Update of Newborn Screening and Therapy for Congenital Hypothyroidism

Abstract

Unrecognized congenital hypothyroidism leads to mental retardation. Newborn screening and thyroid therapy started within 2 weeks of age can normalize cognitive development. The primary thyroid-stimulating hormone screening has become standard in many parts of the world. However, newborn thyroid screening is not yet universal in some countries. Initial dosage of 10 to 15 g/kg levothyroxine is recommended. The goals of thyroid hormone therapy should be to maintain frequent evaluations of total thyroxine or free thyroxine in the upper half of the reference range during the first 3 years of life and to normalize the serum thyroid-stimulating hormone concentration to ensure optimal thyroid hormone dosage and compliance.Improvements in screening and therapy have led to improved developmental outcomes in adults with congenital hypothyroidism who are now in their 20s and 30s. Thyroid hormone regimens used today are more aggressive in targeting early correction of thyroid-stimulating hormone than were those used 20 or even 10 years ago. Thus, newborn infants with congenital hypothyroidism today may have an even better intellectual and neurologic prognosis. Efforts are ongoing to establish the optimal therapy that leads to maximum potential for normal development for infants with congenital hypothyroidism.Remaining controversy centers on infants whose abnormality in neonatal thyroid function is transient or mild and on optimal care of very low birth weight or preterm infants. Of note, thyroid-stimulating hormone is not elevated in central hypothyroidism. An algorithm is proposed for diagnosis and management.Physicians must not relinquish their clinical judgment and experience in the face of normal newborn thyroid test results. Hypothyroidism can be acquired after the newborn screening. When clinical symptoms and signs suggest hypothyroidism, regardless of newborn screening results, serum free thyroxine and thyroidstimulating hormone determinations should be performed. INTRODUCTIONCongenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation. In most cases, the disorder is permanent and results from an All clinical reports from the American Academy of Pediatrics automatically expire 5 years after publication unless reaffirmed, revised, or retired at or before that time.The guidance in this report does not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.Key Words congenital hypothyroidism, thyroid hormone, thyroid-stimulating hormone, newborn screening Abbreviations CH-congenital hypothyroidism TH-thyroid hormone T 4 -thyroxine T 3 -triiodothyronine TSH-R-thyrotropin receptor TRBAb-thyrotropin receptor-blocking antibody FT 4 -free thyroxine TSH-thyroid-stimulating hormone TBG-thyroid-binding globulin LBW-low birth weight VLBW-very low birth weight L-T 4 -levothyroxine TRH-thyrotropin-releasing hormone PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).

Simple and rapid in vitro assay for detecting human thyroid peroxidase disruption

“…There is a high prevalence of thyroid peroxidase (TPO) mutations in patients with low levels of thyroid hormones at birth, a condition known as congenital hypothyroidism (Avbelj et al, 2007). Left untreated, this disease negatively affects growth and leads to mental retardation (Rose and Brown, 2006). The environment, through chemical inhibitors, can also affect TPO function.…”

Wrodzona niedoczynność tarczycy — polskie rekomendacje dotyczące leczenia, monitorowania terapii i badania przesiewowego w specjalnych kategoriach noworodków z wysokim ryzykiem niedoczynności tarczycy

“…TSH levels have no significant diagnostic value, since in the foetus and in preterm newborns the pituitary-thyroid axis is not always efficient. In preterm newborns and SGA babies, with low and very low body weight (VLBW) of 1500-1000 g and extremely low body weight (ELBW) below 1000 g, the maintenance of normal levels of fT4 and fT3 is very important [33][34][35][36].…”

“…Stężenia TSH nie mają tu istotnej wartości diagnostycznej, gdyż u płodu i wcześniaka oś przysadkowo--tarczycowa nie zawsze działa sprawnie. U wcześniaka, dziecka z niską masą urodzeniową w stosunku do wieku ciążowego (SGA), z niską i bardzo niską masą urodzeniową (VLBW, very low body wieght -1500-1000g i ELBW, extremely low body wieght -poniżej 1000 g) najważniejsze jest utrzymanie prawidłowych stężeń fT4 i fT3 [33][34][35][36]. Przyczyną pierwotnej niedoczynności tarczycy u wcześ niaków mogą być: -agenezja lub dysgenezja tarczycy; -ektopia tarczycy; -defekty enzymatyczne syntezy hormonów tarczycy; -obwodowa oporność na hormony tarczycy; -znaczny niedobór jodu w środowisku; -nadmierna podaż jodu (stosowanie leków zawierających jod, np.…”

Recommendations for the medical evaluation of children prior to adoption in South Africa

“…Various algorithms are used globally, each with their own advantages and disadvantages, as outlined by the American Academy of Pediatrics. [31] For children with a birth weight of >2 500 g, thyroid-stimulating hormone (TSH) has proved to be an effective screening test. Since delayed TSH elevation is particularly common in infants of low birth weight (i.e.…”