Premium
TRANSIENT THYROTOXICOSIS IN ENDEMIC GOITRE PATIENTS FOLLOWING EXPOSURE TO A NORMAL IODINE INTAKE
Author(s) -
LIMA N.,
MEDEIROSNETO G.
Publication year - 1984
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.1365-2265.1984.tb01405.x
Subject(s) - euthyroid , iodine , medicine , endocrinology , thyroid , iodised salt , excretion , endemic goitre , goiter , chemistry , organic chemistry
SUMMARY Twenty‐three endemic goitrous subjects (goitre grade: III and IV) that were living in a chronic iodine‐deficient area (iodine intake: less than 40 μg I/d) were submitted to clinical and laboratory evaluation within 3–8 weeks of arrival at the metropolitan area of São Paulo, where daily iodine intake is estimated to be 150–200 μg I/d. Eight patients developed a mild thyrotoxic state (T4 = 14.7 ± 2.3 μg/dl, T3 = 279 ± 55 ng/dl, no TSH response to TRH). Five additional subjects, although euthyroid, had a blunted TSH‐response to TRH, and the remaining ten patients were euthyroid and had a normal TSH response to TRH. Thyrotoxicosis was associated with larger goitres (mean thyroid weight: 133 ± 46 g), with high thyroid uptake of RAI (mean 24 h 131 I uptake: 40 ± 15%) but not with increased urinary iodine excretion. Serum Tg levels were more elevated in the first two groups of patients (respectively, geometric means 68 and 72 ng/ml), than in the euthyroid, TRH‐responsive group (52 ng/ml). Thyrotoxicosis resolved spontaneously after three to six months without the need for any specific medication. It was concluded that a relatively small and normal iodide intake due to regular consumption of iodized salt and industrialized foods may induce a transient form of thyrotoxicosis in endemic goitre patients arriving into urban areas.