Objective: Analyze CCH detection program results from 3 Autonomous Communities: TSH and total T4 (TT4) in dried blood spot (DBS) at initial screening (48 hours of life) and at retesting. Describe the characteristics of neonates with screening compatible with CCH. Consider whether TBG deficiency (TBGD) is an added difficulty in said study.
Materials and Methods: Retrospective study (May 2016-May 2020) of all neonates ≥33 weeks and/or ≥1500 grams referred to the Child Endocrinology services of 3 Communities due to low T4 (<6 µg/dl), out of a total of 105,858 CH screenings. The positives for low T4 in the retesting compatible with CCH (low T4 and low/normal TSH) were analyzed. After determination in serum, the diagnoses were: 1.CCH: low free T4 (FT4) and low/normal TSH. 2.TBG deficiency (TBGD): normal FT4 and TSH. 3.Hyperthyrotropinemia: normal FT4 and elevated TSH. 4.Euthyroid sick syndrome. Clinical and laboratory variables were compared between CCH and TBGD. The evolution of the cases considered CCH was assessed.
Results: Forty-four neonates were referred due to low TT4, 15 corresponding to primary CH and 29 cases were compatible with CCH. The final diagnosis of the positives with initial suspicion of CCH was: 15 TBGD, 8 CCH, 5 hyperthyrotropinemia and 1 euthyroid sick syndrome. CCH prevalence in this period was 1/13,333 screenings. Statistically significant differences were found in FT4 values when comparing CCH and TBGD (table). All CCH started treatment with levothyroxine with a median age of 9.5 days (7-155). 1 multiple hormonal deficiency and 7 isolated CCHs have been diagnosed (according to evolution data). 6 out of 8 patients with CCH also had TBGD.
|*U Mann-Whitney||CCH (mean ± DE) n=8||TBGD (mean ± DE) n=15|
|TSH screening (mIU/l)||1.8 ± 0.2||1.9 ± 0.9||ns|
|TT4 screening (mcg/dL)||2.2 ± 0.2||4.4 ± 0.9||0.000*|
|TSH retesting (mIU/l)||2.0 ± 0.0||1.9 ± 0.2||ns|
|TT4 retesting (mcg/dl)||2.3 ± 1.4||3.7 ± 1.3||0.034*|
|TSH serum (mIU/l)||2.8 ± 1.8||3.8 ± 0.9||ns|
|FT4 (ng/dl)||0.7 ± 0.1||1.5 ± 0.4||0.000*|
Conclusions: The determination of TT4 in neonatal screening has diagnosed 8 patients with CCH. TBG defect is very common in the population; TBGD diagnosis does not exclude a CCH, since they can coexist. Genetic studies would help to confirm CCH diagnosis.
22 Sep 2021 - 26 Sep 2021