As cats age many of them develop renal insufficiency, which is a decrease
in the function of the kidneys to the point that they are not able to
adequately do their job. This happens because kidney cells die and are not
replaced. To compensate, the remaining kidney cells learn to do their job
better. Fortunately, it is possible to slow the rate of cell death and to
encourage the other kidney cells to function better, making it possible to
slow the progress of the disease. Still, the disease is incurable and will
eventually lead to the death of the patient over time. We have managed cats
with renal insufficiency for as long as ten years before that happened,
though. Although that is an exceptional case, many cats live several years
with good quality of life.
If the signs are very mild, we will sometimes rely on diet alone. When we
do this, we ask owners to let us check lab values after 2 weeks to one
month and then every three to six months. We are not really looking for
improvement, we are trying to make sure we catch any deterioration in
kidney function quickly. Many cats do actually show improvement in the
kidney related blood work with dietary control alone, often by the time we
do the initial blood work.
The things that help prevent loss of kidney function are adequate
hydration. Feeding canned food is preferable to dry food due to this and I
think that going to subcutaneous administration of fluids early in the
disease process is beneficial. Medications to control blood pressure are
sometimes necessary and may be helpful even when increases in blood
pressure can not be documented. Potassium supplementation is helpful in
many cats. While its use is controversial, calcitriol administration seems
to make many cats feel better. Phosphate binding agents (such as Amphogel
tm) are helpful but less necessary when using a low protein/low phosphorous
diet. Figuring out when to add each of these medications is difficult
because each patient is different but all may be necessary at some point.
Making sure that complicating diseases are not present is a good idea, too.
The most common one is hyperthyroidism, which should be tested for if there
is weight loss, especially if it is accompanied by an increase in appetite.
Monitoring urine specific gravity is helpful. I like this test a lot when
it is easy to get urine, because it helps to determine how well the kidneys
can concentrate urine. Keeping track of Genny's weight helps a great deal,
too. Weight loss can actually be good for patients with kidney problems but
if it is occurring too fast it can be a sign that additional therapy is
It is critical for cats with kidney problems to drink water on a regular
basis. A great increase in thirst often indicates that the kidney
situation is becoming unstable again and when cats with kidney disease stop
drinking they need to be checked to see if the kidney disease is getting
I don't know of any food supplements other than those mentioned above that
are helpful. Potassium administration seems to help even when potassium
levels are in the normal range, so if it isn't too much trouble (some cats
hate the potassium preparations) it would be worth considering
There is a very good web site for chronic renal failure
Hope this helps some.
Mike Richards, DVM