We have known since the early 1970s that infections can trigger autoimmune diseases and now we have an interesting hypothesis on the potential triggering of Hashimoto’s disease by COVID-19 infection.

A recent case study out of Singapore published in the Singapore Medical Journal entitled, “COVID-19 complicated by Hashimoto’s thyroiditis” presents an individual who developed Hashimoto’s thyroiditis after contracting COVID-19.

COVID-19 can cause a hyperinflammatory state in the body which is a potential recipe for developing autoimmune disease. The authors begin by pointing out the most current literature on COVID-19 connections to the autoimmune diseases antiphospholipid syndrome, autoimmune thrombocytopenia, autoimmune hemolytic anemia, and Guillain-Barre syndrome.

This patient was a 45-year-old Chinese man who developed a non-productive cough and rhinorrhea for one day after exposure to COVID-19 in his dormitory. On the second day of his symptoms he was diagnosed with confirmed COVID-19 infection.

His symptoms went away after 7 days, but he reported new onset of severe generalized fatigue and muscle weakness. Before these symptoms happened, he was in good health, not taking any medications or supplements, working productively, and no history of smoking. He had no family history of autoimmune disease.

His physical examination was unremarkable and his thyroid was normal without goitre. However, his TSH level was high at 6.49 and his free T4 was low at 9.19 which is a classic presentation for hypothyroidism. His thyroid peroxidase antibody was extremely high at >2,000 confirming Hashimoto’s disease. His inflammatory markers were normal as well as electrolytes and other metabolic tests. Chest x-ray was completely normal.

He was prescribed 25mcg of levothyroxine once a day and five weeks later he reported increased energy, and he had started running again. His TSH was 6.59 and free T4 was 10.91 so those markers did not improve despite the medication and his energy improving.

The authors state that the onset of his symptoms from the time he first developed COVID-19 to the time he developed Hashimoto’s disease was similar to the onset of the other 4 autoimmune disease connections noted above in previous studies.

The authors conclude that the hyperinflammatory state triggered by COVID-19 also known as a “cytokine storm” can predispose patients to developing autoimmune diseases such as Hashimoto’s thyroiditis.

Dr. Hedberg’s Comments

Some patients will develop Hashimoto’s disease after getting the flu or other infections such as Epstein-Barr virus, H. pylori, Yersinia enterocolitica, Blastocystis hominis, Parvovirus-B19, Hepatitis C, and Herpes 6 to name some of the most common triggers.