Myasthenia gravis
 
http://www.veterinarypartner.com/Content.plx?P=A&C=10&A=1544&S=0
 
One form is genetic, and another is acquired autoimmune according to this
veterinary source.  (Though I did find elsewhere that among humans some
cases of Myasthenia gravis, some cases of MS, and some other things now
are known to also sometimes trace to certain zoonotic viruses like Simian
Foamy Virus, so there can be other causes.)
 
It includes:
> What muscles are affected depend on which junctions have been
> destroyed. Therapy centers on stopping this immune reaction and
> prolonging what acetylcholine activity is still present. This is
> done with a combination of immunosuppressive agents and medications
> to inhibit acetylcholinesterase.
 
Although I can not recall hearing of this in ferrets and did not find any
vet articles specifically on it in ferrets it does mention that in dogs
it is one consideration when Megaesophagus occurs.  I do not know if any
MegaE ferrets have been checked for Myasthenia gravis.
 
and some dog and cat info:
 
>Once a dog or cat has been found to have myasthenia gravis, it is
>important to consider that immune mediated conditions often go together.
>There may be other problems afoot.
>
>A chest radiograph set should be taken to check for thymoma.
 
There can be some good news for a number of dogs, though, so hopefully,
there also can be for ferrets:
 
>Myasthenia gravis often goes into remission without treatment. In
>one study of 53 dogs, 89% went into remission an average of 6.4
>months (and within 18 months) after diagnosis.
 
but
 
>In this study, the dogs that did not go into remission all developed
>cancer within 3 years of their myasthenia diagnosis.
 
and
 
>Removing the thymus gland?
>The thymus gland, located in the chest generally shrivels up after
>childhood/puppyhood/kittenhood. It is involved in the maturation of
>the immune system. In humans, tumors and excessive growths of the
>thymus frequently accompany the development of myasthenia gravis.
>Thymectomy (removal of the thymus gland) is a well-accepted part of
>treatment for myasthenia gravis in humans but is still unproven to
>help in the treatment of dogs and cats.
 
>Pyridostigmine (brand name Mestinon(R)) is the usual medication used
>to prolong the action of acetylcholine.
 
>Corticosteroids, such as prednisone, and similar drugs can suppress
>the production of the antibodies that are destroying the neuromuscular
>junctions.  In general these medications are avoided unless the
>anticholinesterase therapy does not yield acceptable results.  Other
>stronger immune suppressive drugs (such as azathioprine) are only used
>if there are reasons that corticosteroids cannot be used
 
but ferrets usually do NOT tend to have the high number of problems with
steroids seen in other species.  (See past posts of multiple vets.)
 
Don't vaccinate this one.
 
There is a lot more there for you.
 
I saw that someone else found info for you but did not have a chance to
read that post that day.  If I am duplicating the data, I hope that at
least i am not also duplicating the source.
 
A case in a polar bear with thyoma:
<http://www.bioone.org/bioone/?request=get-document&issn=1042-7260
&volume=035&issue=03&page=0409>
 
-- Sukie (not a vet)
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replacing
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[Posted in FML issue 5163]