Thyroid scintigraphy in three-year-old children with congenital hypothyroidism in correlation with neonatal TSH

Abstract

Introduction:A large number of congenital hypothyroidism (CH) cases in Iran are transient. This study was designed to investigate the aetiology of permanent CH (PCH) by thyroid scintigraphy (TS) and its relationship with the first diagnostic thyrotropin (TSH). Material and methods: During 12 years (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017) of CH screening in southwest Iran, all infants referred with the diagnosis of CH were followed until their third birthday, when they were re-evaluated for serum T4, TSH after discontinuing the treatment for 3-4 weeks. If the last test indicated a PCH state (TSH >10 mU/L with any levels of T4), TS was performed, and, based on the results, the patients were categorised as agenesis, dysgenesis (sublingual, thyroglossal cyst), and normal/diffuse goitre (indicating dyshormonogenesis). Results: After excluding all transient CH subjects, 224 permanent CH cases were enrolled (52.7% female). Seasonal distributions were as follows: spring: 25.7%, summer: 27.9%, autumn: 20.3%, and winter: 26.1%. No significant differences were found between females and males and the different modes of delivery (55.4% were delivered by caesarean section) regarding T4, TSH (p > 0.05). Of a total of 213 performed scans, 20.7% had agenesis, 36.2% had dysgenesis, and 43.2% were normal or goitrous. Those with agenesis/dysgenetic thyroid had a lower T4 and a higher TSH than those with normal scans. However, the differences were not significant. Compared to those who had TSH < 40 mU/L, patients with TSH ≥ 40mU/L had 46% (95% CI; 1.06-2.02) more risk of agenesis or dysgenesis in TS. Conclusions: More than 40% of PCH are caused by dyshormonogenesis in Iran. Having a TSH ≥ 40 mU/L after the first week of life significantly raises the probability of thyroid agenesis/dysgenesis as the cause. (Endokrynol Pol 2019; 70 (1): 43-48) StreszczenieWstęp. W populacji irańskiej wrodzona niedoczynność tarczycy (CH) ma w wielu przypadkach charakter przemijający. Przedstawione badanie przeprowadzono w celu oceny etiologii trwałej CH (PCH) na podstawie scyntygrafii tarczycy oraz zależności między wynikami tego badania a stężeniem tyreotropiny (TSH) w pierwszym badaniu diagnostycznym. Materiał i metody. W okresie 12 lat (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017), w którym prowadzono przesiewowe badania pod kątem CH w południowo-wschodnim Iranie, wszystkie dzieci skierowane do ośrodka autorów obserwowano do ukończenia 3. roku życia, kiedy przeprowadzano ponowną ocenę stężenia w surowicy T4 i TSH po zaprzestaniu leczenia na 3-4 tygodnie. Jeśli ostatnie badanie sugerowało PCH (TSH >10 mj./l, niezależnie od stężenia T4), wykonywano scyntygrafię tarczycy i w zależności od wyniku przydzielano chorych do jednej z następujących kategorii: agenezja, dysgenezja (tarczyca podjęzykowa, torbiel przewodu tarczowo-językowego), tarczyca prawidłowa/wole guzkowe (wskazujące na dyshormonogenzę). Wyniki. Po wykluczeniu z badania wszystkich dzieci z przemijającą CH do analizy włączo...