Yet another organ seems to be affected by a bout of COVID-19: the thyroid.
Italian researchers have examined the thyroids of dozens of patients who've recovered from moderate-to-severe cases of COVID-19. The study found evidence that SARS-CoV-2 infection may trigger an inflammation of the gland in some patients.
Whether that inflammation can cause long-term dysfunction is still unclear, however.
"After three months, patients' thyroid function has normalized, but signs of inflammation were still present in about one-third of patients," study lead researcher Dr. Ilaria Muller, of the University of Milan, said in a news release from The Endocrine Society. Her team presented their findings Monday at the virtual annual meeting of The Endocrine Society.
The thyroid is a butterfly-shaped gland located at the base of the front of the throat. It's very important to a wide range of physiological functions, including metabolism.
Muller's group noted that in the spring of 2020, 15% of COVID-19 patients hospitalized in intensive care units at a medical center in Milan had changes in their thyroid hormones due to a number of causes, including thyroid inflammation.
In comparison, only 1% of hospitalized patients during the same period in 2019 had changes in thyroid hormones.
Viral infections can trigger inflammation of the thyroid gland, known as thyroiditis.
"It is not unique that subacute thyroiditis would occur after a significant viral infection," noted Dr. Minisha Sood, a U.S. expert who wasn't connected to the new research.
"Typical cases of subacute thyroiditis do resolve after several weeks," added Sood, an endocrinologist at Lenox Hill Hospital in New York City.
To investigate whether thyroiditis associated with COVID-19 follows the same pattern as thyroid inflammation caused by other viruses, Muller's group started a surveillance program to check the thyroid function of patients every three months after they were hospitalized for moderate-to-severe COVID-19.
Blood and ultrasound tests were used to assess the patients' thyroid function and check for signs of inflammation.
The researchers found that thyroiditis in people with moderate-to-severe COVID-19 differs from typical thyroiditis in several ways. For example, there's an absence of the typical neck pain that accompanies the condition. Many patients also had mild thyroid dysfunction, and rates of thyroid issues were higher among men than women. Thyroid dysfunction also appeared tied to cases of more severe COVID-19 disease, the Italian team reported.
So far, 53 patients have completed the evaluation at the three-month point.
"We are continuing to monitor these patients to see what happens during the following months. It is important to know whether SARS-CoV-2 has late-onset negative effects on the thyroid gland, in order to promptly diagnose, and eventually treat, the condition," Muller said.
Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal, and Sood cautioned that "it is too early to draw conclusions."
However, Sood believes that "ongoing monitoring of thyroid function in a person with symptoms even suggestive of thyroiditis is important if they have had COVID-19."
The American Thyroid Association has more on thyroiditis.
SOURCES: Minisha Sood, MD, endocrinologist, Lenox Hill Hospital, New York City; The Endocrine Society, news release, March 20, 2021