Kidney disease is a serious health problem in dogs that requires medical attention. Other common terms for kidney disease include renal failure, kidney failure, and renal insufficiency. There are different forms of kidney disease, and the signs that indicate this disease can vary depending on each dog's case. Owners of dogs with kidney disease may observe symptoms like nausea, increased thirst, lethargy, loss of appetite, and increased urination as the disease progresses into a chronic stage.
Kidney failure can be either acute or chronic, occurring suddenly or gradually happening over time. While acute kidney disease can be caused by toxins or other health conditions, chronic kidney disease typically affects aging dogs. When a dog's kidneys are not working properly, it can affect every other system in the body, and kidney disease can be fatal when left untreated.
What Is Kidney Disease?
Canine kidney disease is a condition that inhibits the organ's ability to filter waste from the body, eventually leading to renal failure. Like humans, dogs cannot survive without any kidneys, but they can live with only one kidney. To understand how kidney disease affects the dog's body, it's helpful to learn how the kidneys function.
The kidneys are vital organs in vertebrates, including dogs and humans. A dog's kidneys are located in the mid-abdomen near the back (very similar to the location of human kidneys). They are attached to an extensive network of blood vessels that connect to other vital organs. The kidneys are complicated organs that serve several purposes.
Kidneys are responsible for maintaining a proper electrolyte and pH balance in the blood. They also filter out waste from the blood and produce urine through which the waste is excreted. Another function of the kidneys is to produce hormones and enzymes that help regulate various functions throughout the body. The heart and kidneys work together to keep the body in operation.
Types of Kidney Disease in Dogs
- Acute Renal Failure: When the kidneys suddenly fail in an otherwise healthy dog, it is considered acute renal failure. This form of kidney disease develops over a few days, causing a dog to go from normal to very sick in that short period of time.
- Chronic Kidney Disease (CKD): Chronic kidney disease is sometimes called chronic kidney failure. More vets have begun calling it chronic kidney disease because it seems to be a better way to describe the disease. Kidney function becomes worse over time, eventually leading to death.
Symptoms of Kidney Disease in Dogs
The signs of acute renal failure and chronic kidney disease are fairly similar. The main difference is that the acute form comes on fairly quickly (a few days) while the chronic form develops gradually over a longer period of time (months to years). The following signs are the most common early indicators of kidney disease in dogs:
When dogs have acute renal failure, these signs can worsen rapidly over a period of days. In the case of chronic kidney disease, signs gradually get worse over a period of months to years depending on the dog's response to treatment.
Increased thirst and urination typically present first, which is called compensated renal failure. These signs are followed by others like loss of appetite, nausea, depression, and more once a majority of the kidney tissue is no longer viable. This occurs when about one-third of the kidney's healthy tissue is left and more waste begins contaminating the blood.
Causes of Kidney Disease
While chronic kidney disease tends to affect older dogs, acute renal failure can happen for a variety of reasons. Dogs may experience this life-threatening condition due to toxin exposure, infection, or other bodily issues that decrease blood flow or oxygen to the kidneys.
The following causes of chronic and acute kidney disease can occur:
- Aging: Chronic kidney disease is the result of degenerative changes in the kidney that affect its ability to function properly. CKD is most common in aging dogs and tends to come on gradually.
- Exposure to toxins: Acute renal failure in dogs is most commonly caused by toxin exposure. Common culprits include antifreeze, some over-the-counter human painkillers, and rat poison (the form containing the chemical cholecalciferol).
- Infection: Kidney infections are another potential cause of acute renal failure. Severe urinary tract infections may develop into kidney infections if left untreated (although this is not the only cause of kidney infections).
- Decreased blood flow or oxygen: Acute renal failure may also occur if there is decreased blood flow or oxygen delivery to the kidneys. Examples include trauma, severe dehydration, and heatstroke. Certain congenital or acquired health conditions may lead to acute renal failure.
Diagnosing Kidney Disease in Dogs
It is important to know that chronic kidney disease signs typically do not appear until the disease has progressed to a certain point. This is why it is so important to bring your dog to the vet for routine exams and follow your vet's recommendations for routine lab work. Screening healthy dogs allow vets to detect small changes over the years. Kidney disease may be detected early, and treatment can begin before your dog even gets sick.
If you notice signs of kidney disease or any other signs of illness, it is essential that you take your dog to the veterinarian right away for a physical examination. Next, your vet will likely recommend laboratory tests including:
- Complete blood count (CBC): Evaluates red blood cell and white blood cells, looking for evidence of anemia, infection, and other abnormalities
- Blood chemistry panel: Measures components in the blood that indicate how well the organs are functioning; blood urea nitrogen (BUN) and creatinine are the kidney values
- Blood electrolytes: Measures the amounts of electrolytes in the blood to determine if they are balanced (one of the main jobs of the kidneys)
- Urinalysis: Evaluates what is leaving the body through the urine; tests urine concentration, measures protein, and looks for signs of infection or other problems)
The results of these tests can usually give your vet enough information to diagnose kidney disease. When kidney disease is present, the BUN and creatinine will be elevated. These chemicals build up when the kidneys aren't filtering the blood properly. Blood phosphorus levels may also be high. The urine is often diluted and may have excess protein—an indication that the body is losing protein because the kidneys cannot properly filter. Anemia might be noted on the CBC as this is sometimes caused by kidney disease.
Once a diagnosis of kidney disease has been made, further tests may be warranted to determine how severe the disease has progressed. Blood pressure measurement is an important test because hypertension is common in dogs with kidney failure. Your vet may also recommend abdominal radiographs (X-rays) and/or abdominal ultrasounds.
Once your vet has a complete picture of your dog's health, a treatment plan will be developed based on your specific dog's condition. Lab tests must be repeated often. Treatments are adjusted according to the results, which usually change over the course of the illness.
Dogs being treated for acute renal failure may need lab work one or more times per day. For dogs with chronic kidney failure, lab tests are usually repeated every few weeks to months (depending on how the dog is doing).
Fluid therapy is the cornerstone of kidney disease treatment. Intravenous (IV) fluid diuresis is necessary to treat acute renal failure. It may also be used when a chronic kidney is first diagnosed. IV fluids are administered through an IV catheter at a rate to flush the system of toxins. Care is taken to avoid a fluid rate high enough to negatively impact the dog's heart. Dogs with kidney disease may need to be on IV diuresis for several days, during which they must stay in the hospital.
Dogs with chronic kidney disease are often maintained on subcutaneous fluids given by the owner at home. This involves placing a needle under the loose skin between the shoulder blades and infusing a set amount of fluid. This may need to be done daily or only a few times a week. Your veterinarian will show you the simple process for giving your dog fluids at home, which maintains hydration and provides extra fluid to support the kidneys.
Therapeutic diets are often used to manage chronic kidney disease. It is believed that adjusting the levels of certain components in the diet can lower the burden on the kidneys. Therapeutic kidney diets are often low in protein, phosphorus, calcium, and sodium. Palatability is a common issue with these diets, but several commercial brands are available to try.
Medications and supplements are used for a variety of reasons. Phosphate binders taken with food can decrease the amount of phosphorous the body absorbs, lessening the burden on the kidneys (which normally filter phosphorous out of the blood). Antacids are used to reduce the excess acid produced in the stomach (this occurs when the pH is not well-regulated by the kidneys). Antiemetics help relieve nausea and vomiting often caused by kidney disease, sometimes improving appetite. ACE inhibitors can control protein loss through the kidneys and help regulate blood pressure. Additional blood pressure medications may be necessary. Certain vitamins and supplements may be recommended based on your dog's needs and your vet's opinion.
Dialysis is not commonly used due to its expense and scarcity. This treatment involves the use of a machine that filters the blood. Dialysis is generally only offered at certain large specialty hospitals. Dogs with acute renal failure may benefit most from dialysis if it is available.
A kidney transplant is rare. This expensive, high-risk procedure is only performed by certain veterinary surgeons.
Prognosis for Dogs With Kidney Disease
Sadly, many dogs with acute renal failure will not survive more than several days. However, if caught early enough and treated aggressively, some dogs can fully recover. Treatment generally involves intravenous fluid therapy and supportive medications. Veterinarians will also try to determine the underlying cause of renal failure and treat it accordingly.
Remember that acute renal failure cannot always be reversed, despite best efforts. Talk to your vet about the pros and cons of specific treatments. Ask for expected outcomes so you can be as prepared as possible. Know that your vet will do everything possible to save your dog, but treatment may not be successful.
There is no cure for chronic kidney disease in dogs. However, there are treatment options that can manage the disease, improving the dog's quality of life and extending survival time. Some dogs with chronic kidney disease can live for years with careful treatment, while others will only live for a few months (even with the best treatment available). Keep in communication with your vet about your dog's signs at home.
Always go in for all recommended check-ups. Be flexible and positive, but also realistic. Most dogs eventually stop responding to treatment and become very sick. At this time, many owners choose humane euthanasia to end suffering.
How to Prevent Kidney Disease
Kidney disease cannot always be prevented, but there are a few steps owners can take to lower their dog's risk. Most importantly, keeping your dog healthy and visiting the vet at recommended intervals can help catch the disease early if it begins to develop.
Avoid Toxin Exposure
Since acute renal failure occurs in many dogs that have been exposed to toxins, it's essential for owners to monitor their home for these substances. Always prevent your dog from coming into contact with chemicals like antifreeze near your car or poisons to treat pest infestations.
Schedule Vet Check-Ups
Your veterinarian will run laboratory work at certain intervals to monitor your dog's health. In some cases, the development of kidney disease can even be prevented when it's caught at an early stage.
A common cause of acute kidney disease is dehydration, which can decrease the blood or oxygen flow to the kidneys. Whenever your dog is active, and especially on hot days outdoors, provide plenty of water and bring your dog inside to cool down.
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