A disease that frequently occurs in senior and geriatric cats is kidney (renal) disease.  The most common form is called chronic renal insufficiency (which progresses to renal failure).  This syndrome is a result of a cat’s kidneys becoming less and less effective.  The disease typically starts once a cat is over the age of 8 years, but younger cats can become affected. The kidneys' primary function is to filter waste products out of the body and into the urine. These waste products are produced on a daily basis through normal eating and activity.   The kidneys also play a role in regulating blood pressure and producing red blood cells.  The result of kidney disease is that the kidneys become less able to filter natural waste products and toxins out of the bloodstream.  Additionally, blood pressure may become unregulated and red blood cell production may decrease.

Symptoms of kidney disease can include increased drinking, increased urination, decreased appetite, failure to groom, weight loss, and vomiting.  Some cats show absolutely NO signs of a problem (or signs go unnoticed as they are slowly progressive) until disease is severe.  Diagnosis of kidney disease is often made by blood tests.  There are two blood values known as BUN (blood urea nitrogen) and Creatinine which are often very important in the diagnosis, but other blood tests also help in making a diagnosis.  See our blood work page for further information.  Chronic renal disease can be further confirmed with a concurrent urine sample to determine the concentration level of the urine (urine specific gravity).  Because urine concentrating ability decreases before the ability to clear blood waste products decreases, a urinalysis AND blood work at the same time should be performed to pick up early disease in the urine prior to changes in the blood.  There is now a test that can pick up kidney damage very, very early in the course.  It is called an ERD.  Please see the urinalysis page for further information.

Different cats live different lengths of time with kidney disease.   This can vary from 1 month to several years.  Early diagnosis of the disease can often help slow its progression and help provide good quality of life for whatever time is left.  There are many steps that can be taken to help slow the disease.  One of the foundations of treatment is providing the pet with a low protein, low phosphorus diet.  Excess protein and phosphorus in diets can overwork the kidneys and cause further damage.  There are a few prescription diets available that a veterinarian can recommend for treatment of kidney disease.  Also, drinking water helps flush the kidneys and helps keep them working.  Encouraging water intake by providing fresh clean water (or a pet water fountain) at all times is often helpful. 

As kidney disease progresses, the cat may have a diminished appetite due to toxins building up in the bloodstream, causing nausea.  They may also become lethargic because anemia (lack of red blood cells leading to decreased supply of oxygen in circulation) and/or hypertension (high blood pressure) can develop.  There are methods to treat these problems as they arise.  Frequent contact with your veterinarian is recommended as symptoms develop.  Regular checkups every 2 to 3 months are helpful to assure the symptoms are controlled as much as possible.  Even though kidney disease is progressive and there is no specific cure, a good relationship between an owner, the veterinarian, and the pet can provide the cat with the best opportunity for a good quality of life and keep the disease under control as long as possible.

Kitty G. developed severely elevated blood pressure secondary to chronic kidney disease.  Her initial kidney values in the blood were perfectly normal, and we did not have a urine sample to analyze.  Since secondary problems can develop, it is wise to check blood pressure as well as lab work in senior and geriatric cats (see blood work page, senior wellness page, and blood pressure measurement page).  As you can see from Kitty G's case, severe changes can occur inside the body that are not visible outside until they cause a noticeable problem.  Kitty's blood pressure was high normal at her last appointment then increased high enough in only 4 months to cause blindness again!!!  By looking at her otherwise, she looked just like any other cat her age with her problem but actually had serious changes occurring inside.

Please let us know if you would like to have your cat's blood pressure measured.  It is measured just like on a human but using a little bitty kitty cuff that goes around the tail or foot.  We do have to shave just a little bit of fur for the procedure, and it only takes a few minutes as long as the kitty is cooperative.  The blood pressure should be measured prior to exam, taking lab samples, and other stressful events.  It is best for the owner to be present to help calm the cat and decrease "white coat syndrome."

Jenny is measuring this kitty's blood pressure while Rachel holds the kitty.  Rachel is quietly talking and soothing the patient and trying to help him remain calm by hugging him as a restraint method.  Measuring the blood pressure does not hurt.  It feels strange for just a few seconds, and then the pressure releases (exactly like when a human has a blood pressure test).

To measure the blood pressure, a small area on the base of the tail (or a front or rear foot) is shaved.  A small kitty-sized cuff is placed around the tail (or arm/leg).  A probe (with a small amount of ultrasonographic gel to aid in sound conduction) is positioned directly over the vessel just a little further outward from the cuff.  When the probe is in proper position, the sound of blood pulsing through the vessel (like a swish-swish) can be heard.  The rectangular box shown in the picture is the doppler unit used to amplify the sound (rather than using a stethoscope like in people since a kitty's vessels are too small).  The cuff is blown up to occlude the vessel so the sound of pulsation is no longer audible, and then the pressure is released slowly until the blood flow sound is heard again.   When the first sound of blood flow returning is heard, the pressure number on the pump unit (sphygmomanometer) is the magic number.  It is called the systolic measurement (the top number of a blood pressure reading, such as 120 for a blood pressure reading of 120/80).  In cats, we usually  cannot obtain a diastolic (bottom) measurement.  Normal blood pressure measurements are similar to humans.  The difference is that we must account for stress.  Some people get "white coat syndrome" and their blood pressure increases when they go to the doctor.  Likewise, MOST cats get stressed just from being put in a carrier, traveling in a vehicle, being in an unfamiliar room with unfamiliar people, sights, sounds, and smells, and THEN having something blown up around their tail or foot while someone is restraining them, all with the sound of swish-swish nearby!  To account for this, our "normal" is dramatically increased for a stress factor.

For a more complete description and additional pictures about blood pressure monitoring, please visit our blood pressure measurement page.

Thank you to Kitty G. and her owners for allowing us to use her story as an educational experience for others!