Chronic Kidney Disease in Cats: Causes, Symptoms, Treatment, and Management

Chronic kidney disease (CKD) is one of the most common health conditions affecting older cats. The kidneys play a vital role in filtering waste products from the blood, balancing fluids, and regulating essential minerals. When kidney function declines, toxins build up in the bloodstream, leading to serious health issues.

CKD is a progressive and incurable condition, but with early diagnosis and proper management, affected cats can maintain a good quality of life for months or even years.

This guide will cover everything you need to know about chronic kidney disease in cats, including causes, symptoms, diagnosis, treatment options, and long-term care.

What is chronic kidney disease in cats?

Chronic kidney disease (CKD), also known as chronic renal failure (CRF), occurs when the kidneys gradually lose their ability to function over time. This condition primarily affects older cats, with studies showing that more than 30% of cats over the age of 10 develop some degree of CKD.

As the kidneys fail, they become less effective at filtering toxins, producing urine, and maintaining fluid balance, leading to a buildup of waste products in the body.

Causes of chronic kidney disease in cats

CKD can be caused by a variety of underlying conditions, though in many cases, the exact cause is unknown. Common causes include:

Age-related degeneration

The most common cause of CKD is the natural aging process, where the kidneys wear out over time.

Genetic predisposition

Some cat breeds, such as Persians, Abyssinians, and Siamese, have a higher risk of developing CKD.

Kidney infections (pyelonephritis)

Bacterial infections can damage kidney tissue and contribute to long-term kidney failure.

Kidney stones and blockages

Obstructions in the urinary tract can cause kidney damage, especially if left untreated.

Polycystic kidney disease (PKD)

An inherited condition, particularly in Persian and related breeds, where fluid-filled cysts form in the kidneys.

Toxins

Exposure to toxic substances such as antifreeze, lilies, or certain medications can cause acute kidney damage, which may lead to chronic kidney disease.

High blood pressure (hypertension)

Uncontrolled high blood pressure can damage the delicate blood vessels in the kidneys, leading to kidney failure.

Autoimmune diseases

Conditions such as glomerulonephritis, where the immune system attacks the kidney’s filtration system, can cause CKD.

Symptoms of chronic kidney disease in cats

CKD develops gradually, so early signs can be subtle. Symptoms become more noticeable as kidney function declines.

Early symptoms

• Increased thirst (polydipsia)
• Increased urination (polyuria)
• Weight loss
• Reduced appetite
• Bad breath with a uraemic odour
• Lethargy and reduced activity

Advanced symptoms

• Vomiting and nausea
• Dehydration despite increased water intake
• Weakness or muscle wasting
• Poor coat condition
• Mouth ulcers
• High blood pressure (which can lead to sudden blindness)
• Anaemia, causing pale gums and lethargy

Diagnosing chronic kidney disease in cats

Early detection of CKD is essential to slow its progression. A vet will use a combination of tests to diagnose and assess the severity of the disease.

Blood tests

• Creatinine and blood urea nitrogen (BUN): Indicators of kidney function; high levels suggest reduced kidney efficiency.
• SDMA (symmetric dimethylarginine): A more sensitive marker that detects kidney disease earlier than creatinine.
• Phosphorus levels: High phosphorus levels can indicate worsening kidney function.
• Potassium levels: Low potassium can contribute to weakness and muscle wasting.

Urinalysis

• Urine specific gravity (USG): Measures the kidney’s ability to concentrate urine.
• Protein levels: High protein in urine can indicate kidney damage.
• Presence of bacteria or blood: May indicate infection or inflammation.

Blood pressure measurement

High blood pressure is a common complication of CKD and can cause further kidney damage.

Imaging

Ultrasounds or X-rays may be used to check for structural abnormalities such as cysts, kidney stones, or tumours.

Treatment and management of chronic kidney disease

While CKD is not curable, treatment focuses on slowing disease progression, managing symptoms, and improving quality of life.

Specialised renal diet

A prescription kidney diet is one of the most effective ways to slow CKD progression. These diets contain:

• Low phosphorus levels to reduce kidney strain.
• Moderate protein levels to minimise toxin buildup.
• Omega-3 fatty acids to support kidney health.
• Increased water content to improve hydration.

Hydration support

Cats with CKD are prone to dehydration. Strategies to maintain hydration include:

• Providing fresh water at all times.
• Offering wet food instead of dry kibble.
• Using cat water fountains to encourage drinking.
• Administering subcutaneous fluids at home (as advised by a vet).

Phosphate binders

High phosphorus levels contribute to kidney damage. If diet alone does not control phosphorus, phosphate binders such as aluminium hydroxide may be prescribed.

Blood pressure control

If a cat has hypertension, medications such as amlodipine are used to prevent further kidney damage and reduce the risk of sudden blindness.

Anti-nausea medication

Many cats with CKD experience nausea and vomiting. Medications such as maropitant (Cerenia) or ondansetron can improve appetite and prevent weight loss.

Potassium supplements

Some cats with CKD develop low potassium levels, leading to weakness and lethargy. Potassium supplements may be necessary to maintain muscle function.

Anaemia treatment

As CKD progresses, cats may develop anaemia due to reduced red blood cell production. Treatment options include:

• Iron supplements
• Erythropoietin injections to stimulate red blood cell production

Managing chronic kidney disease at home

Cats with CKD require lifelong management and regular vet check-ups. Here are some tips for improving their quality of life:

• Feed a kidney-friendly diet and avoid high-phosphorus foods.
• Encourage hydration with water fountains and wet food.
• Monitor litter box habits for changes in urination.
• Weigh your cat regularly to track weight loss.
• Provide a stress-free environment to reduce anxiety.
• Follow your vet’s recommendations on medication and dietary adjustments.

Can chronic kidney disease be prevented?

While CKD cannot always be prevented, certain measures can help reduce the risk:

• Provide a high-quality diet with balanced phosphorus and protein levels.
• Encourage regular hydration to support kidney function.
• Avoid exposure to toxins such as antifreeze, lilies, and certain medications.
• Schedule routine veterinary check-ups to detect early signs of kidney disease.
• Monitor blood pressure in older cats to prevent kidney damage.

When to see a vet

Seek veterinary advice if your cat shows any of the following symptoms:

• Increased thirst and urination
• Weight loss and poor appetite
• Vomiting or nausea
• Lethargy and weakness
• Bad breath or mouth ulcers
• Sudden blindness or disorientation

Early diagnosis can significantly improve a cat’s prognosis, so regular vet check-ups are essential, especially for senior cats.

Conclusion

Chronic kidney disease is a progressive but manageable condition in cats. With early detection, dietary changes, hydration support, and appropriate medications, many cats can live comfortably for years after diagnosis.

By working closely with a vet and providing the right care, cat owners can improve their pet’s quality of life and ensure they remain as happy and healthy as possible.

If you suspect your cat may have kidney disease, schedule a veterinary check-up as soon as possible. Early intervention is key to slowing the progression of CKD and helping your cat live a longer, healthier life.