Session: SAT 622-631-Pediatric Endocrinology: Thyroid
Poster Board SAT-625
Aim: Determine if 123I imaging may help support clinical decision-making regarding treatment in infants with mild hyperthyrotropinemia.
Methods: Retrospective chart review of clinically asymptomatic infants with mild elevations of TSH (5-20 uIU/mL) and normal free T4 and T3 values who underwent 123I imaging at Mount Sinai Medical Center between 2007 and 2013. All studies were evaluated by a single observer (JM). Images were obtained at 4 hours (h) and 24h after oral administration of 4uCi/kg of 123I. Normal uptake values based on adult data were 6-12% at 4h and 10-30% at 24h. Normal expected increase in uptake between 4h and 24h was ³50%. Data collection included age at imaging, TSH value just prior to scan, 4h 123I uptake, 24h 123I uptake, and levothyroxine (LT4) dose 1 year after treatment initiation.
Results: Twenty infants were identified. None had evidence of recent iodine exposure. Three had scans after 3 years of age for re-evaluation and were excluded from this analysis. Of the remaining 17, 8 were male and all but 1 were appropriate in weight and length for gestational age. TSH at the time of imaging was 4.72-17.12 uIU/mL (mean 8.74±3.4 uIU/mL). Four had TSH >10 uIU/mL. All had normally configured thyroid glands in eutopic locations and were placed on treatment after imaging. There was no significant difference between the group of infants with TSH >10 compared with those <10 with respect to 123I uptake at 4h, 24h, or change in uptake at 24h compared to 4h. Only 2/17 had 4h and 24h 123I uptake values close to standard normal adult values. 15/17 had abnormal imaging: 3 had high 123I uptake at 4 and/or 24h and 12 had low 4h uptake, low 24h uptake, and/or lack of an adequate increase in uptake between the 2 time points. After 1 year of treatment the mean LT4 dose was 3.28±1.2 mcg/kg (mean age 1.34±0.45 yr). There was no correlation between LT4dose and pre-treatment TSH or imaging result.
Conclusion: Fifteen of the 17 infants (88%) had what appeared to be abnormal 123I imaging based on adult normative data suggestive of hypothyroidism and/or dyshormonogenesis, supporting initiation of treatment. Genetic studies are needed to confirm their diagnoses. We are unaware of any normative data for 123I uptake in infants. Studies in additional patients are needed to confirm the value of 123I imaging in the evaluation and management of infants with mild hyperthyrotropinemia.
Nothing to Disclose: EG, MOR, EC, AB, AK, MK, DJC, EW, FG, CD, RA, JM, RR
*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm
See more of: Abstracts - Orals, Featured Poster Presentations, and Posters