Euthyroid athyroxinemia ? a novel endocrine syndrome #MMPMID28567292
Woodhouse N; Bahowairath F; Elshafie O
Endocrinol Diabetes Metab Case Rep 2017[]; 2017 (ä): ä PMID28567292show ga
A 55-year-old female was referred with abnormal thyroid function tests (TFTs); the free thyroxine level (FT4) was undetectable <3.3?pmol/L (normal: 7.9?14.4), while her FT3, TSH and urinary iodine levels were normal. She was clinically euthyroid with a large soft lobulated goitre that had been present for more than thirty years. She received an injection of recombinant human TSH (rhTSH) following which there was a progressive rise of the FT3 and TSH levels to 23?pmol/L and >100?mIU/L respectively at 24?h, The FT4 however remained undetectable throughout. Being on thyroxine 100?µg/day for one month, her FT4 level increased to 15?pmol/L and TSH fell to 0.08?mIU/L. Four years earlier at another hospital, her FT4 level had been low (6.8?pmol/L) with a normal TSH and a raised Tc-99 uptake of 20% (normal<4%). We checked the TFTs and Tc-99 scans in 3 of her children; one was completely normal and 2 had euthyroid with soft lobulated goitres. Their Tc-99 scan uptakes were raised at 17% and 15%, with normal TFTs apart from a low FT4 7.2?pmol/L in the son with the largest thyroid nodule. This is a previously unreported form of dyshormonogenesis in which, with time, patients gradually lose their ability to synthesize thyroxine (T4) but not triiodothyroxine (T3).Learning points:: This is a previously unreported form of dyshormonogenetic goitre.This goitre progressively loses its ability to synthesize T4 but not T3.The inability to synthesize T4 was demonstrated by giving rhTSH.
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Endocrinol+Diabetes+Metab+Case+Rep 2017 ; 2017 (ä): ä
