TRH stimulation test in patients with repeatedly elevated TSH and normal FT4

ABSTRACT Subclinical hypothyroidism (SCH) is defined by elevated thyroid-stimulating hormone (TSH) with normal free thyroxine (FT4). We aimed to evaluate the thyrotropin-releasing hormone (TRH) stimulation test in patients with repeatedly elevated TSH (up to 10 mIU/l) and normal FT4, but without apparent thyroid disease. Women with TSH> 4.5 and ≤ 10 mIU/l (in two measurements) and normal FT4 were selected. Women with a known non-thyroid cause of TSH elevation, those treated with anti-thyroid drugs, amiodarone, lithium, and those with a history of thyroidectomy, neck radiotherapy and 131I treatment were excluded. Seventy women had negative antithyroperoxidase antibodies. Ultrasonography revealed a eutopic thyroid, usual echogenicity, and a volume ≤ 15 ml, and they underwent the TRH stimulation test during initial evaluation. After stimulation with TRH, TSH> 30 mIU/l was observed in 38 women (expected response), while 32 women had TSH< 20 mIU/l (inadequate response). Age, basal TSH or thyroid volume did not differ between both groups, but FT4 concentrations were significantly lower in the first group. Follow-up was available for 66/70 women. Seven women developed a need for levothyroxine, all of them in the group with an adequate response to TRH [7/36 (19.4%) versus 0/30]. The results suggest that some cases of TSH elevation (even persistent) do not represent the early stage of thyroid insufficiency.RESUMEN El hipotiroidismo subcl ínico (HSC) es definido por la ...
Source: Jornal Brasileiro de Patologia e Medicina Laboratorial - Category: Pathology Source Type: research