Kidney Failure in Dogs
Get the Facts About Kidney Failure in Dogs
Kidney failure in dogs is the inability of the kidneys to clean the blood of waste products and toxins, and not the inability to make urine. In fact, the production of large quantities of urine is a potential sign that your dog’s kidneys may be under strain and the body’s wastes are not being eliminated effectively.
Chronic Kidney failure does not happen overnight and is often the result of old age: the kidneys have simply worn out. One big factor is your dog’s size: the larger the dog, the sooner you may see signs of kidney failure, perhaps as soon as seven years old. Smaller dogs are more likely to show the earliest signs of kidney disease at between 10 and 14 years.
As your dog gets older his kidneys become less and less inefficient as a filter. His body’s reaction to this it to produce more and more urine to try to flush the toxins out. Because of this, he will become thirstier and you may notice his water bowl needs topping up much more often.
What are the Symptoms of Kidney Failure in Dogs?
Signs of more advanced kidney failure include loss of appetite, weight loss, depression, vomiting, diarrhoea and very bad breath. Sometimes, mouth ulcers also form. By now, you will probably be seeking the advice of your vet and they will want to carry out blood tests to monitor the concentration of two waste products: blood urea nitrogen (BUN) and blood creatinine. An accompanying urine test measures kidney function.
Elevated BUN and creatinine levels may not indicate dog kidney failure stages. Dogs with borderline kidney function may still have normal blood tests and pets who have suffered a major illness or surgery may also experience acute kidney failure, sending blood test values soaring.
Sadly, sometimes the damage is so advanced, the kidneys cannot be revived. Even so, if your pet is in this unlucky position he may live for several months or years with aggressive treatment.
Stage 1
There are two stages to treatment for chronic Kidney Failure. The first phase aims to “restart” the kidneys buy giving large amounts of intravenous fluids to “flush” them out. The aim of this process – properly known as diuresis – is to stimulate the kidney cells to function again. If there are enough functional kidney, they may be able to satisfy the body’s needs for waste removal. Fluid therapy also replaces necessary electrolytes, especially potassium.
In addition, your vet will administer drugs to control vomiting and diarrhoea as well as advising on proper nutrition.
If all goes well, the kidneys will start up again and may function for a few weeks to a few years, but it is possible that they will fail again and the usual symptoms of kidney failure in dogs will reappear as soon as treatment stops. The worst possible outcome is that the restart does not work. Sadly, there is no easy way to predict which of these three outcomes is likely.
Ultimately, you must remember that if your dog has suffered kidney failure they will never be normal again. Continuing treatment at home is essential or he will soon be back in in kidney failure.
Stage 2
The second phase of treatment is aimed at keeping the kidneys functioning for as long as possible and revolves around diet and nutrition.
Your vet will be able to give you detailed information, but as a general guide you will need to feed a low-protein, low-phosphorus diet which is non-acidic. This will help to keep your dog’s BUN and creatinine levels as close to normal as possible, which will make him feel better. A reduced-protein diet decreases the strain on the kidneys. Because phosphorous is not being removed efficiently by the damaged kidneys, the levels will start to rise in the blood resulting in lethargy and poor appetite. Your vet may prescribe drugs which bind excess phosphates in the intestinal tract, meaning that do not pass into the blood.
While Phosphorus may increase, Potassium levels can decrease with excess urine production, which in turn can further harm kidney function. A potassium supplement will help to replace the nutrient loss and maintain kidney function.
Your vet will also probably show you have to give subcutaneous fluids at home which will continually “reboot” the kidneys. Whether this is done once a day or once a week will depend on how poorly your dog is.
Dogs with Chronic Kidney Failure may also be prescribed other drugs including medicines to regulate calcium levels which can otherwise be robbed from his bones making them brittle and easily broken. Another drug which may be used stimulates the bone marrow to produce new red blood cells, the production of which is partly controlled by a hormone called erythropoietin which is produced in the kidneys. With compromised kidneys, the numbers of red blood cells can be reduced leading to anaemia. In the short term, synthetic erythropoietin supplements can correct anaemia but in some animals the immune system recognizes it as "foreign" and make antibodies against it.
Dogs with kidney failure can also suffer with high blood pressure, and in some cases drugs are prescribed to treat it.