ABSTRACT
COVID-19 is a severe acute respiratory syndrome. Recent reports showed that autoimmune thyroiditis might occur following COVID-19 infection. We aimed to review the literature to assess the prevalence, clinical features and outcome of autoimmune thyroid disorders triggered by COVID-19. We reviewed case reports, case series, and observational studies of autoimmune thyroiditis including Graves' disease, Hashimoto thyroiditis, and silent thyroiditis developed in COVID-19 patients by searching PubMed, SCOPUS and Web of Science and included in the systematic review. Our search yielded no prevalence study. We noted 20 reported cases: Fourteen cases of Graves' disease, 5 cases of hypothyroidism due to Hashimoto's thyroiditis and one case of postpartum thyroiditis. The majority (16/20, 80%) were middle-aged (mean age: 40 years) female patients. Autoimmune thyroiditis was diagnosed either concomitantly or 7-90 days after the COVID-19 infection. Eight out of 14 cases with Graves' disease had a known thyroid disorder and they were stable in remission. One out of 5 cases with Hashimoto's thyroiditis had known prior hypothyroidism. The majority of the patients achieved remission within 3 months. One patient with thyroid storm due to Graves' disease and one patient with myxedema coma have died. Current data suggest that COVID-19 may cause autoimmune thyroid disease or exacerbate the underlying thyroid disease in remission. It is reasonable to routinely assess the thyroid functions both in the acute phase and during the convalescence so as not to overlook a thyroid disorder and not to delay treatment especially in patients with preexisting autoimmune thyroid diseases.