Geriatric Cats

Medical Needs of Geriatric Cats

The aging cat goes through a variety of changes that result in the ultimate failure of individual body organs and systems. Recent research has identified a problem related to potassium balance that is common in many older cats. Fortunately, the problem can be treated. As a result, many elderly cats are now living longer and healthier lives.

Potassium

Potassium is an electrolyte found in the cat's blood and within every cell of the body. It is essential for cellular function. Potassium is probably most important for the cells which make up skeletal and cardiac (heart) muscle. Severe muscle weakness can result when the body becomes depleted of potassium.

Recently, two important discoveries have been made about potassium and older cats. A mild form of hypokalemia (low blood potassium) has been identified in the older cat and is associated with depression and inactivity, a poor appetite and haircoat, and the development of mild anemia. Previously, we considered these to be a part of the normal aging process. Now we know that this process can be reversed with potassium supplementation. Unfortunately, we do not have a test to conclusively identify these cats because the blood test for potassium is a poor reflection of the body's total store of potassium. Blood potassium may be normal in cats that are actually depleted of potassium. For these cats, a 30 to 45 day trial of potassium is necessary. If response occurs and potassium supplementation is continued, the cat will continue to feel, act, and eat better and will live longer.

The second discovery about low blood potassium is related to the effect of potassium on the kidneys. The kidneys are the organs that usually wear out first in the older cat. As the kidneys become less efficient in removing waste products from the blood, the cat drinks more and more water in an attempt to flush toxins from the body (via the kidneys). Increased urination will result. This is a natural body process that is similar to dialysis performed on people with poor kidney function. An undesired consequence of the increased urination is the loss of potassium from the body in the urine. As urine production increases, more and more potassium is lost, eventually leading to hypokalemia. The potassium wasting associated with increased urine production has a negative effect on the kidneys. Research has demonstrated that low potassium will depress kidney function. This results in a vicious cycle: declining kidney function results in increased loss of potassium, and the loss of potassium then speeds up the deterioration of the kidneys.

Treatment.

The research described above has provided us with the opportunity to interrupt this viscous cycle by supplementing the cat with potassium. By so doing, kidney function is supported and prolonged, and the cat will also feel better.

Potassium is available in three forms: 1) a tablet, 2) a powder that can be mixed with canned food, and 3) a tasty gel. All are readily available through veterinarians. Potassium is also sold for human use as a grape-flavored liquid. However, most cats object to the taste of this product.

If your cat eats canned food, you should try the powder first. It can be mixed in canned food and will be eaten by most cats. If your cat does not eat canned food and is cooperative about taking pills, you should try the tablets. If these are not successful, the tasty gel is a good approach. Many, but certainly not all, cats will take this readily.

by William M. Fraser, D.V.M.

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