Subacute thyroiditis associated with thyrotoxic periodic paralysis after COVID-19 vaccination: a case report.

Following coronavirus disease 2019 (COVID-19) vaccination, subacute thyroiditis may develop regardless of the vaccine type. If persistent fever, anterior neck pain, swelling and tenderness of thyroid gland, and symptoms of thyrotoxicosis are observed immediately after the COVID-19 vaccination, examination in consideration of the onset of subacute thyroiditis is recommended. HLA-B35 may be associated with the onset of subacute thyroiditis after the COVID-19 vaccination. Although rare, subacute thyroiditis can be associated with thyrotoxic periodic paralysis, especially in Asian men. Glucocorticoid therapy for subacute thyroiditis may induce thyrotoxic periodic paralysis through hypokalemia.