Endocrine Abstracts

Introduction

Subacute thyroiditis is a rare cause of thyrotoxicosis arising in the context or following viral infections. This disorder is more frequent in women than in men (male/female ratio of 1:4). In addition to respiratory symptoms, the SARS-CoV-2 infection (COVID-19) has been associated with extrapulmonary manifestations. Herein we report a male patient with hyperthyroid symptoms starting four-week after a positive test for COVID-19.

Case presentation

We present the clinical case of a 63-years-old caucasian man, with a past medical history of obesity, hypertension, and a recent COVID19 infection. He started complaining of neck discomfort together with anorexia, fatigue, palpitations and, heat intolerance, four weeks after a positive RT-PCR nasopharyngeal swab for SARS-CoV-2. He remained asymptomatic the 2 weeks after the positive test and was discharged from the COVID19 surveillance program. When first seen by one of us, he was anxious, tachycardic (108 beats/min), presenting a fine tremor of both hands and a discrete bilateral eyelid retraction. He had lost 8 Kg during the previous two weeks. His thyroid was slightly tender. The patient denied a past medical history of thyroid disorders. Blood tests revealed a high C-Reactive Protein (CRP) 5.65 mg/dl (<0.5); TSH 0.007 mIU/l (0.7–4.20); FT4 2.81 ng/dl (0.70–1.48); FT3 7.41 pg/ml (1.58–3.91); TPO ab 137.7UI/ml (0–60); Thyroglobulin of 127 ng/ml (<10). TRAB <1.10. Hemoglobin was 11.2 g/dl and white blood cells count of 10.2x10⁶ (59.4% neutrophils). Serum titers of IgG anti SARS-CoV-2 was 100.0 U/ml (<12) and IgM 2.74 U/ml (<1.1). Thyroid ultrasounds showed a heterogeneous gland of normal size with areas of low echogenicity and decreased tissue vascularity in Color Doppler evaluation. He was started on prednisone 40 mg/day PO. One week later blood test revealed FT4 2.03 ng/dl; FT3 3.95 pg/ml and TSH 0.01. Prednisone was reduced to 20 mg/day. One more week and CRP was 0.750, TSH 0.01 mIU/l with normal FT4 and FT3. Prednisone was taper. Two weeks later, he reported complete resolution of the symptoms. At this time, blood tests showed an increase in TSH indicating a clear biphasic evolution of thyroid function.

Conclusion

Subacute thyroiditis can be triggered by the new coronavirus (SARS-CoV-2) in a similar way to other viral infections. Therefore, clinicians must be aware of the possibility of thyroid dysfunction after COVID-19 infection. Early recognition and timely steroid treatment may successfully improve the outcome of the disorder, preventing permanent hypothyroidism.