level of phosphorus can lead to mineralization of various sites in the body. Your vet may prescribe drugs that bind phosphorus in the intestine and do not allow it to be absorbed. Managing high blood pressure with medications like vasodilators, ACE inhibitors, ARBs, and specifically amlodipine, is also a key part of the comprehensive treatment plan for cats with chronic kidney disease.
  3. The third goal of treatment is to prevent stomach ulcers, which often occur due to the uremic toxins. Drugs such as Tagamet, Zantac, and carafate are often prescribed for this purpose. The role of bone marrow in treating anemia associated with chronic kidney disease is also significant, as stimulating the bone marrow to produce more red blood cells can be a potential treatment for anemia in cats with kidney failure.

There are special prescription diets for cats with kidney problems.

There is a new feline kidney transplant procedure that has been successfully developed and performed a the University of Pennsylvania Matthew J. Ryan Veterinary Hospital (VHUP).  The $12,500 procedure has been  performed over 100 times as of 2009.

Your veterinarian may or may not choose to use prescription medications to control other associated conditions your cat might have including medicines for phosphorous control and other therapies.

Diet for Cat with Kidney Disease

Dietary change is the most frequently used approach to treat cat's with chronic kidney disease (called CKD). Since cats tend to be choosy regarding what they eat some veterinarians like to use dietary supplements. One approach might be to slowly change the cat renal diet vs. doing it in one step.  Approaches include lowering the amount of protein in the diet.

Recent studies show that a diet specifically made to help with feline kidney disease will help a cat live longer with minimal negative effects.

Natural Approaches for a Cat with Kidney Problems

There are several herbal supplements that may help support kidney function. Remedies are available in drop form and combine with your cat's food. Common herbal ingredients and what they do include:

  • Arctium lappa (Burdock): - studies on mice show that this substance has a positive effect on blood sugar (Swanston-Flatt SK, Day C, Flatt PR, et al. “Glycaemic effects of traditional European plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice. Diabetes" Res . 1989;413:69–73. ) 
  • Taraxacum officinalis (Dandelion): may help with blood sugar levels and fluid balance (Rcz-Kotilla, E., G. Rcz, A. Solomon. 1974. “The action of Taraxacum officinale extracts on the body weight and diuresis of laboratory animals. Planta Med 26(3):212217.) 
  • Galium aperine(Cleavers): lymph cleaner and blood purifier and supports urinary system. 

One natural supplement made for this purpose is Pet Alive Kidney Support . Discuss this option with your veterinarian so that he or she can monitor progress.



7. Feline Kidney Disease, Duval, Derek DVM
8. Treating Feline Kidney Disease: an Evidence-Based Approach, D. Polzin, College of Veterinary Medicine, University of Minnesota