{"id":31110,"date":"2022-06-13T11:16:14","date_gmt":"2022-06-13T10:16:14","guid":{"rendered":"https:\/\/touchendocrinology.com\/?p=31110"},"modified":"2022-10-07T16:36:22","modified_gmt":"2022-10-07T15:36:22","slug":"thyroid-function-during-and-after-covid-19-infection-a-review","status":"publish","type":"post","link":"https:\/\/touchendocrinology.com\/covid-19\/journal-articles\/thyroid-function-during-and-after-covid-19-infection-a-review\/","title":{"rendered":"Thyroid Function During and After COVID-19 Infection: A Review"},"content":{"rendered":"

On 31 December 2019, the World Health Organization (WHO) was notified of several cases of pneumonia of unknown aetiology in Wuhan, China. After a relatively short period, officials confirmed the first case of coronavirus disease 2019 (COVID-19) reported outside of China, in Thailand, on 13 January 2020.1<\/span>\u00a0From the start of the pandemic to 11 November 2021, there have been 251,266,207 confirmed cases of COVID-19, including 5,070,244 deaths, reported to the WHO, and the virus is still spreading.2<\/span><\/p>\n

The pathogenesis of COVID-19 may affect multiple human organ systems in several ways. In particular, severe COVID-19 is characterized by organ dysfunction, hypercytokinemia and lymphopenia. The direct cytopathological damage of host cells and the dysregulated immune response caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is assumed to be the primary underlying mechanisms of COVID-19.3<\/span><\/p>\n

SARS-CoV-2 enters the lungs and into the lung parenchyma through the respiratory system. Eventually, spike proteins of the virus attach to angiotensin-converting enzyme 2 (ACE2), which is expressed at the surface of pneumocytes.4,5<\/span>\u00a0ACE2 binds to the spike proteins of SARS-CoV-2 and acts as a receptor, mediating the entry of the virus to the host cells. This virus mechanism is also used to gain entry to other cell types of the human body. Many endocrine system organs have ACE2-expressing cells, such as the pancreas, testis, ovary, adrenal gland, pituitary gland and thyroid gland.6,7<\/span>\u00a0The testis has the highest level of ACE2 expression, followed by the thyroid, whereas the hypothalamus has the lowest level.6<\/span><\/p>\n

The pituitary\u2013thyroid axis should be regarded as a vulnerable target of SARS-CoV-2, and pituitary damage, whether direct or indirect, has been recognized as a determining factor of secondary hypothyroidism (functional or organic).8<\/span>\u00a0As\u00a03,5,3<\/span>\u2032<\/span>-triiodothyronine (T3) and thyroxine (T4)<\/span>\u00a0are positively correlated with serum\u00a0ACE<\/span>\u00a0levels, the\u00a0ACE<\/span>\u00a0<\/span>level could be used as a marker to investigate the action of peripheral thyroid hormones.9<\/span>\u00a0A study by Rotondi et al. also proposed the thyroid as a potential target for SARS-CoV-2, as thyroid follicular cells encode the messenger RNA for ACE2 receptors.10<\/span><\/p>\n

After entering the body, SARS-CoV-2 may cause numerous clinical symptoms, SARS and multisystem organ failure by causing both direct and indirect injury to the body. The direct effect is due to the cytotoxic effect of the virus on the target cell, and the indirect effect is caused by the aberrant immune inflammatory responses, which include cytokine, complement systems and coagulation.6,7,9,11<\/span>\u00a0Innate and adaptive immune responses are regulated by thyroid hormones via genomic and nongenomic pathways.12<\/span>\u00a0Cytokine production and release are triggered by\u00a0T4 and T3<\/span>; this results in a \u201ccytokine storm\u201d, which usually accompanies systemic viral infections.13,14<\/span><\/p>\n

Furthermore, thyroid hormones can enhance the antiviral activity of interferon-\u03b3<\/span>, thus explaining why some immune system pathways, such as cytokine and T helper 1 cell hyperactivation, occur in response to virus infections in thyroid disorders.12<\/span>\u00a0It is also worth noting that T4 is capable of activating human platelets, which lead to pathological clotting, which is a complication of virus infection.15<\/span>\u00a0This article reviews up-to-date clinical information about the interactions between the thyroid gland and COVID-19, including thyroid pathology, thyroid function, drug interactions, cytotoxic effect and thyroid diseases.<\/p>\n

Methods<\/h1>\n

We conducted a literature search of MEDLINE, EMBASE and Google Scholar to identify articles reporting on thyroid dysfunction in patients diagnosed with COVID\u201019. Articles eligible for inclusion were observational cohort studies, case\u2013control studies and randomized controlled trials, case reports and expert opinions published between 1 January 2019 and 15\u00a0March 2021. Search terms included \u201cSars-coV-2\u201d, \u201ccoronavirus\u201d, \u201cCOVID\u201d, \u201csubacute thyroiditis\u201d, \u201cDe Quervain thyroiditis\u201d, \u201csubacute thyroiditis\u201d, \u201cnon thyroidal illness syndrome\u201d, \u201cHashimoto\u2019s thyroiditis\u201d, \u201cGraves\u2019 disease\u201d, \u201chypothyroidism\u201d, \u201ccoagulopathy\u201d, \u201cbaricitinib\u201d, \u201cmethimazole\u201d, \u201cREGN-COV2\u201d, \u201cremdesivir\u201d and \u201ctocilizumab\u201d. No exclusions were made for language, disease severity or outcomes reported.<\/p>\n

Two reviewers independently undertook a two\u2010step selection, with studies screened via titles and abstracts followed by a full\u2010text review. Data were extracted from the articles\u2019 text, tables and figures. Data were collected, analysed and discussed to answer the following clinical questions:<\/p>\n