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

To identify factors that discriminate between transient and permanent congenital hypothyroidism.

Retrospective evaluation of 58 children with congenital 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 of age were analyzed.

Median (IQR) initial TSH levels were 73.3 (276.5) µIU/mL in permanent hypothyroidism and 24.24 (52.7) µU/mL in transient hypothyroidism (P =0.0132). The optimum cut-off value of initial TSH to predict transient hypothyroidism was 90 µIU/mL. Mean (SD) L-thyroxine doses at 24 months of age were 2.64 (0.98) µg/kg/day in permanent hypothyroidism and 1.91 (0.65) µg/kg/day in transient hypothyroidism. Requirement of L-thyroxine dose at 24 months of ≤0.94 µg/kg/day had the highest sensitivity (100%) to predict transient hypothyroidism.

L-thyroxine doses at 24 months can predict transient hypothyroidism in patients with eutopic thyroid gland earlier than at 36 months.