Thyroid Function during COVID-19 and Long Covid complications

Thyroid Function during COVID-19 and Long Covid complications

Panesar, A. et al. (2025) summarised by Nikky Yusifova

Introduction

In addition to respiratory symptoms, COVID-19 can affect multiple organs and systems, including the endocrine (hormone) system. Several studies have suggested interactions between thyroid function with both acute and Long Covid conditions. This systematic review summarises recent literature on COVID-19 related thyroid dysfunction in adults.

Summary

A comprehensive search of the PubMed and EMBASE databases was conducted for this review. A total of 53 studies, published in English between January 2020 and April 2024, were included. This review analysed case reports, retrospective studies, and prospective studies. These studies identified the main types of thyroid dysfunction following COVID-19, including:

• Subacute thyroiditis is characterised by anterior neck pain, fever, and symptoms of thyrotoxicosis such as weight loss, changes in heart rate, and emotional instability
• Painless thyroiditis presents with symptoms of thyrotoxicosis but without neck pain
• Graves’ disease is an autoimmune condition featuring hyperthyroidism (nervousness, anxiety, mood swings, sleep difficulties), thyroid eye disease (Graves’ orbitopathy), heart issues, and periodic paralysis
• Hashimoto’s thyroiditis is associated with hypothyroidism (fatigue, weight gain, dry skin, constipation), and in rare cases, encephalopathy that may lead to coma
• Nonthyroidal illness syndrome presents with clinically normal thyroid function despite low thyroid hormone levels on tests.

Subacute thyroiditis was reported in 64% of case studies, though some retrospective studies reported a 14.5% incidence. One large-scale study involving over 400,000 patients showed a higher incidence of subacute thyroiditis in COVID-19 patients compared to non COVID-19 patients. Graves’ disease was reported in 21% of case studies. Hashimoto’s thyroiditis appeared in 9% of case studies. Painless thyroiditis was diagnosed in 5% of cases. Nonthyroidal illness syndrome was identified in 18.5% and 58.8% of patients in different retrospective studies. Some prospective studies reported double the prevalence of thyroid disorders in COVID-19 survivors. The majority of patients with thyroid dysfunction were women (66%).

Thyroid dysfunction was more common in severe COVID-19 cases than in mild or moderate ones. Although the mechanisms behind this association are not yet fully understood, one leading hypothesis is that COVID-19 triggers a hyperinflammatory response, potentially leading to autoimmune thyroid conditions.

Conclusion

This systematic review indicates that COVID-19 may lead to various thyroid dysfunctions, these conditions are more frequently observed in severe COVID-19 cases and mostly affect women. While the exact relationship remains unclear, it is hypothesized that COVID-19 may trigger autoimmune reactions through systemic inflammation, affecting thyroid health.

Read the review here