Three Cases

of Chronic Kidney Failure

The following case histories focus on chronic renal failure and three of our special feline patients. Kidney failure is one of the many problems faced by older cats and dogs. Fortunately, we are all born with ample kidney function and the fact is that most cats and dogs can do well with only 25% of their normal kidney function. That means that throughout their lives our pets can withstand various insults to the kidneys and the normal loss of kidney function as a result of aging. As long as they maintain at least 25% of their renal function, they will be able to adequately remove waste from the body, conserve fluids, produce red blood cells (most people are surprised to learn that the kidneys have anything to do with this), and feel and act healthy. Problems become apparent when that vital remaining 25% becomes compromised. Early signs may be as subtle as an increased thirst or more frequent urination. The urine becomes very dilute and the volume of urine increases as the kidneys loose their ability to concentrate the urine. An owner might notice that the litter pan shows evidence of more urine or that their dog needs to go outside during the night. As renal failure progresses the signs become much more pronounced. Toxic products cause loss of appetite and malaise and ultimately pronounced nausea and even seizures. As renal failure progresses, many patients become anemic because the kidney is also responsible for the production of Erythropoietin, a hormone that stimulates the bone marrow to produce red blood cells. This anemia worsens the kidney failure because of poor oxygen delivery to the oxygen sensitive kidneys.

Historically kidney disease has been frustrating to treat because unlike some organs, the kidneys do not regenerate when damaged. Treatment has centered on maximizing the function of the remaining kidney tissue. This involves treating coexisting diseases that may be further damaging the kidneys, improving the diet to minimize waste products, and fluid therapy to improve the blood flow to the remaining kidney tissue and help maintain hydration. In recent years, with the development of synthetic Erythropoietin, renal failure related anemia can often be treated. Due to the small size of most of our patients, Dialysis, commonly used to treat renal failure in people, is very difficult and rarely available. Kidney transplants have been successfully accomplished in cats but complication rates are still very high.

We would like to tell you about three of our patients that have been diagnosed with chronic renal failure and that are doing well on supportive care.

Strawberry recieving intravenous fluids

Ping is a dainty 12-year-old Siamese cat. She was brought to Berkshire Veterinary Hospital on May 1, 1998 because she was lethargic and not eating. She was dehydrated, had advanced dental disease, and was thin. A urinalysis, blood count, and metabolic profile were done. She had an elevated white blood cell count. Her BUN was 153 and her Creatinine (another renal function test) was 9.6 (normal values 1.1-2.0). Her urine was extremely dilute indicating a failure of her kidneys ability to concentrate her urine. It was clear that Ping was in serious trouble. Her Bun and Creatinine were very high and the elevated white blood cell count suggested that she might have a condition called Pyelonephritis, a condition where the kidneys themselves are infected. It was possible that Ping's dental condition had served as a source of bacteria for this life threatening condition. A urine culture was submitted.

Ping with her mom and Dr. Lyn

An Intravenous catheter was placed and Ping was placed in intensive care with IV fluids delivered with a fluid pump. Antibiotic treatments were started. Within twenty-four hours she was feeling a better and miraculously, over the next four days her BUN dropped to 52. Ping was discharged from the hospital with prescription food and antibiotics and after a week at home she was eating well and feeling better. She had a recheck examination on May 13th and her BUN was 43.6. She was doing great but once again we had a difficult decision to make. Her dental disease needed to be addressed to hopefully prevent recurrent infection. After reviewing the risks with Ping's owners, the decision was made to go forward with anesthesia and the dental work. On May 14th Ping had her teeth cleaned, polished, and received a fluoride treatment. Nine of her teeth needed to be extracted. Her anesthetic protocol was the same as Strawberry's and she recovered from the anesthesia uneventfully. She was bright and alert the following day and was discharged from the hospital on May 15th. She went home with antibiotics and prescription diet designed for patients with kidney disease.

Dr. Lemieux monitors Feisty while he recieves his subcutaneous fluid treatment

Feisty is an older male cat (his exact age is not known). He came to our hospital for the first time on June 8th, 1998. He did not feel well and was not eating. He was severely dehydrated and had a swollen, infected area in his mouth involving the lower left mandible. Dr. Lyn Lemieux was very concerned with these physical findings. Oral infections of this type are often associated with oral cancer. Feisty was in no condition for a surgical biopsy. The only hope would be to treat the infection and see if his condition would stabilize. A blood count and metabolic profile revealed a BUN over 200 (normal values 16.5-38.6); his Creatinine was 14.2 (normal values 1.1-2.0). IV fluids and antibiotics were started. The level of waste products in Feisty's blood was very high; he was so toxic that he had a short seizure while hospitalized. Feisty's prognosis was guarded and after twenty-four hours of intravenous treatment, his owner's decided to have him treated as an outpatient. For the next ten days Feisty's owners brought him to the hospital for fluid treatments. They administered oral antibiotics at home. At first it seemed that progress was slow but on June 15th his BUN was down to 96.7 and he was eating a little better. The oral swelling was smaller. By June 19th the BUN was 58.4 and he continued to gain strength. His fluid treatments were reduced to every other day. On his June 25th recheck Feisty's BUN was 49.7 and his mouth appeared to be completely healed. He continues to come to our hospital every other day for his fluid therapy and as of this writing on October 5th, he is doing well.

While all of our renal failure patients may not respond this well these three individuals illustrate several points about older cats and kidney disease. Kidney disease is one of the most common medical problems seen in older cats. In all three of these cases borderline kidney function was complicated by dental or oral infections. The bacteria from these oral infections can further damage the kidneys leading to anorexia and dehydration. Fluid therapy can correct the dehydration and serves to "flush" the system of toxic byproducts, which build up when the kidneys aren't functioning well. The BUN (blood urea nitrogen) test measures one of these toxic byproducts. The fluids can be given intravenously in the hospital, subcutaneously as an outpatient, or in some cases by a pet's owners at home. In all three of these cases we were able to treat the underlying dental disease and infection. Hopefully there is enough normal kidney tissue remaining to keep these cats healthy and happy. Eating a prescription diet low in protein, phosphorus, calcium, and sodium helps to prevent ongoing buildup of waste products. By carefully monitoring blood tests (especially the BUN) the frequency and amount of fluid therapy is adjusted to each patients needs.

It has been satisfying to see these patients do well.