ESPE Abstracts

Background: Profound hypothyroidism due to Hashimoto thyroiditis (HT) is a cause of severe growth arrest in children. Although it is commonly thought that thyroxine replacement fully restores height deficit, no data on catch up growth are available.

Objective and hypotheses: Assess the growth pattern and final height in a series of 10 patients with severe HT afec L-thyroxine therapy was initiated.

Method: Monocentric retrospective observational study of 10 children referred for growth failure and diagnosed with severe hypothyroidism between 1999 and 2015. Values are presented as medians (min–max). Individual growth charts will be shown.

Results: In total of eight girls and two boys aged 8 to 13.5 years at diagnosis of HT were included. HT was diagnosed based on TSH, T4L and anti-thyroperoxydase of 624 [100–1844] mUI/L (N:0.5–4), 0.645 [undetectable – 5.4] pmol/L (N:10–18) and 18 850 [310 – 25 310) (N<34) UI/ml, respectively. Children presented with severe growth failure as shown by the decrease in height SDS before diagnosis from −0.25 [−1; 2] SDS, to −2.9 [−4.7; 1] SDS (<0.0001). L-thyroxine replacement partially improved height SDS up to −2 [−3.8; 0] SDS (n=9) then −1 [−2.7; 1] SDS (n=5), at 1 and 3 years, respectively. In four children, final height was attained with a median of −1.1 [−2.7; 1.5] SDS.

Conclusion: Despite the correction of hypothyroidism and improved growth velocity upon treatment, catch up growth is incomplete.