Cats Introduction
Choosing a Cat
Pedigree Cats
Choosing a Cattery
Moving House with you Cat
Hyperthyroidism
Dental Care
Vaccination
Neutering
Worming
Fleas
Insurance
Identichipping
Training and Socialisation
Feeding
Caring for the Older Cat
Arthritis
Cat Friendly Garden
First Aid for Cats
Kidney Disease
Polycystic Kidney Disease
Kidney Transplants
F.I.V.
Further Information
|
Polycystic Kidney Disease in Cats
|
|
Martin C. James
|
What is the Disease?
In
Polycystic Kidney Disease (or PKD) large numbers of fluid filled cysts
develop in the kidneys. These cysts are tiny when the cat is born, but
over several years they gradually grow, compressing the surrounding normal
kidney tissue. The end result is kidney failure by the time is 7 -8 years
old although occasionally it can happen as early as 2 – 3 years
– unfortunately it will always be fatal.
The disease is caused by a defective gene in Persians and exotic short-haired
breeds. Frighteningly, world wide estimates are that one third of cats
of these breeds are affected. It may also be present in a small number
of British Short-Haired cats due to out-crossing. The gene is a single
dominant one. That means that every cat with the gene will have polycystic
kidneys. Only one parent has to have the gene to pass it onto offspring.
If both parents have the gene then any kittens that are unlucky enough
to receive two copies of the gene will die in their mother’s uterus
– this means that all affected cats will only have one copy.
Treatment
Cats with PKD will show no signs of illness until more than 70% of their
kidneys have been destroyed by cysts. They will then start drinking more
than usual, eating less and losing weight just like any other cat with
kidney disease. Unfortunately there is no cure nor specific treatment
for PKD – the cysts can’t be removed drained nor stopped from
growing. We can reduce the workload on the kidneys by using low protein
and phosphate diets and control secondary problems like high blood pressure.
However, as the condition is progressive it is inevitable that these cats
will die prematurely no matter what is done.
|
What can be done? |
|
The reason PKD is so prevalent is because affected cats are completely
normal until late middle age. A queen can have had several litters
by this stage, while a stud tom can have sired hundreds or even
thousands of kittens. As 50% of offspring from a mating where one
of the parents has PKD, are affected, the result is a lot of sick
cats. X-rays and blood tests are completely normal until renal failure
starts, but fortunately ultrasound scanning can pick up PKD in 95%
of affected cats once they are more than 10 months old, so animals
can be checked before they are used for breeding.
The Feline Advisory Bureau (FAB) has set up the FAB PKD Screening
Scheme based at Bristol Vet School, and now available throughout
the country. The cats need to be microchipped for identification,
and if they pass the painless and non-invasive scanning procedure,
they are issued with an FAB PKD certificate. As the cysts can be
very small a high quality ultrasound machine together with an experienced
operator is needed – a list of vets who can carry out the
test is available on the FAB website – see below.
All breeding stock should be scanned even if both parents have
certificates; although the test is 95% effective, there is still
a tiny risk of affected cats slipping through the net. If this is
seen to have happened, FAB will investigate free of charge. The
cost of the scan is extremely reasonable - £30 - £100
depending on where it is done, and once the certificate is issued,
it last the cat’s lifetime. If every Persian, Exotic and British
Short Hair breeder in the country followed the FAB scheme for PKD,
the disease could be eliminated completely in a few years. However,
just a few breeders not getting their cats scanned will keep this
distressing disease going for ever. The moral of the story is ensure
that you buy kittens of affected breeds, only from breeders who
have FAB PKD certificates for all their adult cats. |
Update
In 2004, FAB and Bristol Vet School launched a DNA gene test for PKD. This revolutionary test is based upon PCR technology and costs approximately £35 per cat. Your vet can send either a blood or cheek swab sample from your cat (which is still required to be identichipped) to Bristol, and the results are generally available in 3-4 weeks.
© Darwin Veterinary Centre Limited 2002-2006.
All rights reserved.
|