Kidney Disease, the undetected killer

Recently an 11-year-old Golden Retriever was brought to my office for a routine physical exam. The patient was apparently in excellent health, goo coat, mobile in spite of mild arthritis of the spine, alert and responsive, good teeth and gums, and a normal temperature.

I told the owner her dog was in good shape, but that I wanted to order a chemistry panel and urine sample because many older dogs have kidney or bladder problems that go undectected.

Reviewing the chemistry profile, I was stunned to see that this apparently healthy dog was suffering from kidney failure. In spite of appearing and behaving in a healthy manner, the patient was in real trouble. I took a deep breath and privately rehearsed how I would deliver this shocking news to an unsuspecting owner.

Undoubtedly, this scene will be repeated many times today, tomorrow, and the next day all across the country.

Healthy kidneys maintain internal homeostasis, or keep in balance the body's chemical reactions, blood pressure, acid-base balance, mineral levels, and elimination of waste products. The kidneys also influence red blood cell numbers and glucose conservation.

Damage to the delicate tissues within the kidneys can eliminate them from contributing to maintaining internal homeostatic balance. A number of things cause kidney damage. Bacterial infections such as leptospirosis and Borrelia, and common bladder pathogens such as Proteus and staphylococcus, can work their way into one or both kidneys.

Fortunately, antibiotics over a period of weeks often cure kidney infections, but any kidney infection has the potential to cause irreparable harm to delicate filtering structures.

Cystic kidney disease can be inherited and those affected seldom live to an old age. Tumors, although rarely originating in the kidneys, present challenging health problems for dogs. Amyloidosis, where immune proteins are deposited in kidney tissues, is often untreatable and nearly always fatal.

Toxins such as antifreeze with propylene glycol are terrible threats to kidney tissues. Blood vessel damage caused by heat stroke, blood loss, and gastric torsion may also be fatal. Lead poisoning, chemotherapeutic agents, some antibiotics, and most NSAIDs can have potentially deleterious effects on kidney function.

If you are feeding a healthy dog a low-protein diet with the intention of preventing kidney damage, you may not be doing your dog a favor. The protein level in a dog's diet does not cause kidney damage because dietary protein consumption does not harm the kidneys.

Dietary protein restriction is often helpful in the alleviation of clinical signs in dogs that already have chronic renal disease, one of the types of kidney problems most often encountered in dogs, says a specialist in animal nutrition and a consultant to the pet food industry. “However, there is no evidence that protein plays a role in the initial development of the disease, or that the levels of protein found in commercial foods would cause chronic renal disease in healthy animals.”

Preventing kidney disease is the goal of all veterinarians. Part of the difficulty in detecting kidney damage is that the kidneys function adequately while destruction of tissue is in progress. As much as 75 percent of the dog's kidney tissue may be non-functional before routine blood tests indicate something is wrong. In other words, there's is not much indication of trouble until there's very serious, and often irreversible, damage.

To prevent kidney disease in your dog, be pro-active, not reactive. Ask your veterinarian about blood test and don't wait until your dog has problems. Have a urine sample taken from your dog at least yearly.

Be alert for frequent urinating, discomfort while urinating, increased thirst, or dribbling of urine. Even a trace of blood in the urine is never normal, so always have the dog evaluated if this is the case.