Feline chronic kidney disease (CKD) is a condition marked by the gradual loss of kidney function over a period of months or years. It is particularly common in older cats, with some studies indicating it affects up to 40% of cats over the age of 10. This progressive deterioration means the kidneys become less able to perform their necessary tasks, leading to a decline in the cat’s overall health.
Causes and Key Kidney Functions
A cat’s kidneys perform several functions that maintain health. They filter waste products from the blood to create urine, regulate blood pressure, and produce hormones. The kidneys also play a part in maintaining the body’s hydration and balancing essential minerals like potassium and sodium.
The primary risk factor for developing CKD is advancing age, as kidney function can naturally decline over time. However, other factors can contribute, including genetic predispositions in breeds like Persian, Abyssinian, and Maine Coon cats. Past events such as kidney infections, exposure to toxins like lilies, or other diseases such as hyperthyroidism and high blood pressure can also lead to the development of CKD. In many situations, a specific underlying cause is never identified.
Recognizing the Signs of Kidney Disease
In the early stages of chronic kidney disease, a cat might not show any obvious signs of illness because the body can compensate for the initial loss of function. As the condition progresses, one of the first noticeable changes is often an increase in thirst and urination. This happens because the damaged kidneys can no longer concentrate urine effectively, leading to greater water loss that the cat tries to offset by drinking more.
Owners may also observe gradual weight loss, a decreased appetite, and lethargy. The cat’s coat might appear unkempt or dull. As waste products build up in the bloodstream, a cat may experience nausea and vomiting. This accumulation also causes bad breath with an ammonia-like odor, sometimes called uremic breath.
Veterinary Diagnosis and Staging
A veterinarian will perform a combination of tests to confirm the diagnosis. The primary diagnostic tools are blood tests and a urinalysis. Blood tests measure the levels of waste products like blood urea nitrogen (BUN) and creatinine. A newer marker, symmetric dimethylarginine (SDMA), is also valuable as it can detect changes in kidney function earlier than creatinine levels.
A urinalysis provides information about the urine’s concentration and whether it contains abnormal amounts of protein. Persistently dilute urine is a common finding in cats with CKD. Once a diagnosis is confirmed, veterinarians use a standardized system from the International Renal Interest Society (IRIS) to classify the disease’s severity. This system stages the disease from Stage 1 (early) to Stage 4 (advanced) based on blood test results and helps guide treatment recommendations and provide a clearer prognosis.
Disease Management and Supportive Care
Since there is no cure for chronic kidney disease, management focuses on slowing its progression and maintaining the cat’s quality of life. This is achieved through a multi-faceted approach involving dietary changes, hydration support, and medications.
Dietary Changes
A primary part of managing feline CKD is a switch to a therapeutic renal diet. These specialized diets are formulated to be low in phosphorus and protein. Restricting phosphorus helps to protect the kidneys from further damage. While some protein reduction is necessary to decrease the workload on the kidneys and limit the production of waste products, these diets still provide high-quality protein to prevent muscle loss. Studies have shown that cats with CKD that eat a prescription kidney diet live longer and have a better quality of life compared to those on standard diets.
Maintaining Hydration
Ensuring adequate hydration is important for a cat with CKD. Because their kidneys lose water, these cats are prone to dehydration, which can worsen their condition. Encouraging water intake can be achieved by providing multiple sources of fresh water, using water fountains, and feeding wet food, which has a much higher moisture content than dry kibble.
In more advanced stages, a veterinarian might recommend administering subcutaneous fluids at home. This procedure involves injecting a balanced electrolyte solution under the cat’s skin, where it is slowly absorbed by the body. Many owners can learn to perform this simple technique, typically giving fluids from a few times a week to daily, depending on the cat’s needs.
Medications
Veterinarians may prescribe various medications to manage the complications associated with CKD. These can include:
- Phosphate binders, which bind to phosphorus in the food to prevent its absorption.
- Medication to control high blood pressure, a frequent complication of CKD.
- Potassium supplements to correct low levels.
- Appetite stimulants for cats that are not eating well.
- Anti-nausea drugs to control vomiting.