Concurrent Subacute Thyroiditis and Graves' Disease After COVID-19: A Case Report

Area of Science:

• Endocrinology
• Infectious Diseases
• Immunology

Background:

• Subacute thyroiditis (SAT) is an inflammatory thyroid condition often triggered by viral infections.
• Graves' disease (GD) is an autoimmune disorder causing hyperthyroidism.
• While SAT post-COVID-19 has been reported globally, its occurrence in Korea and co-diagnosis with GD are undocumented.

Observation:

• A 27-year-old woman presented with fever, respiratory symptoms, and neck pain following a second COVID-19 infection.
• Initial findings suggested SAT, characterized by thyrotoxicosis and neck tenderness with spontaneous improvement.
• Atypical features included elevated thyroid-stimulating immunoglobulin, recurrent thyrotoxicosis, and increased radionuclide uptake, indicating coexisting Graves' disease.

Findings:

• The patient exhibited clinical and biochemical evidence of both subacute thyroiditis and Graves' disease.
• This represents the first reported case of simultaneous SAT and GD following COVID-19 in Korea.
• The presentation highlights the complex interplay between viral triggers and autoimmune thyroid responses.

Implications:

• This case expands the understanding of potential post-COVID-19 thyroid complications.
• It underscores the importance of considering coexisting autoimmune thyroid diseases in patients presenting with SAT after viral infections.
• Further research is needed to elucidate the mechanisms linking COVID-19 infection to combined SAT and GD.