Feline Kidney Disease
By Dr. Leslie Kuczynski, VMD, DACVIM | Internal Medicine
The kidneys play a crucial role in a cat’s wellbeing, affecting everything from waste excretion to hormones to blood pressure. Kidney failure is one of the leading causes of death in cats, so as an owner it’s important to recognize the onset of kidney problems before they can cause permanent damage. Dr. Leslie Kuczynski, VMD, DACVIM (Small Animal Internal Medicine) answered all of our questions regarding feline kidney disease to help identify symptoms of kidney disease and know when a cat needs treatment.
What are signs of feline kidney disease?
Common symptoms of kidney disease in cats include increased thirst (polydipsia) and increased urination (polyuria). These symptoms occur because as the kidneys become diseased, they can no longer produce concentrated urine. Increased thirst and urination are often the first symptoms noted in cats with kidney disease. Other symptoms result from the inability of diseased kidneys to excrete waste products. These symptoms can include decreased appetite (either entirely or a preference for more novel foods), weight loss, poor hair coat or unkempt appearance, malodorous breath, vomiting, weakness or lethargy.
There are two categories of kidney disease, acute and chronic. How are they different?
Acute kidney disease occurs more suddenly while chronic kidney disease is a more smoldering or insidious process.
Acute kidney disease occurs when there is a sudden insult to the kidneys – this could include the blood vessels supplying the kidneys or any of the intrinsic parts of the kidneys themselves. Causes of acute kidney disease can include infections, toxic insults, vascular compromise (blood clot formation or reduced blood flow to the kidneys), and cancer, as some examples. Protracted urinary tract obstruction (from stones, mucus plugs, blood clots or tumors) can also result in kidney damage and acute kidney disease. In some cases, acute kidney disease can be entirely reversible. In other cases, there is persistent damage that leads to secondary chronic kidney disease. In other cases, the patient does not survive an acute insult to the kidneys.
Chronic kidney disease occurs when there is irreversible damage to the tissues of the kidneys. It is technically defined as kidney damage that has persisted for at least three months. Chronic kidney disease can be initiated by congenital or acquired conditions. For example, developmental abnormalities, such as renal dysplasia (when the kidneys do not develop normally in the body) can be a cause of chronic kidney disease. In older cats, chronic tubulointerstitial nephritis is the most common cause of chronic kidney disease. It is not entirely clear what triggers this condition but it is a common ailment of aging cats. Patients with chronic kidney disease often survive for months to years with good quality of life; however, the condition is typically progressive and irreversible.
When are cats more likely to develop chronic kidney disease (age, certain breeds, etc.)?
Although frequently considered a condition affecting older animals, chronic kidney disease occurs with varying frequency in cats of all ages. Cats can range in age from less than one year to geriatric (over ten years of age) with over 50 percent of cats with chronic kidney disease described in one study being over seven years of age. Although any breed of cat can be affected, in one study, Maine coon, Abyssinian, Siamese, Russian blue and Burmese cats were over-represented. Polycystic kidney disease is a condition that can lead to chronic kidney disease, and this is more common in Persian and Himalayan cats.
There are also certain household items that can be damaging to cats’ kidneys. What are they and how can owners protect their cats from coming in contact with them?
Certain household items can lead to acute insult to the kidneys in cats. Included in this list are anti-freeze (ethylene glycol), certain pesticides or herbicides, lilies (as little as two leaves or part of a flower from lilies of the genera Lilium or Hemerocallis (day lilies)), and certain medications that the humans or animals in the family may be taking (including but not limited to NSAIDs, certain antibiotics, and ACE inhibitors). Owners can protect their cats by being meticulous with storage of personal medications, avoiding use of pesticides or herbicides in the presence of their cats, and avoiding exposure to lilies.
When should someone take their cat to the vet if they suspect kidney failure?
If there is any concern that a family cat is not feeling well, for example, he or she is not eating well, is showing signs of nausea, or has a recent increase in thirst or urination, an owner should bring the cat to their family veterinarian for a physical exam as well as lab work including a complete blood count, biochemistry panel to assess organ function, and urinalysis. It is also important to take note of any possible toxins or medications that the cat has been exposed to and make the veterinarian aware of these exposures at the time of the visit.
What are some of the tests a veterinarian will run to determine if a cat has chronic kidney disease?
Routine blood and urine testing is the mainstay of identifying chronic kidney disease. Initial testing includes a complete blood count (CBC), biochemistry panel, and urinalysis. Often secondary testing such as urine protein quantification, blood pressure measurement, urine culture, abdominal radiographs and/or abdominal ultrasound is recommended.
Can routine, physical examinations help prevent kidney disease?
Routine evaluation by a veterinarian that includes examination, body weight and discussion of a cat’s habits at home (thirst, urination, appetite, etc.) can help to identify changes in the cat’s appearance or behaviors that may indicate a problem. The exam and history performed by a veterinarian is unlikely to prevent kidney disease, but may help identify a problem early and help start a proactive management strategy.
Once diagnosed how can cat owners help manage chronic kidney disease and how is chronic kidney disease treated?
Cat owners can help manage chronic kidney disease at home by feeding special veterinary prescription diets that are restricted in phosphorus and protein and therefore, easier on the kidneys. Owners can also work with their family veterinarian to utilize medications and supportive care at home to help alleviate symptoms related to chronic kidney disease. This could include antacids, anti-nausea medications, antibiotics if indicated, supplemental fluid therapy at home, or appetite stimulant medications. Owners can also follow-up with their family veterinarians on a regular schedule to monitor for progression or secondary complications of chronic kidney disease.
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