ODP516 Subacute Thyroiditis due to SARS-CoV-2 Vaccine

Abstract

Abstract Background Coronavirus disease 2019 (COVID-19) is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that resulted in a pandemic in 2019, causing systemic complications including endocrine system diseases. Subacute thyroiditis (SAT) of COVID-19 infection is believed to be due to direct virus entry into cells and cell destruction, cellular dysfunction due to inflammation and immune/antibody-mediated hormonal dysfunction. Here we present a case of SAT after the SARS-CoV-2 vaccine (Pfizer-BioNTech). Clinical Case A 39-year-old male healthcare worker presented with four weeks history of symptoms: fullness of the anterior neck, odynophagia, enlarged cervical lymph nodes, palpitations, anxiety and weight loss. Onset of symptoms was two days the second dose of Pfizer-BioNTech vaccine. There was no recent history of upper respiratory system infection or COVID-19 infection. Vital signs and physical exam findings were unavailable, as it was a telephone encounter. Initial workup was significant for a TSH of 0. 020 uIU/mL (n 0.45-5.330 uIU/mL), free T4 of 2.42 ng/mL (n 0.45-1.80 ng/mL) and total T3 225.4 pg/mL (n 87-179 pg/mL). There was no evidence of leukocytosis. Ultrasound of the thyroid gland was unremarkable for nodules or hyperemia. Autoimmune thyroid disease was ruled out with negative levels of thyroid stimulating immunoglobulin, thyroid receptor antibody and anti-microsomal antibody. Thyroid scintigraphy was significant for abnormally low uptake, consistent with SAT. Clinical and biochemical improvements (TSH 4.193 uIU/mL; free T4 0.98 ng/dL) were seen after 5 months. Conclusion Subacute thyroiditis (SAT) is an acute inflammatory disorder of the thyroid usually related to a viral infection. It was described in total of 27 patients of COVID-19 infection (3) . There are only a handful of cases related to COVID-19 vaccine and most of them are due to the inactivated vaccine (1,2) . To our knowledge, there are only three documented cases of subacute thyroiditis after receiving the Pfizer mRNA vaccine (1) . The pathophysiology in generating an autoimmune response is believed to be due to molecular mimicry and cross recognition between the coronavirus spike protein targeted with the mRNA vaccine and healthy thyroid cell antigens (1,2) . Clinicians should be alert and consider the possibility of SARS-CoV-2 vaccine as an etiology when evaluating patients for subacute thyroiditis.