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What is it?
Polycystic kidney disease (PKD) is
characterised by the growth of numerous
cysts filled with fluid in the kidneys. PKD cysts can reduce kidney function,
leading to kidney failure. PKD can also
cause cysts in the liver and problems in
other organs, such as the heart and
blood vessels in the brain. The most
common cause of PKD is the autosomal
dominant form.
Cysts are present from birth, but start
out small, slowly increasing in size.
Cysts can range from very small to
several centimetres in diameter. The
increasing size of the cysts damage the
normal kidney tissue, eventually causing
kidney failure. The number of Cysts, the
size of Cysts and the speed at which
they grow varies from one cat to another
and so the life expectancy of a cat with
PKD is equally variable and indeed it
may be that the cat dies from another
cause before PKD progresses to fatality.
The average life expectancy of a cat
diagnosed with PKD is currently
estimated to be about seven years,
however some may live longer and others
may live considerably shorter lives.
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Ultrasound Image Showing Feline
PKD Cysts |
How is it contracted?
The autosomal dominant form is
contracted genetically from one or both
parents. So if one parent has the
disease then there is a 50% chance of
offspring from that cat being infected
with PKD.
Clinical Symptoms
Many of the symptoms are consistent
with what you would expect in renal
failure including excess thirst,
increased urination, lethargy, weight
loss and vomiting. In conjunction with
these the Kidneys are usually found to
be considerably enlarged.
How is it identified
Up until fairly recently the only
way possible to diagnose the disease was
by an ultrasound scan of the kidneys by
a skilled sonographer experienced in
diagnosing PKD. This expensive diagnosis
method provided approximately a 98%
accurate diagnosis and could be
performed on a cat from about the age of
10 months old. Not an ideal scenario but
the best technology we had available to
us.
Now a 100% accurate diagnosis can be
achieved from genetic material obtained
either from a buccal swab (a swab taken
from the inside cheeks of the cat) or a
blood sample. The main advantage of this
test other than the accuracy is the low
cost of sampling and the low laboratory
costs of getting the sample analysed.
Prognosis
Unfortunately there is currently no
way of slowing the progression of the
disease and the cysts can not be
removed. So the treatment is in effect
the same for a cat with renal failure.
Typically prognosis is poor and very
upsetting for owners.
What Should I Do?
All breeding cats should be tested
for the presence of the autosomal
dominant PKD form. The British Group
Breed Advisory Council strongly
recommends this course of action. The
SBSHCC recommends the use where possible
of the PKD Gene Test to ensure 100%
accuracy of the results. All cats which
show positive for PKD should be removed
from your breeding programme. This is
the only way that Autosomal Dominant PKD
will be removed from our breeds and the
Club strongly urges our members to take
this course of action.
What is the SBSHCC Doing? - The PKD
Testing Day
We organised a PKD testing day which
was open to all our members cats on
the 29th June 2008. This day had been
organised with the assistance of the
Feline Advisory Bureau and Langford
Veterinary College Diagnostics. Martha
Cannon one of Langford's experienced
vets provided her services free
of charge to the club enabling us to
offer this test at a significantly
reduced cost.
We plan to
repeat this event in early 2009. Details
of what we did can be seen by following
the link to
PKD Testing - An Idiot's Guide