ESPE Abstracts

Introduction: Congenital hypothyroidism (CH) is diagnosed with neonatal screening and treated early in the neonatal period. Among these patients, transient congenital hypothyroidism (TCH) is included and requires re-evaluation. In this study, we aimed to identify factors that would allow discrimination between permanent and transient hypothyroidism in patients with eutopic thyroid gland.

Methods: We retrospectively analyzed medical records of 77 patients with congenital hypothyroidism and with eutopic thyroid gland. All subjects were treated with levothyroxine and underwent re-evaluation after 3 years of age.

Results: Thirty subjects were permanent CH (PCH) group, and 47 subjects were TCH group. Clinical parameters including TSH and free T4 (fT4) at initial diagnosis were not significantly different between two groups. At re-evaluation after drug discontinuation, TSH and fT4 levels were all significantly different between two groups (P<0.01). The optimal cut-off value on the receiver operating characteristic (ROC) curve for permanent prediction with TSH level was greater than 9.2 µIU/ml (sensitivity of 83% and specificity of 94%). The optimal cut-off value on the ROC curve for transient prediction with fT4 level was greater than 1.13 ng/dL (sensitivity of 68% and specificity of 80%).

Conclusion: Thirty patients (40%) with CH and eutopic thyroid gland needed to continue levothyroxine therapy after re-evaluation. TSH and fT4 levels at re-evaluation might have a predictive role in differentiating TCH from PCH in patients with eutopic thyroid gland.