>One month after having 5cc's of blood taken, Puff's PCV is back to 75%.
>Post-phlebotomy, she has been about 20% more lethargic.  Her weight is
>down slightly to 980g.  Before her phlebotomies she was a normally active
>older ferret who experienced cyclic malaise - eating less, sleeping
>constantly, no fever, normal poop.  These spells would last 2-3 days, and
>then she'd be back to normal activity levels for a few weeks.
>
>Over the past few days she seems to have caught a cold bug that's going
>around.  Vomiting, sleeping, drinking but not eating, no temperature,
>normal poop.  Her PCV, at 65% only two weeks ago, is back up to 75%.  As I
>mentioned, she's been 'down' during the month since her phlebotomy -more
>sleeping and less eating than normal.  It's possible she's been fighting a
>bug for that time; her neck lymph nodes are up (no other nodes in her body
>are) and she's making the 'smacking' noise with her mouth that I associate
>with sore throats in ferrets (I currently have a sore throat as well).
>
>My questions are: First, why would her PCV jump 10% in two weeks?  I'm
>willing to believe her current malaise is related to that as well as to
>her having a cold, but we had hoped to 'buy more time' with the
>phlebotomy.  My vet speculates her body could be trying to keep her PCV at
>75%.  Our approach so far has been to try the phlebotomy and see what
>transpires.  Obviously, we have had disappointing results.  Second, what
>now?  We're going back in a week for another PCV and to talk about drug
>therapies.  Prednisone has been mentioned, as has a drug which suppresses
>the bone marrow's RBC production..  Can anyone identify this drug and
>explain its usage and side effects in ferrets?  My vet's colleague had
>used it in a no-other-hope case, but my vet couldn't recall the name
>during my visit yesterday.
>
>With the exception of high PCV/RBC, neck lymph nodes being up, and
>observed malaise, there are no symptoms to indicate anything is wrong.
>In the next few visits we will do another full CBC and explore other
>treatment options, as mentioned above.  The only other high PCV
>symptomatic ferret my vet had seen was the untreatable lung malignancy to
>which I referred above; obviously I hope that doesn't turn out to be the
>case here.
 
Dear X:
 
You seek insight into a rare disease which few to no people have ever
experienced.
 
Let's first say that ferrets don't catch colds, and vomiting probably
would not be the result of a "cold".  Vomiting is generally a GI sign,
and my concern with the smacking of the lips that you described, not
eating, and vomiting, as well as the high PCV, which may result in blood
stasis in small vessels throughout the body, would be the possibility of
a gastric ulcer at this point.
 
Regarding possible treatments for polycythemia vera - phlebotomy continues
to be the best and safest for this condition, especially when only the red
cell lines are hyperplastic.  The only possible adverse reaction of a
phebotomy is that she gets anemic if too much is removed - this doesn't
seem to be the problem.
 
Some p.vera human patients (my father was one) early in their treatment
require weekly phlebotomy - he gave a pint of blood every week for two
months right after his diagnosis.
 
Yes there are drugs that in humans are used to treat p.  vera, but
prednisone is not one of them, and I am not sure why it was discussed in
this case.  Chemotherapeutic agents are used in humans especially when
other marrow elements, such as white blood cells or platelets are also
elevated - hydroxyurea, interferon, and rarely chlorambucil are used in
this cases.
 
AT this point, my recommendations would probably be to continue with the
phlebotomies, look closely for an unrelated GI problem, and at last
resort, try one of the chemotherapies at a low dosage, as you are charting
new ground here.
 
With kindest regards,
Bruce Williams, dVM
[Posted in FML issue 3642]