Euthyroid athyroxinemia - a novel endocrine syndrome.

Autor: Woodhouse N; Department of Medicine, Sultan Qaboos University Hospital, MuscatSultanate of Oman., Bahowairath F; Department of Medicine, Sultan Qaboos University Hospital, MuscatSultanate of Oman., Elshafie O; Department of Medicine, Sultan Qaboos University Hospital, MuscatSultanate of Oman.
Jazyk: angličtina
Zdroj: Endocrinology, diabetes & metabolism case reports [Endocrinol Diabetes Metab Case Rep] 2017 May 25; Vol. 2017. Date of Electronic Publication: 2017 May 25 (Print Publication: 2017).
DOI: 10.1530/EDM-17-0019
Abstrakt: 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.
Databáze: MEDLINE