Types of Kidney Disease

Chronic Kidney Disease (CKD):

• A gradual, irreversible loss of kidney function.
• Develops over months or years, most common in senior cats.
• Focus is on management and slowing progression, not cure.

Acute Kidney Injury (AKI):

• A sudden, often severe decline in kidney function.
• Can be reversible with immediate, aggressive treatment.
• Typically caused by toxins (e.g., lilies, antifreeze), infections, or trauma.
• Constitutes a veterinary emergency.

Congenital Kidney Disease:

• Present from birth, such as Polycystic Kidney Disease (PKD).
• Has strong breed predispositions (e.g., Persians, Himalayans).
• Progressive and currently unpreventable.

Causes and Risk Factors

Primary Causes of CKD

Key Risk Factors

Age:

• Risk increases significantly with age.
• Approximately 30% of cats over 12 show some kidney dysfunction.
• This rises to about 50% in cats over 15.

Breed Predispositions:

Additional Risk Factors:

• History of frequent urinary tract infections.
• Long-term use of certain medications (e.g., NSAIDs).
• Systemic hypertension (high blood pressure).
• Severe dental disease (source of bacteria).
• Obesity, which increases metabolic workload.

The Stages of CKD

IRIS Staging System

The International Renal Interest Society (IRIS) system classifies CKD into four stages based primarily on blood creatinine levels, with substages for proteinuria and hypertension.

Stage 1 (Early Kidney Disease):

• Creatinine: <1.6 mg/dL
• Symptoms: Typically none apparent.
• Action: Close monitoring, address any underlying causes.
• Prognosis: Can remain stable for months to years.

Stage 2 (Mild CKD):

• Creatinine: 1.6 - 2.8 mg/dL
• Symptoms: Mild increases in thirst and urination may begin.
• Action: Initiate dietary management and baseline treatment.
• Prognosis: 1-3+ years with proper management.

Stage 3 (Moderate CKD):

• Creatinine: 2.9 - 5.0 mg/dL
• Symptoms: Weight loss, poor appetite, vomiting, lethargy.
• Action: Aggressive medical and dietary intervention required.
• Prognosis: Several months to 2 years.

Stage 4 (Severe CKD):

• Creatinine: >5.0 mg/dL
• Symptoms: Severe, life-threatening clinical signs.
• Action: Intensive supportive care with a focus on quality of life.
• Prognosis: Days to a few months.

Symptoms and Early Detection

Early Stage Symptoms (Often Subtle)

• Slightly increased water consumption.
• Larger or more frequent urine clumps in the litter box.
• Minor, gradual weight loss.
• Slight decrease in grooming or appetite.

Why Early Detection is Critical: Kidneys possess a large functional reserve. Up to 75% of function can be lost before clear symptoms emerge, making early screening vital for long-term success.

Middle to Late Stage Symptoms

Hypertension (High Blood Pressure)

Affects 20-30% of CKD cats and is a serious complication. Consequences: Sudden blindness (retinal detachment), worsening kidney damage, heart disease, and neurological issues.

Diagnosis

A comprehensive diagnosis involves multiple tests:

Essential Blood Tests

Urine Tests

• Urine Specific Gravity: Measures concentrating ability (<1.035 is concerning).
• Urine Protein:Creatinine Ratio (UPC): Quantifies protein loss, a key prognostic indicator.
• Culture & Sensitivity: Rules out underlying infection.

Additional Diagnostics

• Blood Pressure Measurement: Essential for all CKD patients.
• Abdominal Ultrasound: Evaluates kidney size, structure, and rules out cysts or stones.

Treatment and Management

1. Dietary Management: The Cornerstone

Prescription renal diets are the most proven intervention to slow CKD progression.

Key Dietary Goals:

• Restrict Phosphorus: To prevent further kidney mineralization.
• Provide Moderate, High-Quality Protein: Reduces nitrogenous waste while maintaining muscle mass.
• Increase Omega-3 Fatty Acids: For anti-inflammatory benefits.
• Supplement Potassium & B Vitamins: Often depleted in CKD.
• Promote Hydration: Wet food is vastly preferred over dry.

2. Hydration Support

• Encourage intake with water fountains, flavored broths, and wet food.
• Subcutaneous (Sub-Q) Fluids: Administered at home, often a game-changer for quality of life, helping flush toxins and combat dehydration.

3. Phosphorus Control

If diet alone doesn't control serum phosphorus, phosphate binders (e.g., aluminum hydroxide, calcium acetate, lanthanum) are given with meals.

4. Medication Management

• For Hypertension: Amlodipine is the most common, effective medication.
• For Nausea/Vomiting: Medications like Cerenia® (maropitant) or ondansetron.
• For Appetite Stimulation: Mirtazapine or capromorelin (Entyce®).
• For Anemia: Synthetic erythropoietin agents (e.g., darbepoetin) and iron supplements.
• For Proteinuria: Medications like telmisartan or benazepril may be used.

Prognosis and Life Expectancy

Prognosis varies widely based on stage at diagnosis, response to treatment, and owner commitment.

Positive Prognostic Factors: Early diagnosis, good appetite, controlled phosphorus and blood pressure, and dedicated home care.

Living with and Caring for a CKD Cat

Daily & Weekly Monitoring

• Daily: Observe appetite, water intake, energy level, and litter box habits.
• Weekly: Track weight using a baby scale.
• Monthly/Veterinary: Scheduled rechecks for blood work and blood pressure.

Quality of Life Assessment

Regularly ask:

• Is my cat eating and drinking willingly?
• Is she maintaining weight?
• Does he interact with the family and show interest in surroundings?
• Is she comfortable and free from persistent pain or nausea? A consistent decline in these areas signals a need to discuss next steps with your veterinarian.

Cost of Treatment

Costs are variable but important to anticipate.

• Initial Diagnostic Workup: $650 - $1,300.
• Monthly Maintenance (Stage 2-3): $200 - $500 (food, medications, supplements).
• Advanced Care (Stage 4): $500 - $1,200+ per month. Pet insurance, if purchased before diagnosis, or dedicated savings plans are highly recommended.

Prevention and Early Detection

While CKD is not always preventable, proactive care helps:

• Annual Senior Wellness Exams: Start at age 7, including blood work with SDMA and urinalysis.
• Regular Blood Pressure Checks: Especially in senior cats.
• Dental Care: Prevent oral bacteria from affecting the kidneys.
• Toxin Prevention: Absolutely no lily exposure; secure antifreeze.
• Weight Management: Maintain an ideal body condition.

Frequently Asked Questions (2026)

Q: Can feline kidney disease be cured? A: No. CKD is a progressive, irreversible condition. However, with modern management, we can often slow progression and maintain excellent quality of life for years.

Q: My cat refuses the prescription kidney diet. What can I do? A: Transition slowly, try different brands/textures (pate, stew), warm the food, or use appetite stimulants. Hydration is paramount—if they only eat non-prescription wet food, that is better than a prescription dry food they refuse. Discuss all options with your vet.

Q: Are subcutaneous fluids painful or difficult to give at home? A: Most cats tolerate them very well once a routine is established. The needle is very small, and the fluid is given under the skin, not into a vein. Your veterinary team will provide thorough training.

Q: When is it time to consider euthanasia? A: This is a deeply personal decision made with your veterinarian. Key indicators include: persistent refusal of food and water, unmanageable pain or nausea, severe difficulty moving, and a consistent decline where "bad days" far outnumber "good days."

Q: Are there any promising new treatments on the horizon? A: Research is ongoing in areas like regenerative medicine (stem cells), advanced phosphate binders, and more targeted therapies for anemia and proteinuria. Always discuss the latest options with your veterinarian.

Disclaimer: This guide is for educational purposes to empower cat owners. It is not a substitute for professional veterinary diagnosis, advice, or treatment. Always work closely with your veterinarian to develop a care plan tailored to your individual cat.

Last Updated: March 2026