Endocrine Abstracts

Background: There are a lot of painless thyroiditis cases without symptoms diagnosed on health check up or thyroid hormone screening, but there is a few data about it compared to much data about painful subacute thyroiditis. So, we collected data about diagnostic routes, laboratory and clinical characteristics of painless thyroiditis.

Method: Painless thyroiditis patients diagnosed between 2010 and 2016 were reviewed. We defined painless thyroiditis as disease with typical clinical courses of thyrotoxicosis and sequential hypothyroid phase and decreased uptake on thyroid scan.

Result: Total 191 patients (139 female, 52 male) were involved. The diagnostic routes were classified under four entry. First, health check up: 47 patients, 24.6%. Second, patients evaluated with thyroid function test because of nonspecific other symptoms or routine check up of inpatient: 68 patients, 35.6%. Third, patients evaluated with thyroid function test because of thyrotoxic symptoms or signs (fatigue, palpitation, tremor, goiter etc): 59 patients, 30.9%. Fourth, patients associated with postpartum: 17 patients, 8.9%. Permanent hypothyroidism was not uncommon (7/191; 3.7%). Higher peak TSH level (P value below 0.001) was related with permanent hypothyroidism. 11.5% (22/191) experienced recurrence. Lower peak TSH (P value 0.018) and short duration of thyrotoxicosis phase (P value 0.001) was associated with recurrence.

Discussion: More than 50% of painless thyroiditis was diagnosed on health check up or accidental thyroid function test without typical thyrotoxic symptoms. Many patients with heterogenous parenchymal echogenecity on sonography finding without history of thyroid disease could be go for that cases. Higher peak TSH was related with permanent hypothyroidism. In contrast, lower peak TSH was associated with recurrence and short duration of thyrotoxicosis phase was also related with recurrence.