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THE ASSESSMENT OF 125 I TREATMENT OF THYROTOXICOSIS
Author(s) -
BREMNER W. F.,
SPENCER CAROLE A.,
RATCLIFFE WENDY A.,
GREIG W. R.,
RATCLIFFE J. G.
Publication year - 1976
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1976.tb01948.x
Subject(s) - euthyroid , medicine , endocrinology , thyroid , incidence (geometry) , hormone , reference range , physics , optics
SUMMARY 257 patients have been reviewed 1‐5 years (mean 3 years 2 months) after receiving one of five dose regimes of 125 I for thyrotoxicosis. The cumulative incidence of hypothyroidism was 34% and of persistent thyrotoxicosis 17%. The group receiving doses between 351 and 500 μCi/g had the highest proportion of euthyroid patients (65%) with the lowest requirement for repeat therapy (46%). In the euthyroid patients, increasing dose of 125 I was associated with progressive decline in mean thyroxine (T4) level and free thyroxine index (FTI) within the respective normal ranges, and increase in mean thyroid stimulating hormone (TSH) level to above the normal range. Euthyroid patients with elevated TSH levels had significantly lower T4 and FTI values compared with those with normal TSH, and showed a 3‐4‐fold increased rate of development of hypothyroidism over 1 year. Euthyroid patients with elevated T3 levels remained euthyroid during the subsequent year and mean T3 levels declined significantly, suggesting that abnormally elevated T3 levels after 125 I do not generally indicate impending relapse of thyrotoxicosis. It is concluded that the potential advantages of 125 I therapy for thyrotoxicosis in reducing the incidence of hypothyroidism have not been realized in practice.