Kidney disease is the leading source of death for cats. Your cat's chance of survival increases when you know the causes, symptoms and treatment.
Kidney failure is one of the most serious medical problems encountered by the feline community. In its acute stage, it comes on suddenly, and will cause death unless immediate treatment is obtained. For this reason, all people with companion cats should familiarize themselves with the following:
Which cats are susceptible?
All felines run the risk of developing kidney disease, but the most vulnerable are older cats (10 years and up), especially those who are Abyssinian, Burmese, Maine Coon, Persian, Siamese, or Russian Blue.
What is acute kidney disease?
As with humans, felines require good kidney function in order to get rid of toxins and maintain normal balances of sodium, phosphorus, and other elements in their blood stream. When urine and blood tests indicate that the kidneys are not doing their job, the condition is classified as either Acute Renal Failure (ARF), if it comes on suddenly, or Chronic Renal Failure (CRF), if it develops over time.
The distinction between these two diagnoses is very important, because ARF is reversible but not treatable, while CRF is treatable, but not reversible. Especially in younger cats, ARF may be caused by poison, injury, or obstruction of the kidney due to injury or disease. If the cat timely receives antidotes, surgery, or other treatment alleviating the cause, kidneys function may be completely restored, and the cat may live a normal lifespan.
Unfortunately it may be difficult for even a veterinarian to make the call between the two forms of kidney failure. While CRF may be discovered at an early stage, particularly if it is caused by another disease such as cancer, many times a cat will show no symptoms at all until over 75% of the kidney cells have shut down. Once the 75% mark is passed, the cat's body is no longer able to cope with the problem. Suddenly the cat will have all of the symptoms of ARF and will likely be treated as having acute rather than chronic kidney disease.
What are the causes?
In addition to end-stage CRF, toxins most often cause acute kidney failure. For an outside cat, antifreeze tops the list of suspects, because even a minuscule amount of this poison can cause irreversible damage unless emergency treatment is obtained. Other substances, which have adverse effects on kidneys, are pesticides, herbicides, venoms, and heavy metals.
Inside cats should be kept away from any solvents as well as the contents of the medicine cabinet, as aspirin, antibiotics, and other "people" medication may have fatal effects. Cat medication may also be the culprit. If a cat is already under treatment for another condition, possible drug interactions or side effects should be considered. In addition, the cat should be screened for cancer, cysts, parasites, viruses, hidden traumas, infections, and immune system disorders, all of which can affect the kidneys.
What are the symptoms?
The two main symptoms of kidney failure are vomiting and excessive urination, usually combined with listlessness and depression. If the failure is caused by CRF, the cat may have previously experienced poor appetite, loss of weight and loss of interest in grooming. Because kidney failure results in high blood pressure, a frightening symptom can be the dilation of the cat's pupils even in bright light, which may signify permanent blindness.
While most cats with kidney problems will be drinking and urinating frequently, if ARF is caused by a toxin, the result may be inability to urinate. This condition in and of itself is life-threatening, and the cat must receive immediate treatment.
How is it diagnosed?
Besides a physical examination to determine the size and shape of the kidneys, a veterinarian will perform a blood panel to monitor the levels of various substances in the blood. The two most common indicators of kidney malfunction are revealed by the creatinine and Blood Urea Nitrogen (BUN) tests, which measure the ability of the kidneys to filter out various compounds. Of the two, the creatinine test is considered the more reliable, because the BUN may be affected if the cat is dehydrated, as often will be the case. The veterinarian will also examine the levels of phosphorus, sodium, and amylase, all of which may be elevated when the kidneys are not performing, and will perform a urinalysis to see if an abnormal amount of any substance is being excreted..
If a Doppler machine is available, the vet may check the cat's blood pressure for signs of hypertension. In cases where injuries, tumors or cysts are suspected, the cat may receive an ultrasound to reveal any kidney abnormalities.
While these tests and procedures may not always reveal the cause, elevated levels of the various markers will be a strong indication that kidney failure has occurred. However, the degree of kidney failure may be debatable, particularly if some readings are closer to normal than others. Even in borderline cases, the veterinarian will probably recommend treatment rather than run the risk of further deterioration.
How is it treated?
The first goal is to immediately get fluids into the cat to relieve dehydration and flush out built up toxins. In most cases, this will require hospitalization so that the cat may be hooked up to an i.v. or have fluids injected under the skin. Most cats experiencing acute kidney disease are considered to be in guarded condition, and it may take two to three days of treatment and monitoring before kidney function is regained. If the cat does not respond after 72 hours of treatment, the prognosis is considered even less favorable, because the likelihood is that the kidneys are no longer able to sustain life even with support.
However, if the kidneys do regain at least partial function, the condition may be reclassified as CRF. While the longevity of any cat with CRF is dependent on many difference circumstances, many have lived for months and years. The cat's diet may be changed, and the cat may require regular subcutaneous fluid treatments, which may be given at the vet's office or at home. People providing treatment to their cats for CRF may find support at the Feline CRF Information Center at http://www.felinecrf.com.
What should I do if I think my cat has acute kidney disease?
1. Get your cat to the vet immediately. Do not pass GO, do not collect $200, this is as much of a medical emergency as if you just saw your cat get hit by a car.
2. Be prepared to tell the vet about any encounters your cat may have had with toxins or with any other potential cause of the problem.
3. Make sure your cat receives the blood panel, especially the creatinine test. Do not settle for simply an urinalysis.
4. Ask that your cat be tested for high blood pressure, and if necessary receive medication for the condition before loss of vision or blindness occurs.
5. Make certain that your cat receives adequate nourishment during treatment, even if that means putting in feeding tubes or force feeding.
6. Be prepared for the worst, but hope for the best.