What is Kidney Disease?
Kidney disease can be referred to as kidney failure, kidney insufficiency, kidney dysfunction, or kidney disease. However, you word it, it means the kidneys aren’t able to do all the hard work they should be doing, making the dog sick.
The main role of the kidneys is to filter out toxins in the bloodstream. When the kidneys aren’t working, those toxins and waste products build up in the blood. This condition is known as azotemia.
This disease is classified in two categories, chronic or acute. Chronic kidney disease is a progressive process in which the function is lost over time. It often takes months or even years before the dog develops clinical signs. Chronic disease can be caused by an inherited abnormality at birth or with age, which is more common. Chronic disease is most commonly found in cats but can be diagnosed in dogs as well. Dogs are more commonly diagnosed with acute kidney injury. This is where there has been a sudden injury to the kidneys, causing them not to be able to function. The most common causes are toxins such as certain medications (NSAIDs), grapes/raisins, ethylene glycol (antifreeze), or an infection such as leptospirosis or Lyme disease.
Clinical Signs
A dog with this disease may lose weight, stop eating or eat less, vomit, have diarrhea, show muscle wasting, drink more water than normal, urinate more than normal, have a decreased energy level, be anemic, or have ulcers in the stomach or mouth.
Diagnosis
A veterinarian can diagnose kidney disease through a combination of tests such as a physical exam, bloodwork, urinalysis, radiographs, ultrasound, and blood pressure.
Dog Kidney Failure Stages
The International Renal Interest Society (IRIS) has developed guidelines to help us better understand chronic disease, the diagnosis of this disease, the stages of this disease, and the best course of treatment and management based on the stage. These stages are based on tests such as blood creatinine levels, the SDMA test, blood pressure, and the level of proteinuria (protein in the urine).
There are 4 stages of chronic kidney disease according to the IRIS guidelines.
Stage 1
Chronic kidney disease occurs when the blood creatinine is less than 1.4 mg/dl and the SDMA level is 14-18mg/dl. There is none to very little protein in the urine and the dog usually has a normal blood pressure in this stage. This stage is often referred to as pre-failure and typically, the dog isn’t symptomatic.
Stage 2
Chronic kidney disease occurs when the blood creatinine is between 1.4-2.8mg/dl and the SDMA level is 18-35mg/dl. These dogs may start leaking protein into their urine and experience slightly high blood pressure. Dogs in stage 2 disease have mild kidney failure and still don’t typically show clinical signs.
Stage 3
Chronic disease occurs when the blood creatinine is between 2.9-5.0mg/dl and the SDMA level is 36-54mg/dl. These dogs often have protein in their urine and elevated blood pressure. They are in moderate kidney failure and start showing signs of sickness.
Stage 4
Chronic disease occurs when the blood creatinine is greater than 5.0 mg/dl and the SDMA level is greater than 54mg/dl. These dogs have more protein in their urine and elevated blood pressure. They are in severe kidney failure and are often very sick.
There are 5 stages of acute kidney injury according to IRIS guidelines.[2] Acute injury, although overall is a sudden and severe form of disease, it can vary in how severe based on the insult. Some dogs can do well and recover with quick and effective treatment, others develop some chronic disease stages, while others fail quickly and die suddenly.
The stages of acute injury are more difficult to define, but overall are characterized by varying levels of increased blood creatinine levels and decreased urine production, often leading to anuria, or no urine production. In the early stages, dogs will respond to replacement fluids through an IV, while in the later stages, dogs are not responsive to replacement fluids.
How to treat Kidney Disease in Dogs?
Once a dog is in stages 3 or 4 of kidney failure, about 70%-75% of the function is already lost, and in most cases, is gone for good. Because chronic disease can’t be cured, treatment is aimed at supportive care and treating failure’s secondary effects. Some common secondary issues dogs can suffer from with kidney disease include anemia, hyperphosphatemia (increased phosphorus levels in the bloodstream), hypokalemia (low potassium blood levels), dehydration, nausea or vomiting, urinary tract infections, and anorexia. By addressing these concerns, this dogs can buy some time and live out a more comfortable and happy life.
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Chronic Kidney Disease Treatment
Treatment guidelines for chronic kidney disease are based on the IRIS guidelines.[3]
Stage 1:
- Use drugs with side effects concerning the kidneys with caution. These include NSAIDs (Non-steroidal anti-inflammatory drugs) and some antibiotics.
- Increased fluid intake to correct dehydration and to prevent dehydration. This includes keeping several sources of freshwater available at all times, adding water to food, or feeding more of a wet food diet than dry.
- Treat underlying urinary tract infections if present.
- Monitor bloodwork changes and trends with regular bloodwork and urine tests.
- Treat secondary effects of kidney disease. Most dogs aren’t clinically ill at this stage, but they may have changes such as high blood pressure, high blood phosphorus, or protein leaking into the urine.
Stage 2:
- All the same steps as in Stage 1.
- Start a specific diet.
There are several high-quality commercial prescription kidney diets that your veterinarian can recommend. These include restricted protein content but with high-quality protein sources and restricted phosphorus and sodium levels. And it is best to offer canned or wet food to increase water intake.
Stage 3
- All the same steps as in Stage 1 and Stage 2.
- Phosphorus should be restricted in the diet, but if phosphorus is high, a phosphorus binding medication may be required to get the levels down in the blood.
- Treat secondary illness. Dogs can start feeling sick in this stage and those secondary effects will need to be treated: treat anemia with supplements and medications as recommended by your veterinarian; control vomiting with anti-nausea medications and gastrointestinal ulcers with antacids; anorexia and a decreased appetite can be supported with appetite stimulants; dehydration can be corrected with intravenous fluids or with regular subcutaneous fluid therapy.
- Supplements to support kidney function and overall health can be helpful: immune supplements, fish oil/fatty acid supplements, pre and probiotics
Stage 4:
- All the same steps as in Stages 1, 2, and 3.
- Continue treating secondary effects and illnesses.
- Continue supplements.
- Continue diet therapy. A feeding tube may be needing depending on how little the dog is eating.
Acute Kidney Injury Treatment
Acute kidney injury is a very sudden and serious condition that requires urgent treatment and still only has about a 50 percent survival rate.
If the cause of the kidney injury is known, such as a specific virus, bacteria, or toxin, specific therapy can be initiated. Dogs with injury are typically hospitalized for 24-hour monitoring and treatments and started on intravenous fluid therapy and various medications as needed. Their fluid intake and output (urination) is monitored carefully, and they are provided with high quality nutritional support.
The same types of supplements can be used for acute kidney injury as those mentioned for chronic kidney disease.
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Frequently Asked Questions
How long does a dog have to live with kidney failure?
The survival time for a dog with kidney failure depends on the underlying cause, what stage of failure they are on, if it is a chronic or acute kidney disease, and their other secondary illnesses or symptoms. Early stages of chronic kidney disease have survival times of around a year while later stages have survival times around a few months. With successful treatment and supportive care, dogs can live longer with kidney disease.
Can you reverse kidney failure in dogs?
Kidney failure cannot be reversed. Typically, once there is an insult to the kidneys or diagnostic tests show decreased kidney function, there has been permanent damage.
While kidney failure cannot be reversed or cured, it can be supported, and a dog can live out a good quality of life in many cases.
Is kidney failure in dogs painful?
Kidney failure in dogs can be painful depending on the type of injury, insult, or disease that causing kidney failure. It is always difficult to determine pain in dogs, as they cannot speak to us, but we can tell if they are uncomfortable or sick. Your veterinarian can help you keep your canine friend as comfortable as possible while fighting kidney failure.
Article Sources:
- Brooks, Wendy. Kidney Failure in Dogs and Cats: Where to Begin. 1 Jan. 2001, veterinarypartner.vin.com/default.aspx?pid=19239&id=4951452.
- “IRIS Staging of CKD.” IRIS, International Renal Interest Society, iris-kidney.com/pdf/IRIS_Staging_of_CKD_modified_2019.pdf
- “Diagnosing, Staging, and Treating Chronic Kidney Disease in Dogs and Cats.” IRIS, International Renal Interest Society, iris-kidney.com/pdf/IRIS_Pocket_Guide_to_CKD.pdf.
- “Grading of Acute Kidney Injury.” IRIS, International Renal Interest Society, iris-kidney.com/pdf/4_ldc-revised-grading-of-acute-kidney-injury.pdf
- Brown, Scott. “Renal Dysfunction in Small Animals – Urinary System – Merck Veterinary Manual.” Merck Veterinary Manual, 1 Oct. 2013, merckvetmanual.com/urinary-system/noninfectious-diseases-of-the-urinary-system-in-small-animals/renal-dysfunction-in-small-animals
- Brown, Scott. “Noninfectious Diseases of the Urinary System in Dogs – Dog Owners – Merck Veterinary Manual.” Merck Veterinary Manual, 1 June 2018, https://www.merckvetmanual.com/dog-owners/kidney-and-urinary-tract-disorders-of-dogs/noninfectious-diseases-of-the-urinary-system-in-dogs
- “Chronic Kidney Disease and Failure.” VetMed, vetmed.wsu.edu/outreach/Pet-Health-Topics/categories/diseases/chronic-kidney-disease-and-failure
- Foster, JD, et al. “Canine Chronic Kidney Disease | Diagnostics & Goals for Long-Term Management.” Today’s Veterinary Practice, 22 Oct. 2019, todaysveterinarypractice.com/canine-chronic-kidney-diseasecurrent-diagnostics-goals-long-term-management/
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