Increase in doses of levothyroxine at the age of 3 years and above is usefulfor distinguishing transient and permanent congenital hypothyroidism

摘要

There are no recommended diagnostic criteria for transient congenital hypothyroidism (CH)during early childhood. In this study, we aimed to identify the factors that distinguishpermanent (P)- and transient (T)-CH. We retrospectively analyzed the clinical,biochemical, and imaging data of 42 children with a definitive diagnosis of P- or T-CH byre-evaluation tests at our institution from November 1986 to October 2019. Patients whocontinued levothyroxine (L-T4) treatment after the re-evaluation tests wereclassified as group P (n = 19), while patients who were diagnosed with T-CH anddiscontinued L-T4 treatment were classified as group T (n = 23). Initialtesting performed during infancy showed that the mean serum TSH and free T4 (FT4) levelsdid not differ significantly between groups P and T. None of the patients in group Trequired an increased dosage of L-T4 at the age of 3 yr and above while 85% ofthe patients in group P required increased dosages of L-T4. Hence, T-CH wassuspected in patients who did not require an increase in L-T4 dosage at the ageof 3 yr and above.