Frejya is a very pretty tabby cat who, along with her sister
Cleopatra, found herself in a rescue centre at 12 months of
age. They weren't there for very long though, landing on their
paws with a caring family where for the next 9 months, they
led very happy, healthy lives. However, in February 2002, Frejya's
owner noticed that she wasn't as bright & cheerful as usual.
It wasn't any one thing that you could put your finger on, just
a general feeling of malaise. More worrying was occasional short
episodes where Frejya seemed not to be able to see things properly.
This
all culminated one evening in a seizure which warranted a trip
to the emergency vets. By the time she got there, Frejya was
fully conscious and aware of where she was, although quite understandably
very subdued. The first thing found on examination was that
the mucous membranes in her mouth and inside her eyelids were
a deep red colour compared to the pale pink they should be in
a healthy animal. Because the owner mentioned the blindness
episodes, the vet had a good examination of her eyes and found
that the blood vessels inside the eye looked much darker than
they should. The vet immediately started to suspect a condition
that caused the blood to be thicker than normal so took a sample
to check this. It took a while to get the sample as the blood
didn't seem to want to come out the vein. Sure enough the Packed
Cell Volume (PCV) (the percentage of the blood which is made
up of red blood cells) was much, much higher than normal at
78%- about twice the normal value.
There can be a number of causes of this, such as dehydration
where the fluid levels in the body drop so there seem to be
more red cells in the bloodstream in proportion to the liquid
part of blood - plasma - but Frejya wasn't dehydrated. This,
when added to the appearance of the blood vessels in the eyes,
led to a diagnosis of Polycythaemia Vera (an increase in the
number of red blood cells). Instead of the blood being watery,
Frejya's blood was very thick & sludge-like, not very nice to
have going through your veins. Left to its own devices, the
blood would just sludge up the system until it came to a grinding
halt. The most obvious and immediate thing to do was to physically
remove some blood from Frejya She was sedated and some blood
was taken off by using a cannula in her vein, but even this
was done with great difficulty because the blood was so thick.
She was sent home the next day but she would have to make another
visit to the Clinic in 48 hours to repeat the procedure as her
body will very quickly replace the blood taken away. Two days
later, she hadn't had any more fits but we took more blood from
her and also sent a sample away to check the diagnosis. This
confirmed diagnosis of Polycythaemia Vera, an extremely rare
diagnosis in cats. The problem was that Frejya's body was producing
too many blood cells so to control the condition we either have
to keep removing excess blood or we have to try to stop the
body producing too many cells.
The immediate approach is to physically remove the blood but
longterm control is usually achieved through medication which
helps to suppress the red cell production. The condition is
so rare in cats that there isn't a licenced veterinary drug
for the problem but we were able to obtain it from a specialist
pharmaceutical manufacturer (hydroxyurea).
We
started Frejya on I capsule a day. To start with it was necessary
to check her blood every few days to see how she was responding
to the treatment. After the first week, her Packed Cell Volume
(PCV) was down from 78% to 62%, she was looking fairly bright
and hadn't had any more fits. As Frejya was starting to improve,
the dose was reduced from 7 capsules a week to 6 a week and
another blood sample taken 10 days after the last one. Again
the PCV had reduced, this time to 60%. The dose was maintained
on 6 capsules weekly but bloods taken 2 weeks later showed that
the PCV had risen slightly to just over 62%, so we increased
the capsules to one daily. At the next visit two weeks later
Frejya was acting lethargic again, so although the PCV had gone
back to 60%, we advised to give her 1 capsule a day for 6 days
and on the 7th day to give her 2 capsules together (a total
of 8 a week).
Two
weeks on the new regime revealed a PCV of just under 55%, and
a further fortnight later, it was down to just under 45%, within
the normal range. This was excellent news but the worry now
was that it stabilised and didn't continue to drop too much!
The dose was kept at 8 per week and repeated monthly blood tests
showed the PCV as being between 40 and 50%. Several years after
the initial diagnosis, Frejya is to all intents and purposes
a bright, happy normal cat. She will have to undergo regular
blood tests and be kept permanently on her medication but both
she and her owners are coping well. Frejya's rare condition
served to remind us that the old clichés in veterinary medicine
still apply- common things occur commonly but always expect
the unexpected!
MEET
SOME OF OUR PATIENTS: “Frejya"
This
all culminated one evening in a seizure which warranted a trip
to the emergency vets. By the time she got there, Frejya was
fully conscious and aware of where she was, although quite understandably
very subdued. The first thing found on examination was that
the mucous membranes in her mouth and inside her eyelids were
a deep red colour compared to the pale pink they should be in
a healthy animal. Because the owner mentioned the blindness
episodes, the vet had a good examination of her eyes and found
that the blood vessels inside the eye looked much darker than
they should. The vet immediately started to suspect a condition
that caused the blood to be thicker than normal so took a sample
to check this. It took a while to get the sample as the blood
didn't seem to want to come out the vein. Sure enough the Packed
Cell Volume (PCV) (the percentage of the blood which is made
up of red blood cells) was much, much higher than normal at
78%- about twice the normal value. 
We
started Frejya on I capsule a day. To start with it was necessary
to check her blood every few days to see how she was responding
to the treatment. After the first week, her Packed Cell Volume
(PCV) was down from 78% to 62%, she was looking fairly bright
and hadn't had any more fits. As Frejya was starting to improve,
the dose was reduced from 7 capsules a week to 6 a week and
another blood sample taken 10 days after the last one. Again
the PCV had reduced, this time to 60%. The dose was maintained
on 6 capsules weekly but bloods taken 2 weeks later showed that
the PCV had risen slightly to just over 62%, so we increased
the capsules to one daily. At the next visit two weeks later
Frejya was acting lethargic again, so although the PCV had gone
back to 60%, we advised to give her 1 capsule a day for 6 days
and on the 7th day to give her 2 capsules together (a total
of 8 a week). 
Two
weeks on the new regime revealed a PCV of just under 55%, and
a further fortnight later, it was down to just under 45%, within
the normal range. This was excellent news but the worry now
was that it stabilised and didn't continue to drop too much!
The dose was kept at 8 per week and repeated monthly blood tests
showed the PCV as being between 40 and 50%. Several years after
the initial diagnosis, Frejya is to all intents and purposes
a bright, happy normal cat. She will have to undergo regular
blood tests and be kept permanently on her medication but both
she and her owners are coping well. Frejya's rare condition
served to remind us that the old clichés in veterinary medicine
still apply- common things occur commonly but always expect
the unexpected!