Understanding Kidney Disease in Cats: Symptoms, Causes and Treatment

Kidney disease is one of the most common chronic illnesses affecting senior cats. Since kidneys perform the vital function of filtering waste from the bloodstream, kidney impairment can create a dangerous buildup of toxins and result in life-threatening complications. However, with prompt veterinary treatment and supportive care, many cats can still enjoy a good quality of life despite kidney disease. This guide covers everything cat owners should understand about detecting, managing and coping with chronic kidney disease (CKD) in cats.

What Happens When a Cat Develops Kidney Disease?

The kidneys act as natural filters for the blood, removing toxins and waste products so they can exit the body in urine. Kidney disease occurs when the kidneys become damaged and lose their ability to properly filter blood.

As kidney function declines, toxins accumulate in the bloodstream and the body retains excess fluids. This creates a cascade of problems:

  • Elevated toxins lead to loss of appetite, vomiting, diarrhea, lethargy, and a host of other symptoms
  • Reduced urine output means toxins are not adequately flushed from the body
  • Increased thirst and urination as the kidneys attempt to flush waste via large urine volumes
  • High blood pressure strains the heart and damages blood vessels
  • Anemia develops from reduced red blood cell production
  • Weakened bones due to abnormal calcium and phosphorus levels
  • Damaged organs including the heart and liver
  • Urinary tract infections from excessive waste products in urine
  • Metabolic acidosis occurs when fluids become too acidic

Left untreated, this accumulation of toxins, electrolyte imbalances and metabolic disruption leads to kidney failure and ultimately death. However, with prompt treatment guided by a veterinarian, these consequences of kidney disease can be controlled to extend and improve patients’ lives.

What Causes Kidney Disease in Cats?

Kidney disease has many potential causes in cats. Some of the most common include:

  • Kidney function naturally declines with age. Chronic kidney disease is common in senior cats over 10 years old.

Inflammation & Infection

  • Bacterial infections, immune disorders, toxins, and inflammation can damage kidney tissue.


  • Stones, crystals or masses blocking urine flow increase infection risk.

High Blood Pressure

  • Uncontrolled hypertension damages tiny filters and blood vessels in the kidneys.

Dental Disease

  • Bacteria from severe tartar buildup enter the bloodstream and infect the kidneys.


  • Antifreeze (ethylene glycol), lilies, grapes/raisins, vitamin D, among other toxins damage kidney cells.

Underlying Illnesses

  • Diabetes, hyperthyroidism, cancer and other conditions can impair kidney function.

Genetics & Congenital Issues

  • Some purebred cats have a higher risk due to hereditary kidney defects.

In many cases, veterinarians are unable to determine an exact cause, especially in elderly cats where age-related decline is most often the culprit. Regardless of the initial trigger, chronic kidney disease involves an ongoing cycle of nephron damage and scarring that worsens over time.

Signs & Symptoms of Kidney Disease in Cats

Signs & Symptoms of Kidney Disease in Cats

Signs of kidney disease arise from the buildup of toxins and resulting electrolyte/hormone imbalances:

Increased Urination & Thirst

  • Attempting to flush toxins causes more frequent urination and thirst

Reduced or Absent Urination

  • Severe kidney damage can lead to decreased or no urine production

Weight Loss

  • Toxins reduce appetite causing muscle wasting and weight loss

Vomiting & Diarrhea

  • Stomach upset from waste buildup

Lethargy & Weakness

  • Low red blood cell production causes weakness and tiredness

Poor Coat Condition

  • Toxins and dehydration affect skin and coat health

Bad Breath & Oral Ulcers

  • Uremic ulcers and stomach toxins create a foul, ammonia-like odor

Other Possible Symptoms:

  • Pale or dry gums
  • Increased urinary accidents
  • Difficulty jumping or navigating stairs
  • Hunched posture or reluctance to move
  • Constipation
  • Seizures
  • Vision problems

Any combination of these symptoms in an older cat warrants bloodwork and urinalysis to check kidney function. The sooner treatment begins, the better the long-term prognosis.

Diagnosing Kidney Disease in Cats

Veterinarians use the following diagnostic tests to assess kidney function and guide treatment:

Complete Blood Count (CBC)

Checks for anemia and evidence of infection or inflammation

Chemistry Panel

Measures kidney markers such as blood urea nitrogen (BUN) and creatinine to evaluate filtration ability


Checks concentration, protein, and sediment to assess kidney damage and function

Urine Culture

Determines if infection is present

Blood Pressure

Monitors for hypertension which damages kidneys


X-rays, ultrasound or CT scans visualize kidneys and rule out masses, stones, cysts


Removes kidney tissue sample for pathology if cancer is suspected

The International Renal Interest Society (IRIS) developed a standardized staging system to grade the severity of kidney disease based on labwork results. Treatment is tailored according to the IRIS stage.

Treatments for Kidney Disease in Cats

Treatments for Kidney Disease in Cats

While kidney disease cannot be cured, progression can be slowed with proper veterinary treatment to extend and improve patients’ lives.


  • Phosphate binders – Control abnormally high phosphorus levels
  • Potassium supplements – Treat low potassium which causes muscle weakness
  • Anti-nausea medication – Allows appetite improvement
  • ACE inhibitors – Reduce protein in the urine and high blood pressure
  • Erythropoietin – Stimulates red blood cell production to fight anemia
  • Antibiotics – If infection is present

Fluid Therapy

  • Subcutaneous, intravenous or intraperitoneal fluids flush toxins and correct dehydration

Diet Change

  • Prescription kidney diets reduce phosphorus and provide optimal nutrition

Blood Pressure Medication

  • Hypertension damages kidneys, so controlling blood pressure is crucial

Dental Care

  • Professional cleanings treat infection from advanced dental disease

Additional Care

  • Bloodwork monitoring, vitamins, supplements, medication adjustments

With this supportive care guided by a veterinary professional, many cats can live 1-3 years or longer with good quality of life after a CKD diagnosis. Regular treatment and attentive home care are key.

At-Home Care Tips for Cats with Kidney Disease

Though frequent vet visits are needed, owners also play a key role providing daily care at home:

  • Follow prescription kidney diet recommendations carefully
  • Encourage drinking by feeding wet food or adding water to meals
  • Provide easy access to multiple fresh water sources
  • Give intravenous fluids and medications as instructed
  • Assist in grooming and cleaning litter to preserve energy
  • Weigh regularly to monitor for muscle loss
  • Limit stress and make litter box easily accessible
  • Monitor for decreased appetite, increased lethargy, vomiting, etc.
  • Maintain dental hygiene and monitor mouth for ulcers
  • Avoid toxins around the home that could further damage kidneys

Cats often require more intensive at-home care as their condition advances. Anecdotal remedies like supplements or herbs should only be given under a vet’s guidance. Managing this chronic disease is a team effort between pet owners and the healthcare team.

Coping with a CKD Diagnosis in Your Cat

Learning your cat has kidney disease can be emotionally difficult. However, treatment has improved greatly in recent decades allowing cats to live well with CKD. Focus care on maximizing quality of life vs. quantity.

  • Learn all you can about kidney disease and ask your vet questions
  • Develop a treatment plan with realistic goals for your cat’s individual situation
  • Focus on each good day vs. worrying about the disease’s progression
  • Monitor for signs of pain, nausea, depression impacting quality of life
  • Seek support from online groups of owners dealing with CKD
  • Consider pet insurance, care credit, or other assistance with treatment costs
  • Focus care around your cat’s comfort, happiness and normal routine

While kidney disease shortens lifespan, your cat can still enjoy their golden years with thoughtful management. Home care combined with close veterinary guidance helps cats live well with this common age-related condition.

Key Takeaways on Kidney Disease in Older Cats

  • Kidney disease is very common as cats age over 10 years old
  • Damaged kidneys cannot properly filter waste from the bloodstream
  • Toxins and fluid buildup cause symptoms like vomiting, weight loss and lethargy
  • Diagnosis is made by checking organ function with bloodwork and urinalysis
  • Treatment includes fluids, diet change, medication and blood pressure control
  • At-home care like fluids, dental monitoring and diet are also crucial
  • Proper treatment can extend life 1-3 years after diagnosis in many cases
  • Focus care on maximizing comfort and quality of life for your cat

While incurable, kidney disease in cats can often be well-managed to allow pets to live happily despite the diagnosis. Working closely with your veterinarian and providing attentive daily care at home helps cats enjoy their golden years.

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