Overview of kidney failure in cats
Kidney disease is a common condition in elderly cats, with studies estimating the prevalence at 13% in cats under 4 years old, increasing to 24% in cats aged 4-10 years, 31% in cats aged 10-15 years and 32% in cats 15 years and older (1). Kidney failure, also known as chronic kidney disease (CKD), occurs when the kidneys can no longer function normally to filter waste products out of the blood. In cats, kidney disease tends to be chronic in nature and progressive over time.
Signs of kidney failure in cats include increased thirst, increased urination, weight loss, poor appetite, vomiting, diarrhea, and bad breath. In advanced kidney failure, cats may show signs of nausea, mouth ulcers, blood in the urine, anemia, high blood pressure, weakness, and seizures (2).
Kidney disease is typically diagnosed through bloodwork, urinalysis, imaging tests like ultrasound or xrays, and urine culture. Bloodwork assesses levels of waste products like creatinine and BUN to evaluate kidney function, while urinalysis checks for signs of infection, crystals, and kidney damage. Imaging and urine culture help identify underlying causes for the kidney dysfunction (3).
(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4414065/
(2) https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-cats
(3) https://journals.sagepub.com/doi/10.1177/0300985815622975
Causes and risk factors
Kidney failure in elderly cats often results from age-related changes that reduce kidney function over time. As cats age, the kidneys gradually lose their ability to efficiently filter waste from the bloodstream. Older cats are also more prone to kidney infections and kidney cancer.
Other common causes and risk factors for kidney failure in cats include:
- Congenital kidney diseases present from birth
- Exposure to toxins like antifreeze, lilies, or other poisons (source)
- Bacterial, viral or fungal kidney infections
- Kidney cancer, especially lymphosarcoma in cats over 10 years old
Kidney failure progresses through stages, from mild decline in kidney function to complete kidney failure. Catching kidney disease early allows for better management. However, acute kidney injuries from toxins or obstructions can cause sudden kidney failure.
Stages of Kidney Disease
Kidney disease in cats can be categorized as either acute or chronic. Acute kidney disease comes on suddenly and causes severe illness, while chronic kidney disease (CKD) develops gradually over months or years. CKD is further classified into stages according to guidelines set by the International Renal Interest Society (IRIS).
The IRIS staging system is based on levels of creatinine in the blood, a waste product filtered by the kidneys. There are four stages of CKD in cats:
Stage 1 – Creatinine less than 1.6 mg/dL. Kidney function is normal but there are some minor kidney changes.
Stage 2 – Creatinine 1.6-2.8 mg/dL. Mild decrease in kidney function of about 25-50%.
Stage 3 – Creatinine 2.9-5.0 mg/dL. Moderate decrease in function of 50-75%. Significant clinical signs may be present.
Stage 4 – Creatinine over 5.0 mg/dL. Severe loss of over 75% of kidney function. Severe clinical signs and renal failure.
In addition to creatinine levels, IRIS also considers urine protein levels for further substaging. The stage of CKD helps determine prognosis and guides treatment recommendations.
Treatment Options
There are several ways to treat kidney failure in elderly cats. The main goals of treatment are to maintain adequate hydration, balance electrolytes, and reduce the workload on the kidneys.
Fluid therapy involves administering intravenous or subcutaneous fluids to correct dehydration and flush toxins from the body. This helps reduce strain on the kidneys and improve their function. Fluids can be given at home or during regular vet visits (VCA).
Switching to a kidney-friendly diet low in phosphorus and protein can help reduce waste buildup. Prescription kidney diets contain nutrients that are easier for compromised kidneys to process (PetMD).
Phosphate binders help block excess phosphorus absorption from food. Too much phosphorus strains the kidneys. Binders are given with meals (South Wilton Vet).
Anti-nausea medication can stimulate appetite and prevent vomiting from uremia. Uremia is a buildup of toxins due to kidney failure (South Wilton Vet).
ACE inhibitors help dilate blood vessels and lower blood pressure. This reduces strain on the kidneys (VCA).
Antacids help reduce gastric ulcers and vomiting. Ulcers are a common effect of kidney failure (PetMD).
At-home care
There are several ways to provide at-home care for a cat with kidney failure to help manage symptoms and slow the progression of the disease. Some of the main at-home care recommendations include:
Subcutaneous fluids – Giving subcutaneous fluids under the skin helps flush toxins from the body and prevent dehydration. Fluids can be given at home once or twice per day based on your vet’s recommendation (PetMD).
Special diet – Feeding a diet lower in phosphorus and protein but higher in moisture can help reduce strain on the kidneys. Canned food or a prescription kidney diet is usually recommended (Pet Hospice Vet).
Litter box changes – Changing the litter box more frequently, even multiple times per day, can help avoid toxins from building up and reduce stress for the cat.
Stress reduction – Reducing stress by providing a quiet, comfortable area and maintaining a consistent routine is important. Using pheromone diffusers can also help relax the cat.
When to euthanize
One of the most difficult decisions cat owners face is determining when to euthanize a cat with kidney disease. As kidney function declines, your cat’s quality of life diminishes. Euthanasia may be the most humane option when:
Your cat’s quality of life is very poor. They have little interest in food, activity, or social interaction. They seem constantly uncomfortable or in pain despite medication. Your vet determines your cat is suffering without reasonable hope for improvement. In this case, euthanasia spares your cat further distress and discomfort. According to PetMD, cats with advanced kidney disease often show signs like vomiting, diarrhea, apparent abdominal pain, weight loss, and seizures which indicate very poor quality of life warranting euthanasia.
Your cat’s kidney disease is very advanced. Blood and urine tests show your cat’s kidneys are functioning at less than 15% capacity, also known as end-stage kidney disease. Your vet determines the damage cannot be reversed or managed to any reasonable extent. According to Pet Euthanasia, when kidney values are extremely high and other clinical signs are present, euthanasia may be most appropriate.
Your cat shows no response to treatments over 4-6 weeks. You’ve worked closely with your vet to provide medications, IV fluids, dietary changes and other interventions, but your cat’s condition continues to deteriorate. This lack of response, combined with clinical signs like vomiting and weight loss, indicate treatment is no longer worthwhile. According to Cloud9 Vets, euthanasia at home allows your cat to pass peacefully when kidney disease treatment proves ineffective.
Preventing kidney disease
There are several ways cat owners can help prevent kidney disease in their feline companions:
Get annual checkups. Annual veterinary checkups allow early detection of any signs of kidney issues. Blood and urine tests can identify problems before they become advanced. This allows for earlier treatment which leads to better outcomes.
Regular dental care. Dental disease is correlated with kidney disease in cats. Tartar buildup and gingivitis introduce bacteria into the bloodstream that can damage the kidneys over time. Professional dental cleanings and daily tooth brushing helps minimize this risk.
Avoid toxins. Exposure to toxins like antifreeze, chemicals, medications, lilies, and xylitol can lead to acute kidney injury or chronic kidney disease. Keeping cats indoors and locking up any toxic substances reduces their exposure.
Feed a high quality diet. Diets specifically formulated for kidney health have reduced protein, phosphorus, and sodium levels to take strain off the kidneys. They are also supplemented with omega-3 fatty acids and antioxidants for kidney support.
Sources: https://www.petfinder.com/cats-and-kittens/health-wellness/concerns/tips-preventing-kidney-failure-in-cats/, https://bluepearlvet.com/pet-blog/five-ways-to-prevent-kidney-disease-in-cats/
Prognosis
The prognosis for cats with kidney disease depends on several factors, including the stage or progression of the disease, the cat’s age, and how well the cat responds to treatment. With aggressive treatment and careful management, cats with kidney disease can live for months to years after diagnosis. However, kidney disease is a progressive condition and most cats will eventually succumb to its effects.
Cats diagnosed in early stages of kidney disease (stage 1 or 2) and who respond well to treatment typically have a better long-term prognosis. With proper care like dietary changes, IV fluids, medication, and regular vet monitoring, these cats may live 1-3 years or longer after diagnosis. Older cats or those diagnosed in later stages may only live weeks to months with treatment.
According to one study cited in VCA Animal Hospitals, the median survival time for cats with advanced kidney disease was 7 months with treatment. However, about 25% survived over 2 years. Factors like breed (Persian and Siamese cats tend to do worse), severity of proteinuria, and response to medications impacted prognosis.
While kidney disease shortens life expectancy, aggressive treatment from diagnosis can prolong a cat’s life for as long as they maintain a good quality of life. Regular vet visits, lab work, and owner attentiveness to any changes are key to optimizing prognosis.
Cost of treatment
The cost of treating chronic kidney disease (CKD) in cats can vary depending on the stage of the disease and what treatments are necessary. According to Embrace Pet Insurance, long-term management of CKD may range from $100-500 a month, depending on prescribed medications and frequency of fluid therapy.
Some common expenses include:
- Blood and urine tests – $200-500 to diagnose initially and then $100-300 every 3-6 months to monitor
- Prescription kidney diet food – $50-100 per month
- Phosphate binders like aluminum hydroxide – $30-50 per month
- Anti-nausea medication like Cerenia – $2-5 per pill
- Erythropoietin injections to stimulate red blood cell production – $15-30 per injection every 1-2 weeks
- Subcutaneous fluids – $100-300 per week for at-home administration
- Hospitalization for intravenous fluids – $1000-2000 per stay
Pet insurance can help offset some of these costs. Policies like Embrace cover diagnostic testing, prescription medications, therapeutic kidney diets, and more. Depending on the plan, insurance may reimburse 70-90% of eligible vet bills after a deductible is met.
For elderly cats, it’s ideal to get pet insurance when they are young and healthy. As a chronic condition, CKD is unlikely to be covered if it develops before enrollment.
New treatments
Exciting new treatment options for kidney disease in cats continue to emerge, providing hope for improved quality of life and longevity. Two cutting-edge therapies on the horizon are stem cell therapy and gene therapy.
Stem cell therapy involves harvesting stem cells from the cat’s own fat or bone marrow, culturing them, and then injecting them back into the cat. The stem cells can help repair damaged kidney tissue and stimulate regeneration. Early research indicates stem cell therapy may help stabilize kidney function and delay progression of disease (Novel treatment options for cats with kidney disease).
Gene therapy delivers functional genes directly to the cat’s kidneys to compensate for mutated genes causing kidney disease. One promising target is the klotho gene, which plays a key role in kidney function. In one study, cats with kidney disease treated with the klotho gene showed improved kidney function, proteinuria, and blood pressure. While not yet commercially available, gene therapy represents an innovative approach on the horizon.
These cutting-edge treatments demonstrate the potential for improved care and survival times for cats with kidney disease. With continued research and development, new therapies provide hope for effectively managing this serious feline health condition.
