The cytokine storm and thyroid hormone changes in COVID-19

Abstract

Background COVID-19 is now a worldwide pandemic. Among the many extra-pulmonary manifestations of COVID-19, recent evidence suggested a possible occurrence of thyroid dysfunction. Purpose The Aim of the present review is to summarize available studies regarding thyroid function alterations in patients with COVID-19 and to overview the possible physio-pathological explanations. Conclusions The repercussions of the thyroid of COVID-19 seem to be related, in part, with the occurrence of a “cytokine storm” that would, in turn, induce a “non-thyroidal illness”. Some specific cytokines and chemokines appear to have a direct role on the hypothalamus–pituitary–thyroid axis. On the other hand, some authors have observed an increased incidence of a destructive thyroiditis, either subacute or painless, in patients with COVID-19. The hypothesis of a direct infection of the thyroid by SARS-Cov-2 stems from the observation that its receptor, ACE2, is strongly expressed in thyroid tissue. Lastly, it is highly probable that some pharmaceutical agents largely used for the treatment of COVID-19 can act as confounding factors in the laboratory evaluation of thyroid function parameters.

The spectrum of thyroid function tests during hospitalization for SARS COV-2 infection

“…Since one of the possible explanations of the discrepant results reported in the literature is the interference exerted on serum free TH and TSH determinations by drugs frequently used for the treatment of these patients (3), all the possibly interfered cases were excluded from the study or analysed separately. Moreover, because data on atypical COVID-19 associated painless thyroiditis were recently published, still lacking Campi et al,4 thyroglobulin (Tg) determination and not consistent with our findings (7)(8)(9), Tg levels were retrospectively measured on the stored samples corresponding to a reduced/suppressed TSH.…”

“…An alteration in thyroid function tests (TFT), mainly characterized by the reduction of TSH levels has been recorded during SARS-CoV-2 infection as associated to either a destructive thyroiditis or a non-thyroidal illness (NTI). Indeed, cases of destructive thyrotoxicosis (3)(4)(5)(6)(7)(8)(9) or subacute thyroiditis (3,4; 8-14) have been reported in patients with COVID-19 infection. On the other hand, SARS-CoV-2 coronavirus can cause immune response hyperactivity leading to the release of proinflammatory cytokines which may cause a cytokine storm (17).…”

Subacute Thyroiditis and Heart Failure in a Patient Presenting With COVID-19

“…mRNA encoding for ACE2 receptors have also been identified in thyroid tissue samples, making them a potential target for inflammation. [3][4][5][6] In this article, we present a case of a 67-year-old male who presented with COVID-19-induced subacute thyroiditis and heart failure.…”

Thyroid sequelae of COVID-19: a systematic review of reviews

“…A certain role for systemic inflammation might also be envisaged. Indeed, the cytokine storm occurring during SARS-CoV-2 infection often results in an uncontrolled inflammatory response that is detrimental to host cells [17,22]. As far as the thyroid gland is concerned, it should be highlighted that several models, including the chronic low-level inflammation associated with aging, the so-called "inflammaging" [28], and the oxidant/antioxidant imbalance associated with thyroid chronic inflammation [29], proved to have a role in the pathogenesis of thyroid diseases.…”

“…By the search strategy, a number of 247 records was initially found. Among these, according to the above criteria, 238 studies were excluded since they were not review articles, and nine reviews were finally included [7,[11][12][13][14][15][16][17][18] (Fig. 1).…”