Figure 5.

Changes in thyroid function tests in four representative patients with COVID-19 pneumonia. Panels A and B: two female patients previously submitted to total thyroidectomy and radioiodine ablation for a differentiated thyroid cancer and in complete remission. They were on L-T4 replacement treatment and TSH levels were repeatedly normal before COVID-19 diagnosis. At admission, they both had a reduced TSH, which normalized along with the improvement of CRP. The patient in panel A is an ICU doctor with a bilateral pneumonia who asked to be discharged to home after 9 days of hospitalization with domiciliary oxygen supply. The patient in panel 2 had a milder disease, and oxygen supply was prescribed during the hospital stay. Panel C: thyroid function test assessed during the hospital stay in a female patient with mild COVID-19 pneumonia. During the acute phase, a slight reduction of TSH levels was observed, with rising levels of FT4 and decreasing levels of FT3, but still in the normal range. This pattern reverted upon disease improvement. Panel D: in a male patient, for whom pre-COVID 19 infection parameters were available, TSH decrease, paralleling CRP increase, FT4 increase and Ft3 decrease were observed at admission and during hospitalization in a low intensity care unit. Interestingly, 1 month after discharge, thyroid function tests fully recovered their original setup point. No neck pain was reported in the patients depicted in panels C and D and thyroglobulin levels were normal at the time of TSH reduction (6.6 and 19.6 mcg/L, respectively). CRP, C-reactive protein.