Kidney disease is a severe problem that can occur in cats and dogs. Chronic Kidney Disease (CKD) is the chronic form of Acute Kidney Injury (AKI) and is when a patient experiences renal failure and its clinical signs for more than three months. This blog post will focus on CKD but check out Are you Kidney me?!–AKI in cats and dogs to learn more about the acute form of the disease!
Although CKD can appear in cats and dogs of all ages, it is seen more in older animals. It is the most common renal disease occurring in elderly patients.
Clinical Signs of CKD
Early diagnosis and treatment of CKD can lead to better disease outcomes. Clinical signs tend to develop gradually and are persistent. Common symptoms may include weight loss, loss of energy, altered thirst and urination patterns, loss of appetite, vomiting, and unusual breath odor.
How is CKD diagnosed?
When examining a pet and considering a diagnosis of CKD, veterinarians refer to the staging system established by the International Renal Interest Society (IRIS). The IRIS system uses a patient’s blood creatinine and Symmetrical Dimethylarginine (SDMA) concentrations to assess the severity of renal failure. Creatinine is a waste product from the normal breakdown of muscle tissue in the body, so when the kidneys are unable to filter toxins properly, the concentration of creatinine builds up in the bloodstream. SDMA is a molecule released during the breakdown of protein and excreted into urine, so it reflects how well the kidneys are working.
The IRIS staging system uses a four-grade scale, with grade I/IV being less severe and grade IV/IV the most severe.
Can CKD be Managed with Nutrition?
If your pet is diagnosed with CKD, your doctor can provide the best therapeutic plan. Nutritional management of CKD is essential and is implemented to slow the progression of the disease. There are a few changes that can be made to your pet’s diet based on the severity of their disease.
Water
Some animals with renal failure may experience a dramatic increase in thirst and urination. This occurs more often in cats than dogs. It is important to provide enough fluid to help support your pet’s kidney function. Depending on the extent of the disease, some patients may not be able to urinate at all. Regularly monitoring your pet’s water intake and urination frequency is important to assess their hydration status. On average, dogs and cats need 50-70 mL of water per kg of body weight daily. So, a dog weighing 10 kg would need about 0.5 Liter (or between 500-700 mL) of water per day. If you have questions or concerns about your pet’s water intake, please contact your veterinarian.
Phosphorus
Studies have shown that an increase in dietary phosphorus intake can increase the risk of complications with CKD. Providing a diet reduced or restricted in phosphorus can help slow the progression of kidney damage, especially in cases with advanced disease.
Protein
Proteinuria is the presence of protein in the urine and is a sign of severe kidney damage. When the kidneys are healthy, they keep large protein molecules from leaking out of the blood. Smaller proteins that do get into the kidneys are either returned to the blood or broken down. But when the kidneys are damaged, they can’t filter properly, and that means some proteins enter the kidneys and end up in urine. The amount of protein in urine can indicate the rate at which CKD is worsening. Reducing proteinuria can improve survival rates, and this can be done with a protein-restricted diet. Generally, diets with less than 6 grams of protein per 100 Calories for dogs and less than 8 grams of protein per 100 Calories for cats are considered low in protein.
Renal diets
Depending on the extent of disease, your veterinarian may recommend a therapeutic renal diet. These diets are specifically designed to slow the progression of the disease and alleviate some of its symptoms. When transitioning to a new diet, it is always important that it is done slowly. An example diet transition can look like this:
Day 1-3: feed 75% of current diet + 25% of new diet
Day 4-6: feed 50% of current diet + 50% of new diet
Day 7-9: feed 25% of current diet + 75% of new diet
Day 10: feed 100% of new diet
Prognosis
The prognosis of CKD depends on its severity and the timing of intervention. Early diagnosis and treatment can significantly improve a pet’s quality of life and help manage the disease more effectively. Regular veterinary check-ups, monitoring kidney function, and adhering to the prescribed treatment plan are crucial.
Living with a pet diagnosed with CKD can be challenging, but with the right care and support, many pets continue to live happy and comfortable lives. Remember, your veterinarian is your best resource for managing your pet’s health, so don’t hesitate to reach out with any concerns or questions. By being proactive and informed, you can help ensure your pet enjoys the best possible quality of life.
Written by: Brianna Chan, Clinical Studies Summer Research Student
Reviewed by:
Dr. Sarah K. Abood, DVM, PhD, Associate Professor, Nestlé Purina Professorship in Companion Animal Nutrition
Dr. Ashley Spencer, MHSc, DVM, DACVIM
References
Böswald, L.F., Kienzle, E., Dobenecker, B. (2018). Observation About Phosphorus and Protein Supply in Cats and Dogs Prior to the Diagnosis of Chronic Kidney Disease. Journal of Animal Physiology and Animal Nutrition, 102(Suppl. 1): 31–36. https://doi.org/10.1111/jpn.12886
Boyd, L.M., Langston, C., Thompson, K., Zivin, K., Imanishi, M. (2008). Survival in Cats with Naturally Occurring Chronic Kidney Disease. Journal of Veterinary Internal Medicine, 22:1111–1117. https://doi.org/10.1111/j.1939-1676.2008.0163.x
Harley, L., Langstone, C. (2012). Proteinuria in Dogs and Cats. The Canadian Veterinary Journal, 53(6): 631–638.
Kidder, A.C., Chew, D. (2009). Treatment Options for Hyperphosphatemia in Feline CKD: What’s Out there? Journal of Feline Medicine and Surgery, 11(11):913-924. https://doi.org/10.1016/j.jfms.2009.09.012
Nabity, M.B., Lees, G.E., Boggess, M.M, Yerramilli, M., Obare, E., Yerramilli, M., Rakitin, A., Aguiar, J., Relford, R. Symmetric Dimethylarginine Assay Validation, Stability, and Evaluation as a Marker for the Early Detection of Chronic Kidney Disease in Dogs. Journal of Veterinary Internal Medicine, 29(4):1036-1044. https://doi.org/10.1111/jvim.12835
(2023). IRIS Staging of CKD. International Renal Interest Society, http://www.iris-kidney.com/pdf/2_IRIS_Staging_of_CKD_2023.pdf