Biopsy Confirmed Subacute Thyroiditis Associated With COVID-19

Subacute thyroiditis is a transient inflammatory disease of the thyroid associated with anterior neck pain, and systemic symptoms. The diagnosis is generally reserved for a specific type of thyroiditis characterized by granulomatous inflammation and the presence of giant cells. We hereby present a case of a woman with a COVID-19 diagnosis, and a compatible biopsy result for subacute thyroiditis. On 06/03/2020, a 28 year old woman with previous history of ankylosing spondylitis managed with certolizumab pegmol, presented with fatigue, headache, odynophagia, and fever (38.1°C). 2 days later an oropharyngeal swab (PCR) for SARS-CoV-2 turned out positive. On the 4th day the fever spiked to 39°C with added malaise. Acetaminophen 1 gr PO TID was prescribed. The patient denied dyspnea, and thorax CT-Scan was normal. Complete remission was achieved in 3 weeks. On 08/01/20 she returned to work after a negative swab test. On 08/04/20, she presented with fever (38.7°C), malaise, distal tremors, anorexia, tachycardia, myalgias, arthralgias, and fatigue. 2 days later anterior neck pain that radiated to the jaw, and diffuse goiter was noticed. A thyroid function panel reported Total T4: 24 µg/dL (4.5-12.5), fT4 5.2 ng/dl (0.8-1.8), TSH: 0.001 mUI/L (0.37-4.7), thyroglobulin 135 ng/ml (3-42). TPO-Ab <35 IU/mL and TgAb <20 IU/mL. A neck US showed increased volume in the right lobe with multiple hypoechoic regions on both lobes, and diminished vascularization at color Doppler. I-131 scan showed no uptake. A biopsy of the right lobe reported fibrosis with inflammatory infiltrate composed of lymphocytes, plasma cells, histiocytes, and scarce neutrophils. Some cells with epithelioid appearance and a multinucleated giant cell were also found. Residual thyroid follicles showed colloid depletion and degenerative changes to the epithelium, which was consistent with a diagnosis of subacute thyroiditis. Treatment was initiated with prednisone 10 mg PO QD, propranolol 20 mg PO BID for 2 weeks, and acetaminophen 1 gr PO TID PRN. Fever and pain were intermittent for 6 weeks, but the rest of the symptoms subsided within 2 weeks. On 11/15/20, the patient attended a check-up with lab results that were consistent with hypothyroidism, negative IgM, and positive IgG SARS-CoV-2. Replacement therapy with levothyroxine 88 mcg per day was initiated. This case, which confirms the diagnosis of subacute thyroiditis via biopsy, among the others reported worldwide suggests that there’s an increased risk for women for subacute thyroiditis associated with COVID-19. Further research is needed to confirm risk factors for the development of the disease.