A Literature Review on SARS-CoV-2 and Other Viruses in Thyroid Disorders: Environmental Triggers or No-Guilty Bystanders?

Abstract

A growing number of findings indicate a relationship between COVID-19 infection and thyroid dysfunction. This association is also strengthened by knowledge on the potential of viral infections to trigger thyroid disorders, although the exact underlying pathogenetic process remains to be elucidated. This review aimed to describe the available data regarding the possible role of infectious agents, and in particular of SARS-CoV-2, in the development of thyroid disorders, summarizing the proposed mechanisms and levels of evidence (epidemiological, serological or direct presence of the viruses in the thyroid gland) by which the infection could be responsible for thyroid abnormalities/diseases. Novel data on the association and mechanisms involved between SARS-CoV-2 vaccines and thyroid diseases are also discussed. While demonstrating a clear causal link is challenging, numerous clues at molecular and cellular levels and the large amount of epidemiological data suggest the existence of this relationship. Further studies should be taken to further investigate the true nature and strength of this association, to help in planning future preventive and therapeutic strategies for more personal and targeted care with attention to the underlying causes of thyroid dysfunction.

Subacute Thyroiditis Complicating COVID-19 Infection

“…In addition, the authors reported significant correlations of IL-6 with free and total T4 and free and total T3, indicating the devastating properties of cytokines that may play a cardinal role in the pathogenesis of painless SAT. 1 The clinical examination of our patient revealed a painful and voluminous thyroid gland and moist and warm skin.…”

“…Moreover, because subacute thyroiditis seems to be also associated with other viral infections, the same diagnostic strategy could be considered for other viruses as well. 1,25 In addition, due to the spread of SARS-CoV-2 disease, it has been observed that clinicians focus greatly on COVID-19 infection, which could affect the correct diagnosis of other 26 or co-existing diseases, for example, SAT. As such, physicians' vigilance constitutes a fundamental part of patients management.…”

“…Accumulating evidence highlights a causal relationship between SARS-CoV-2 infection and various thyroid disorders including subacute thyroiditis (SAT), nonthyroidal illness syndrome (NTIS), and autoimmune thyroid diseases, such as Graves' disease (GD) and Hashimoto's thyroiditis. 1 Recent research data demonstrate SAT as a potential manifestation of ongoing COVID-19 infection or a post-viral complication of the disease. 2 Direct viral toxicity and post-viral inflammatory reaction-the so-called "cytokine storm," term which describes a systemic hyperinflammatory status resulting in pleomorphic thyroid disturbances-may represent the major pathogenetic mechanisms of the disease.…”

The Influence of Autoimmune Thyroid Diseases on Viral Pneumonia Development, Including COVID-19: A Two-Sample Mendelian Randomization Study

“…It can be inferred that inadequate management of potential thyroid disorders may heighten the risk and severity of viral pneumonia. Nevertheless, epidemiological studies on the causality between thyroid diseases or hormones and viral infection-induced pneumonia remain scarce [ 19 , 20 ].…”

The course of subacute thyroiditis from COVID-19 infection

“…Подострый тиреоидит (тиреоидит де Кервена, ПТ)воспалительное заболевание щитовидной железы (ЩЖ), основным этиологическим фактором которого считается вирусная инфекция. Доля данной нозологии в структуре заболеваний ЩЖ составляет 1-5%, и она считается относительно редкой, при этом число случаев значительно возрастает на фоне эпидемий, вызванных различными вирусами (гриппа, аденовирусами, вирусамивозбудителями эпидемического паротита) [2][3][4][5]. Схожий тренд в статистике ПТ наблюдался после начала пандемии, связанной с SARS-CoV-2.…”