Subacute thyroiditis in a patient infected with SARS-COV-2: an endocrine complication linked to the COVID-19 pandemic

Subacute thyroiditis (SAT) is an inflammatory thyroid disorder of viral origin, generally preceded by an upper respiratory tract infection. Since the disorder is self-limiting, it is frequently underdiagnosed. However, the disease should not be overlooked since the associated thyrotoxicosis may worsen the clinical course of concomitant disorders (e.g., respiratory distress) and long-term sequelae, such as autoimmune hypothyroidism, have been reported.

Here we describe a woman who developed SAT with thyrotoxicosis after SARS-COV-2 infection. Coronavirus disease (COVID-19) symptoms were mild and the patient was managed with no specific treatment and recovered rapidly.

Six weeks after the onset of the upper respiratory tract infection, the patient developed pain and tenderness in the anterior cervical region, fatigue, tremors, and palpitations. Physical examination revealed mild tremors of the extremities, a diffuse and painful goiter, and enlarged and tender cervical and submandibular lymph nodes. At biochemical evaluation, TSH was suppressed, FT3 and FT4 were high, and serum thyroglobulin was markedly increased (188 pg/mL; n.v. 0-40). Thyroid scintigraphy showed markedly reduced ^99mTc-perthecnetate uptake in the gland. All findings were consistent with SAT, and treatment with oral prednisone (25 mg/day as the starting dose, gradually tapered) was started. Under the corticosteroid therapy, there was progressive resolution of symptoms and signs, and, within 4 weeks, all thyroid functional tests and inflammatory indexes normalized.

Clinicians should be aware of thyroid manifestations potentially associated with COVID-19.