Relation between Early Over- and Undertreatment and Behavioural Problems in Preadolescent Children with Congenital Hypothyroidism

Abstract

Objective: Congenital hypothyroidism (CH) per se, when not treated or undertreated, may lead to severe behavioural problems (cretinism), whereas overtreatment of CH seems associated with attention problems. Design and Methods: For 55 CH patients, prospectively followed from birth until 11 years, parents rated the Child Behaviour Checklist and teachers the Teacher’s Report Form at children’s ages 6 and 11 years. We related scores regarding Attention, Delinquency, and Aggression (ADA scores, indicative for attention deficit hyperactivity syndrome, ADHD), and scores regarding Withdrawn, Anxious, Social, and Thought problems (WAST scores, indicative for autism) to the occurrence of over- and undertreatment in five age periods. Over- and undertreatment were defined as free thyroxine (fT₄) concentrations above/below the range of the patient’s individual fT₄ steady state concentration. Results: ADA scores at 6 and 11 years for patients overtreated in the period 1–3 months postnatally were higher than those for patients who were not overtreated. Patients with severe CH undertreated in the period 3–6 months postnatally had higher WAST scores at 6 and 11 years than all other patients. Conclusions: This is the first study suggesting that permanent ADHD as well as autism in CH patients at ages 6 and 11 years are the result of early overtreatment and undertreatment, respectively.

Congenital Hypothyroidism: A 2020–2021 Consensus Guidelines Update—An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology

“…Data on the effects of clearly increased serum (f)T4 concentrations are scarce. In two studies, long-term follow-up after periods of overtreatment during the first 2 years of life suggested a decreased IQ at the age of 11 years, and an increased rate of attention deficit hyperactivity disorder ( 108 , 109 ). Earlier studies suggested adverse effects on attention span ( 110 ).…”

Hypothyroxinemia in Preterm Neonates: Not Always Hypothyroidism

“…Current guidelines do not recommend treatment of THoP in the absence of elevated TSH [3], particularly keeping in mind the deleterious effects of overtreatment on neurocognition [4]. Also, due to the frequent finding of delayed TSH rise in preterms, guidelines recommend a Bsecond screen^in TSH based NBS programs, at the age of 2 to 4 wk, so as not to miss true CH in preterms [3,5].…”

Referrals for Elevated Thyroid Stimulating Hormone to Pediatric Endocrinologists

“…Overtreatment is a possibility (and occurs in 20% of adults taking levothyroxine [9]). Although the pediatric data have been quite limited, there is some evidence that overtreatment of congenital hypothyroidism, at least during infancy, can have adverse cognitive effects [10].…”