Thyroid Function Before, During and After COVID-19

Abstract

Context: The effects of COVID-19 on the thyroid axis remain uncertain. Recent evidence has been conflicting, with both thyrotoxicosis and suppression of thyroid function reported. Objective: We aimed to detail the acute effects of COVID-19 on thyroid function and determine if these effects persisted upon recovery from COVID-19. Design: Cohort observational study. Participants and Setting: Adult patients admitted to Imperial College Healthcare National Health Service Trust, London, UK with suspected COVID-19 between March 9 to April 22, 2020 were included, excluding those with pre-existing thyroid disease and those missing either free thyroxine (FT4) or TSH measurements. Of 456 patients, 334 had COVID-19 and 122 did not. Main Outcome Measures: TSH and FT4 measurements at admission, and where available, those taken in 2019 and at COVID-19 follow-up. Results: Most patients (86·6%) presenting with COVID-19 were euthyroid, with none presenting with overt thyrotoxicosis. Patients with COVID-19 had a lower admission TSH and FT4 compared to those without COVID-19. In the COVID-19 patients with matching baseline thyroid function tests from 2019 (n=185 for TSH and 104 for FT4), both TSH and FT4 were reduced at admission compared to baseline. In a complete cases analysis of COVID-19 patients with TSH measurements at follow-up, admission and baseline (n=55), TSH was seen to recover to baseline at follow-up. Conclusions: Most patients with COVID-19 present with euthyroidism. We observed mild reductions in TSH and FT4 in keeping with a non-thyroidal illness syndrome. Furthermore, in survivors of COVID-19, thyroid function tests at follow-up returned to baseline.

Spectrum of Thyroid Illness in COVID-19

“…Cortisol, which has been shown to decrease TSH release even at healthy levels, could be another cause. A third possibility is that SARS-CoV-2 has a direct cytotoxic effect on thyrotrophs because the virion binding receptor, ACE2, is expressed in the pituitary 19,20 .…”

Potential relationships between COVID-19 and the thyroid gland: an update

“…In individuals with COVID-19, Khoo et al . 56 found a slight temporary reduction in the circulating TSH concentration, which might also be interpreted as hyperthyroidism, but ESS is probably the most likely explanation. A recent prospective study that compared 125 patients with mild COVID-19 pneumonia to 125 with severe COVID-19 pneumonia revealed that 13% of those with severe pneumonia had hyperthyroidism (6.4% overt and 5.6% subclinical), whereas the mild pneumonia group had a lower prevalence (1.6% overt and 4.8% subclinical).…”

“…In individuals with COVID-19, Khoo et al 56 32 Patients with thyrotoxicosis may be at a higher risk of infection-related complications, such as thyroid storm. 57 To reduce this risk, it is highly recommended that thyrotoxicosis should be well controlled.…”

Thyroid stimulating hormone levels in children before and during the coronavirus disease‐19 pandemic

“…Coronavirus disease‐2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) may have a direct effect on several endocrine glands, including the thyroid 1 . SARS‐CoV‐2 enters cells using the angiotensin‐converting enzyme‐2 (ACE‐2) receptor, expressed by the thyroid 2 .…”