Archive for December, 2016

Feline Renal Disease

Tuesday, December 13th, 2016

kidney-adult-catOver the years we have seen many changes in feline health, from advancements in medical knowledge and techniques to increasing longevity in our feline companions. At Carlson Animal Hospital our feline patients benefit from the most current, advanced medicine and knowledge. Feline kidney disease is one area where both our feline caregivers and your Carlson Animal Hospital team can make a big impact.

Renal disease refers to any form of impaired function of the kidneys.

The kidneys are paired organs that are located in the abdomen just behind the ribs and directly below the spine on the left and right side. They are part of the urinary system and along with the two ureters are designated as the upper urinary system. Each ureter leads from the kidney to the lower urinary tract which is comprised of the bladder and the single urethra taking urine out of the body.kidney-kitten

One cat out of every three has the probability of developing some form of kidney disease in their lifetime. As cats age this probability increases. We see all types of feline renal disease each and every day, so we are very familiar with diagnosis and treatment of this illness.

Normal Kidney Function

kidney-nephron-of-kidneyEach kidney is made up of 1,000,000 nephrons. Some nephrons are  functional and are doing the work while others are in reserve. When the blood from the heart comes to the kidneys it travels through a network of decreasingly sized vessels until it arrives at the smallest structures in the nephrons called glomeruliIt is here that the blood is filtered. Greater than 90% of the blood and its contents is returned to the body freshly cleaned and filtered by the kidneys. The fluid that remains contains the waste products and exits the body as urine. The kidneys also produce a variety of substances and hormones that the body depends on and uses to regulate other functions such as electrolyte balance, red blood cell production, vitamin D levels, and blood pressure to name a few.

If the kidneys begin to malfunction or become less efficient in their role many complications can occur throughout the body. These complications can lead to varying levels of illness and even death.

Renal Disease

Feline kidneys can be affected by many factors that can decrease their ability to function properly. Some of these factor can be related to the environment like diet, toxic substances, age, and genetics, while others are not completely understood at this time.


Persian patient

Some forms of kidney disease can be inherited and breeds such as PersianHimalayanMaine CoonRagdollAbyssinians, and the Rex breeds; these breeds demonstrate a genetic predisposition to kidney disease. Most feline kidney diseases are acquired during a cat’s lifetime and not inherited. These acquired conditions are divided into two categories: acute and chronic disease.

cat renal diseases kidney-pictures

Feline kidney with chronic changes

Acute –  this type of kidney disease is a severe condition with a sudden (acute) presentation of clinical signs that begin over a matter of days to weeks.

Two of the most common causes for acute injury or failure in cats are ingestion of toxins and blockages of either urine flow from the body or blood flow to the kidneys. Examples of kidney toxic substances include household plants and chemicals such as the authentic lily family of plants( Easter, Tiger, Day, Oriental etc.) as well as water in the vase containing these lilies, antifreeze, lead paint, and household cleaning products.

 Accidental ingestion of  some human medications, one of the most common being ibuprofen capsules, can also cause kidney damage.

Decreased blood flow to the kidneys can cause acute injury and can occur in cases of shock or trauma such as a car accident or dehydration. Blockage of urine from leaving the body occurs  commonly in cats because they are predisposed to highly concentrated urine that allows for crystallization of minerals that contribute to forming plugs as well as stones that can obstruct their urinary tract, particularly in male cats.

Chronic – this type of kidney disease is a much slower progressing form of injury and can take months to years to develop. It is common that clinical signs are absent in the early stages of chronic disease. Clinical signs will gradually begin to emerge as the disease progresses. Some factors that contribute to chronic disease include; infections, progressive dental disease, trauma, breed, elderly age, and concurrent diseases. It is not uncommon that the specific cause of chronic renal disease goes undetermined in many cases.

International Renal Interest Society (IRIS) – This is a group of veterinarians from around the world, that has developed a four tier staging of kidney disease based upon specific objective parameters.  It is important and very valuable to stage the kidney disease.

Detecting Renal Disease


Dr. Toncray with one of our patients.

Clinical signs that you may notice in a cat with acute kidney disease can be sudden onset of vomiting, lethargy, anorexia, and general malaise. These signs can be very pronounced.

With early chronic kidney disease there is often an absence of any clinical illness. In the later stages of chronic disease, owners may begin to notice their cats drinking and urinating more as well as losing weight and looking thinner. There may also be lethargy, weakness, vomiting, decreased appetite (possibly related to nausea) and bad breath.

On physical examination our doctors may detect painful or enlarged kidneys in acute disease or small and irregular shaped kidneys in chronic disease. The size and fullness of the bladder can also add information as well as the appearance of the eyes (retinas), mouth, gums, body condition, and hair coat.

If we suspect kidney disease we will advise additional diagnostic tests that will help clarify and further evaluate the kidneys. These tests include blood work (complete blood counts and serum chemistry panels), urinalysis, radio-graphs,ultrasound, and blood pressure evaluations.


Many cats with acute kidney disease do well while others do poorly dependent upon the cause. Ingested toxins such as lilies generally carry a more guarded prognosis, while urinary obstructions in male cats generally have a good prognosis.  If diagnosed early and removed directly,  cats with urinary tract stones/ plugs that are causing kidney damage because of obstructed urine flow can have a favorable outcome. 

The outcome for chronic disease is generally much better particularly if the IRIS stage is 1 or 2.  Treatment is aimed at slowing the progression of nephron loss and damage. Ultimately, all of the nephrons in reserve will be utilized and it is important to help each remaining nephron to function as long as possible.  If diagnosed early, monitored routinely, and treated with supportive therapy, many cats live long full lives with chronic renal disease.

Treating Renal Disease

Treatment will vary depending on the cause, the length of time there has been illness, and the amount of kidney damage that has occurred. Acute cases of kidney disease are considered emergency situations and we will most often recommend hospitalization.  Most cases require intensive care while hospitalized. Treating and/or removing the specific cause, if identified,can be a possible cure in some acute kidney diseases.

We focus on early detection and therapy  to treat chronic kidney disease treatment to increase the working lifetime of the kidney. Diet changes can help decrease the kidney’s work load and allow optimal nutrient availability. Focused treatment to avoid secondary complications like anemia,electrolyte alterations, high blood pressure, and protein loss in the urine will support kidney function. As the condition gradually advances, supplying fluids for support will also increase health and longevity.

We work with each patient and family individually to provide the most comprehensive treatment plan to support their pet’s kidneys.

Preventing kidney disease

       One of the best preventive efforts is to remove potential kidney toxic substances from your cat’s environment. This is a good way to minimize toxic exposure.

water makes the cat's kidneys function better

Lots of water helps a cat’s kidney function and overall health.

Encouraging water consumption such as feeding canned foods as part of the diet ( 70% water) can help maintain hydration and encourage optimal urine concentration. Routine annual monitoring in middle age (7-9 years) and older cats will allow for early detection of chronic kidney changes.  Early monitoring in breeds that are at high risk will allow for specific planning and increased life span.

Everyone at Carlson Animal Hospital is dedicated to the successful management of kidney disease through prevention, treatment and improving quality of life time for our feline companions.

It is our pleasure to serve you and your pets. Please do not hesitate to call our offices if you have any questions or concerns. Thank you for allowing us to be a part of your veterinary healthcare team.

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Carlson Animal Hospital               708.383.3606