Unfortunately we have seen this and it usually means that the serious
seizures have set in for insulonomic ferrets.  I have had 3 ferrets over
the past 8 years die while in screaming seizures.  The ones we have seen
have not been reversible.  I do not mean to frighten you on this...This
is MY experience with the screaming.
 
We tried ferretone, nutracal, honey etc to bring them out of it and
it never seemed to help.  They would scream for a few minutes while
thrashing around and then just lay there for about 20 mins and then
start all over.  It sounds like yours could be different because he/she
came out of it eventually.
 
All 3 of ours had surgery to remove the tumors which DID prolong their
life by about a year.  There comes a point after surgery and after the
pred dosage has been maxed out, I think, where nothing we can do will
help.  You will know when that point has been reached.
 
All the best.
 
Dom
[Posted in FML issue 5182]