From:
Bruce Williams, DVM
Date: 2001-03-20 22:47:00 UTC
Subject: Re: Diabetes following Insulinoma surgery
--- In Ferret-Health-list@y..., ldarkes@a... wrote:
> Back in December my 6 year old female, Mandrake had adrenal and
insulinoma
> surgery. Following the surgery she developed diabetes and required
> hospitalization for insulin treatment. She had started to respond
to the
> insulin, however, sadly we lost her to pneumonia developed during
her
> treatment.
>
> Now Merlin, my 5 1/2 year old male is in need of the same surgery.
Due to
> our experience with Mandy, as well as my vet's additional exerience
with a
> similar case in his practice at the present time, we are looking
for
> preventive measures we can take. Is there anything we can do prior
to the
> surgery to prevent, or minimize the chances of diabetes developing
following
> surgery? I realize there are no sure things with surgeries, but
any
> suggestions, advice or prior experiences would be most appreciated.
>
> Incidently, Merlin had his blood glucose checked today -- it was
21.4! We
> couldn't believe it; he shows absolutely no outward signs of low bg
at all.
> The same glucometer was used to check the diabetic ferret in the
office today
> whose bg was over 600 all day, so its not like it was reading low
or
> anything. Other than sleeping a bit more than usual, Merlin has
never shown
> signs of insulinoma other than one day a couple months ago when his
back legs
> slipped from under him a couple times. He's still playful and
active and
> eats well. We've had his blood tested three times in the past 6 -
8 months
> and his bg has been going down 82, 68 and now 21 -- wasn't
expecting that!
> Should I start him on pred while we are planning surgery, or just
keep up
> with supplemental feeding? I've never had an insulinomic ferret
who showed
> no symptoms before!
Dear Lucie:
First off, in a ferret with a previous BD of only 68, a drop to 21
with no clinical signs suggests the possibility of lab error.
Glucose levels can be tricky - espcially if sent out to a lab. I
might rerun this one.
Regarding the possibility of post-surgical diabetes - this is
occasionally seen in ferrets with long-standing insulinoma.
How does this happen? Well, ferrets with insulinoma have elevated
levels of insulin (duh!) This high level of insulin causes the rest
of the islet cells in the pancreas (the ones that are responsible for
secreting insulinoma) to atrophy - there's enough insulin around, so
they're not needed.
Unfortunately, when you remove the tumor, that source of insulin, the
rest of the islets are at a disadvantage - they're atrophied, and
they may not be able to secrete enough insulin to keep the glucose at
a normal level. In most cases, diabetes, if it is seen, is
transient. These sleepy islet cells will wake up and get back on the
job. Depending on the duration and level of insulin secreted by the
tumor, some cases need insulin therapy on a temporary basis until the
cells can kick in. Rarely, the cells have atrophied or there is
additional disease in the pancreas (usually inflammatory) that there
is nothing left to come back, and permanent insulin therapy is needed.
There is no way to tell which situation you will run into, but the
odds are in your favor - only a small percentage of post-surgical
ferrets will become hyperglycemic, and even fewer will become
permanantly diabetic. This is one reason to do surgery early on
insulinoma cases - even a good response to prednisone and proglycem
will not forestall the feedback mechanism that is put into place by
prolonged insulin secretion.
With kindest regards,
Bruce H. Williams, DVM, DACVP
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