Chronic kidney disease is common in cats. It can affect cats at any age but is most common in older cats.[1] The disease has no cure. The goals of treatment are to slow the progression of the disease and maintain a good quality of life for the cat.
 
Functions of the Kidneys
The kidneys filter the blood and excrete waste products into the urine. When the kidneys don’t work properly, these waste products accumulate in the body. The kidneys balance the body’s water level by adjusting the urine concentration. Kidney disease impairs the ability to concentrate the urine and retain water in the body, so animals with kidney disease become dehydrated. The kidneys also help regulate blood pressure, red blood cell production, and acid-base balance.
 
Signs of Kidney Disease
Kidney disease is already advanced (at least two-thirds of kidney function lost) by the time signs of illness appear. Cats typically have the following signs:

• Increased thirst
• Increased urine volume
• Decreased appetite
• Decreased activity
• Weight loss
• Vomiting
• Unkempt coat

 
Keep an eye on the size of the urine clumps in your cat’s litter box. Enlarging urine clumps can mean that urine volume is increasing, which is one of the earliest signs of kidney disease. Other disorders (like diabetes) can also increase the urine volume, so larger-than-usual urine clumps warrant a visit to the veterinarian.
 
As chronic kidney disease progresses, the loss of kidney function leads to further problems:

• Hypertension (high blood pressure)
• Dehydration
• Muscle wasting
• Mouth ulcers
• Anemia (lack of red blood cells)
• Electrolyte and mineral imbalances

 
Causes of Kidney Disease
Acute kidney injury is a rapid loss of kidney function over hours to days. Some of the many possible causes are toxins, infections, and shock. Depending on the cause and severity, acute kidney damage can sometimes be reversed with treatment.
 
Chronic kidney disease is more common than acute kidney injury in cats. In chronic kidney disease, kidney function gradually decreases over time. The cause is usually not known. The same entities that cause acute kidney injury can lead to chronic kidney failure. Other possible causes are high blood pressure, abnormal kidney development, infection or inflammation of the kidneys, disorders that alter blood flow to the kidneys, and cancer.[2]
 
Diagnostic Tests
Tests are used to diagnose kidney disease, assess the stage of the disease, identify metabolic problems caused by the disease, diagnose other disorders (like thyroid disease) that cats with kidney disease sometimes also have, and possibly reveal the cause of the kidney problem.
 
Blood tests and urinalysis (analysis of urine) are typically the first diagnostic tests for cats with suspected kidney disease. Blood pressure measurement, urine culture to test for bacterial infection, and ultrasound or x-ray imaging of the urinary tract are also commonly performed for cats with kidney disorders.
 
Cats with chronic kidney disease benefit from regular testing to monitor disease progression and adjust treatment. In general, these cats should see a veterinarian for blood tests, urinalysis, and blood pressure measurement every 3 to 6 months.[2]
 
The stage and substage of chronic kidney disease are evaluated with specific tests[3]:

• Blood creatinine level
• In some cases, blood symmetric dimethylarginine (SDMA) level
• Urine protein level
• Blood pressure

 
Treatment
Chronic kidney disease can’t be cured, but it can be managed. The prognosis is variable; some cats can live with the disease for years. If your cat has kidney disease, work with your veterinarian to craft a treatment plan that will give your cat a good quality of life.
 
Treatment strategies are based on the stage of disease and the individual cat’s needs and may include the following[1,4]:

• Diet change to a clinical kidney diet (best done gradually so the cat will accept the new food)
  
• Fluid therapy, often done at home by injecting fluid under the cat’s skin
• Medications and supplements to treat hypertension, loss of appetite, high blood phosphate level, low blood potassium level, protein loss, and anemia

 
References
1. Sparkes AH, Caney S, Chalhoub S, et al. ISFM consensus guidelines on the diagnosis and management of feline chronic kidney disease. J Feline Med Surg. 2016;18(3):219-239.
2. Brown SA. Renal dysfunction in small animals. Merck Veterinary Manual website. https://www.merckvetmanual.com/urinary-system/noninfectious-diseases-of-the-urinary-system-in-small-animals/renal-dysfunction-in-small-animals. Accessed February 26, 2019.
3. International Renal Interest Society. IRIS staging of CKD. http://www.iris-kidney.com/pdf/IRIS_2017_Staging_of_CKD_09May18.pdf. Updated 2017. Accessed February 26, 2019.
4. International Renal Interest Society. Treatment recommendations for CKD in cats. http://www.iris-kidney.com/pdf/IRIS_2017_CAT_Treatment_Recommendations_09May18.pdf. Updated 2017. Accessed February 26, 2019.
 
Photo by Nicolas Picard on Unsplash

There’s something special about living with an older dog or cat. After years in the family, senior pets know the household routine and seem able to read our thoughts. And because of advances in nutrition and veterinary medicine, pets tend to live longer than they once did.
 
Pets’ needs change as they age, and older pets need extra care. Regular veterinary visits and some household adjustments can help keep dogs and cats healthy and comfortable into their senior years.
 
How old is old?
The common belief that 1 dog year equals 7 human years isn’t really true. Dogs don’t all age at the same rates; small breeds tend to live longer than large breeds. Cats and small dogs are traditionally thought of as senior at about 7 years old (although since they can live well into their teens, 7 years may actually be middle age). Large dogs enter the geriatric stage a bit sooner. Check out these resources for more information:

• Senior pet care, including estimated human age equivalents for older pets (American Veterinary Medical Association)
  
• Feline life stages (The Cat Community)

 
What to watch for
Keep an eye out for gradual changes over time. Stiff joints, reduced vision, and picky eating are not necessarily normal effects of aging. They are often symptoms of medical conditions that can be treated.
 
As dogs and cats get older, their risk for arthritis, cancer, kidney disease, thyroid disease, heart disease, and many other problems increases. Watch for symptoms like these:

• Mobility trouble, including reluctance to jump up, stiffness when rising, difficulty going up or down stairs, and reduced participation in family activities
• Sensitivity to touch (such as growling during petting)
• Increased grumpiness
• Urine or stool accidents in the house
• Changes in appetite or food preferences (for example, preferring soft to crunchy food)
• Changes in water intake
• Changes in urine volume or urine frequency (for cats, look for bigger urine clumps in the litter box)
• Unexplained weight gain or loss
• Anxiety or confusion
• Difficulty seeing or hearing
• Changes in the fur
• Lumps or swelling
• Coughing or wheezing
• Exercise intolerance
• Vomiting or diarrhea

 
Veterinary care
Dogs and cats should be examined by a veterinarian at least once a year. Older pets may need to be seen more frequently. Many veterinarians recommend wellness checks every 6 months for senior animals. Think of it this way: if 1 dog year really were the same as 7 human years, then an annual examination for a dog would be the same as an examination every 7 years for you and me.
 
Some diseases progress for a long time before an animal shows any symptoms. Routine diagnostic testing can turn up evidence of chronic disease early in its course, when treatment is most effective. Your veterinarian may recommend these tests for your senior pet:

• Bloodwork, including complete blood count, chemistry profile, thyroid hormone level, and tests for infectious diseases (like heartworm and tick-borne diseases)
• Urinalysis
• Fecal analysis
• Blood pressure measurement

 
Preventive health care includes vaccination. Rabies vaccination is required by law in North Carolina for all dogs, cats, and ferrets over 4 months old (for good reason). Dogs’ and cats’ vaccination needs may change as they age, so talk with your veterinarian about immunizations that make sense for your pet.
 
Things you can do

• Discuss your pet’s changing nutritional needs with your veterinarian.
• Keep your pet in the target weight range. Obesity is linked to diabetes, arthritis, and other conditions in animals.
• Protect your pet from summer heat and winter cold. Geriatric and baby animals cannot regulate their body temperature as easily as healthy young adults.
• Provide soft bedding.
• Make sure your pet has easy access to food bowls, litter boxes, and favorite sleeping areas, ideally without having to navigate stairs to reach them.
• Don’t assume that changes in behavior and activity are normal for older animals.

Photo by Eric Han