Prediction of Transient or Permanent Congenital Hypothyroidism from Initial Thyroid Stimulating Hormone Levels

ABSTRACT

Objective:To identify factors that discriminate between transient and permanentcongenital hypothyroidism. Methods: Retrospective evaluation of 58 children withcongenital hypothyroidism and eutopic thyroid gland. Gender, gestational age, birth weight,TSH and serum thyroxine levels at diagnosis and L-thyroxine dose at 12 and 24 months ofage were analyzed. Results: Median (IQR) initial TSH levels were 73.3 (276.5) ?IU/mL inpermanent hypothyroidism and 24.24 (52.7) ?U/mL in transient hypothyroidism (P =0.0132).The optimum cut-off value of initial TSH to predict transient hypothyroidism was 90 ?IU/mL.Mean (SD) L-thyroxine doses at 24 months of age were 2.64 (0.98) ?g/kg/day in permanenthypothyroidism and 1.91 (0.65) ?g/kg/day in transient hypothyroidism. Requirement of L-thyroxine dose at 24 months of ?0.94 ?g/kg/day had the highest sensitivity (100%) to predicttransient hypothyroidism. Conclusions:L-thyroxine doses at 24 months can predicttransient hypothyroidism in patients with eutopic thyroid gland earlier than at 36 months.