Post-COVID-19 Painless Thyroiditis: A Case Study on Thyrotoxicosis Management

BACKGROUND Painless thyroiditis is a rare variant of thyroiditis characterized by low thyroid-stimulating hormone (TSH) levels and normal or elevated T4 concentrations, without clinical signs of acute inflammation. While thyroiditis, including subacute and atypical forms, has been associated with many viral infections including SARS-CoV-2, the occurrence of painless thyroiditis after acute COVID-19 remains uncommon. CASE REPORT We describe the case of a 67-year-old man with history of hypertension, diabetes, and myocardial infarction who presented with a 4-week history of decreased appetite, nausea, weight loss, and upper-extremity tremors. He reported having a resolved case of COVID-19 2 months previously. Laboratory evaluation revealed a low TSH level (0.01 mIU/L) and elevated free T4 (>7.7 µg/dL), with negative thyroid-stimulating and thyroid peroxidase antibodies. A neck ultrasound showed a normal thyroid gland. The patient was diagnosed with post-COVID-19 painless thyroiditis and managed with beta blockers, methimazole, and corticosteroids. His symptoms improved significantly during hospitalization, and he was discharged with follow-up plans to monitor for potential hypothyroidism. CONCLUSIONS This case highlights the importance of considering post-COVID-19 painless thyroiditis in patients presenting with thyrotoxicosis and a history of COVID-19. Prompt recognition and treatment with beta blockers, anti-thyroid drugs, and corticosteroids can lead to symptom resolution. Regular follow-up is crucial to detect and manage potential long-term thyroid dysfunction.