Q Our 12-year-old Papillon was diagnosed with kidney disease at his March yearly check-up. The vet says he is in Stage 1 with rising kidney values. I have learned that there are four stages; how long does it take to progress from the first stage to the fourth stage? Any suggestions to keep him comfortable in the time he has left would be most helpful.

A: Kidney failure implies that the kidneys are no longer able to perform their duties, of which there are many. The kidneys remove waste from blood and eliminate these from the body in the urine. They help maintain hydration by eliminating water when there is too much and retaining water when there is not enough. They help keep potassium and sodium levels normal, and balance calcium and phosphorus levels, too. They produce a hormone called erythropoietin that tells the bone marrow when to make red blood cells to prevent anemia. They also help regulate blood pressure.

In order for renal failure to be detected on routine lab work, 75 percent of the total renal mass (both kidneys) must stop functioning. This means we would have to remove one kidney and half of the other kidney to reach this point.

Acute vs. chronic

Kidney failure is classified as either acute or chronic. In acute disease, there has been a sudden injury to the kidneys from things such as toxins (for example grapes, raisins in dogs, lilies in cats and antifreeze in both), infections, cancer, obstructions or high blood calcium.

Depending on the degree of injury the kidneys may completely recover, partially recover or not recover at all resulting in death. Partial recovery sets up chronic renal failure. If known, everything should be done to eliminate the cause to prevent progressive injury.

Unfortunately, as in your dog's case, the underlying problem is not always known. Odds are that the pet had an incident several years earlier that was undetected. The frustrating thing about kidney disease is that it is progressive. Once a certain level of injury occurs, the disease cannot be stopped and is considered chronic.

Chronic renal failure is broken down into four stages. In Stage 1, the kidneys cannot concentrate urine, protein is lost from the body into the urine and/or the shape, size or architecture has changed. Often dogs and cats in this stage are asymptomatic. Animals enter Stage 2 when their blood creatinine (a substance they should filter from the blood) elevates slightly. There are still generally no outward symptoms. Stages 3 and 4 are based on further creatinine elevations and the development of clinical signs.

Symptoms

Since one of the first changes is the inability to conserve water, one of the first symptoms noted may be an increased volume and frequency of urination with a subsequent increase in drinking to prevent dehydration.

Anorexia and lethargy occur as the kidneys lose their ability to filter blood toxins. These increased blood toxins may cause a malodorous breath, as gum and tongue ulcers may develop.

Vomiting and diarrhea may be noted.

In cats where hypertension is more common, sudden blindness or changes in mentation may occur from bleeding into the eyes or brain.

Treatment

As we often tell clients whose pets have been diagnosed with renal disease, if there was a magic pill to reverse changes, humans would take it instead of having to be on dialysis or wait for a kidney transplant.

Early detection with annual blood work and urine evaluations is the best treatment of all. Sometimes the inciting cause can be determined and eliminated to prevent progression. The main thing you want to do is prevent further renal injury. Check urine to insure there is not a concurrent infection. Have blood pressure measured as this is commonly associated with renal disease and will cause the disease to progress more rapidly.

It is important to maintain adequate nutrition to ensure that muscle is not broken down for energy. There are many renal diets that are phosphorus-restricted and protein-limited that have been developed for dogs and cats with renal disease. You also can find recipes for homemade diets.

Maintaining hydration is important, too. When dehydrated, the kidneys have trouble filtering the blood resulting in the already elevated toxins elevating even more. Water intake can be promoted by feeding canned food or getting a pet water fountain. In many patients, as the disease progresses, we will teach owners to give fluids at home.

Phosphorus levels should be watched closely. When they become elevated, medications should be started to decrease absorption.

The red blood cell level should be watched as anemia may occur from gastrointestinal ulcers or decreased bone marrow production. The kidneys clear the hormone gastrin, which promotes stomach acid secretion. Acid blockers are often recommended to improve appetite and prevent ulcers.

Dogs given omega-3 fatty acids showed decreased mortality, increased renal function, decreased renal lesions and decreased proteinuria in one study.

Azodyl and Rubenal are two newer medications that have been developed and claim to improve renal function and quality of life. However, no clinical studies prove this yet.

It's important to come up with a treatment and monitoring plan with your vet. It is difficult to predict how rapidly renal disease will progress, but there are ways to keep your pet comfortable and slow down the progression.

Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to petdocs@postandcourier.com.