ABSTRACT
Thyroid hormone is essential for normal development, especially during the first several years of life when crucial brain and somatic growth are in progress. Since its inception in developed countries during the 1970s, newborn screening (NBS) for congenital hypothyroidism (CH) has essentially eradicated the neurocognitive disability of this condition. CH encompasses disorders of the thyroid gland (primary hypothyroidism) and pituitary/hypothalamic axis (central hypothyroidism). Early detection and treatment of CH by NBS avert the classic clinical phenotype of CH and its serious neurodevelopmental sequelae. The classic clinical findings of severe, untreated CH are uncommon due to early detection but can include prolonged jaundice, cold and mottled skin, large tongue, umbilical hernia, facial puffiness, and open posterior fontanelle. Once confirmatory serum labs are obtained on a newborn with suspected CH, treatment should begin promptly with 10–15 mcg/kg/day of oral levothyroxine. The highest dose range is recommended for infants with severe hypothyroxinemia.
