The IRIS Stages of Kidney Disease in Dogs

Ensuring the health and happiness of our canine companions is a top priority for responsible pet owners. Kidney disease is a significant challenge among the various health concerns that can affect dogs.

To ensure proactive care and early intervention, one must understand dog kidney failure stages, from subtle symptoms to life-threatening conditions.

This blog navigates you through the intricate landscape of kidney disease in dogs. It discusses everything you need to know about canine renal health, including causes, symptoms, dog kidney failure treatment, and how to prevent its development.

What Causes Kidney Failure in Dogs?

Several factors can contribute to the development of kidney failure in dogs:

• Age: Older dogs are more prone to kidney disease as organs naturally decline with age.
• Genetics: Certain breeds, such as Cocker Spaniels, German Shepherds, and Doberman Pinschers, may have a genetic predisposition to kidney issues.
• Toxicity: Ingesting certain toxins, such as antifreeze, grapes, raisins, and certain medications, can damage your dog’s kidneys.
• Infections: Leptospirosis and other bacterial infections can attack your dog’s system and cause the kidneys to inflame, leading to renal failure.
• Chronic dehydration: Your canine companion can also develop kidney failure due to inadequate water intake.
• Dental disease: Bacteria build-up in your dog’s teeth and gums can lead to advanced dental disease. The bacteria can enter your pet’s bloodstream, potentially causing more damage to other organs.

Symptoms of Dogs with Kidney Disease

It’s best to recognize the signs of kidney failure early on to provide timely and appropriate intervention. Common symptoms include:

• Significant increase or decrease in thirst and urination
• Appetite loss
• Weight loss
• Lethargy and weakness
• Vomiting and diarrhea
• Bad breath with an ammonia-like odor
• Pale gums
• Difficulty urinating or bloody urine
• Seizures
• Loss of balance

Categories of Dog Kidney Failure

Chronic Renal Failure

This condition is characterized by the gradual loss of kidney function over an extended period, usually months to years. It is more common in older dogs and is associated with aging or underlying health conditions, such as kidney infections, immune-mediated diseases, genetic predisposition, or long-term exposure to toxins.

While most dogs can’t fully recover from chronic kidney failure, it can be managed so your pet enjoys a good quality of life for many months or years.

Acute Renal Failure

Acute kidney failure is a sudden and severe decrease in kidney function that occurs over a short period. Various factors, such as bacterial infections, urinary tract obstruction, severe dehydration, or trauma, often cause it. However, it can also result from ingesting toxins, such as antifreeze, certain medications, grapes, or raisins.

Acute renal failure’s primary difference with its chronic countertype is it can often be cured if diagnosed and treated early.

What are the IRIS Dog Kidney Failure Stages?

Veterinarians commonly use the International Renal Interest Society (IRIS) staging system to classify the severity of kidney disease in dogs. Depending on the stage of kidney disease, treatment may include dietary modifications, fluid therapy, medications to manage symptoms, and supportive care to improve your pet’s quality of life.

Stage 1: Subclinical

Dogs with kidney disease involve the kidneys functioning at a reduced capacity, but clinical signs may not be apparent. Laboratory tests may reveal slight elevations in blood creatinine or abnormalities in urine tests. Your pet may have Stage 1 kidney disease if they have a normal creatinine but also have:

• Dilute urine
• Kidneys that feel abnormal on exam
• Kidneys that look abnormal on ultrasound
• Abnormally high amounts of protein within the urine

Stage 2: Mild

Canines in this stage may begin to show mild clinical signs, such as increased thirst and urination, mild weight loss, or a slightly decreased appetite. Blood tests may reveal higher levels of creatinine and other waste products, indicating reduced kidney function. Urine tests may also show abnormalities, such as dilute urine or proteinuria.

Stage 3: Moderate

This stage significantly compromises your dog’s kidney function, leading to more pronounced clinical signs. Dogs may experience moderate to severe dehydration, vomiting, diarrhea, lethargy, and muscle weakness. Blood tests often show higher levels of creatinine and other waste products, while urine tests may reveal further abnormalities, such as concentrated urine.

Stage 4: Severe

Severe renal dysfunction and a marked decline in overall health are significant characteristics of Stage 4 kidney disease. Other symptoms of this stage include profound lethargy, anorexia, weight loss, vomiting, diarrhea, and difficulty breathing. Urine tests often show severe abnormalities, including marked proteinuria and dilute urine. Blood tests will often result in significantly elevated levels of creatinine and other waste products, indicating severe impairment of kidney function.

Creatinine and SDMA

Two substances, creatinine and symmetric dimethylarginine (SDMA), help veterinarians determine the severity of your pet’s kidney disease.

Creatinine appears in the blood as a result of muscle activity. The kidney excretes it at a constant rate and can be used to assess other substances' excretion rates. Meanwhile, SDMA is a compound that rises in the blood in kidney disease earlier than creatinine. It can help detect kidney disease when as little as 25-40% of kidney function is lost.

The IRIS guidelines divide the progression of kidney failure into four sequential stages, with varying creatinine and SDMA levels.

There can be instances when creatinine levels put your dog in one stage and SDMA in another. IRIS guidelines remind vets that creatinine levels can be influenced by muscle mass, so dogs that have lost significant muscle can have inaccurate creatinine levels, which can underestimate the severity of their condition. 

With the discrepancy between the two tests, IRIS guidelines recommend retesting in two to four weeks. Once retested, and the values still place your canine companion in two different categories, it is recommended that they be assigned to the higher stage.

Dog Kidney Failure Treatment

Treating dogs with kidney disease aims to manage their symptoms, slow the condition’s progressions, and improve their overall quality of life.

• Dietary changes: To reduce the workload on the kidneys, opt for a diet low in phosphorus and high in protein.
• Fluid therapy: Your pet may receive intravenous fluids to maintain hydration and flush out toxins.
• Medications: Phosphate binders, anti-nausea drugs, and blood pressure medications may be prescribed by your veterinarian to manage symptoms.
• Supportive care: Nothing compares to regular monitoring, supplements, and supportive therapies to alleviate discomfort and address other health issues.

What Can I Do to Protect My Dog from Renal Failure?

Reduce the risk of kidney failure in dogs by following these tips:

• Provide fresh water: Prevent dehydration by ensuring your pet has constant access to clean and fresh water.
• Maintain a balanced diet: Feed your dog a high-quality, balanced diet appropriate for its age and breed. Consult your veterinarian to learn more about your dog's specific needs.
• Regular veterinary check-ups: Schedule regular visits to your veterinarian to ensure everything is in good condition, especially kidney function. Doing so also detects issues early on.
• Avoid toxins: Keep harmful substances, plants, and medications away from your dog to avoid accidental ingestion.
• Consider fish oil supplements: Fish oil is rich in omega-3 fatty acids and has been shown to have anti-inflammatory properties to support kidney health in dogs.

Protect Your Pet’s Renal Health

Ensure your furry friend’s well-being with early detection and proactive management. Be vigilant of the signs of kidney disease and understand its various stages. By implementing preventive measures, you can make a profound difference in your dog’s health and quality of life, ensuring they have a long and comfortable time with you.

Remember to seek guidance and support from your veterinarian as you navigate your dog’s renal health journey. With love, care, and informed decision-making, you can provide the best for your canine companion.

Learn more about your dog’s health by visiting the Stryde blog.