In order to understand Chronic Kidney Disease (CKD) in pets and assess how to treat each animal depending on how far their CKD has progressed, the International Renal Interest Society (IRIS) developed a staging system for CKD. This staging system allows veterinary professionals to determine what the next step should be in treating each pets CKD, depending on the progression of their disease.
Staging of CKD must be done when the disease is not actively getting worse. Veterinarians will need to repeat the lab work after making changes to the pet's treatment plan so they can see if the plan is working and stabilizing the kidneys. To get the most accurate picture of your pet's kidney health various tests need to be repeated every few weeks to months until the values remain steady.
The IRIS staging system is meant to be a guideline for vets to use, but it should be noted that this system is ever-evolving as new research about CKD in animals continues to emerge. This blog post will go over the basics of how CKD in pets is typically staged, and what treatment looks like for each stage.
NOTE: It is vital to note that the clinical signs of CKD do not typically become apparent until the later stages of the disease. This is why it is incredibly important to screen for CKD regularly using a tool like Kidney-Chek™, as early diagnosis is one of the most important steps in treating your pets CKD - Waiting until clinical signs become apparent is often too late.
Stage 1
The following symptoms may be present in pets currently in Stage 1 of CKD:
- A mild increase in blood SDMA (amino acid symmetric dimethylarginine) and/or blood creatinine may be detected during blood work. These values may still be in the normal range, but annual lab work can show increasing trends
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Dilute urine may be present in cats specifically
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Protein may be found in the urine (proteinuria), most often in dogs at this stage
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The kidneys may feel abnormal when your vet does a physical exam
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The kidneys may appear abnormal in radiographs or during an ultrasound
Treatment for pets in Stage 1 of CKD:
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Use of drugs that may damage the kidneys should be limited
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Fresh water must be available at all times
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Trends in creatinine and SDMA must be monitored to document stability or changes
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Investigate for and treat underlying disease and/or complications
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Treat high blood pressure if present
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Treat persistent proteinuria with a therapeutic diet and medication
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Limit phosphorus intake or use phosphate binder
Stage 2
The following symptoms may be present in pets currently in Stage 2 of CKD:
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Further mildly increased creatinine and mild renal azotemia (increase in urea nitrogen and/or creatinine, due to decreased kidney function)
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Further mildly increased SDMA
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Clinical signs may be mild or absent at this stage
Treatment for pets in Stage 2 of CKD:
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Same as the treatment for Stage 1, with a specific focus on dietary changes
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Treat low potassium levels (hypokalemia) in cats
Stage 3
The following symptoms may be present in pets currently in Stage 3 of CKD:
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Moderate azotemia
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Many other signs of illness may arise from poorly functioning kidneys, but the extent and severity may vary
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If clinical signs are absent, the case could be considered as early Stage 3, while presence of clinical signs might justify classification as late Stage 3
Treatment for pets in Stage 3 of CKD:
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Same as the treatment for Stage 2, with a specific focus on limiting phosphorus through dietary changes
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Treat metabolic acidosis (increased acidity in the blood)
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Consider treatment of anemia (low numbers of red blood cells)
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Additional fluids may be required to maintain hydration
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Consider calcitriol therapy in dogs to prevent low levels of calcium and bone disease
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Treat emerging clinical signs, including:
- Vomiting
- Lack of appetite
- Nausea
Stage 4
The following symptoms may be present in pets currently in Stage 4 of CKD:
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Increased severity of clinical signs
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Greatly increased levels of urea in the blood, called a uremic crisis, can occur due to kidneys no longer filtering properly
Treatment for pets in Stage 4 of CKD:
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Same as Stage 3, with a specific focus on further limiting phosphorus
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A feeding tube may be used for nutritional and hydration support and ease of medication administration
Early detection of CKD is one of the most important steps in maintaining your pets quality of life and keeping them comfortable. While it is recommended that your pet visit the vet at a minimum of once per year for regular blood work, pet owners may not be able to do this for a variety of reasons including time, budget restraints, and more.
Kidney-Chek™ can help. Kidney-Chek™ is an affordable, easy to use saliva test strip that allows you to screen for kidney concerns in your pet, right from home. Kidney-Chek™ can alert you to changes in the markers for CKD and allow you to know when it’s time to get your pet to the vet.