A Grave Case of COVID-19: SARS-CoV-2 Induced Autoimmune Hyperthyroidism

Abstract

Background: Autoimmune hyperthyroidism also known as Graves’ disease is the leading cause of hyperthyroidism. The pathogenesis of Graves’ disease is still an area of active research. We present a case of Graves’ disease, which developed following SARS-CoV2 infection. Clinical Case: A 43-year-old man with no prior history of thyroid disease, presented for evaluation due to fatigue palpitations, tremors, and hair loss in June 2020. Earlier that month, he was diagnosed with SARS-CoV2 infection and his thyroid function tests (TFTs) during a visit to the emergency department revealed thyroid stimulating hormone (TSH) level of <0.010 mIU/L (0.35-4.94) with a free T4 (FT4) 1.4 ng/dL (0.7-1.5); consistent with subclinical hyperthyroidism. He continued to report palpitations and tremors and further workup was done. A thyroid ultrasound showed two sub-centimeter nodules. A thyroid uptake scan followed, which showed heterogeneous activity in the thyroid gland, (12% and 32% uptake at 6 and 24 hours respectively) with focal increased uptake in the medial lobes, without cold nodules or hot nodules. Repeat TFTs one month later showed a suppressed TSH <0.010 mIU/L, and a normal FT4 1.3 ng/dL. Given suspicion for Graves’ disease, further labs were ordered. Thyroid stimulating immunoglobulin (TSI) were found to be elevated at 173 % baseline (<=140). Thyroid peroxidase (TPO) antibodies and thyroglobulin antibodies were also elevated at 362 IU/mL H* (<=9) and 2 IU/mL H* (<=1) respectively. The overall picture was consistent with evolving early Graves’ disease. Conclusion: Multiple factors are frequently cited in the pathogenesis of autoimmune hyperthyroidism including viral and bacterial infections1 and there have been several reported cases of autoimmune disease related to SARS-CoV2 infection2. This case is one of several emerging cases of autoimmune hyperthyroidism possibly linked to COVID-19.