The Silent Killer Stalking Your Senior Cat

The Leading Killer of Senior Cats

Kidney disease is the number one cause of death in senior cats, accounting for more than 1 in 3 deaths according to recent studies. As cats reach old age, their kidneys gradually lose function and the risk of failure rises dramatically. Kidney disease often has no obvious symptoms initially, so annual screening is critical to detect problems early and improve outcomes.

In this article, we will dive into the root causes of kidney disease, how to recognize the subtle signs, diagnosis and treatment options, and how to maximize quality of life for senior cats suffering from this condition. By understanding the implications of kidney disease, cat owners can help their aging felines live longer, healthier lives.

Defining Senior Cats

Cats are generally considered to be senior once they reach 11 years or older (Whitney Veterinary Hospital). As cats enter their senior years, there are some noticeable changes. They tend to become less active and playful. Their metabolism slows down so they may gain weight more easily. Senior cats sleep more often during the day. Many develop some degree of arthritis or stiffness in their joints. Their senses like vision, hearing, and smell may start to decline. In general, the body’s normal regeneration processes slow down, so it takes longer to recover from illness or injury. While each cat ages differently, the senior years typically bring more frequent vet visits and extra care to maintain quality of life.

Major Health Risks

Senior cats face an increased risk for certain health conditions as they age. Some of the most common ailments and diseases in senior cats include:

Kidney Disease

Kidney disease is very prevalent in older cats. According to Dr. Marty Becker, more than half of cats over 15 years old have some form of kidney disease. As cats age, their kidneys gradually become less efficient at removing toxins from the blood. This can lead to a buildup of waste products and cause symptoms like increased thirst and urination, weight loss, poor appetite, vomiting, and bad breath.


Cancer is unfortunately common in senior cats. Some of the most prevalent cancers in older cats include lymphoma, mast cell tumors, and mammary cancer. Catching cancer early greatly improves the chances of successful treatment. That’s why regular veterinary checkups are so important for senior cats.


Diabetes mellitus is another condition that becomes more common in cats as they age. When a cat has diabetes, its body either doesn’t produce enough insulin or can’t use insulin properly, leading to high blood sugar. Symptoms include increased thirst and urination, increased appetite, and weight loss. Diabetes requires lifelong management with insulin injections, diet, and monitoring.


Hyperthyroidism results from an overactive thyroid gland producing excess thyroid hormone. It’s a very common condition in older cats. Symptoms include weight loss despite increased appetite, hyperactivity, vomiting, increased thirst and urination, and unkempt coat. Hyperthyroidism is treatable with medication, radioactive iodine, surgery, or dietary therapy.


Arthritis causes joint pain, stiffness, and difficulty moving around. It can result from normal wear and tear on the joints as a cat ages. Signs of arthritis include hesitating to jump, use stairs, or get in the litter box. Managing arthritis involves weight control, medications, joint supplements, gentle exercise, and providing easy access to food, water, and litter.

Kidney Disease

Kidney disease is one of the most common health issues affecting senior cats. It can be either acute (sudden onset) or chronic (gradually develops over time). Chronic kidney disease (CKD) is most prevalent, affecting up to 32% of cats aged 15 years and older. The kidneys have a large functional reserve, so cats can lose up to two-thirds of their kidney function before outward symptoms appear.

As CKD progresses, the kidneys become less efficient at removing toxins from the blood. This leads to a buildup of waste products and electrolyte imbalances. Early symptoms include increased thirst and urination. Cats will drink more to compensate for failing kidneys. As the disease worsens, symptoms can include weight loss, poor appetite, vomiting, lethargy, and bad breath. Acute kidney injury involves a sudden loss of kidney function over days or weeks, usually caused by ingesting toxins, urinary obstruction, or decreased blood flow. It requires immediate veterinary treatment.

Root Causes

There are several root causes that can lead to kidney disease in senior cats:

Age-related degeneration of the kidneys is one of the most common root causes in older cats. As cats age, their kidneys naturally decline in function and efficiency. According to Pet Health Network, kidney function begins to decline after around age 7 for most cats.

Infections such as pyelonephritis, which is an inflammation of the kidney tissues due to bacteria, can also cause kidney disease and failure. These bacterial infections often start in the urinary tract and spread to the kidneys via the ureters.

Toxins from things like antifreeze, lilies, grapes/raisins, vitamin D, lead, or other substances can damage and impair kidney function in cats. Exposure to these toxins introduces compounds that are toxic to the kidneys.

Dental disease can also contribute to kidney issues. Bacteria from severe periodontal disease can spread through the bloodstream and infect the kidneys. This leads to inflammation and damage over time.

Other potential causes include kidney stones, kidney cancer, polycystic kidney disease, high blood pressure, and damage from injuries.


There are several methods vets use to diagnose kidney disease in cats:

Blood tests can measure levels of substances like creatinine and BUN (blood urea nitrogen) which tend to increase as kidney function declines. Changes in these blood values over time can indicate worsening kidney disease.

Urine tests look for dilute urine, proteinuria (too much protein loss in the urine), or other abnormal findings. Elevated protein in the urine is a common sign of kidney dysfunction.

Imaging tests like X-rays, ultrasounds, or CT scans allow vets to visually assess the size, shape and structure of the kidneys. This can reveal issues like small, irregular kidneys or the presence of stones, cysts or masses.

Kidney biopsies can definitively diagnose some underlying kidney disorders like glomerulonephritis. But biopsies carry risks so are not commonly performed unless the diagnosis is unclear.

Overall, vets use a combination of blood work, urinalysis, imaging and sometimes biopsy to fully diagnose the cause and severity of kidney disease in cats (Zoetis Petcare).


There are several treatments available for cats with kidney disease, depending on the stage and severity of the condition. Some common treatments include:

  • Fluids – Providing extra fluids, usually subcutaneously or intravenously, helps flush toxins from the body and prevent dehydration. Fluids may be given at home or during vet visits. (VCA Hospitals)
  • Diet Changes – Feeding a kidney-friendly diet low in phosphorus and protein can reduce strain on the kidneys. Prescription renal diets are commonly recommended. (Cornell University)
  • Medications – Drugs like ACE inhibitors help control blood pressure and reduce protein in the urine. Anti-nausea meds relieve vomiting. (Pet Hospice Vet)
  • Dialysis – In severe cases, dialysis can filter waste from the blood. This requires anesthesia and specialized equipment.

The combinations of treatments are tailored to each cat’s individual needs. The goal is to slow disease progression, manage symptoms, and maintain a good quality of life.

Managing Kidney Disease

Kidney disease in cats can often be managed at home with some adjustments to their care. The main focuses for home management are special diet, extra hydration, and regular vet checkups.

Feeding a special veterinary kidney diet reduces stress on the kidneys by limiting protein, phosphorus, and sodium levels. Cats with kidney disease should have unlimited access to fresh water. Adding extra bowls around the house, using fountains, or feeding wet food can all increase fluid intake. Subcutaneous fluids administered under the skin may be recommended by your vet to support hydration and kidney function.

Regular vet checkups every 3-6 months allow monitoring of kidney values to detect progression and make any needed adjustments to treatment. At home, watching for changes like increased thirst, weight loss, vomiting, appetite changes, and lethargy can help identify worsening kidney function between appointments.

With treatment tailored to your cat’s needs, many cats can live comfortably with kidney disease for years. Focus on their quality of life and make adjustments as their condition progresses.

Quality of Life

Even with a diagnosis of kidney disease, there are many things cat owners can do to maintain and even improve their cat’s quality of life. Proper treatment and management of the condition are key. Medications prescribed by a veterinarian, along with dietary changes and supplements, can help reduce symptoms and slow the progression of kidney disease.

In addition to medical interventions, focusing on your cat’s happiness and comfort is important. Providing soft, comfortable bedding, keeping food and water easily accessible, maintaining a consistent routine, and spending quality time together through play, petting, and affection can also boost their quality of life. Some cats benefit from mild exercise and environmental enrichment through accessing outdoor spaces or cat trees and toys.

As the disease progresses, the quality of life declines. Discuss options like fluid therapy, adequate pain management, and dialysis with your veterinarian as needed. But keep in mind that euthanasia may eventually be the most humane option to prevent your cat from suffering once their quality of life diminishes to a point they are consistently uncomfortable or in pain. Monitor their health and behaviors closely and make end-of-life decisions in consultation with your vet.1

The Takeaway

Ensuring quality of life for senior cats comes down to early detection and proactive care when it comes to kidney disease. By understanding kidney disease is the leading cause of death for older cats, cat owners can better monitor their cat’s health and wellbeing. An annual senior exam, blood work, and urinalysis can catch kidney disease in early stages when treatment is most effective. Managing kidney disease revolves around a customized treatment plan that may include diet change, intravenous fluids, medication, and more based on your cat’s needs. While kidney disease cannot be cured, early intervention and dedicated at-home care can prolong and improve your cat’s life. The key is partnering closely with your vet and prioritizing your cat’s quality of life above all else.

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