Kidney Copes With Chronic Renal Failure
By: Carrie Gustavson
University of Illinois College of Veterinary Medicine
Chronic renal failure is the most common kidney problem in dogs and cats. Though it is a condition that worsens with time, special care and treatment can help keep your pet feeling good. Chronic renal failure can be congenital, genetic, acquired, or of unknown cause. Cats, especially Maine Coon, Abyssinian, Siamese, Russian Blue, and Burmese breeds, are more commonly diagnosed with chronic renal failure than are dogs.
Early signs that may indicate chronic renal failure include weight loss, poor coat condition, dehydration, and lethargy. "More often than not, the signs are non-specific and the animal just doesn't seem himself," says Dr. Shelia McCullough, veterinarian formerly at the University of Illinois Veterinary Teaching Hospital in Urbana. "With chronic renal failure, people often report that the pet has been going downhill for a long time. Pets may drink and need to urinate more than usual, and sometimes they urinate in inappropriate places."
The kidney performs many important and diverse jobs in the body. Thought the kidneys were just helping to eliminate excess fluid after drinking a large soft drink? Think again! It's true, the kidney's main role is to keep the right amount of water in the body. To do this, when the body needs more water, the kidney sends signals to the brain that you recognize as thirst. Drink too much and the excess fluid sends you searching for the nearest facilities.
But the kidney also plays a very important role in keeping blood pressure in check, maintaining salt and electrolyte balance, keeping blood at the correct pH, helping the body absorb calcium, and eliminating waste products, such as urea, a product of protein breakdown. To do this, the kidney continuously filters the blood. Of the180 liters of plasma filtered from the blood throughout the day, the kidney normally reabsorbs all but the 1 to 2 percent that is eliminated in the urine. "The kidney is the hardest working and the smartest organ in the body," says Dr. McCullough.
Because the kidney performs so many important functions in the body, when it is diseased, the effects may be felt in many places. "When chronic kidney failure is left untreated, the results may be seen in the gastrointestinal system with vomiting and diarrhea. Commonly, ulcers will form in the mouth. High blood pressure is a side effect of kidney failure that can lead to heart problems, or a detached retina. The buildup of waste products in the blood can cause behavioral changes, irritability, seizures, weakness, and depression," says Dr. McCullough.
If your veterinarian suspects chronic renal failure, she may suggest blood work to measure the components of the blood, including urea, phosphate, and creatinine, that would normally be removed by a properly working kidney. Radiographs or ultrasound may also help the clinician make a diagnosis.
In general, treatment is aimed at making the kidney's job a little easier. It usually includes intravenous fluid therapy, potassium supplementation, and feeding a special low-protein, low-phosphate diet. Special diets for kidney patients are available commercially or can be homemade. Depending on the case, your veterinarian may offer options to combat some of the other problems your pet may experience due to chronic renal failure to make your pet as comfortable as possible.