From:
williams@ex-pressnet.com
Date: 2001-03-05 07:50:00 UTC
Subject: Possible insulinoma
Dear Glenn:
10 mg.dL is very low, and I would have to recommend another glucose test.
Sometimes we get falsely low glucose values due to lab error (not quickly
spinning down the blood and removing the erythrocytes will cause decreased
levels due to the erythrocytes' use of glucose for energy). This animals
should be retested with attention to every detail inthe processing of the
bloodwork to ensure the veracity of the results.
Neurologic signs in ferrets, though, are probably 90%+ due to insulinoma,
and with a low glucose, that has to go on the top of the list. Anything
less than 80 is questionable, and 60 is definite. His response to
prednisone, which peaks the glucose is also supportive of insulinoma.
The pred in this case is a blessing and a curse. While it appears to have
brought some stability back, it also will mask the signs of hypoglycemia on
a retest. However, retest we shall, and hope that the values are still low
enough to be diagnostic.
Other far less likely ruleouts would be inflammatory disease of the CNS, and
CNS neoplasia. Both of these are difficult to diagnose, as intracranial
infectious causes only rarely cause significant changes to the CBC, and
until insulinoma is definitively ruled out, we would probably not pursue
them with tremendous vigor.
With kindest regards,
Bruce Williams, DVM, DACVP
Join the Ferret Health List:
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******************************
Dear Doctor,
My ferret, a neutered male just under 3 1/2 years old, with no significant
medical history other than an anaphylactic reaction to a distemper
vaccination, began exibiting symptoms not unlike vertigo several days ago.
He has a noticable 'list' to the left as well as head tilt to the same side.
Initially, he was appeared listless and reluctant to move/ambulate and did
not eat that evening. He was not, however, 'disoriented'; though unsteady,
he used his litter box and knew how to get back to and into his hammock. As
a physician, I feel that he showed no evidence of hypoglycemia as I know
them (I mention this as the veterinarian I spoke with did indicate that
ferrets are, indeed, prone to episodes of hypoglycemia). He exibited no
other significant sypmtoms.
He and two other ferrets share a room. They never go outside nor are they
ever exposed to any other animals. The other ferrets are fine. They are
fed Iams adult cat food, with a treat of one raisin in the morning and on in
the evening.
Having just relocated, I was unable to find a veterinary office open until
morning, at which time, I spoke to the veterinarian and promptly took him in
for an examination. The veterinarian confirmed the prescence of the
neurological symptoms, prescribed baytril 10mg. q.d., prednisone 2.5mg. q.d.
and a high calories supplement, and sent out a CBC/diff and chemistry panel.
Results of the CBC were normal. Chemistry panel showed normal kidney and
liver function, with the only abnormal values being a slightly elevated
chloride level [113meQ/L - ref 90-110], and a glucose level of...10mg/dL!
The ferret, after 2 days of medication and nutritional supplement, has
responded well in that his appetite has ,in part, returned and his activity
level has increased (all certainly attributable to steriod therapy).
Neurological symptoms appear slightly improved (or his ability to compensate
has increased).
Though I am aware of the incidence of insulinomas in ferrets, his symptoms
with regard to orientation/alertness seemed inconsistent with a blood
glucose level of 10mg/dL (at least from my experience with humans).
I would certainly welcome and appreciate your opinion and expertise as to
the differential diagnosis regarding the neurologic symptoms, whether such
symptoms are common in ferrets, and the significance of the laboratory
results with regard to further testing and therapy.