Two cases of Hashimoto's thyroiditis with transient hypothyroidism

Two cases of Hashimoto's thyroiditis are presented: a woman who suffered twice from transient hypothyroidism (Case 1), and a woman with polycystic ovary syndrome who had transient hypothyroidism which was inferred to have been caused by exacerbation of Hashimoto's disease (Case 2). In both cases, fluctuation in titers of both anti-thyroglobulin (TGHA) and antimicrosomal antibodies (MCHA) was observed. Although an increased serum thyroid stimulating hormone (TSH) concentration in Case 2 was associated with the increased titer of MCHA, this was not true of Case 1. Measurement of serum iodine concentration in Case 1 disclosed no correlation between serum TSH and iodine concentrations, suggesting that episodes of hypothyroidism in this patient are not due to iodine-induced hypothyroidism. The transient hypothyroidism in Case 2 was considered to be due to fluctuations in immune mechanism(s), but the reason in Case 1 was not clear in the present study.