CASE REPORT
A sixty-nine-year-old male started hemodialysis in 2017 due to diabetic
kidney disease. Roxadustat (a HIF-PH inhibitor) was started at a dose of
100mg for recombinant human EPO-resistant anemia in August 2020. The
dose of roxadustat was increased to 200 mg to improve his anemia. TSH
and fT4 were within the normal range during recombinant human EPO
administration. General malaise gradually developed after starting
roxadustat. His TSH and fT4 gradually decreased to 0.47μIU/mL and 0.15
ng/dL, respectively. Furthermore, cholesterol levels were markedly low
(Total-C 84 mg/dL, HDL-C 48 mg/dL, LDL-C 31 mg/dL). Levothyroxine (a
synthetic thyroxine) was started at a dose of 12.5 μg for hypothyroidism
in February 2021 and was admitted to the hospital for further
examination. Oral medications at an administration were levothyroxine,
antihypertensive drugs, and antiplatelet drugs. There was no fever or
hypothermia, blood pressure was 160/84 mmHg, and pulse rate was 78
beats/minus. There were no abnormal physical findings, including
thyroid.
Laboratory data is shown in Table 1. Thyroid-related auto-antibodies
were negative. No abnormalities were observed in other pituitary
hormones. Brain MRI revealed no abnormality in the pituitary gland. A
TRH stress test was performed and the patient was diagnosed with central
hypothyroidism (Table 2).
The dose of levothyroxine was increased for central hypothyroidism.
After administration of 200 μg of levothyroxine, fT4 recovered quickly
into the normal range, but TSH did not recover. Central hypothyroidism
might be speculated as an adverse effect of roxadustat. In January 2021,
roxadustat was switched to daprodustat (Fig.1). After discontinuing
roxadustat, TSH recovered rapidly into the normal range. Moreover,
cholesterol levels increased. TRH test was performed again, and the
results were normal. Therefore, central hypothyroidism was reversible.
Levothyroxine was tapered and discontinued, but thyroid function
remained within the normal range.