I hope this is of some hekllp to you.
It says that the 1st is about Bengals, but deals with what you asked
about too..& there are several other links for your friend here as
well.
I hope that they help you Rene
http://www.hdw-inc.com/healthhyperthyroidism.htm
http://www.uspharmacist.com/index.asp?show=article&page=8_1498.htm
http://www.catthyroid.com/
http://cats.about.com/cs/healthissues/p/hyperthyroid.htm
http://www.vetinfo.com/chyperthyroid.html
S;o)