Epsilon Archive for Student Projects

Abstract

Hyperthyroidism has become the most commonly diagnosed endocrine disorder in
cats. The recommended treatment of choice in the literature is administration of
radioactive iodine. This treatment has been available at a few veterinary clinics in
Sweden since 1999. Forty-six cats treated with a standard dose (80 MBq) of
radioactive iodine (131I) at the Swedish University of Agricultural Sciences in the
period 2000-2004 were followed for a median of 13 months (range 3-42 months)
by means of a retrospective cohort study design. Tables predicting time of survival
after treatment were made.
At final follow-up thirty-nine cats (85%) were euthyroid, six cats (13%) remained
hyperthyroid and one cat (2%) was hypothyroid. The seven cats which were
hyperthyroid at the six-weeks follow-up had significantly higher serum thyroxin
values before treatment than the cats that became euthyroid (p=0,015). Seventy-five
per cent of the cats (median age 13 years) are estimated to survive 13 months posttreatment,
which is comparable to other similar studies.
Possible improvements of the handling of these cases such as the calculation of
acquired dose of radioactive iodine is discussed in this article.

Hypertyreoidism är numera ansedd som kattens vanligaste endokrina rubbning.
Behandling med radioaktivt jod har funnits tillgänglig på ett fåtal kliniker i Sverige
sedan 1999. Samtliga katter behandlade vid SLU från november 2000 - april 2004
följdes i en retrospektiv kohortstudie avseende tillfrisknande och överlevnad genom
journalstudier och djurägarintervjuer. Vid slutlig uppföljning 3-42 månader efter
behandling hade 85 % av katterna återfått normal tyreoideafunktion och 75%
förväntades överleva mer än ett år efter behandling. De sju katter som vid katter
som vid kontroll ej tillfrisknat hade signifikant högre (p=0,015) högre T4-värden
före behandling än de 39 vars behandling lyckats.