ESPE Abstracts

Introduction:Subclinical hypothyroidism (SH) is defined in children by a moderate rise in TSH (TSH: 4.5-10 mU/l) compared to a normal level of free T4. However, the clinical consequences remain a subject of controversy, hence the need to take a position on the relevance of treating it.

Objective: Description of the clinical, biological and evolutionary characteristics of SH in children.

Patients and Methods:It was a descriptive retrospective study including patients under the age of 15 diagnosed and followed for SH in the Pediatrics and Neonatology Department of the Ben Arous Hospital over a period of 8 years (January 2015- December 2022)

Results:30 patients were collected. The average age at diagnosis was 3 years. The sex ratio was 0.8. The circumstances of discovery of SH were: constipation (11%), goiter (11%), hypotonia (17%), psychomotor retardation (11%), pericardial effusion (3%), systematic screening (60%) in the context of: prematurity (33%), autoimmune disease (7%), growth hormone deficiency (7%) and down syndrome (26%). The mean TSH level was 8.33 (5.94; 10UI/l) and that of FT4 was 15 (10.8; 24 pmol/l). The biological exploration objectified: a normochrome normocytic aregenerative anemia (38%), positive antithyroid antibodies (20%). The etiological exploration concluded to: subclinical hypothyroidism associated with Down syndrome (8 cases), associated with growth hormone deficiency (4 cases), associated with congenital adrenal hyperplasia due to 21hydroxylase deficiency (1 case), Hashimoto's thyroiditis (6 cases), transient hypothyroidism of premature infants (7 cases), thyroïd hormone disorder (3 cases), hypothyroidism secondary to hemochromatosis (1 case). Substitution treatment was started in 18 patients. The others patients, while being asymptomatic, were kept under biological monitoring and etiological treatment. The evolution was marked by normalization of the TSH level: after an average of 35 days of monitoring for untreated patients and after an average of 41 days for treated patients. The intelligence quotient (IQ) of patients evaluated after the age of two years were: IQ<70% (30%), 70<IQ<105% (70%); QI>115%(0). Patients with low intelligence had: late start of treatment (50%); poor treatment compliance (66%); other associated pathologies (33%). All patients with untreated SH had an IQ >70%.

Conclusion:The course of subclinical hypothyroidism in children depends on its etiology. Whether primary or secondary, treated or not, it requires clinical and biological monitoring in order to prevent its complications, mainly those affecting neurocognitive development.