Watching your beloved cat age can be bittersweet. As cats grow older, they become more vulnerable to various health issues, from minor problems to serious conditions like kidney disease, which is one of the most common concerns in aging felines.
Kidney disease in cats can develop gradually, often before any obvious symptoms appear, making early detection challenging but essential. Learning that your cat has kidney disease can be difficult, but it’s important to know that it doesn’t mean the end of their happy, active life.
While there is no cure for chronic kidney disease, understanding the symptoms and following a proactive treatment plan can make a significant difference. With timely care and proper management, you can help add years of comfort, vitality, and quality of life to your cat’s later years.
What Is Kidney Disease In Cats?
The kidneys are essential organs in your cat’s body, responsible for filtering waste products, such as urea and creatinine, from the bloodstream. They also regulate water, minerals, and electrolytes, keeping the body in balance.
According to PetMD, the kidneys help produce hormones that control blood pressure and stimulate red blood cell production, making them critical for overall health.
When a cat develops kidney disease, the kidneys can no longer effectively remove toxins from the body. These toxins, known as uremia, accumulate in the bloodstream, disrupting the cat’s internal balance and leading to serious health problems over time.
There are two main types of kidney disease in cats:
Acute Kidney Injury (AKI): This occurs when the kidneys suddenly stop functioning properly, often due to illness, toxins, or injury. AKI can sometimes be reversed if treated promptly, but if left untreated, it can lead to kidney failure.
Chronic Kidney Disease (CKD): CKD develops gradually over months or years and is irreversible. The damage is progressive, but with proper management—including diet, medication, and regular veterinary care—cats with CKD can still enjoy a good quality of life for several additional years.
What Causes Kidney Disease in Cats?
If you notice signs of kidney disease in your cat, it’s important to visit your veterinarian as soon as possible. While the exact cause of chronic kidney disease (CKD) is often unknown, understanding potential risk factors can help guide treatment and management.
Age-Related Degeneration
Kidney problems are common in older cats. As cats age, the tiny filtering units in the kidneys, called nephrons, gradually lose their ability to function. By the time symptoms appear, a cat may have already lost up to 75% of their kidney function, which is why early detection is so important.
Toxins
Certain substances can damage a cat’s kidneys, sometimes suddenly or over time. Common culprits include:
Antifreeze (ethylene glycol)
Toxic plants, such as lilies
Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen
Rodenticides or other household poisons
Even small amounts of these toxins can lead to acute kidney injury (AKI) or contribute to chronic kidney damage, so prevention and awareness are crucial.
Hereditary Conditions
Some cats are genetically predisposed to certain kidney problems. Specific breeds are more prone to kidney disease due to hereditary factors:
British Shorthairs, Himalayans, and Persians are more likely to develop Polycystic Kidney Disease (PKD).
Abyssinians and Siamese cats are at higher risk for amyloidosis, a condition in which abnormal proteins build up in the kidneys.
According to the National Institutes of Health (NIH), PKD is caused by fluid-filled cysts that form in the kidneys, which gradually reduce kidney function over time. Early diagnosis and monitoring are key to managing hereditary kidney conditions and helping affected cats maintain a good quality of life.
Infections
Certain infections can lead to kidney damage in cats. For example:
Feline Infectious Peritonitis (FIP) and toxoplasmosis can cause permanent scarring and reduce kidney function over time.
Recurrent kidney infections, such as pyelonephritis, can also contribute to kidney disease if left untreated.
Early detection and prompt veterinary care are essential to minimize long-term damage and support your cat’s kidney health.
Obstructions
Obstructions in the urinary tract, such as ureteral stones or urolithiasis, can block urine flow. This blockage puts pressure on the kidneys and can cause severe damage to kidney tissues if not treated promptly.
Systemic Diseases
Sometimes, kidney problems are secondary to other health conditions. Diseases affecting other organs—such as hypertension, heart disease, or immune-mediated conditions like cancer—can damage blood vessels in the kidneys, leading to chronic kidney stress or infections.
Early detection and management of both the underlying condition and kidney health are essential to prevent further deterioration.
Cat Kidney Disease Symptoms
In the early stages of chronic kidney disease (CKD), the symptoms are often subtle, easily overlooked, or mistaken for the normal changes that come with aging. Cats are naturally good at hiding discomfort, so these early signals may be mild — but recognizing them sooner can make a meaningful difference in slowing disease progression and improving quality of life.
Stage | Symptom | Description |
Early Symptoms of Kidney Disease in Cats (Stage I & II) | Increased Thirst & Urination (PU/PD) | When the kidneys can’t concentrate urine, your cat drinks more water and produces larger, more frequent litter box clumps. |
| Weight Loss | Your cat may lose weight over time, even if their appetite seems normal. |
| Poor Coat Quality | Dehydration and reduced grooming can cause the coat to become dry, dull, or unkempt. |
Advanced Symptoms of Kidney Disease in Cats (Stage III & IV) | Vomiting & Nausea | Uremic toxins build up in the bloodstream, making your cat feel nauseated or causing vomiting. |
| Dehydration | Advanced kidney dysfunction prevents the body from conserving water. |
| Mouth Ulcers & Bad Breath | A buildup of toxins can lead to oral ulcers and a distinctive ammonia-like odor. |
| Lethargy & Weakness | Severe toxin buildup and anemia contribute to fatigue and low energy. |
| Anorexia | Reduced appetite leads to rapid weight loss and muscle wasting. |
| Sudden Blindness or Behavior Changes | High blood pressure can cause retinal detachment or neurological changes. |
Chronic Kidney Disease (CKD)
Chronic Kidney Disease in cats is a progressive condition that worsens over time. Many pet parents first notice CKD as “renal failure” in their senior cats. According to the Cat Care Societ, around 40% of cats develop CKD by age 10, and over 80% of cats older than 15 experience some degree of kidney failure.
CKD in cats typically progresses through two major phases:
1. Compensation Phase
In the early stage, the healthy parts of the kidneys work harder to make up for the damaged areas. This increased effort leads to more frequent urination and greater water intake as the body attempts to flush out toxins.
2. Decompensation Phase
As the disease advances, the kidneys can no longer perform their essential functions. Waste products begin to accumulate, leading to nausea, weight loss, dehydration, and anemia. High blood pressure and reduced erythropoietin (the hormone that stimulates red blood cell production) further worsen the condition. This stage marks the clear onset of feline kidney disease.
How Veterinarians Diagnose Kidney Disease in Cats
Once you suspect that your cat is showing signs of kidney disease, a veterinary exam is essential. Your veterinarian will perform a full physical assessment and request laboratory tests to determine how well the kidneys are functioning and how advanced the disease may be.
Bloodwork
Blood tests are the first and most important step in diagnosing CKD and evaluating its severity.
BUN and Creatinine
Blood Urea Nitrogen (BUN) and creatinine are waste products normally filtered by the kidneys.
High levels indicate that the kidneys are no longer removing toxins effectively.
Creatinine typically rises after 75% of kidney function is lost, which is why early CKD can be missed without additional testing.
SDMA (Symmetric Dimethylarginine)
SDMA is one of the most reliable markers for early kidney disease.
It can detect kidney function loss as early as a 40% reduction, far sooner than creatinine.
This makes SDMA crucial for diagnosing CKD in its early, more manageable stages.
Phosphorus, Calcium, and Electrolytes
Electrolyte imbalances are common in cats with CKD.
High phosphorus levels (hyperphosphatemia) often appear as kidney function declines.
Cats may also develop imbalances in potassium, calcium, and other electrolytes, contributing to muscle weakness, dehydration, and heart irregularities.
Urinalysis
After bloodwork, the next step in diagnosing kidney disease is urinalysis, which provides essential information about how well the kidneys are concentrating and filtering urine.
Urine Specific Gravity (USG)
USG measures how concentrated the urine is.
A low USG indicates the kidneys are unable to retain water—one of the earliest signs of kidney dysfunction.
This test checks for the presence of protein in your cat’s urine.
Protein loss suggests that the kidney’s filtering units (the glomeruli) may be damaged.
More Required Tests
Urine Protein:Creatinine (UPC) Ratio
This test measures how much protein your cat is losing through their urine.
Elevated protein levels can indicate kidney inflammation or worsening kidney damage.
Blood Pressure Measurement
High blood pressure is common in cats with kidney disease.
Monitoring it helps diagnose hypertension early and prevent complications such as vision loss or further kidney deterioration.
Imaging (X-rays or Ultrasound)
Your veterinarian may recommend imaging to evaluate the kidneys’ size, shape, and structure.
In cats with CKD, the kidneys often appear smaller, irregular, or shrunken.
Thyroid Testing
Hyperthyroidism is a common condition in older cats and can mask or mimic the symptoms of kidney disease.
Testing thyroid levels ensures an accurate diagnosis and helps guide safe treatment planning.
IRIS Staging
The International Renal Interest Society (IRIS) provides a standardized staging system used worldwide to assess the severity of kidney disease in cats. This system ranges from Stage I to Stage IV and is based primarily on serum creatinine and SDMA levels.
In addition to these markers, veterinarians also evaluate:
Proteinuria (UPC ratio)
Blood pressure levels
These measurements help determine how advanced the kidney damage is and guide decisions about treatment and long-term management.
According to the Cornell Feline Health Center, the IRIS guidelines serve as the global gold standard for diagnosing, monitoring, and managing cat kidney disease. Veterinarians rely on this framework to create individualized treatment plans and provide accurate prognoses.
Cat Kidney Disease Treatment
Chronic kidney disease (CKD) is not reversible, but with the right management plan, you can slow its progression and significantly improve your cat’s comfort and quality of life. Treatment focuses on supporting kidney function, reducing toxin buildup, and addressing symptoms as they appear.
Dietary Management
Diet is one of the most critical parts of CKD treatment.
Therapeutic Renal Diets
Veterinarians typically recommend prescription kidney diets that are:
Low in phosphorus and sodium
Moderate to low in high-quality protein
Enriched with omega-3 fatty acids, antioxidants, and B vitamins
These diets help reduce kidney workload, slow disease progression, and support overall health.
Transition Tips for Picky Eaters
Switching foods can be challenging. Try:
Gradually mixing the new diet with their old food
Warming the food slightly to enhance aroma
Offering smaller, more frequent meals
Consulting your vet if appetite issues persist
Never force the diet abruptly—maintaining consistent eating is more important than rushing the transition.
Hydration
Proper hydration is essential for cats with CKD, as their kidneys can no longer conserve water efficiently.
Encouraging Water Intake
Use multiple water bowls around the home
Try cat fountains, which many cats find more appealing
Add water or low-sodium broth to wet food (if approved by your vet)
Medical Hydration Support
If your cat becomes dehydrated, your veterinarian may recommend:
Subcutaneous (SQ) fluids administered at home
Intravenous (IV) fluids during more severe episodes
These treatments help flush toxins, maintain hydration, and stabilize your cat during flare-ups.
Supplements and Medications
Cats with chronic kidney disease often need additional medications to manage symptoms and prevent mineral imbalances. Your veterinarian will determine the safest and most effective combination for your cat’s specific stage of CKD.
Phosphate Binders
When blood phosphorus levels rise (a common issue in CKD), phosphate binders help prevent further kidney damage by reducing phosphorus absorption from food.
Common options include:
Aluminum hydroxide
Lanthanum carbonate
Calcium-based binders (used cautiously)
Blood Pressure & Proteinuria Control
High blood pressure and protein loss in urine are common in CKD and can accelerate kidney decline. Medications include:
Telmisartan – helps reduce proteinuria and manage hypertension
ACE inhibitors (e.g., benazepril, enalapril) – support blood pressure control and protein reduction
Potassium Supplements
Many cats with CKD develop low potassium (hypokalemia), which can cause muscle weakness and poor appetite.
Your vet may prescribe oral potassium supplements to restore normal muscle and nerve function.
Anti-Nausea and Appetite Stimulants
CKD often leads to nausea, vomiting, or reduced appetite. These medications help improve comfort and encourage healthy eating habits:
Mirtazapine – appetite stimulant and anti-nausea properties
Maropitant (Cerenia) – effective for managing nausea and vomiting
Ondansetron – another option for nausea control
As kidney function declines, the kidneys produce less erythropoietin, a hormone needed to make red blood cells. This often leads to anemia.
Treatments may include:
Erythropoiesis-stimulating agents (ESAs) such as darbepoetin
Iron supplements, if needed
Regular monitoring of red blood cell levels
Managing Complications
Cats with chronic kidney disease are more vulnerable to secondary health issues, so monitoring and prevention are essential. Regularly checking your cat’s blood pressure, hydration status, and overall organ function helps reduce the risk of additional problems.
Urinary tract infections (UTIs) are especially common in cats with CKD because they often produce dilute urine. If left untreated, UTIs can worsen kidney damage. Your veterinarian may recommend periodic urine testing and prescribe antibiotics when needed to keep infections under control.
Advanced Care
It's better to ask for extra support for severe cases, like:
Dialysis and kidney transplants are rare and typically reserved for severe cases. In some cases, these treatments may be the only option for effectively managing kidney problems.
When symptoms become overwhelming and your cat's quality of life is significantly affected, it may be time to have a conversation with your vet about humane euthanasia. This decision, though difficult, ensures that your pet is not suffering unnecessarily.
Prognosis and Life Expectancy
In severe cases of kidney disease, some cats may require more intensive medical support. These advanced treatments are not common but can be life-saving in certain situations:
Dialysis: Helps remove toxins from the bloodstream when the kidneys can no longer do so effectively.
Kidney transplant: A highly specialized option available only at select veterinary centers. It can offer long-term improvement, but it involves strict lifelong care and medications.
While these interventions can extend a cat’s life, they are typically reserved for select cases due to cost, complexity, and the cat’s overall health.
When symptoms progress to the point where your cat’s comfort and daily functioning are significantly affected, it may be time to have an open conversation with your veterinarian about end-of-life care. Although the decision is extremely difficult, humane euthanasia can prevent unnecessary suffering and allow your cat to pass peacefully.
Prevention and Early Detection Tips
Life expectancy for cats with CKD varies widely and depends on the stage of disease, response to treatment, and how consistently the condition is managed.
Stage I–II:
With early diagnosis, a renal-supportive diet, good hydration, and regular monitoring, many cats can live several years with a good quality of life.
Stage III–IV:
Advanced CKD requires intensive care, including fluids, medications, and frequent reassessments. In these stages, life expectancy may range from several months to about a year, though some cats live longer with dedicated management.
Managing complications—especially high blood pressure, phosphorus levels, dehydration, and nausea—plays a major role in improving comfort and extending life.
Conclusion
Cat kidney disease in cats can be a serious challenge, but with proactive care and early intervention, it is possible to manage the condition and maintain your cat’s quality of life. Building a strong partnership with your veterinarian is key—regular check-ups, early dietary adjustments, and consistent medication can slow disease progression and keep your cat comfortable.
Stay vigilant for early signs of kidney problems, adhere closely to the treatment plan, and focus on making your cat’s daily life as comfortable and happy as possible. With attentive care and love, even cats with CKD can enjoy meaningful, fulfilling years with their families.
Frequently Asked Questions
What does CKD in cats refer to?
Chronic kidney disease (CKD) is a serious, irreversible condition in which a cat’s kidneys gradually lose function over time. As the kidneys fail to filter waste effectively, toxins build up in the bloodstream, and the body can no longer maintain proper fluid and mineral balance.
How much time does kidney disease take to progress in cats?
The progression of CKD varies. In the early stages (IRIS I–II), it may progress very slowly over several years. In more advanced stages (IRIS III–IV), kidney function can decline more rapidly, sometimes within just a few months.
How can I make my cat’s life better when she has chronic renal failure?
There are several ways to support a cat with CKD:
Schedule regular veterinary visits and follow their guidance closely.
Feed a therapeutic renal diet recommended by your vet.
Encourage increased water intake, using wet food or multiple water sources.
Monitor and maintain healthy blood pressure levels.
Administer prescribed medications, such as phosphate binders, potassium supplements, or anti-nausea treatments.
With consistent care, monitoring, and attention, cats with CKD can still enjoy a comfortable and happy life.
Reference List
https://www.petmd.com/cat/conditions/urinary/kidney-disease-cats
https://vcahospitals.com/know-your-pet/kidney-failure-acute-in-cats
https://friendshiphospital.com/friendship-news/pet-poisons-and-common-toxicities/
https://www.animalgeneralct.com/site/blog/2022/07/15/stages-kidney-failue-cats
https://www.mayoclinic.org/tests-procedures/blood-urea-nitrogen/about/pac-20384821
https://www.idexx.com/en/veterinary/reference-laboratories/sdma/
https://www.kidneyfund.org/all-about-kidneys/other-kidney-problems/protein-urine
https://my.clevelandclinic.org/health/diagnostics/23933-urine-protein-creatinine-ratio
https://www.vin.com/apputil/project/defaultadv1.aspx?pid=11290&catid=&id=4252603&meta=&authorid=
