The cytokine storm and thyroid hormone changes in COVID-19

Area of Science:

• Endocrinology
• Virology
• Immunology

Background:

• The COVID-19 pandemic presents numerous extra-pulmonary manifestations.
• Emerging evidence suggests a potential link between COVID-19 and thyroid dysfunction.

Purpose of the Study:

• To review existing studies on thyroid function in COVID-19 patients.
• To examine the potential physiopathological mechanisms underlying these alterations.

Main Methods:

• Literature review of studies investigating thyroid function in COVID-19.
• Analysis of proposed etiological factors and clinical observations.

Main Results:

• COVID-19 may induce thyroid dysfunction via a "cytokine storm" leading to "non-thyroidal illness."
• Cytokines and chemokines can directly impact the hypothalamus-pituitary-thyroid axis.
• Increased incidence of destructive thyroiditis (subacute or painless) observed in COVID-19 patients.
• SARS-CoV-2 receptor (ACE2) is highly expressed in thyroid tissue, suggesting potential direct viral infection.
• Pharmaceuticals used for COVID-19 treatment may confound thyroid function test results.

Conclusions:

• Thyroid dysfunction in COVID-19 is multifactorial, involving inflammatory responses and potential direct viral impact.
• The "cytokine storm" and associated "non-thyroidal illness" are key contributors.
• Direct viral effects on the thyroid gland are plausible due to ACE2 expression.
• Further research is needed to elucidate the precise mechanisms and clinical implications of COVID-19-related thyroid dysfunction.