Efficacy of oral selenium as an alternative treatment for mild cases of thyroid orbitopathy: a literature review

Purpose: Conduct a literature review about the role of oral selenium as a therapeutic alternative for patients with mild thyroid eye disease.Thyroid orbitopathy is the main extrathyroidal manifestation of Graves' disease.It is an autoimmune disease characterized by the infiltration of T lymphocytes of the orbital tissue, thyroid tissue, and extraocular muscles.Increased oxidative stress has been discovered in autoimmune thyroid disease, encouraging research into new forms of treatment.The choice of treatment should be based on the evaluation of the clinical activity and severity of thyroid orbitopathy.Based on the role of oxidative stress in the pathogenesis of thyroid orbitopathy, therapy with antioxidant agents such as selenium has been proposed as a useful alternative in the management of this disease.Methods: A bibliographic search was conducted in the electronic databases Scopus and Pubmed from 2020 onwards, using the terms "thyroid and eye and disease" or "selenium".Experimental studies, case-control studies, cohort studies, case series, and surveys in english, french, and spanish were included.Of the 62 initially selected articles, 33 studies were included.A full review of the 33 included articles was conducted, of which 24 were studies on definition, diagnosis, classification, and general treatment.Nine studies related to the use and benefits of selenium in thyroid orbitopathy were also included, with only one examining the effect of orally administered selenium in patients with mild thyroid orbitopathy.Results: In the thyroid orbitopathy; tissue hypoxia, as well as reactive oxygen species, are involved in the typical changes that occur in the fibrofatty orbital tissue and the perimysium of the extraocular muscles.Antioxidants have been proposed to improve the effects of antithyroid drugs in patients with Graves' disease, as well as the remodeling of orbital tissues in patients with thyroid orbitopathy.Selenium was the only antioxidant recommended according to a high-level randomized controlled trial.The primary outcome in human studies was improvement in severity, activity scores, and/or quality of life scores.There was a decrease in the level of H 2 O 2 -dependent oxidative stress, hyaluronic acid release and reactive oxygen species.Conclusion: Selenium has been described as a treatment option given its antioxidant properties.Although the actual efficacy of selenium in patients with thyroid orbitopathy remains questionable, its use in the treatment of mild thyroid orbitopathy is generally believed to be beneficial and its administration has already been included in routine clinical practice for patients with this disease.There are no data available on its effectiveness in more severe forms of thyroid orbitopathy.