Endocrine Abstracts

Aim: Analyzing the evolution of thyroid function in thyroiditis and related disease between 1–20 years.

Material and method: i). Diagnostic: Hashimoto thyroiditis (HT): 1. antithyroperoxydase antibodies (ATPO), cut-off 34 ui/ml. 2. if ATPO=normal, thyroiditis was considered if high antithyroglobuline antibodies (T-ATG); 3. idiopathic mixedema (IM): hypothyroidism with no ATPO, no ATG, no TRAB. ii). Thyroid function: normal TSH: 0.4–4 u/ml. iii). Statistic analysis: z test.

Results: I. HT: Re-evaluated patients =484. i). At the diagnostic moment. Euthyroid (EUT): 202 (41.75%), Hypothyroid (HOT): 208 (42.98%), Hyperthyroid (HIT): 74 (15.29%) – all with high TRAB (Graves-Basedow disease-GBD).

ii). Follow-up. a. 35 (17.33%) with EUT became HOT after 0.2(!)-8 years (av=2.88, S.D.=2.31). b. 4 (1.98%) with EUT become HIT (all GBD). c. Almost all HOT remained HOT, 1 become HIT (GBD) and still under methimazole. d. 41 (55.41) with HIT become EUT after 1.5–2 years and maintain at least 8 years. e. 3 (4.05%) with HIT become spontaneously HOT, under levothyroxine, vi). 2 relapsed after 2 years treatment, g. 28 are still under antithyroidian treatment (5 between 5-11 y).

II. T-ATG: Re-evaluates patients =30. A. At the diagnostic moment. EUT: 15 (50%, significantly more than in HT), HOT: 12 (40%), HIT: 3 (10%) - only one high TRAB (GBD association).

B. Follow-up. a. 1 EUT (6.67%) become HOT (vs HT P=0.008). b. 2 HIT become EUT, 1 under treatment. c. All HOT remained HOT.

III. IM

IM: HOT: 86 (100%). All remained HOT after 5–20 years.

Conclusions: i). Thyroiditis with only hyperATG could be considered different from HT: more EUT than HOT, less HOT evolution. ii). Only few EUT-HT adult patients developed HOT (17.3%). iii). No EUT-HT patient modified function after 8 years of observation. iv). Patients with HOT at diagnostic time, either HT, T-ATG or IM, remained HOT.