Canine kidney failure is one of the leading causes of death in dogs more than 10 years old. As the kidneys age, they begin to lose some of their ability to filter out toxins and waste products in the dog's bloodstream and then properly divert these to be eliminated via urine or fecal matter. There are some preventive measures dog owners can take to slow down the process. But for most canines afflicated with this disease, canine kidney failure is simply a part of the ageing process.
There are two types of canine kidney failure. The first is sudden onset kidney failure. Its causes include fast-acting dehydration or infection, congestive heart failure, heat stroke, shock, blood clots in the kidney or poisoning that can occur when a dog licks antifreeze off the pavement. The second type of kidney failure afflicting dogs is called canine chronic kidney failure. It develops over time and is related to immune deficiencies, parasites, poor diet, kidney stones, cancer and structural defects within the kidney itself.
Other than the sudden onset form of canine kidney failure, the disease is difficult to detect. This is due to the structure of the kidney itself. Kidneys are made up of a nephrons, which are a microscopic biological unit that does the filtering work. Canines are born with thousands of nephrons. Not all work at the same time. As the dog ages and or the kidney is worked too hard, some nephrons die. Other nephrons take over. Eventually there are not enough nephrons to do the filtering work and failure can begin. This is why veterinarians recommend feeding high-quality protein diets and vitamin supplements to help delay the ageing process.
Dogs with kidneys that are beginning to fail have significant increases in how often and how much water they drink and how often they urinate. They often experience incontinence or leaking of urine at night. Diarrhoea, vomiting, weight loss, fatigue, lethargic behaviour, depressed appearance, pale gums and overall weakness are also symptoms of kidney failure.
Veterinarians use various blood and urine tests to identify canine kidney failure. Increased phosphorous levels and increased urea nitrogen indicates that waste products normally filtered by the kidneys are not being removed. Large drops or large increases of protein and bacteria in urine are also indicators of kidney failure.
Once a diagnosis is confirmed, veterinarians use additional tests to determine the level of disease advancement. By taking abdominal X-rays and/or ultrasound images, veterinarians can see the size of the diseased kidney. In general, the smaller the kidney is from its normal size, the more advanced the disease is.
There is no cure for kidney failure. Once it begins, a dog may live for months or years. Feeding the dog a diet with less protein but higher quality protein and making water readily accessible can help reduce the work a strained kidney must do to filter out waste products. Reducing stress and maintaining a temperature-controlled environment with no sudden hot or cold changes for a canine with kidney failure improves the dog's comfort level. While it is expensive, kidney dialysis is available for dogs. Kidney transplants for canines are performed at some veterinary colleges in the United States on a research basis with limited success.
Due to certain genetic factors, some dogs breeds are more likely to develop canine kidney disease. These breeds include cocker spaniels, Lhasa apso, Shih Tzu, German shepherd, Norwegian elkhound, Doberman pinscher, golden retriever, soft-coated wheaten terrier, bull terrier, cairn terrier and the Samoyed.