Learning that your dog has kidney disease can be a stressful time in any pet owner’s life. Whenever there is something wrong with a major organ, there is definitely a cause for alarm. The kidneys are often overlooked despite their life-sustaining attributes that are vital for nearly every living creature to exist. Before we discuss kidney disease in dogs, let’s first revisit exactly what the kidneys are and why they are so crucial for survival.
Things You Should Know About the Kidneys
The kidneys play an important role in overall health, but we rarely appreciate this organ pair until damage causes them to be unable to perform their jobs properly.
Where Are The Kidneys?
Dogs have two kidneys that are located atop of the bladder, along the spine in the abdomen.
What Do Kidneys Do?
You may be surprised to learn that a dog’s kidneys have very similar roles to their owner’s kidneys.
- The kidneys remove wastes and extra fluids from the body. The wastes and extra fluids become urine which is stored in the bladder until the dog goes to the bathroom. If the kidneys did not rid the body of these wastes, the toxicity would build up in the dog’s body and cause severe, often irreversible, harm to your four-legged friend.
- The kidneys also control blood pressure. By controlling fluid levels and producing hormones that cause blood vessels to constrict, the kidneys are able to increase or decrease the blood pressure based on what the dog needs.
- Additionally, the kidneys produce a hormone called erythropoietin that encourages red blood cell production. Red blood cells carry oxygen from the lungs to the rest of the body. Red blood cells are also needed to produce energy for your dog’s normal, day-to-day activities.
- The kidneys also produce an active form of Vitamin D. Vitamin D is necessary for the bones to absorb calcium and phosphorus. These minerals are responsible for making sure the bones are strong and healthy.
- Finally, the kidneys regulate pH levels. When cells break down they become acids. Food can alter these acids causing them to be too high or too low. The kidneys balance the pH levels in the body by removing or adjusting the level of acids.
As you can see, the kidneys are extremely vital for life and when they don’t work properly, things can start to deteriorate very quickly.
What is Kidney Disease in Dogs (aka Renal Disease)
Any condition that damages the kidneys is referred to as kidney or renal disease. In some instances, dogs may show early signs of kidney disease. However, in most cases, clinical signs of the disease only surface after the dog has already lost approximately 75% of kidney function.
This staggering number leaves the majority of dogs fighting for their lives once a diagnosis is finally made. With that being said, early detection of kidney disease, before it develops into a progressed stage of kidney disease (kidney failure), can be the difference between life and death for your dog.
We should also mention that the terms kidney disease and kidney failure are often used interchangeably. There are four stages of kidney disease. Commonly, people will refer to the first two stages of the condition as kidney disease, due to the fact that it can often be reversed at that point, and the last two stages as kidney failure, as many times the condition is irreversible and the dog’s life is in danger.
Renal is defined as relating to, affecting, involving, or located in the region of the kidneys. The terms renal disease and renal failure are often used interchangeably with kidney disease and kidney failure.
General Kidney Disease Symptoms
In the beginning stages of kidney disease, most dogs do not show any symptoms of the condition. Some pet owners usually notice that their dog is much more water than usual as the dog tries to rid its body of the excess toxins that the kidneys are not able to remove. Eventually, the excess toxins reach a level that extra water intake is not able to flush out.
Pet owners will often not notice symptoms of kidney disease until the condition reaches stage 3 (of 4 total stages). When this occurs, pet owners will likely see the following symptoms:
- Increased urine production (caused by the increased thirst)
- Loss of appetite
- Weight loss
- Bad breath
- Sore mouth
- Lack of energy
- Increased sleeping
- Poor or dull coat appearance
Causes of Kidney Disease in Dogs
A number of factors can contribute to a dog developing kidney disease. The specific causes of the renal disease are also dependent on which type of kidney disease the dog has.
These factors include:
- Poor quality or processed dry food diets
- Congestive heart failure
- High blood pressure
- Blood loss
- Kidney trauma
- Kidney stones
- Blood clots in the kidneys
Additionally, studies show that the following factors make dogs more prone to kidney disease.
The probability of dogs developing kidney problems increases after the age of seven.
Studies have found that dog food with high levels of phosphorus and increased levels of protein can further the progression of kidney disease.
Research shows that some breeds are at a predisposition for developing certain types of canine kidney disease.
The breeds predisposed to chronic renal disease include:
- Bull Terrier
- Cairn Terrier
- German Shepherd
- English Cocker Spaniel
Additionally, abnormal kidney growth due to genetics (known as renal dysplasia) is seen in the following breeds more so than others:
- Shih Tzu
- Lhasa apso
- Golden retriever
- Norwegian elkhound
- Chow chow
- Standard Poodle
- Soft-coated Wheaten Terrier
- Alaskan malamute
- Miniature Schnauzer
- Dutch Kooiker
Environmental toxins such as chemicals, certain disinfectants, lead paint, antifreeze, human medications, among many others have the potential to not only damage the kidneys but cause irreversible damages if ingested.
Types of Kidney Disease in Dogs
If your veterinarian diagnoses your dog with kidney disease, most likely, they will next diagnose your dog with either acute kidney disease or chronic kidney disease.
Acute Kidney Disease in Dogs (AKD)
Acute kidney disease happens when there is an abrupt decline in kidney function. This sudden decline can happen within a matter of days. AKD occurs as a result of a dog ingesting toxins such as antifreeze, medications meant for humans, poisons, among others.
Additional problems such as decreased blood flow, decreased oxygen delivery to the kidneys, infections and urinary obstruction can also lead to acute kidney disease.
Most of the time, these kidney problems have specific causes that a veterinarian will be able to pinpoint and treat appropriately.
Chronic Kidney Disease in Dogs (CKD)
Chronic kidney disease (CKD) is more difficult to diagnose because the disease slowly progresses over a period of months or even years. Therefore, the underlying cause is challenging to pinpoint and treat.
What does Chronic Mean?
Chronic refers to the illness persisting for a long time. Chronic can also mean that the illness is constantly recurring.
What is Chronic Renal Insufficiency or Renal Failure
Chronic renal insufficiency and renal failure are two other ways that veterinarians may refer to chronic kidney disease in dogs.
What Causes Chronic Kidney Disease in Dogs?
CKD can occur from the same factors that cause acute kidney disease. Additionally, inherited tendencies and specific breeds, in coordination with immune system defects and nutritional deficiencies, can also cause chronic kidney disease in dogs.
Pet owners may be surprised to learn that one of the main causes of chronic kidney disease in dogs is actually a dental disease. In advanced cases of dental disease, the oral bacteria enters the bloodstream and invade the organs. This bacterial invasion causes irreversible damage to the heart, liver, and kidneys.
Furthermore, there is a group of veterinarians (The International Renal Interest Society or IRIS) who have been studying and specializing in kidney disease in dogs and cats. IRIS made a list of risk factors that make pets more susceptible to developing chronic kidney disease.
These factors include:
- Glomerulonephritis (acute inflammation of the kidneys)
- Pyelonephritis (kidney infection)
- Nephrolithiasis (kidney stones)
- Ureteral obstruction & hydronephrosis (stones causing a blockage)
- Tubulointerstitial disease (involving the kidney tubules)
- Amyloidosis (protein problem)
- Hereditary nephropathies (genetic issue)
Chronic Kidney Disease Symptoms
Symptoms of CKD are comparable to the general symptoms associated with kidney damage and include:
- Urinary incontinence (urine leakage)
- Reduced appetite
- Weight loss
- Bad breath with a chemical odor
- Oral ulcers
- Pale appearance
Stages of Kidney Disease
There are four stages of chronic kidney disease in dogs.
- In Stage 1 of chronic kidney disease, the kidney function has decreased enough to allow toxins to build up in the dog’s body. However, the toxicity in the blood has not yet reached dangerous or irreversible levels.
- Stage 2 of chronic kidney disease usually doesn’t cause any symptoms but there is toxicity in the blood. While damage has certainly been done, it is not irreversible at this point.
- In Stage 3 of chronic kidney disease, the dog will show symptoms of the disease. Remember, when a dog starts showing signs of the disease, the dog has already lost approximately 75% of liver function.
- Stage 4 of chronic kidney disease occurs when the liver damage continues to progress and more and more symptoms begin appearing. Many vets consider stage 3 and stage 4 of kidney disease one in the same.
What is Stage 3 Kidney Disease in Dogs?
Stage 3 kidney disease in dogs is one of the final stages of the illness and often when pet owners will first begin seeing clinical signs of kidney failure. More times than not, by stage 3 of kidney disease, the damage is irreversible.
This concept is terrifying for owners. How could it be possible that for the last several months (even years) your dog’s kidneys have been losing function and you had no idea? We understand the frustration and fear.
Kidney disease can show up unannounced and without much say in the matter. Again, this is why it is so important for dog owners to recognize the signs of early stage kidney disease (if they appear) so they can act quickly.
Stage 3 Kidney Disease Symptoms
Your dog probably won’t show many (if any) signs of kidney disease until it reaches stage 3. Therefore, if you do see any of the symptoms we are about to discuss, it is critical for your dog to see a veterinarian immediately.
In most cases, pet owners will first notice that their dog is urinating much more than usual. This is because the kidneys are desperately trying to rid the body of the built up toxins. The dog will also seem to constantly be thirsty due to the increase of urination.
Dogs with stage 3 kidney disease will also show the following signs:
- Oral lesions
We cannot stress enough that if your dog is showing any symptoms of stage 3 kidney disease, up to 75% of kidney function may already be lost. Your dog’s life depends on getting medical intervention ASAP.
What is Kidney Failure in Dogs / What is Renal Failure
As a reminder, kidney failure and renal failure are used interchangeably as renal means “of or relating to the kidneys.”
As with the beginning stages of kidney disease, renal failure is also categorized as either acute or chronic. In both types, immediate treatment is necessary and often the damage will not be able to be reversed.
General Renal Failure Symptoms
- Anemia (pale gums and weakness)
- Dehydration (with a sudden and increased thirst)
- Increase in urination and/or trouble urinating
- Loss of appetite and weight loss
- Vomiting and/or diarrhea
- Fluid accumulation, causing swelling in the abdomen and limbs
- Changes in the kidneys (enlarged or small and irregular)
- Abdomen tenderness
- Hunched over posture, reluctance to move
- Withdrawal behavior
Acute Kidney Failure Symptoms
Acute kidney failure symptoms develop quickly and can be severe. The most prevalent symptoms to look out for are:
- Complete loss of appetite
- Marked lethargy
Additionally, dog owners may also see the following symptoms which are also clinical signs of acute kidney failure:
- Straining to urinate
- Decreased urine production
- Lack of coordination
- Physical weakness
Dogs may also exhibit any of the general renal failure symptoms listed above.
Acute renal (kidney) failure is classified as a medical crisis. Therefore, if you see any of these symptoms in your dog, take them to an emergency animal clinic immediately.
Chronic Renal Failure Symptoms
A strong indication of chronic renal failure (CRF) is urine that is either concentrated or diluted or abnormal in some other way. The abnormal urine is an indication that the kidneys are not able to process the urine correctly.
Other symptoms of chronic renal failure include:
- Increased thirst
- Increased urination
- Decreased urination or lack of urination
- Urinating in the night
- Mouth ulcers
- Bad breath
- Small, enlarged, or painful kidneys
- Bloody urine
- Anorexia leading to weight loss
Again, chronic renal failure happens over time, often several months or even years. The kidneys are designed to be able to work even as they slowly lose function. Therefore, when symptoms do arise, the disease is already in its end stages and it is too late to treat the condition effectively.
Kidney Failure Causes
The factors that cause acute and chronic kidney failure are the same factors that cause acute and chronic kidney disease. Many people refer to stage 3 and stage 4 of kidney disease as kidney failure because it is infrequently able to be reversed or successfully treated.
Ultimately, renal failure occurs when kidney problems are left untreated.
Kidney Failure Stages
To reiterate, there are four stages of kidney disease. When the disease reaches stage 3 and 4, most veterinarians diagnose the condition as kidney failure although it is entirely possible that you hear someone refer to Stage 2 Kidney Disease as ‘Stage 2 Kidney Failure.’
Diagnosing Kidney Failure
If you suspect that your dog is suffering from kidney problems, or unfortunately, kidney failure, your veterinarian will do a routine blood work exam and a urinalysis exam. The blood work will be able to detect kidney disease through measuring the blood urea nitrogen (BUN) and creatinine levels.
What is the BUN Level?
BUN stands for blood urea nitrogen and is a waste product found in the blood. The bun level is the amount of waste product in the blood which indicates what level the kidneys are functioning at.
High Bun Level
If your dog’s blood biochemistry analysis comes back showing high bun levels, it is more often than not a clear indicator of kidney disease. After all, if the kidneys were functioning properly they would be able to rid the body of such wastes.
What are Creatinine Levels?
Creatinine (CREA) is a byproduct of the breakdown of proteins. Creatinine levels are also used to monitor the amount of waste product in the dog’s blood. Measuring creatinine levels can be an even more sensitive form of testing than measuring BUN levels thus leading to an even more accurate diagnosis.
What Does High Creatinine Mean?
Likewise, high creatine levels indicate that there has been damage to the kidneys that therefore won’t allow them to function properly and clear the waste.
Additionally, using BUN and creatinine levels allows veterinarians to monitor the kidney disease. If the levels are decreasing, it may indicate that the disease is improving. On the other hand, if the levels are increasing it generally indicates that the disease is getting worse.
While BUN and creatinine levels indicate kidney disease, neither are able to predict it.
Your veterinarian will also order a urinalysis test. A urinalysis is a chemical and physical analysis of a urine sample. Dilute urine will appear as a low specific gravity test result. If the analysis shows a high protein level in the urine, it is often an indicator that the kidneys are unable to conserve it properly.
Additional Tests for the Diagnosis of Kidney Disease in Dogs
Symmetric Dimethylarginine (SMDA)
A new scientific breakthrough has led to the creation of a test (SMDA) that allows veterinarians to diagnose chronic renal failure months and sometimeseven years earlier than other testing allowed. Therefore, there is now ways to intervene before the disease becomes irreversible.
Dogs May Also Be Tested for:
- Potassium levels
- Blood Pressure
Lastly, it is also possible for your veterinarian to order x-rays, an abdominal ultrasound, or a kidney biopsy in order to make an accurate diagnosis.
Kidney Failure Treatment
Treatment for kidney disease in dogs will vary depending on the type of renal disease that your dog has and what stage of the disease the dog is in.
However, there are certain treatment recommendations that apply to both. For example, low-protein, low-phosphorous diets help to slow the progression of renal disease. Studies show that reducing protein levels in food can aid in restoring normal acid-base levels.
Treatment for Acute Kidney Disease (AKD)
If your dog is diagnosed with acute kidney disease, their life and recovery depend on the degree of organ damage, determining the underlying cause of the condition, and how quickly they receive treatment.
A dog that receives a positive acute kidney disease diagnosis will most likely be hospitalized right away so that the underlying cause can be determined and treated. The primary goal of treatment is to support the rest of the dog while the kidneys are healing. This process can take anywhere from several days to weeks.
Acute kidney disease can progress extremely fast so time is of the utmost importance when it comes to seeking medical treatment.
Treatment for Chronic Kidney Disease (CKD) and Chronic Renal Failure (CRF)
Chronic kidney disease and chronic renal failure are rarely able to be cured. The only real way to reverse CKD or CRF is if there is some other underlying cause of the condition other than damaged kidneys. For instance, a urinary tract obstruction. In those uncommon cases, it is possible to reverse the condition if the underlying condition is determined and treated appropriately.
In the majority of other cases, CKD and CRF are caused by irreversible kidney tissue damage. The kidney disease will continue to progress and worsen. However, in many cases, the dog’s symptoms can be greatly decreased with supportive care.
Your veterinarian will be able to formulate an appropriate treatment plan depending on factors such as your dog’s overall health, the stage of the kidney disease, age, etc.
Your veterinarian may also suggest treatment such as:
- A change in diet
- A phosphate binder
- Home fluid therapy
- Varying medications
Kidney Disease in Dogs: A Final Thought
While we may not always acknowledge it, there is no doubt that the kidneys play an essential role in dog’s (and dog owner’s) lives. For this reason, we completely understand how a kidney disease diagnosis can easily send pet owners into a panic. However, kidney disease in dogs does not have to be a death sentence. By knowing the beginning signs, avoiding potential causes, and acting appropriately when necessary, you can help keep your dog’s kidneys healthy and fully functioning.