Introduction
There's no need to complicate this subject with a long introduction. We vets all pretty much agree on this subject:
As pets become old, the kidneys slowly lose their ability to work well. Young healthy kidneys contain approximately 1 million individual kidney tubules, each able to process and excrete urea, eliminate excess electrolytes and concentrate the urine. With age, many of these tubules are damaged, clogged up, scarred, and become non working and go into retirement. The pet's own immune system will often attack damaged tubules and replace them with a type of scar tissue.
Protein molecules, which are too large to be excreted through a young and healthy kidney begin to pass through the less healthy kidneys of older pets.
It becomes harder and harder for the kidneys to process and eliminate urea. This is one of the most important functions of the kidney.
Another function of the kidneys is to product a hormone (erythropoietin) that stimulates the bone marrow to produce red blood cells. As the kidneys age, this function is compromised as well leading to anemia.
Kidney disease tends to be a slow degenerative process that owners and veterinarians alike miss in the early stages of the disease because there are no obvious symptoms and we don't have simple, accurate, or inexpensive urine or blood tests that detect the disease in the early stages.
There are often no symptoms of illness until the kidneys are down to about 25% of normal function.
As the disease progresses the observant owner will often notice that the pet is drinking and urinating more. This happens as a result of the kidneys attempting to flush out urea and lose their ability to concentrate the urine. We have test kits that detect excessive amounts of protein in the urine at this stage of the disease and routine blood tests that may or may not confirm the disease at this mid stage of the disease.
As the disease gets worse, pets start acting sluggish, have poor appetites, often are nauseated, and just don't feel well. They'll have good days and bad days. Routine blood tests will confirm the disease.
Kidney disease IS THE NUMBER ONE CAUSE OF DEATH IN OLD CATS AND DOGS
In the United States, kidney disease is the number 2 cause of death in old humans.
Treatment:
In human medicine, kidney transplants and dialysis are commonly available, but not for pets.
For pets, the most important part of managing kidney disease is through therapeutic diets specially designed for kidney disease patients.
Note: it's a common misunderstanding; diseases of the bladder or lower urinary tract diseases (bladder stones, bladder infections, etc) are treated differently than Kidney problems. Therapeutic diets are an important part of treating lower urinary tract diseases too, but they are different.
There are several excellent therapeutic kidney diets to choose from... simply find one that your cat or dog likes.
These diets tend to be low in sodium to prevent fluid retention and prevent renal hypertension, have reduced phosphorus to slow the progression of kidney disease.
Increased Omega-3 Fatty Acids to improve blood flow to the kidneys.
Proteins chosen to minimize urea production, buffering to prevent metabolic acidosis, and increased B vitamins and potassium to compensate for urinary losses associated with kidney disease. Added soluble fiber designed to bind and lower serum urea nitrogen.
Studies indicate that kidney disease patients live about 30% longer and with fewer symptoms when fed prescription diets made for treating kidney disease. Here are the prescription only diets that I know about that are often very successful in managing kidney disease:
Hill's K/D diet for cats or dogs.
Royal Canin's Renal diets for cats and dogs
Purina NF (Nephritis Formula) for cats & dogs
Supplements that should be considered for patients with kidney disease:
Omega fatty acids: all of the special diets discussed on this page already have added omega fatty acids. They help with blood flow to the kidneys and may help reduce inflammation and aid in healing. Adding more may or may not be helpful. I vote for more.
Phosphate binders: Phosphorous levels rise with kidney disease which initiates a destructive cycle further reducing kidney functions. All of the recommended renal diets have reduced phosphates to help prevent this problem. But, by adding medications that further reduce serum phosphorus has been shown to inprove quality and quanity of life in kidney patients. Phosphate binders come in tablets that your vet may prescribe if blood tests indicate your pet has high phosphorus levels.
New on the market is Epakitin which has helped a lot of my patients and has the advantage of tasting good... an important plus especially for cats.
Phosphate binders are especially important for pets that refuse low phosphate renal diets.
Renal Essentials: a product for cats and dogs made by the VetriScience people.
Active Ingredients Per 2 Tablets:
Eicosapentaenoic Acid (EPA) . . . . . . . .180 mg
Docosahexaenoic Acid (DHA) . . . . . . . . 120 mg
Astragalus Root Powder . . . . . . . . . . .60 mg
Lecithin . . . . . . . . . . . . . . . . . .50 mg
Rehmannia (Root) Extract. . . . . . . . . . 50 mg
L-Arginine . . . . . . . . . . . . . . . . .50 mg
Nettle (Urtica dioica) Seed Extract. . . . .50 mg
Cordyceps sinensis Extract . . . . . . . . .50 mg
N,N-Dimethylglycine HCl. . . . . . . . . . .25 mg
Potassium (Gluconate). . . . . . . . . . .8.25 mg
Pyridoxal 5-Phosphate (Vitamin B6) . . . . . 8 mg
Inositol . . . . . . . . . . . . . . . . . . 8 mg
Thiamine (Vitamin B1) . . . . . . . . . . . .4 mg
Riboflavin (Vitamin B2) . . . . . . . . . . .4 mg
Choline . . . . . . . . . . . . . . . . . . .4 mg
Folic Acid . . . . . . . . . . . . . . . .0.15 mg
Methylcobalamin (Vitamin B12). . . . . . 0.050 mg
Click on any of the links below to go to the page describing the diets and/or supplements that are often recommended for certain disease conditions:
