Abstract #1395500: Silent Thyroiditis as a Complication of Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine

Abstract

Silent autoimmune thyroiditis, a type of chronic autoimmune thyroiditis, as an adverse effect of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is infrequently reported in the literature. We hereby describe a case of silent thyroiditis followed by Grave’s orbitopathy after vaccination against SARS-CoV2. An 84-year-old male presented to clinic with a 10-pound weight loss with no other symptoms of hyperthyroidism, no personal history of thyroid illnesses, or recent viral infections. He had normal thyroid function 3 months prior to presentation. He had received 3 doses of SARS-CoV2 Pfizer-BioNTech vaccine with the last dose 5 months prior to presentation. Thyroid exam was normal. Laboratory testing revealed thyroid stimulating hormone (TSH) level of 0.005 IU/ml (0.45-4.5 IU/ml), total T4 14.4 g/dl (4.5-12.1 g/dl), and total T3 1.22 nmol/l (0.6-1.81 nmol/l). Thyroid Ultrasound revealed a heterogeneous atrophic thyroid gland with no nodules or hypervascularity. He was started on Methimazole by primary care provider. Four months later, he was seen in the Endocrinology clinic and reported no hyperthyroidism symptoms. His TSH level at that time was 65.9 IU/ml, free T4 0.47 ng/dl (normal: 0.82-1.77 ng/dl), total T3 level 75 ng/dl (normal: 71-180 ng/dl), thyroid stimulating immunoglobulin 2.05 IU/l (0-0.55 IU/L), thyrotropin receptor antibody level 2.8 (0-1.75). Methimazole was discontinued. At 6 months after initial presentation laboratory testing showed TSH 5.010 IU/ml, free T4 1.2 ng/dl, thyroid peroxidase antibody of 148 IU/ml (normal 0-34 IU/ml), thyroglobulin antibody 131.6 IU/ml (normal 0.0-0.9 IU/ml). He was diagnosed with silent autoimmune thyroiditis. A few weeks later, the patient presented to an ophthalmologist with bilateral eye bulging and impaired vision. He was diagnosed with acute Graves’ orbitopathy and started on pulse-dose of intravenous Methylprednisolone 250 mg twice daily and urgently referred to a tertiary ophthalmology center for teprotumumab infusion. His thyroid function tests were normal at that time on no thyroid medications. The underlying mechanisms of thyroid impairment following SARS-CoV2 vaccination are not completely understood. There is a role of molecular mimicry between SARS-CoV2 antigens and thyroid antigens that may help to hasten the emergence of autoimmunity in vulnerable individuals. Our patient developed multiple thyroid-related antibodies following vaccination. Silent painless thyroiditis is a self-limiting condition, characterized by temporary thyrotoxicosis, followed by a brief period of hypothyroidism and then a complete return to normal thyroid function. A radioactive iodine uptake scan can help differentiate between the different causes of thyrotoxicosis in the acute thyrotoxic phase. Development of severe Graves orbitopathy following silent autoimmune thyroiditis after SARS COV2 vaccination has not been previously reported.