Endocrine Abstracts

Introduction: Massive anti-SARS-CoV-2 vaccination campaigns have been established as the cornerstone of confronting the current COVID-19 pandemic. Subacute thyroiditis (SAT) comprises an inflammatory process in the thyroid gland, mostly due to viral infections of the upper respiratory tract, although it may rarely occur after vaccine administration. To date, a few cases of SAT related to anti-SARS-CoV-2 vaccines have been reported globally. Hereby, we present the case of a patient with solitary kidney who developed SAT, mild thyroid autoimmunity activation and subsequent permanent hypothyroidism after mRNA-based anti-COVID-19 vaccination.

Case report: A 79-year old male patient with solitary kidney due to nephrectomy after drug-induced acute renal failure presented for evaluation in terms of newly detected subclinical hyperthyroidism and neck pain starting 20 days ago. The patient had a known history of mild subclinical hypothyroidism diagnosed 2 years ago without laboratory-confirmed autoimmune etiology (negative thyroid-related autoantibodies) and without levothyroxine supplementation. Neck pain and tenderness as well as low grade fever with intermittent episodes of hypothermia had an onset 10 days after the first dose of the mRNA vaccine Comirnaty and continued after administration of the second dose 2 weeks before the patient’s visit. The neck ultrasound revealed a pattern typical of subacute thyroiditis with bilateral volume growth and diffuse heteroechogenicity and inhomogeneity accompanied by reduced blood flow; the adjunctive laboratory evaluation showed elevation of the inflammatory markers (CRP, ESR) with first documentation of slightly elevated TPO-autoantibodies. As the patient reported remission of his symptoms no anti-inflammatory medication was initiated. One month later the patient reported no SAT-related symptoms but the laboratory evaluation revealed overt hypothyroidism. He was started on levothyroxine 88 μg daily and remained euthyroid under supplementation. Neck ultrasound 4 months after the first visit showed a remission of the inflammatory process with reduction of both the thyroid volume and the hypoechoic inflammatory zones.

Conclusion: The above case presentation comprises the first official report of subacute thyroiditis in adjunction with mRNA COVID-19 vaccination in northern Greece. SAT is a self-limiting process and is rarely reported as a mild complication of the anti-SARS-Cov-2 vaccination with only few documented cases related to all types of available vaccines. Therefore, clinicians should be aware of this rare post-vaccination adverse event. Despite the development of permanent hypothyroidism in the present case the definitive benefits of the anti-COVID-19 vaccination outweigh the rare and mostly mild and transient side-effects which shall not comprise an inhibitory factor against vaccination.