ESPE Abstracts

Objectives: -To determine children diagnosed with central congenital hypothyroidism (CCH) by a screening program using TSH and total T4 between May 2016 and January 2019.

-To analyze the characteristics of the disease in these children.

Material and Methods: During the time of the study, 14.743 newborns have been screened. Cut-off points are used for TSH ≥10MU/ml and T4 6 and 20 mg/dl as lower and upper limits.

When the result was positive, a second sample was performed on filter paper and if the second sample was also positive, the patient was sent to the Pediatric Endocrinology Unit to confirm the results. Diagnosed of CCH was made with the combination of low FT4 and inappropriate low TSH. If the patient was diagnosed with CCH, hormonal studies, skull MRI and genetic analyses were performed.

Results: For total T4 values, first simple screening was positive in 112 patients (0'76% of total). Of these cases, the second sample continued to be positive in 17 cases (0'11% of the total), in which 10 the diagnosis was confirmed.

There were 2 cases with alterations of total T4 above the limit due to a resistance to thyroid hormones and another by insensitivity of thyroid hormones. The other 8 cases, had total T4 below the limit, being 2 hipothyroxinemias of the prematurity and 6 CCH.

There were 6 cases diagnosed of CCH and all were male. The incidence of HCC was 1/2500. In the screening, TSH was 1'5±0,61 mU/l and Total T 1'89±0,25 ug/dl; In the confirmation TSH was 2.44±1,36 mU/l and FT4 0'79±0,07 ng/dl. Treatment was initiated with a medium age of 9'4±1,82 days (except one case with 5 months) with L-thyroxin at a medium dose of 7 mcg/K/d. None of them had symptoms of hypothyroidism. At present, all continue treatment at a medium dose of 3 mcg/k/d. None of the patients have their TSH undetectable. In all patients the study of the pituitary hormones have been normal, and the MRI of the skull showed hypoplasic adenohypophysis in 3 cases. Genetic analysis of all genes known to be involved in central congenital hypothyroidism (IGSF1, TRHR, TSHB, TBLX1..) are under investigation.

Conclusions: -The analysis of TSH and total T4 in neonatal screening makes it more accurate the diagnosis of thyroid disfunction.

-CCH represents a challenging condition in clinical practise

-The prevalence of HCC in our community is high, not being able to know the cause, although the genetic study can help with the diagnosis