Objectives Congenital hypothyroidism (CH) is the most frequent endocrinopathy of infancy caused by thyroid dysgenesia, ormonogenesis defects or ipotalamo-hypophyseal alterations preventable through neonatal screening. We studied in Calabria the impact on neonatal screening for CH of the TSH new cut-off (8 mU/L) that was introduced from 2002, and the revaluation of cases of CH with thyroid “in situ” with graduated reduction of substitutive hormonal therapy.
Methods From January 1991 to December 2006, 202 patients (85M-117F) with CH have been identified through neonatal screening and followed for almost one year after diagnosis. The parameters valued for the suspension of the substitutive therapy were: age>1 year and unchanged therapy since the diagnosis.
Results From 1991 to 2001 positive cases/year have always been <10; from 2002 they have been >20. In patients with thyroid dysgenesia TSH average values at the first sample of neonatal screening (2002–2006), was 223 mU/L (range 15–1100) while with thyroid “in situ” was 60 mU/L (range 8–390). Etiology was: 47% thyroid “in situ”, 22% hypoplasia, 21% agenesia, 10% ectopia.
45 males and 29 females had thyroid “in situ”, 10 were detected in 1991–2001 and 64 in 2002–2006: 7 patients have interrupted therapy; 33 are now in graduated reduction therapy; 34 are going on with therapy. These will be followed up to the 18th year.
Conclusions Most of these patients have had a transitory CH. It is important the follow-up after a break in therapy to detect future deficits tied to the neonatal transient malfunction of the thyroid. It is possible that some more CH patients with thyroid “in situ” would not have been diagnosed with the preceding TSH cut-off (20 mU/L).