Cat Kidney Failure Symptoms & Treatment｜Vet Guide to Preventing Feline Kidney Disease

Cat kidney failure is one of the most common health problems in middle-aged and senior cats, and is the leading cause of death in felines. Statistics show that more than one-third of cats over 10 years old will develop chronic kidney disease, and early symptoms are often subtle and easily overlooked by owners. This article provides a detailed veterinary perspective on cat kidney disease symptoms, diagnostic methods, treatment options, and preventive measures to help you protect your cat's kidney health.

What Is Feline Chronic Kidney Failure?

Feline chronic kidney failure (Chronic Kidney Disease, or CKD) is a progressive and irreversible kidney disease. The kidneys are composed of countless tiny nephrons responsible for filtering waste from the blood and regulating water and electrolyte balance. When most nephrons are damaged, the kidneys cannot function effectively, leading to toxin accumulation in the body.

Causes of Feline Kidney Disease

There are many causes of cat kidney failure, including:

• Ageing: Kidneys deteriorate with age; risk increases significantly in cats over 7 years old
• Chronic Dehydration: Cats naturally have low thirst drive; long-term dehydration increases kidney burden
• High Protein/High Phosphorus Diet: Long-term excessive phosphorus intake accelerates kidney function decline
• Urinary Tract Diseases: Urethral obstruction, cystitis, and other conditions can damage the kidneys
• Genetic Factors: Persian cats, British Shorthairs, and other breeds have higher disease risk
• Poisoning: Ingestion of lilies, antifreeze, certain medications (such as NSAIDs)
• Infections: Pyelonephritis, feline infectious peritonitis, etc.
• Other Diseases: Hypertension, diabetes, and hyperthyroidism can lead to kidney disease

Acute vs Chronic Kidney Failure

Cat Kidney Disease Symptoms: 7 Warning Signs Every Owner Must Know

Cat kidney disease symptoms are often subtle in the early stages. By the time symptoms become obvious, kidney function may have already declined by more than 70%. Below are common symptoms in cats with kidney disease that owners should watch for closely:

1. Increased Thirst and Urination (Earliest Warning Sign)

This is the most common early symptom of feline chronic kidney failure. When the kidneys cannot effectively concentrate urine, cats will produce large amounts of dilute urine and need to drink more water to compensate. If you notice your cat:

• Drinking noticeably more water
• Larger or more frequent urine clumps in the litter box
• Lighter coloured urine

You should bring your cat for a kidney function test as soon as possible.

2. Weight Loss

Cats with kidney disease often experience muscle wasting and gradually become thin even with normal food intake. This is because the body cannot effectively utilise nutrients, and toxin accumulation affects metabolism.

3. Decreased Appetite and Vomiting

Uraemic toxin accumulation causes nausea, vomiting, and decreased appetite. Your cat may:

• Lose interest in previously favourite foods
• Vomit after eating
• Vomit white foam or yellow bile

4. Bad Breath and Mouth Ulcers

Uraemia causes an ammonia-like odour (similar to urine smell) in the mouth, and severe cases may develop mouth ulcers and red gums. This indicates cat kidney failure symptoms have progressed to mid-to-late stages.

5. Dull and Rough Coat

Cats with kidney disease have poor nutrient absorption and dehydration, causing their coat to become dry, dull, and lacklustre, with possible excessive shedding.

6. Lethargy and Excessive Sleeping

Toxin accumulation makes cats feel tired and listless, with reduced activity levels and spending most of their time sleeping.

7. Other Late-Stage Symptoms

• Anaemia: Gums and tongue become pale
• Constipation: Dehydration causes dry, hard stools
• Seizures: Severe manifestation of electrolyte imbalance
• Vision Problems: Retinopathy caused by hypertension

The 4 Stages of Feline Chronic Kidney Failure

Feline chronic kidney failure is classified into four stages by the International Renal Interest Society (IRIS), primarily based on blood creatinine and SDMA levels:

*SDMA is a newer kidney marker that can detect kidney function abnormalities earlier than creatinine

Feline Kidney Disease Diagnostic Methods

Veterinarians diagnose cat kidney failure through multiple examinations:

Blood Tests

• Creatinine (CRE): Reflects the kidney's ability to filter waste
• Blood Urea Nitrogen (BUN): Concentration of nitrogenous waste in the blood
• SDMA: Symmetric dimethylarginine, can detect kidney disease earlier
• Phosphorus: Cats with kidney disease often have elevated blood phosphorus
• Potassium: Electrolyte balance assessment
• Red Blood Cell Count: Assesses whether renal anaemia is present

Urinalysis

• Urine Specific Gravity: Normal cat urine specific gravity should be > 1.035; cats with kidney disease have dilute urine
• Urine Protein/Creatinine Ratio (UPC): Assesses degree of proteinuria
• Urine Sediment: Checks for infection or crystals

Imaging Examinations

• Ultrasound: Observes kidney size, structure, and presence of stones or tumours
• X-ray: Assesses kidney size and position

Blood Pressure Measurement

Cats with kidney disease often develop hypertension. Normal cat blood pressure should be below 160 mmHg; values above this require medication control.

Feline Kidney Disease Treatment Methods

The goal of cat kidney disease treatment is to slow disease progression, control symptoms, and maintain quality of life. Treatment plans vary according to disease stage:

Fluid Therapy

Fluid supplementation is the foundation of cat kidney disease treatment:

• Hospitalised Intravenous Fluids: Used during acute deterioration or severe dehydration
• Subcutaneous Fluids: Can be administered at home during stable periods, injecting 100–150ml of saline daily or every other day

Subcutaneous fluids effectively dilute toxins in the body and improve dehydration, making it an important part of daily care for cats with kidney disease.

Dietary Management

Prescription renal diets are key to controlling the condition:

• Low Phosphorus: Reduces phosphorus intake to slow kidney function deterioration
• Moderate High-Quality Protein: Uses highly digestible protein to reduce nitrogenous waste production
• Low Sodium: Controls blood pressure
• High Moisture: Wet food is preferred over dry food to increase water intake
• Added Omega-3: Anti-inflammatory and kidney-protective

Common prescription diet brands include Hill's k/d, Royal Canin Renal, and Purina NF.

Medication

Based on cat kidney failure symptoms and complications, veterinarians may prescribe the following medications:

6 Key Points for Daily Care of Cats with Kidney Disease

In addition to medical treatment, daily care by owners is equally important for managing feline chronic kidney failure:

1. Increase Water Intake

• Feed primarily wet food; dry food can be soaked in water
• Set up a water fountain to encourage drinking
• Place multiple water bowls in different locations around the home
• Add unsalted chicken or fish broth to increase drinking interest
• Learn home subcutaneous fluid administration techniques when necessary

2. Dietary Management

• Follow veterinary advice to transition to prescription renal diet
• Avoid high-phosphorus foods (such as organ meats, sardines, cheese)
• Feed small, frequent meals, 4–6 times daily
• Slightly warming food can enhance aroma and improve appetite

3. Regular Follow-up Monitoring

• Blood tests every 1–3 months to monitor kidney values
• Regular blood pressure measurements
• Record daily water intake, food consumption, and weight

4. Reduce Stress

• Maintain a stable living environment
• Use pheromone (Feliway) spray to reduce stress
• Provide a quiet, comfortable resting space

5. Keep Warm

Cats with kidney disease are more sensitive to cold. Provide warm blankets or heating pads, especially in winter.

6. Accessible Environment

Cats with kidney disease may be weaker. Ensure litter boxes, food, and water bowls are placed in easily accessible locations, avoiding the need to jump or climb.

How to Prevent Feline Kidney Disease?

Prevention is better than cure. The following measures can help reduce the risk of cat kidney failure:

Regular Health Examinations

• Cats under 7 years: Annual blood tests
• Cats 7 years and older: Blood tests every 6 months
• Establish baseline values for future comparison

Ensure Adequate Hydration

• Provide fresh, clean water sources
• Feed more wet food to increase water intake
• Monitor daily water intake and urination patterns

Balanced Diet

• Choose quality cat food; avoid long-term high-phosphorus diets
• Don't blindly pursue high protein; protein quality matters more than quantity
• Avoid feeding human food and high-salt treats

Maintain Healthy Weight

Obesity increases the risk of diabetes, which can lead to kidney failure. Maintaining your cat's ideal weight is an important step in protecting their kidneys.

Avoid Exposure to Toxins

• Lilies are highly toxic to cats and can cause acute kidney failure
• Avoid exposure to antifreeze and certain human medications
• Store cleaning agents and chemicals safely

Feline Kidney Disease FAQs

Petcore Veterinary Clinic Kidney Disease Diagnosis & Treatment Services

Petcore Veterinary Clinic provides comprehensive cat kidney disease diagnosis and treatment services:

• Kidney Function Blood Tests: Comprehensive assessment of creatinine, BUN, SDMA, phosphorus, and electrolytes
• Urinalysis: Urine specific gravity and proteinuria testing
• Ultrasound Examination: Assessment of kidney structure and size
• Blood Pressure Monitoring: Screening for kidney disease-related hypertension
• Fluid Therapy: Hospitalised intravenous fluids and home subcutaneous fluid guidance
• Medication Prescriptions: Phosphate binders, anti-emetics, antihypertensives, etc.
• Prescription Diet Advice: Assistance in selecting appropriate renal prescription diets

Contact Us

• Yuen Long Clinic: G/F, 30A Fuk Tak Street, Yuen Long, N.T. | Phone: 2394-7300
• Sai Kung Clinic: Shop 2, 66 Yi Chun Street, Sai Kung, N.T. | Phone: 2394-4228
• WhatsApp: 9889-5518
• Website: www.petcore-vet.com

If you notice your cat showing cat kidney disease symptoms such as increased thirst and urination, weight loss, or vomiting, please bring your cat to a veterinary clinic for examination as soon as possible. Early detection and active treatment are key to extending the life of cats with kidney disease. The professional team at Petcore Veterinary Clinic is dedicated to providing the best medical care for your beloved cat.