COVID-19 Latest: Yet Another Study Showing Effects Of SAR-CoV-2 On The Thyroid Gland Including Thyrotoxicosis
: Italian researchers from Ca' Granda Ospedale Maggiore Policlinico, one of the oldest and largest hospitals in Milan in a new study report that the SARS-CoV-2 coronavirus not only infects and causes thyroid issues but is also capable of causing throxicosis.
The term thyrotoxicosis refers to the hypermetabolic clinical syndrome resulting from serum elevations in thyroid hormone levels, specifically free thyroxine (T4) and/or triiodothyronine (T3).
The study findings were published in the journal: The Lancet Diabetes and Endocrinologyhttps://www.thelancet.com/journals/landia/article/PIIS2213-8587(20)30266-7/fulltext
According to new study, rates of thyrotoxicosis are significantly higher among patients who are critically ill with COVID-19 than among patients who are critically ill but who do not have COVID-19, suggesting an atypical form of thyroiditis related to the SARS-CoV-2 coronavirus infection.
Corresponding author Dr Ilaria Muller, MD, PhD, of the Department of Endocrinology, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico told Thailand Medical News, "We suggest routine assessment of thyroid function in patients with COVID-19 requiring high-intensity care because they frequently present with thyrotoxicosis due to a form of subacute thyroiditis related to SARS-CoV-2."
Importantly the study which compared critically ill ICU patients who had COVID-19 with those who did not have COVID-19 or who had milder cases of COVID-19 indicates that thyroid disorders do not appear to increase the risk of developing COVID-19. The study team stressed that they did not find an increased prevalence of preexisting thyroid disorders in COVID-19 patients contrary to early media reports. Individuals with thyroid disorders need to be reassured of this.
This new study provides some insight on the potential systemic inflammation, as well as thyroid-specific inflammation, of the SARS-Cov-2 virus .
Dr Muller explained that preliminary data from her institution showed thyroid abnormalities in patients who were severely ill with COVID-10. She and her team extended the evaluation to include thyroid data and other data on 93 patients with COVID-19 who were admitted to high-intensity-care units (HICUs) in Italy during the 2020 pandemic.
Subsequently, this data was compared with data on 101 critically ill patients admitted to the same HICUs in 2019 who did not have COVID-19. A third group of 52 patients with COVID-19 who were admitted to low-intensity-care units (LICUs) in Italy in 2020 were also included in the analysis.
In the study, the mean age of the patients in the HICU 2020 group was 65.3 years; in the HICU 2019 group, it was 73 years; and in the LICU group, it was 70 years (P
= .001). In addition, the HICU 2020 group included more men than the other two groups (69% vs 56% and 48%; P
Importantly only 9% of patients in the HICU 2020 group had preexisting thyroid disorders, compared with 21% in the LICU group and 23% in the HICU 2019 group
= .017). These research findings suggest that "such conditions are not a risk factor for SARS-CoV-2 infection or severity of COVID-19," the authors write.
Also all patients with the preexisting thyroid conditions were excluded from the thyroid function analysis.
Significantly, a higher proportion of patients in the HICU 2020 group (13; 15%) were thyrotoxic upon admission, compared with just one (1%) of 78 patients in the HICU 2019 group (P
= .002) and one (2%) of 41 patients in the LICU group (P
Interestingly among the 14 patients in the two COVID-19 groups who had thyrotoxicosis, the majority were male (9; 64%)
Within those in the HICU 2020 group, serum thyroid stimulating hormone (TSH) concentrations were lower than in either of the other two groups (P = .018), and serum free thyroxine (free T4) concentrations were higher than in the LICU group (P = .016) but not the HICU 2019 group.
The researchers said that although thyrotoxicosis relating to subacute viral thyroiditis can result from a wide variety of viral infections, there are some key differences with COVID-19.
Dr Muller explained, "Thyroid dysfunction related to SARS-CoV-2 seems to be milder than that of classic subacute thyroiditis due to other viruses.”
Additionally, thyroid dysfunction that is associated with other viral infections is more common in women, whereas there were more male patients with the COVID-19-related atypical thyroiditis. Also the thyroid effects developed early with COVID-19, whereas they usually emerge after the infections by other viruses.
Significantly, patients did not demonstrate the neck pain that is common with classic viral thyroiditis, and the thyroid abnormalities appear to correlate with the severity of COVID-19, whereas they are seen even in patients with mild symptoms when other viral infections are the cause.
Besides the risk for subacute viral thyroiditis, critically ill patients in general are at risk of developing nonthyroidal illness syndrome, with alterations in thyroid function. However, thyroid hormone measures in the patients severely ill with COVID-19 were not consistent with that syndrome.
A further sub-analysis of eight HICU 2020 patients with thyroid dysfunction who were followed for 55 days after discharge showed that two experienced hyperthyroidism but likely not from COVID-19; in the remaining six, thyroid function normalized.
The study team speculated that, when ill with COVID-19, the patients likely had a combination of SARS-CoV-2-related atypical thyroiditis and nonthyroidal illness syndrome, known as T4 toxicosis.
Importantly, the researchers said that it remains unknown whether the novel coronavirus has longer-term effects on the thyroid, Muller said.
Dr Muller added, "We cannot predict what will be the long-lasting thyroid effects after COVID-19. Typically with classic subacute viral thyroiditis, after a few years, about 5% to 20% of patients develop permanent hypothyroidism, and maybe the same might happen in COVID-19 patients.”
The researchers stressed that in the meantime, diagnosis of thyroid dysfunction in patients with COVID-19 is important, in as much as it could worsen the already critical conditions of patients,
Dr Muller further added, "The gold-standard treatment for thyroiditis is steroids, so the presence of thyroid dysfunction might represent an additional indication to such treatment in COVID-19 patients, to be verified in properly designed clinical trials.”
The study team also note recent research showing that angiotensin-converting enzyme 2 (ACE2) demonstrated to be a key host-cell entry receptor for both SARS-CoV and SARS-CoV-2 is expressed in even higher levels in the thyroid than the lungs, where it causes COVID-19's notorious pulmonary effects.
The team says the implications of ACE2 expression in the thyroid remain to be elucidated.
Dr Muller added ,"If ACE2 is confirmed to be expressed at higher levels compared with the lungs in the thyroid gland and other tissues, ie, small intestine, testis, kidney, heart, etc, dedicated studies will be needed to correlate ACE2 expression with the organs' susceptibility to SARS-CoV-2 reflected by clinical presentation.”
Note that Thailand Medical News also covered how the SARS-CoV-2 coronavirus affects the thyroid and thyroid functions in May and June.
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