Incidence of De Quervain’s thyroiditis during the COVID-19 pandemic in an area heavily affected by Sars-CoV-2 infection

Purpose: To evaluate the possible association between Covid-19 infection and subacute thyroiditis. Methods: We reviewed the medical and imaging records of patients referred to our Department’s outpatient setting dedicated to ‘thyroid emergency’ (records with a ‘bollino verde’—green sticker, classifed as urgent) from April 2020 to October 2020. This outpatient clinic is devoted to patients requiring evaluation for severe hypothyroidism, thyrotoxicosis and neck discomfort or pain. All patients with a newly-diagnosed subacute thyroiditis were selected. The data of all patients receiving a diagnosis of subacute thyroiditis was collected retrospectively, taking into account the same period of time (April–October) and starting from 2016. Results: During the COVID-19 outbreak in our region (April 2020 to October 2020) 396 patients attended the outpatient emergency clinic. Among them, 10 (2.5%) patients received a diagnosis of subacute thyroiditis. In a single patient, a 44-year-old man, a COVID-19 pulmonary infection had been diagnosed 7 weeks before the diagnosis of subacute thyroiditis. All of the remaining patients were and remain COVID-19 free as confirmed by telephone interview. The percentage of patients who received a diagnosis of subacute thyroiditis in the same period starting from 2016 was very similar (2.9%, 2.9%, 2.6% and 3.0% in 2016, 2017, 2018 and 2019, respectively). Conclusions: Our data do not show an increase in the incidence of subacute thyroiditis in the Brescia area, a region with the highest prevalence of COVID-19 in Italy during the period of the pandemic outbreak.