Kidney disease has been suggested to be one of the most common chronic diseases in cats, particularly in those of an older age. Because the disease develops slowly, most cats will appear healthy for many years while their kidneys begin to deteriorate. Paired with the fact that cats are masters at masking signs of illness, this makes the disease especially hard to detect early on. A lot of the time, when behavioural changes or other early warning signs do appear, they are often mistaken for normal signs of ageing. By the time symptoms start to become obvious, it’s possible that the kidneys have already undergone significant damage.
There are two main types of kidney disease seen in cats. The first is acute kidney injury (AKI), which develops suddenly and can be reversed if treated quickly. The other is chronic kidney disease (CKD), which progresses slowly over the course of months or years. This disease is unfortunately irreversible and requires management over the course of the cat’s life. It’s important to understand the difference between these two conditions to set realistic expectations for treatment and respond appropriately.
Early detection for both AKI and CKD is essential to slow the progression of the disease, improve your cat’s quality of life, and prolong their survival. Read on to learn more about kidney disease, including how to identify and treat it accordingly.
How do the Kidneys Work in Cats?
Just like in all other animals, feline kidneys are responsible for filtering the bloodstream by removing any metabolic waste products and excreting them in urine. This prevents the accumulation of harmful toxins such as urea and creatinine, keeping your cat healthy and comfortable. Within each kidney, there are thousands of small units that are responsible for the filtration process (nephrons), and research shows that many of them (over 2/3 of kidney mass) can be lost before symptoms of kidney disease appear.
In addition to metabolic waste removal, the kidneys play another key role: regulating hydration and fluid balance. Healthy feline kidneys produce urine that’s very concentrated, a trait that dates back to their evolution as desert cats, to help conserve water. Since the kidneys regulate fluid balance by adjusting the concentration of urine, when kidney function declines, so does that regulation. As a result, the kidneys produce more dilute urine, and more water is lost from the cat’s body.
The third role of the kidneys in a cat’s body is managing blood pressure and electrolyte balance.
During filtration, the kidneys can decide if key electrolytes like sodium or potassium stay in the body or get excreted, which raises or lowers blood pressure accordingly. Experts report that when these two critical functions become disrupted, many systemic signs of kidney disease may appear (like weakness, nausea, and high blood pressure).
A Deeper Dive into AKI and CKD
As mentioned above, acute kidney disease develops very rapidly, often over the course of a few hours to days. Veterinarians report that some of the most common causes of AKI include exposure to harmful toxins, severe dehydration, urinary obstruction, reduced blood flow to the kidneys, or infection. AKI is considered a medical emergency because without immediate treatment, life-threatening complications can occur.
Conversely, chronic kidney disease has a very gradual onset. Over time, nephrons are slowly damaged and lost, meaning that the remaining nephrons have to compensate until they too become overwhelmed. Because the disease progresses slowly, cats usually appear normal even though they have ongoing internal damage. Scientific consensus highlights that degeneration of the kidneys related to age is the most common risk factor for CKD, and a large percentage of cats over the age of 10 show some degree of kidney changes. Without treatment, CKD can result in the permanent loss of kidney function, so just because it is not an emergency, it doesn’t mean it should be ignored.
Common Causes of Kidney Disease in Cats
Unlike some other diseases, kidney disease in cats can come about from a combination of factors instead of a single cause. Clinical research indicates that some breeds like Persians and Siamese, appear to have a genetic predisposition to developing the disease earlier in life. For other cats, however, age seems to be the number one contributing factor.
Chronic dehydration is another contributing factor to kidney disease because of the reduced blood flow and subsequent long-term strain it places on the kidneys. Likewise, veterinarians report that kidney infections and inflammatory conditions like feline infectious peritonitis (FIP) can also contribute to kidney damage over time, increasing the likelihood of kidney disease.
Finally, when cats are exposed to certain toxins like antifreeze, medications, household chemicals, and some plants like lilies, kidney injury can occur.
Early Signs and Symptoms to Watch For
One of the earliest signs of kidney disease is increased thirst and urination. Owners may notice larger urine clumps in the litter box, more frequent visits to the litter box, or increased nighttime urination. This is because the kidneys have lost their ability to properly concentrate urine and more fluid is being excreted than normal. Cats with kidney disease may also urinate outside of the litter box because of urgency or discomfort.The above-mentioned urinary changes often happen before more obvious clinical signs appear, but they are still valuable clues that your cat’s kidney function may be declining, or that there is another urinary issue. More severe symptoms that tend to appear as the disease progresses include weight loss, reduced appetite, vomiting, nausea, lethargy, or a dull coat. It’s important to contact your veterinarian as soon as you notice any symptoms appearing, to address any concerns immediately.
This section is based on current recommendations from Dr. Michael Kearley, DVM.
Diagnosing Kidney Disease
Kidney Disease is usually diagnosed via blood tests and urine analyses. The goal of the tests is to assess the quantity of waste products like creatinine, urea, and symmetric dimethylarginine (SDMA), evaluate the urine’s concentration, and detect any protein loss. Since hypertension (high blood pressure) is a common symptom of kidney disease, and can further damage the kidneys without treatment, blood pressure monitoring is an important part of both diagnosis and management of the disease.
Your veterinarian may further prescribe ultrasound or x-rays to assess the size and structure of your cat’s kidneys, as well as to look for any stones or obstructions in the urinary system. After diagnosis, kidney disease will be staged using established guidelines from the International Renal Interest Society (IRIS), in order to guide decisions about treatment and monitoring.
Stages range from 1-4 (4 being the worst, with less than 10% of nephrons remaining). Based on all of the information obtained during diagnosis, your veterinarian will formulate an appropriate treatment plan to help ensure your cat remains as healthy and comfortable as possible.
This section was informed by guidance from Dr. Gregory F. Grauer, DVM, MS, DACVIM.
Treatment Options
In terms of treating kidney disease in cats, the primary aim is to slow down the progression of the disease while maintaining the quality of life of the cat. One of the main ways to treat the disease is through prescription diets. Specialists report that this is because they limit phosphorus intake, provide high-quality protein, and support hydration, which all lower the workload of the already exhausted kidneys. In cases where it is not possible to control phosphorus levels through diet, phosphorus binders may be administered to prevent the absorption of phosphorus and reduce the stress on the kidneys. Other medications might be prescribed on a case-by-case basis, if the cat presents with symptoms like nausea, appetite loss, high blood pressure, or electrolyte imbalances.
Hydration support is also critical because of the increased fluid loss associated with kidney disease. There are a few strategies owners can use to help encourage water intake, including: wet food diets, multiple water sources, water fountains, and in more severe cases, administering subcutaneous fluids. Throughout your pet’s treatment, it’s important that their blood and urine are regularly tested so that disease progression can be caught early on, and treatment plans can be adjusted accordingly.
How an Automatic Litter Machine Can Help
Monitoring bathroom habits becomes especially important for cats with kidney disease, because changes often happen slowly over time, and can be hard to detect with day-to-day observation.
Automatic litter machines can help owners by tracking the frequency of litter box visits, identifying changes in urine output (larger or smaller volumes), and identifying missed litter box visits. All of these factors can be indicators of worsening kidney function, and need to be kept track of over time. In addition to pattern tracking, automatic litter machines regularly self-clean, and clean litter boxes have been proven to encourage normal bathroom habits and support urinary health.
Supporting a Cat with Kidney Disease at Home
Caring for a cat with kidney disease involves thoughtful adjustments at home. Any changes to your cat’s diet should be made gradually and combined with appetite support strategies if necessary. The use of the above-mentioned hydration support strategies are another great way to keep your cat comfortable and hydrated, kidney disease or not.
Stress should be minimized as much as possible in the house through the implementation of predictable routines, calm resting spaces, and a litter box set up that is easy to access, placed in a calm location, and regularly cleaned. Owners should also try to monitor body weight and bathroom habits routinely to catch changes early on and report them to their veterinarian.
When to Contact the Vet Immediately
Immediate veterinary attention is required if a cat shows sudden changes in urination, stops eating or drinking, vomits repeatedly, collapses, or shows signs of dehydration. Experts note that these symptoms may point to acute kidney injury or a rapid advancement of CKD, and should always have veterinary intervention.
Long-Term Outlook and Quality of Life
While kidney disease in cats is a common and progressive condition, it doesn’t have to dictate their. With early detection, regular veterinary care, and appropriate adjustments to their home environment, your cat can live a happy and healthy life for many years after their diagnosis.
Because kidney disease often develops silently in its early stages, close observation of your cat’s water intake, urination habits, appetite, body weight, and litter box habits is critical in detecting early signs of disease before it becomes severe.Your management plan will likely change over time to meet the evolving needs of your cat, including the promotion of water intake, dietary support, symptom relief, and regular review of your cat’s condition as the disease progresses. By actively working in partnership with your veterinarian and observing your cat’s condition in their home environment, you can play a vital role in the management of your cat’s kidney disease and the preserve their health and happiness for many years to come.
Disclaimer: Grin Like Cheshire is not affiliated with the featured brands and trademark rights remain the property of their respective owners. Above information is for educational purposes only and does not constitute medical advice. Always seek the advice of a qualified healthcare provider with questions regarding a medical condition.
Sources:
https://www.petmd.com/cat/conditions/urinary/kidney-disease-cats
https://journals.sagepub.com/doi/10.1177/1098612X13495235
https://pubmed.ncbi.nlm.nih.gov/29344508
https://www.mdpi.com/2075-1729/15/12/1856
https://vcahospitals.com/know-your-pet/nutrition-for-cats-with-chronic-kidney-disease
https://www.dvm360.com/view/cats-litter-box-preferences-in-multicat-environments
https://journals.sagepub.com/doi/10.1177/1098612X12464458