Kidney failure (renal failure) is one of the most common diseases we see in middle to ageing cats, so this month we are going to explore the ins and
outs of this condition.
WHAT IS THE FUNCTION OF THE KIDNEY?
In order to understand the seriousness of renal failure we need to look at the essential part the kidneys play in the maintenance of a healthy body.
The kidneys help to control your cat's blood pressure and remove toxic waste products from the body. The kidney is the body's filtration system. Each kidney contains hundreds of thousands of tiny filtration units called 'nephrons'. Nephrons are responsible for removing unwanted waste products
from the blood. After leaving the kidneys, about 95% of the total fluid volume of blood filtered (ie: clean blood) returns to the circulatory system, while the remaining 5%, containing waste products, is passed as urine from the kidneys to the bladder.
HOW DOES IT ALL GO WRONG?
When something happens to disrupt the complex filtration system of the kidneys, toxic waste begins to build up in the cat's blood stream. A disruption in the balance of waste, minerals and electrolytes such as urea, potassium and sodium in the blood stream can have a serious effect on the
normal functioning of other vital organs.
Unfortunately, the kidneys are vulnerable to many disorders that can lead to feline renal dysfunction, particular when a cat reaches middle age.
The most common causes are:
* genetic predisposition - breed predisposition
* acquired renal dysfunction
Most cases presented in practice have what is termed acquired renal failure. This is broken down into two stages:
* Acute renal failure
* Chronic renal failure
Acute Renal Failure
As the name suggests acute renal failure has a relatively sudden onset with the owner becoming aware of symptoms quickly.
Acute renal failure is usually caused by some kind of blockage that either:
* interferes with the blood flow to the kidneys
* interferes with the flow of urine from it.
It is also possible for a cat to develop acute renal failure if it has eaten something that is toxic such as certain pesticides or cleaning fluids but as cats are usually discerning eaters so this is rare. The inappropriate administration of human medications, particularly ibuprofen, can cause severe, acute renal failure.
Chronic Renal Failure
Chronic renal failure usually occurs in older cats and the onset is much longer over months, even years. Renal failure is classified as chronic when 75% of the kidney tissue has been destroyed and replaced with scar tissue.
The cause of chronic renal failure is unclear. However, it is thought that it is a natural progression for many common conditions including:
* advanced dental disease
* kidney infections
* obstructions (i.e.: blocked bladder)
What are the symptoms of Kidney Failure?
The most common symptom that you will see is excessive water drinking and urinating. Your cat may begin lose its appetite and lose weight, become dehydrated and or have bouts of vomiting. If you suspect something is abnormal - take your cat for a check up.
What will your vet do?
The first thing your Vet will probably do is run a series of blood and urine tests. This really is the only way to determine how efficiently the kidneys are working. Your vet may do the tests in the practice or may have to send the samples off to an outside lab. The blood tests will show what
percentages of waste products are circulating in the blood. The urine tests, among other things, will determine how well the kidneys are able to concentrate the urine. Your vet may need to take x rays or do an ultra sound examination. With the results of these tests your vet will be able to establish the extent of the kidney damage and form a treatment plan.
How will my vet treat my cat?
The first thing your vet will probably do is to put your cat on a drip. In acute and chronic renal failure it is important to try to correct the fluid and electrolyte balance as quickly as possible.
In acute renal failure, if possible, your vet will try to establish the cause of the renal failure and will treat your cat accordingly. When diagnosed and treated early cats with acute renal failure have a good
prognosis and should be able to recover fully.
Cats suffering from chronic renal failure will never recover from the loss of renal function. Treatment is usually palliative and aimed at maintaining a good quality of life for the cat for as long as possible.
It is important to adjust your cat's diet in order to help reduce the work load of the kidney and your vet may well suggest the use of prescription diets specifically formulated for cats suffering from renal failure. These diets are an excellent addition to the treatment plan. If you have any concerns regarding your cat's health make an appointment with your Vet!
- Article by Kenilworth Vet