Subacute thyroiditis (SAT) is an inflammation of the thyroid gland characterized by varying degrees of severity regarding thyrotoxicosis, inflammation and the incidence of hypothyroidism. The present study aims to identify whether the severity of SAT depends on the causative agent involved and to identify what is the optimal therapy. To this purpose we retrospectively evaluated 402 patients referred to of the University Hospital of Pisa because of to a SAT from January 2011 to December 2020. 32 patients did not receive pharmacological treatments, 16 were treated with non-steroidal anti-inflammatory drugs (NSAIDs) and 354 with glucocorticoids; among these the most common initial dose (n = 286) was 25 mg of prednisone and most patients were treated for 90 days (n = 277). 88 patients experienced definitive hypothyroidism. Patients with higher levels of free thyroxine (FT4), C reactive protein (CRP), erythrocyte sedimentation rate (ESR) and thyroglobulin (Tg) experienced more frequently hypothyroidism at the end of inflammatory process. Patients treated with glucocorticoids experienced a shorter duration of neck pain (14 days, P <0.001) than patients treated with NSAIDs (28 days) and those not treated (28 days). The more adeguate prednisones starting dose to obtain neck pain remission was 25 mg/day. The third quarter of the year was characterized by the highest number of cases compared to the other quarters in all years except in 2012 and 2015, when there was a high incidence of cases in the first quarter of the year, and in 2020 where most of the SAT cases occurred in the second and fourth quarters. In these same quarters SAT was more severe with regard thyrotoxicosis, inflammatory indices and incidence of hypothyroidism. In a previous study we observed that SAT clusters in 2020 occurred within a month of the Covid-19 waves. Therefore, similarly we have evaluated the Italian epidemiological situation of the winter seasons 2011-12 and 2014-15, in which an anomalous circulation of the influenza virus A.H3N2 emerged; therefore it is might be responsible for SAT clusters in the first quarter of 2012 and 2015. We conclude that the differences about the severity of SAT depend on the different agent responsible and glucocorticoid therapy for SAT is effective even at lower doses than recommended by the latest guidelines.
10 Sep 2022 - 13 Sep 2022