Medically reviewed by Dr. Erica Irish, DVM
My 12-year-old Labrador retriever has chronic renal failure. In hindsight, the early signs were there. However, I attributed her increased thirst and urination to an unusually hot summer. Of course she was thirsty! We’d been outside playing.
That’s what I told myself.
How the Diagnosis of Chronic Renal Failure Was Made
It wasn’t until a scheduled professional dental cleaning that I learned the truth. Chronic kidney disease. Before being anesthetized, my girl underwent standard blood tests to ensure there weren’t any underlying diseases or conditions that would make general anesthesia riskier.
Her age was already a risk factor, but I wasn’t expecting the call I received from the veterinarian that day.
I listened to a lengthy explanation of the disease including jargon and numerical values that meant nothing to me.
All I wanted to know was how long she had to live.
Unfortunately, there is no standard answer to that question. Chronic kidney disease is progressive. How quickly it progresses depends on the dog, the treatment options chosen, and any other conditions a dog may have.
It’s been seven months since the initial diagnosis. At that time, she was in the early stage of the disease. Since then, her muscles have begun wasting, she is drinking more, and she sometimes loses her appetite. A recent complete blood count show that she is stable, for now.
Does Your Dog Have Signs of Kidney Disease?
Kidney disease is really complicated. Unfortunately, a lot of damage can be happening without you even noticing. Usually by the time dogs are diagnosed with chronic kidney failure, the condition has progressed to a more advanced stage.
The clinical signs of kidney disease include:
- weight loss
- poor appetite or loss of appetite
- pale gums due to anemia
- bad breath (may have a chemical smell)
- vomiting
- increased water intake
- increased or decreased urination
- ulcers in the mouth
- uncoordinated movements like stumbling
- blood in the urine
- swelling in the legs, belly and face
Most symptoms tend to occur in the later stages of the disease.
Let’s Talk About Chronic Kidney Disease in Dogs
Before we dive any deeper into this post, you should know that the terms kidney failure and kidney disease are used interchangeably.
The Mechanics of Kidney Function and Why It’s Important
The kidneys are needed to filter waste products from the blood. These waste products are excreted through the urine. The kidneys also help regulate fluid balance and blood pressure. They produce hormones that regulate red blood cell production and promote bone health.
Blood is filtered through cluster of blood vessels known as the glomeruli. Any waste products or excess fluids are then excreted as urine through the ureters. The ureters connect the kidneys to the bladder.
The bladder is essentially the holding tank for the urine until emptied.
As the dog’s kidneys fail, they can no longer filter waste products effectively from the blood. This causes a buildup of toxins in the body. More water is lost through the kidneys because the feedback loop to reabsorb water is altered.
The Progression of Chronic Kidney Disease in Dogs
Over time, dogs with chronic kidney disease (CKD) gradually lose kidney function. Unfortunately, by the time a dog is diagnosed with the disease, over 75% of kidney function may already be lost. Sadly, there is no way to regain lost function for dogs with chronic kidney disease.
Dogs with acute kidney failure have a better chance of regaining some lost function.
There’s no cure for chronic renal failure in dogs. A kidney transplant may be an option depending on your geographical location. That said, cats seem to fare better with transplants compared to dogs.
It will get worse over time, but there are ways to help slow the progression. Before we discuss the treatment options, however, let’s look at some potential causes and how the disease is diagnosed.
Potential Causes of Chronic Renal Failure in Dogs
There are several potential causes of chronic kidney disease (also called chronic renal failure) in dogs. The exact cause can be difficult to pinpoint and is usually irrelevant by the time the dog is diagnosed.
That said, dogs with acute kidney failure can be treated.
The following are some potential causes of the chronic kidney disease in dogs:
Age
Sadly, as our dogs age, their organs simply begin to wear out. This is seen in older dogs and is considered a normal part of aging. Senior dogs may experience something called “geriatric degeneration”. This occurs when cells within the kidneys break down and die as your dog ages. This can lead to kidney disease.
Genetics
Some breeds of dogs may be genetically predisposed to chronic renal failure. These include the Basenji, the Samoyed, and the Cocker Spaniel.
Toxicosis
A dog’s kidneys can become damaged from ingesting toxic substances, including drugs or poisons. This includes substances or foods that are toxic to dogs.
Other potential toxins include the overuse of non-steroidal anti-inflammatory drugs (NSAIDS)
Bacterial Infection
Does your dog drink out of the ditch or other stagnant water sources? Contaminated water can lead to bacterial infections such as leptospirosis.
Renal Cancer
Renal cancers like lymphoma and adenocarcinoma can cause chronic renal failure in dogs.
Exposure to Tick-Borne Disease
According to a recent study by IDEXX, dogs exposed to Lyme disease have a 43 percent higher risk of developing kidney disease. The black-legged tick and the western black-legged ticks are the parasites responsible for transmitting Lyme disease to dogs and people.
Advanced Dental Disease
Bacteria builds up on the teeth and gums if not professionally cleaned. The bacteria accumulate and eventually enter the bloodstream, where they can attack multiple organs. Sadly, this causes irreversible damage to the kidneys, liver, and heart.
The Difference Between Chronic vs Acute Renal Failure in Dogs
Chronic kidney failure in dogs involves is a progressive disease where the kidneys lose function over time and acute renal failure (ARF) involves the sudden loss of kidney function.
You can also have something called “acute on chronic” kidney disease. Sometimes, treatments can get dogs out of the acute phase and back to just managing the chronic phase.
Acute kidney failure is caused by a sudden injury to the kidneys, which results in the kidneys’ inability to function properly. Despite advances in acute kidney injuries, the fatality rate for dogs remains as high as 45% to 60% (Acute Kidney Failure in Dogs, n.d.)
Diagnosing Chronic Renal Failure in Dogs
There are several tests a veterinarian can use to detect kidney failure in dogs. That said, it’s important to note that a complete blood count and urinalysis often don’t register changes until the dog has lost approximately 75% of kidney function.
Physical Examination
The veterinarian will examine the dog, looking for signs of dehydration and weight loss.
Complete Blood Count
A complete blood count (CBC) examines the red blood cells, white blood cells, and platelets. A decrease in red blood cell production may reflect in the CBC as anemia. If the underlying cause of the kidney disease is an infection or inflammation, the white blood cell count may rise.
Urine Tests
Urinalysis can help identify specific kidney markers including:
- Blood urea nitrogen (BUN): Blood urea nitrogen is a by-product of protein metabolism and higher values can indicate kidney disease.
- Creatine levels can tell how well the kidneys are able to filter waste from the blood.
- Phosphorus levels indicate how much kidney damage has taken place. When kidneys cannot filter excess phosphorus out of the body, it builds up in the blood stream. High phosphorus can be temporary, and if your vet puts your dog on phosphorus binders, this can help clear excess phosphorus through the GI tract, making nausea less likely for CKD patients.
Urinalysis can also measure electrolytes and urine specific gravity which indicates how diluted or concentrated the urine is. The veterinarian may also recommend a urine protein to creatinine ratio to determine how much protein is being lost in the urine.
Since dogs with chronic renal failure are more likely to develop a urinary tract infection, a urine culture may also be recommended.
- Symmetric dimethylarginine (SDMA) is an additional test that can be used to detect early signs of kidney disease. This parameter is able to detect kidney disease sooner because it can detect changes sooner. It’s considered six times more sensitive than creatinine. The test, however, isn’t available in all labs.
Imaging Studies
X-rays, ultrasound, or computed topography (CT Scan) can help screen for kidney stones or areas of dead tissue. It’s also used to look for signs of cancer or tumors in the kidneys. These tests are recommended occasionally.
Biopsy
A biopsy can help confirm the diagnosis of kidney failure in dogs, especially with respect to cancer.
Stages of Kidney Disease in Dogs
After a dog has been diagnosed with chronic renal failure, an assessment on how far the disease has progressed is done. This assessment helps to determine the treatment options.
The International Renal Interest Society (IRIS) has established a staging system based on the severity of the disease.
There are four stages of chronic renal disease (with four being the most severe). Your pet will typically exhibit more symptoms as disease progresses.
There’s no exact timeline on how rapidly the disease will progress. The following timeline is by no means linear. In fact, some dogs can jump through stages (forward and backward) and many dogs go on to live for years with treatment.
Median survival time is up to 400 days. At this stage your dog may not be showing any signs of kidney failure.
Stage 2
Median survival time can be anywhere from 200 to 400 days. Again, clinical signs of kidney disease may not be obvious at this stage. As the disease progresses, you may notice your dog is drinking more water than usual and is urinating more frequently.
Stage 3
At stage 3, median survival time is anywhere from 110 to 200 days. At this stage, your dog may have increased thirst, urination, lethargy, vomiting, diarrhea, weight loss, loss of appetite and dehydration. However, not all dogs will all have all of these symptoms.
Chronic renal failure is a progressive disease. For that reason, symptoms will gradually worsen as time goes by. Treatment options (below) may help slow the progression.
Stage 4
With each stage of the disease, the prognosis gets worse, and the survival time gets shorter. According to IRIS, the median survival time for stage 4 kidney disease ranges from 14 to 80 days.
Treatment Options for Dogs with Chronic Renal Failure
Treatment options will depend on the stage at which the dog is diagnosed with kidney disease. Initially, the veterinarian may recommend dietary changes to ease the workload of the kidneys.
Follow-up appointments with blood work and urinalysis will help the veterinarian determine whether the disease has progressed. As this happens, the treatment options may change.
Dietary Changes
A renal diet low in protein and phosphorus may help slow the progression of kidney failure in dogs. In some cases, the veterinarian may suggest a prescription diet for your dog.
Medications
There are a few different medications that may be prescribed at different stages of the disease including high blood pressure medication, appetite stimulants, anti-nausea medication, diuretics, phosphate binders, and omega-3 fatty acid supplements.
Fluid Therapy
In some cases, fluid therapy may be used to help flush toxins from the body and maintain hydration. It can be performed subcutaneously (under the skin) or intravenously (through a vein).
When To Euthanize a Dog with Kidney Failure
Sadly, the time will come when managed treatment of kidney disease isn’t effective anymore. At this stage, your dog will not want to eat any food offered, including his or her favorite treats. You’ll be able to tell that your long-time companion is not feeling well at all.
Unfortunately, there’s no turning back. Once all treatment options fail to relieve the symptoms of kidney disease, it may be time to consider euthanasia.
This decision is extremely hard on dog owners and should be discussed with the veterinarian. It’s important for pet owners to know their options, including what will happen next.
How Do You Know When It’s Time
The veterinarian will be honest with you about the quality of life your dog can expect when he or she reaches the end stages of kidney failure. To help you on this decision, ask yourself the following questions about your dog’s current health:
- Does my dog want to play anymore?
- Does my dog interact with me or acknowledge my presence?
- Does my dog still have an appetite, or has he/she stopped eating?
- Is my dog showing signs of pain (hiding, trembling, shaking, etc.)?
- Is my dog sleeping most of the time?
- Is my dog still able to drink?
- Is my dog vomiting?
- Does my dog have diarrhea?
- Can my dog urinate?
- Does my dog seem dull and depressed?
Sometimes, a dog may just be having a bad day. However, if your dog has reached the end-stage of renal failure, you’ll be able to see a consistent decline in all aspects of health.
Speak with the veterinarian about assessing your dog’s quality of life. It won’t make the decision to euthanize easier, but it may give you some comfort in knowing when the time has come.
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Conclusion
Dog with chronic renal failure require close monitoring and management. Unfortunately, there is no cure for this condition, but early diagnosis and treatment may help slow the progression of the disease while improving quality of life.
Kidney disease is complicated and will affect dogs differently. It’s important to maintain follow-up appointments with the veterinarian so that adjustments can be made in the treatment plan. Ultimately, the important thing is to help your dog maintain a good qualify of life for as long as possible.
As for my beautiful, 12-year-old Labrador retriever? Recent blood work and urinalysis show that she is stable, for now. I wish you and your beloved dog all the best.
Resources Used
“Acute Kidney Failure in Dogs.” Embrace Pet Insurance, www.embracepetinsurance.com/health/acute-kidney-failure-in-dogs. Accessed 23 Jan. 2023.
Rimer, Dar, et al. “Acute Kidney Injury in Dogs: Etiology, Clinical and Clinicopathologic Findings, Prognostic Markers, and Outcome.” PubMed Central (PMC), 1 Feb. 2022, https://doi.org/10.1111/jvim.16375.
“Testing for Kidney Disease | VCA Animal Hospital.” Vca, vcahospitals.com/know-your-pet/kidney-disease-testing. Accessed 23 Jan. 2023.
“Renal Failure in Dogs: Causes, Symptoms and Treatment | Flat Rock Emergency Vet | Western Carolina Regional Animal Hospital & Veterinary Emergency Hospital.” Renal Failure in Dogs: Causes, Symptoms & Treatment | Flat Rock Emergency Vet | Western Carolina Regional Animal Hospital & Veterinary Emergency Hospital, www.wcrah.com/site/blog-flat-rock-vet/2021/05/17/renal-failure-dogs. Accessed 24 Jan. 2023.
“Quality of Life at the End of Life for Your Dog | VCA Animal Hospital.” Vca, vcahospitals.com/know-your-pet/quality-of-life-at-the-end-of-life-for-your-dog. Accessed 24 Jan. 2023.
“Appetite Stimulants in Chronic Kidney Disease.” The Veterinary Nurse, 2 Sept. 2018, www.theveterinarynurse.com/review/article/appetite-stimulants-in-chronic-kidney-disease.