Post-COVID-19 subacute painless thyroiditis: a case report in an anabolic androgenic steroid user

The coronavirus disease of 2019 is still a serious clinical problem. Moreover, its course is now often subclinical or asymptomatic. However, it may lead to the development of diseases of other organs, including thyroid diseases. One of them is subacute thyroiditis. The pathophysiology of this disease is poorly understood. Although it is typically painful, it can also be painless, but these cases are rare. In the cases without neck pain, general symptoms are often mild, which means that it can be insidious and manifest itself primarily as limited exercise capacity. The purpose of the paper is to describe the clinical course of the disease on the basis of a clinical case, to review the literature on subacute thyroiditis after coronavirus disease of 2019 in adults and to summarize the current state of knowledge about this disease.

We present here the case of a 31-year-old amateur weightlifter who developed mild, self-limiting hyperthyroidism after being infected with severe acute respiratory syndrome coronavirus 2. Thyroid ultrasound revealed no abnormalities. At week 17 postinfection, TSH was 0.0016 mIU/L (0.27-4.2), and at week 19, TSH was 0.019 mIU/L with normal FT4 and FT3 values. Autoimmune thyroid disease was ruled out. Thyroid scintigraphy and biopsy were not performed due to the patient's delayed referral to an endocrinologist and the return of thyroid function to normal. Although the diagnosis of subacute thyroiditis was not clearly confirmed, the clinical course supports this diagnosis. The presented clinical case is particularly interesting because the limited endurance caused by this disease prompted him to use anabolic-androgenic steroids (oxandrolone and testosterone enanthate), which significantly hampered the interpretation of the results. We also summarize the current state of knowledge about subacute thyroiditis after coronavirus disease of 2019 and discuss the impact of the use of anabolic-androgenic steroids on thyroid function and laboratory test results.

This case highlights the need to consider subacute thyroiditis in patients with unexplained thyrotoxicosis after COVID-19, especially when confounding factors, such as anabolic steroid use, are present.