Objective: The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has rapidly spread around the world since December 2019. Coronaviruses are known to have direct effects on various endocrine glands, including the thyroid gland. Although adult studies provide useful information and most of these studies are compatible with Non thyroidal illness, there were no data analysed throid function tests in children with COVID-19.
Aim: We aimed to evaluate the levels of free T4 (fT4), free T3 (fT3), thyrotropin (TSH) and thyroid autoantibodies during and after the disease in children with COVID-19.
Methods: We studied 18 patients followed up in our pediatric infectious diseases clinic and pediatric endocrinology clinic with the diagnosis of COVID-19 between September-December 2021. In these patients with COVID-19 a standard set of blood tests including complete blood count, kidney, liver function, thyroid function and thyroid auto antibodies were performed. After 3 months later, we tested thyroid function, thyroid auto antibodies again.
Results: In thyroid function tests taken during the disease, fT4 of all patients was normal. fT3 was low in 6 (33.3%) patients, and TSH was high in 2 (11.1%) patients. In the control tests performed 3 months later, TSH of all patients was normal. Control fT4 was low in 2 (11.1%) patients whose fT4 was normal during the disease. In 5 (27.7%) patients control fT3 was found low. When the relationship of these parameters with the infection criteria was examined, a negative correlation was found between fT3 taken at the time of COVID-19 positive and CRP, and a positive correlation between fT3 and absolute lymphocyte counts at the 3rd month control.
Conclusion: Abnormalities in the examinations taken during the disease were mostly found to be compatible with sick euthyroid syndrome. The persistency of low fT3 and newly detected fT3 and fT4 decreases in the follow up suggested involvement of hypothalamo pituitary-thyroid axis due to Covid 19.