Characteristics of Transient Hypothyroidism Detected by Neonatal Screening Test

Kim, Su Yung

Abstract

PURPOSE: To help differentiate transient hypothyroidism from congenital hypothyroidism, both of which might be confused initially, the clinical characteristics of transient hypothyroidism were compared to those of permanent ones.
METHODS
An analysis of the clinical data, including perinatal history, TFT(thyroid function test), and radionuclide scanning, was performed. The outcome of 18 patients of transient hypothyroidism was also compared to 19 patients of congenital hypothyroidism.
RESULTS
Most of the patients were male(male to female ratio was 5 to 1). The majority of patients(10/18) had history of dressing their umbilical stumps with iodine containing disinfectant. They seemed to have higher titers of T3 and lower titer of TSH at initial checking compared to congenital hypothyroidism and mostly showed normal thyroid image at initial scanning using 99mTc. Five patients, whose thyroid functions were normalized in 22-97 days after birth, were followed up without treatment. Thirteen patients were treated with levothyroxine initially, but able to stop treatment with normalized thyroid function test after at least one month of treatment pause when they were 18-46 months old.
CONCLUSION
Transient hypothyroidism diagnosed via neonatal screening were found in almost male neonates and had a tendency for milder abnormalities of thyroid function test compared to congenital hypothyroidism and had past history of dressing umbilical stumps in over half of the patients with iodine containing disinfectant.