The Long Term Follow up Study of Newborns with TSH Elevation without Low T4

Bae, Sang In; Kim, Su Yung

Abstract

PURPOSE: In this study, we aimed to find useful methods for diagnosis and treatment of hyperthyrotropinemia in neonates showing normal T4 and elevated TSH levels in neonatal screening test.
METHODS
We retrospectively reviewed the medical records of 16 male and 26 female neonates whose T4 were normal and TSH were elevated in the neonatal screening test from 1994 to 2006. The clinical data, including perinatal history, thyroid function test and radionuclide scannig was analysed.
RESULTS
Of the forty-two patients, male was 38.1% and female was 61.9%. Mean T4 and TSH level were 8.61+/-1.55 ug/dL, 49.66+/-36.56 uU/mL respectively. At the recheck, when recalled, TSH were normalized in 8 patients (19.1%), still elevated in 34 patients (80.9%). (99m)TC thyroid scan was performed in 36 cases. The results were normal in 18 cases (50.0%), diffuse enlargement in 11 cases (30.5%), ectopic thyroid, poor visualization, hypoplasia respectly in 11.2%, 5.5%, 2.8%. Fourteen patients (33.3%) had histories of povidone use for umbilical care. Of the 42 patients, 27 (64.0%) cases were treated by thyroid hormone, 15 cases (36.0%) were followed up without treatment. Among 15 cases without treatment, 8 patients showed TSH normalization at 1.5 months, 5 patients at 3 months, one patient at 6 months and one patient at 9 months. Among 27 cases with treatment, 18 cases (66.7%) are being treated, 5 cases (18.6%) are being treated more than 3 years, the 3-years treatment was ended in 6 cases (22.2%), follow up loss was 3 cases (11.1%).
CONCLUSION
At long term follow up, TSH was normalized in many patients who showed normal T4 and elevated TSH levels in neonatal screening test. Imaging study such as (99m)TC thyroid scanning was helpful to decide whether to treat with thyroid hormone replacement. To predict longer term prognosis of cases without thyroid hormone replacement, long term follow up of large number of patients is needed.